We Uc see, We GLAC foo ac Nov /9 FS TECHNICAL REPORT CERC-85-9 PROCEEDINGS OF THE FLOATING TIRE orengieseren? BREAKWATER WORKSHOP 8-9 NOVEMBER 1984 Compiled by Craig T. Bishop Canada Centre for Inlet Waters Canadian National Water Research Institute PO Box 5050, Burlington, Ontario L7R 4A6, Canada and Laurie L. Broderick, D. Donald Davidson Coastal Engineering Research Center DEPARTMENT OF THE ARMY Waterways Experiment Station, Corps of Engineers PO Box 631, Vicksburg, Mississippi 39180-0631 November 1985 Final Report d For Public Release; Distri DOCUMENT LIBRARY Woods Hole Oceanographic Institution ion Unlimited Prepared for DEPARTMENT OF THE ARMY US Army Corps of Engineers Washington, DC 20314-1000 Under Work Unit 31679 Destroy this report when no longer needed. Do not return it to the originator. The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. MBL/W | MA 0091248 HOI {I i MY QO 0301 Unclassified SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) READ INSTRUCTIONS REPORT DOCUMENTATION PAGE 1. REPORT NUMBER 2. GOVT ACCESSION NO.| 3. RECIPIENT'S CATALOG NUMBER Technical Report CERC-85-9 5. TYPE OF REPORT & PERIOD COVERED 4. TITLE (and Subtitle) PROCEEDINGS OF THE FLOATING TIRE BREAKWATER WORKSHOP, 8-9 November 1984 Final report 6. PERFORMING ORG. REPORT NUMBER - CONTRACT OR GRANT NUMBER(s) 7. AUTHOR(s) Craig T. Bishop, Laurie L. Broderick, D. Donald Davidson, Editors PROGRAM ELEMENT, PROJECT, TASK AREA & WORK UNIT NUMBERS Work Unit 31679 10. 9. PERFORMING ORGANIZATION NAME AND ADDRESS : US Army Engineer Waterways Experiment Station, Coastal Engineering Research Center, PO Box 631, Vicksburg, Mississippi 39180-0631, and Canadian | National Water Research Institute, Canada Cen- tre for Inlet Waters, PO Box 5050, Burlington, Ontario L7R 4A6, Canada H11. CONTROLLING OFFICE NAME AND ADDRESS DEPARTMENT OF THE ARMY US Army Corps of Engineers Washington, DC 20314-1000 14. MONITORING AGENCY NAME & ADDRESS(if different from Controlling Office) 12. REPORT DATE November 1985 13. NUMBER OF PAGES 130 15. SECURITY CLASS. (of this report) Unclassified DECL ASSIFICATION/ DOWNGRADING SCHEDULE 15a, 16. DISTRIBUTION STATEMENT (of thie Report) Approved for public release; distribution unlimited. 17. DISTRIBUTION STATEMENT (of the abstract entered in Block 20, if different from Report) 18. SUPPLEMENTARY NOTES Available from National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161. 19. KEY WORDS (Continue on reverse side if necessary and identify by block number) Wave attenuation Coastal engineering Marinas Field research Mooring forces Waves Floating tire breakwaters Pipe-tire design Goodyear design Pressure gage 1 20. ABSTRACT (Continue om reverse side if necessary and identify by block number) These Proceedings provide a record of the papers presented at the Floating Tire Breakwater Workshop conducted on 8-9 November 1984 in Niagara Falls, New York. Topics of discussion included field research efforts, basic design considerations, breakwater performance and maintenance, and alterna- tive fastening and mooring techniques. The Workshop was cosponsored by the Coastal Engineering Research Center of the US Army Engineer Waterways Experi- ment Station and the Canadian National Water Research Institute. DD ,.COR* 1473 ~~ EprTiow oF 1 Nov 65 1S OBSOLETE t JAN 73 qa aLacal SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) SSS eee SECURITY CLASSIFICATION OF THIS PAGE(When Data Entered) SECURITY CLASSIFICATION OF THIS PAGE(When Data Entered) PREFACE On November 8-9, 1984, the Floating Tire Breakwater (FTB) Workshop was held in Niagara Falls, New York, under provisions of Work Unit No. 31679, "Design of Floating Breakwaters," Coastal Structure Evaluation and Design Program, Coastal Engineering Area of Civil Works Research and Development. Authority to conduct this program was contained in a letter from the Office, Chief of Engineers (OCE), US Army, dated 19 May 1972. OCE Technical Moni- tors were Messrs, Bruce L. McCartney, J. H. Lockhart, J. G. Housley, and Jesse A. Pfeiffer, Jr. This document is a compilation of the proceedings of the FTB Work- shop, which was cosponsored by the Coastal Engineering Research Center (CERC) of the US Army Engineer Waterways Experiment Station (WES) and the Canadian National Water Research Institute (NWRI). Mr. C. T. Bishop, NWRI, and Mr. D. D. Davidson and Ms. L. L. Broderick, WES, coordinated the Workshop and edited this report. This report was prepared under the general direction of Dr. Robert W. Whalin, former Chief, CERC, and Mr. C. C. Calhoun, Jr., Acting Chief, CERC; Mr. C. E. Chatham, Jr., Chief, Wave Dynamics Division, CERC; and Mr. Davidson, Chief, Wave Research Branch. At the time of publication of this report, COL Allen F. Grum, USA, was Director of WES, and Dr. Whalin was Technical Director. CONTENTS TORU CID, 6 Gi orbic Oly pOsuOal OC OM On Ow BOSD O) OE Ba.b. 0) Oe aida ‘ob foo 20 CONVERSION FACTORS, NON-SI TO SI eee UNITS OF MEASUREMENT . ...... « ot: Mauls Neh Keuestt tains feet isl eas tolls NITIES 9 9g 0 6 a 0 59 0 6 6 6 0 880 OOO INGEN, 5 e 6 to 6 6) OO G66 O75. 0) oO 0.6.6.0 8 15 solo lo Go 6 9 IRODUGIION «6 6 6 6 6 06 0 6 6 6 6 0 6 89 00 000 oOo oO EXPERIENCE WITH A FLOATING TIRE BREAKWATER AT LAKE CHARLEVOIX, MICHIGAN ClRiBEord Deuba ditcle ie is wei een cellist telnet’ ee cat ven evict ei notmnce ENGINEERING EVALUATION OF ALTERNATE MATERIALS FOR REDESIGNED MOORING SYSTEMS Amidnomsy WKEMCO oo o0006000056058 F082 50 000 0 CONSTRUCTING AND FIELD TESTING A HIGH PERFORMANCE PIPE- TIRE FLOATING BREAKWATER ROIDeae I, PDI@RCA ooo 6 6 46.0066000080063 0 6 A SAILING ORGANIZATION'S EXPERIENCE WITH A GOODYEAR FTB Dayul Tbe Wale 56 4 6 6 6 6 o oo (0 FIELD ASSESSMENT OF FLOATING TIRE BREAKWATER Giesl@ Ws BILGINOD oo0000500005050909000 0 FLOATING BREAKWATER PROTOTYPE TEST PROGRAM Eric Nelson BD Urata tne Ruuoet (he dean iemiteo eh rel ale DATA RESULTS, FLOATING BREAKWATER PROTOTYPE TEST PROGRAM ILGWHeN® Iho Breoderlelk 56:6 6 6 616 656000060000 6 006 Page 11 7 40 61 64 CONVERSION FACTORS, NON-SI TO SI (METRIC) UNITS OF MEASUREMENT Non-SI units of measurement used in this report can be converted to SI (metric) units as follows: Multiply By Lon Obrakm! cubic feet 0.02831685 cubic metres Fahrenheit degrees 5/9 Celsius degrees or Kelvins* feet 0.3048 metres horsepower (550 foot- 745.6999 watts pounds (force) per second) inches 2.54 centimetres knots (international) 0.5144444 metres per second miles (US statute) 1.609347 kilometres pounds (force) per 6.894757 kilopascals square inch pounds (mass) 0.4535924 kilograms pounds (mass) per 16.01846 kilograms per cubic metre cubic foot tons (2,000 pounds, 907.1847 kilograms mass) * To obtain Celsius (C) temperature readings from Fahrenheit (F) readings, use the following formula: C = (5/9)(F - 32). To obtain Kelvin (K) read- ings, use: K = (5/9) (F = 32)) + 273.15. ATTENDEES Speakers Mr. C. D. Biddick Irish Boat Shop Inc. Stover Road Charlevoix, MI 48720 (616) 547-9967 Mr. C. Bishop National Water Research Institute Canada Centre for Inland Waters PO Box 5050 Burlington, Ontario (416) 637-4274 L7R 4A6 Ms..L. L. Broderick US Army Engineer Waterways Experiment Station Coastal Engineering Research Center PO Box 631 Vicksburg, MS 39180 (601) 634-2063 or FTS 542-2063 Mr. Jim Doubt Totton Sims Hubicki Assoc. Cobourg, Ontario (416) 372-2121 Mr. Anthony Franco Suny-Farmingdale Lupton Hall 231 Farmingdale, NY 11735 (516) 420-2187, 2149 Mr. E. Nelson US Army Engineer District, Seattle PO Box C3755 Seattle, WA 98124 (206) 764-3557 or FTS 399-3555 Dr. R. E. Pierce Pensylvania State University Behrend College Station Road Erie, PA 16563 (814) 898-6249 Mr. P. Pirie Stelco Inc. 100 King St. W. Hamilton, Ontario (416) 528-2511, ext. 3271 Participants Mr. Gregg J. Beaty Globe International Corp. PO Box 1062 Buffalo, NY 14240 (716) 824-8484 Mr. Tom Bender US Army Engineer District, Buffalo 1776 Niagara St. Buffalo, NY 14207 (716) 876-5454, ext. 2227 or FTS 473-2227 hes Io ibeehohe Canadian Coast Guard PO Box 1000 Prescott, Ontario (613) 925-2865 KOE 1TO Mr. D. D. Davidson US Army Engineer Waterways Experiment Station Coastal Engineering Research Center PO Box 631 Vicksburg, MS 39180 (601) 634-2722 or FTS 542-2722 Mr. B. Gallant Bermingham Construction Wellington Street Marine Terminal Hamilton, Ontario L8L 4Z9 (416) 528-7924 M. A. Genis Huronia Marine Queen's Cover Marina Box 333 Victoria Harbour LOK-2A0 FTS 534-4100 or 534-4152 Mr. Marvin Glasner US Navy Naval Sea Systems Command Sea 07H, Washington, DC 20362 (202) 692-6377, ext. 1189, 1363 Mr. Rich Gorecki US Army Engineer District, Buffalo 1776 Niagara St. Buffalo, NY 14207 (716) 876-5454, ext. 2230 FTS 473-2230 Mr. P. Grace US Army Engineer Waterways Experiment Station Coastal Engineering Research Center PO Box 631 Vicksburg, MS 39180 (601) 634-2092 or FTS 542-2092 Mr. V. W. Harms University of California/Berkeley Marine Science Group Earth Science Building University of California Berkeley, CA 94702 (415) 642-8407 or (415) 642-6777 Mr. G. W. Hough Pickering Habour Company Ltd. 1295 Wharl Street Pickering, Ontario LI1W 1A2 (416) 839-5036 Mr. J. Jarnot US Army Engineer District, Buffalo 1776 Niagara Street Buffalo, NY 14207 (716) 876-5454, ext. 2316 or FTS 473-2316 Mr. M. Kolberg F. J. Reinders & Associates Canada Ltd. PO Box 278 Brampton, Ontario L6V 2L1 (416) 457-1618 Mr. P. Lane Globe International Inc. 1400 Clinton Street Buffalo, NY 14207 (716) - 824-8484 Mr. J. Loffredo Acting City Engineer Room 503 City Hall Buffalo, NY 14202 (716) 855-5631 Mr. P. Lyons Queen's Cove Marina Victoria Harbour (705) 534-4100 Mr. H. E. Mandell, Jr. D. P. W. - City of Buffalo 605 City Hall Buffalo, NY 14221 (716) 855-5886 Mr. M. Mohr US Army Engineer District, Buffalo 1776 Niagara Street Buffalo, NY 14207 (716) 876-5454, ext. 2227 or FTS 836-4309 Mr. M. Noble Noble Coastal & Harbor Engineering Ltd. 98 Main St., Suite 222 Tiburon, CA 94920 (415) 435-4677 Mies Go Io OYNGsulL, he. NY Sea Grant Extension 405 Administration Bldg. State University College Brockport, NY 14420 (716) 395-2638 Mr. R. Perham US Army Cold Regions Research and Engineering Laboratory 72 Lyme Rd. Hanover, NH 03766 Mr. J. Pfeiffer (DAEN-RDC) Office of Chief of Engineers Department of the Army 20 Massachusetts Ave. Washington, DC 20314 @02)) 272-0257 Yor) ELS) 27/2—0257/ Mr. A. Robertson Canadian Coast Guard PO Box 1000 Prescott, Ontario (613) 925-2865 Mr. L. Rudledge Johnson Sustronk Weinstein & Associates 290 Merton Street Toronto, Ontario M4S 1B2 (416) 488-8552 Ms. L. Ruh US Army Engineer District, Los Angeles PO Box 2711 Los Angeles, CA 90053 (213) 688-4206 or FTS 798-4206 Mr. G. Seaburn Seaburn and Robertson PO Box 23184 Tampa, FL 33623 (813) 877-9182 Mr. J. Shipman Sound Boat Works Box 190 Parry Sound, Ontario P2A 2X3 (705) 746-2411 Mr. C. P. Smith US Army Engineer Division, Huntsville PO Box 1600 Huntsville, AL 35807 (205) 895-5313 or FTS 873-5313 Mr. W. Smutz US Army Engineer District, Kansas City OO Bo Wen Sie. 700 Federal Building Kansas City, MO 64106 (816) 374-5366 or FTS 758-5366 Mr. M. Stegall US Army Engineer District, St. 210 Tucker Blvd. N. St. Louis, MO 63101 (314) 263-5653 or FTS 273-5653 Mr. R. Stephen Dept. of Recreation Services City of Burlington 426 Brant St. PO Box 5013 Burlington, Ontario L/R 3Z6 (416) 335-7722 Mr. Keith Thompson Eastern Designers PO Box 613 Fredencton, NB E3B 5A6 (506) 452-8480 Dr. James H. Thorp Cornell University Dept. of Natural Resources Fernow Hall Ithaca, NY 14853 (607) 256-2106 Mr. Al Wagner Glenora Marina RR4 Pictor Ontario, Canada KOK 2T0O (613) 476-2377 Mr. D. G. Whitney Proctor & Redfern Limited 45 Green Belt Drive Don Mills, Ontario M3C 3K3 (416) 445-3600 FLOATING TIRE BREAKWATER WORKSHOP November 8-9, 1984 Ramada Inn Niagara Falls, New York AGENDA Wednesday, 7 November 7:30 p.m. Registration 8:00 Floating Tire Breakwater (FTB) Slides and Movies Thursday, 8 November 8:30 a.m. Registration 8:45 Welcome 9:00 FTB Design Basics 9:30 A Marina Manager's Experience with a Truck Tire Goodyear FTB 10:00 Break 10:30 Fastening and Strength Tests of Conveyer Belting 11:30 Erie, Pennsylvania, Field Program 12:00 Lunch 1:00 A Sailing Club's Experience with a Car Tire Goodyear FTB 1:20 Burlington, Ontario, Field Program 2:30 Break 3:00 Puget Sound Test Program 4:00 Data Results from Puget Sound Test Program Friday, 9 November 8:00 Bus departs from Niagara Falls, NY, for field trip 330 LaSalle Park Goodyear FTB Clifford T. Biddick, Irish Boat Shop, Inc. Anthony Franco, State University of New York Robert E. Pierce, Penn- sylvania State Uni- versity Paul L. Pirie, Burlington, Ontario, Sailing and Boating Club Craig T. Bishop, Burling- ton, Ontario Eric E. Nelson, US Army Engineer District, Seattle Laurie L. Broderick, US Army Engineer Water- ways Experiment Station Friday, 9 November (Continued) iL) 8 ILS) Tour Hydraulics Laboratory 11:30 Bus departs from Burlington 12:30 p.m. Arrive Niagara Falls, NY Adjourned INTRODUCTION In recent years, there has been increased interest in the use of floating breakwaters for providing protection from wave attack. Several types of float- ing tire breakwaters (FTB's) have demonstrated the ability to effectively dissipate wave energy at a moderate cost in certain locations characterized by relatively short wave periods and fetch lengths. Their value as a functional wave protection alternative is especially apparent in areas where sediment trans- port problems, deep water, poor foundation conditions, or environmental con- straints preclude the use of the more conventional bottom-fixed, rubble-mound or vertical-wall breakwaters. Another advantage lies in their mobility. Unlike the bottom-fixed structures, FTB's may be moved from one location to another, e.g., during severe ice conditions or for easier maintenance access. This Workshop was conducted to provide an opportunity for engineers, contractors, marina owners and operators, and other interested individuals to exchange information on the use of FTB's. Subjects involving individual field experience were emphasized, particularly related to breakwater per- formance and maintenance requirements. Topics discussed included basic design considerations, alternative fastening and mooring techniques, and recent field research programs, to name a few. The scheduled speakers in- cluded representatives of the Coastal Engineering Research Center (CERC) of the US Army Engineer Waterways Experiment Station; the Canadian National Water Research Institute (NWRI); the US Army Engineer District, Seattle (NPS); universities; municipalities; and privately owned marinas. The final day of the Workshop featured a field trip to Ontario, Canada, where participants toured the LaSalle Park Goodyear FTB at Hamilton and the NWRI facilities at Burlington. This document was published to provide a record of the Workshop itinerary, participants, and the scheduled papers that were presented. EXPERIENCE WITH A FLOATING TIRE BREAKWATER AT LAKE CHARLEVOIX, MICHIGAN Clifford D. Biddick BACKGROUND: Irish Boat Shop, Inc. operates two boat yards ~ one in Harbor Springs and one in Charlevoix, Michigan, serving primarily pleasure boats to 75 feet* in length. These marinas maintain and perform all types of boat repair and pro- vide storage and dockage to all customers. In 1977, it was decided to expand the 120-slip capacity at Charlevoix. Water depths varied to 26 feet, making bottom resting breakwaters an expensive proposition. Therefore, we began to investigate the Floating Tire Breakwater concept as an alternative to conven- tional wave protection structures. Following a field trip to the known Floating Tire Breakwaters on the east coast of the U.S.A., we set about to design and build a complete harbor en- closure, utilizing the available Floating Tire Breakwater information. We selected the Goodyear design of 18 tire modules as developed by Richard Candle (Goodyear Tire and Rubber Co.) and Neil Ross (University of Rhode Island). With this as a start we designed an enclosed harbor for 62 boats adjacent to our existing 120-slip facility. This structure extended 450 feet out into the lake and was 330 feet wide. Our exposure was to the southeast with an 18-mile fetch down a relatively narrow (3+ mile) width. The sea approaching us at worst was about 3 feet from trough to crest, with a 2- to 2.5-second period. BREAKWATER DESIGN: The marina has the land forming the west side, a floating car tire breakr water on the southside, with a laid down "F" forming the north and east sides and middle leg. Refer to Figure 1. The "F" was a steel-framed, wood-covered 12-foot-wide dock, supported on fully foamed car tires arranged in a Goodyear pattern (2 modules wide). Outside the top of the "F" was a 3=module row of partially foamed truck tires which formed the major wave reduction breakwater. Refer to Figure 2. The project utilizes 7,500 car tires and 3,500 truck tires. Together they are supported with 10,000 cubic feet of urethane foam. CONSTRUCTION: The entire project was planned to be, and ultimately was, assembled on 12 to 24 inches (thick) ice during the winter of 1978-1979. We utilized a ten man crew and a great deal of equipment including a hydraulic crane, fork lift, front end loader, pickup trucks, welders, generators, pumps to thicken the ice, and many trucks and trailers. The temperature ranged down to 26 below zero (Fahrenheit) and despite the cold, morale of the crew was high. The goal was to have the dock and breakwater intact when the ice melted. Work on the ice began in early January and was finished by late March, 1979. After assembly was complete, we cut holes in the ice and had a diver bury 120 Danforth style anchors and attach them via 1/2 inch 1x7 galvanized cable to the tire modules. With the dock tentatively anchored, we waited anxiously for it to melt through the ice. As it did so, it tipped drastically, but leveled out after all the ice melted. * A table of factors for converting non-SI to SI (metric) units of measurement is presented on page 4. 11 LL-y-)) Bsa a Prov'DIHDIWV Suv Oo) =| anwes Mite Fe AASaa WoLlog - HOI r ‘xlOAarenr> ‘aaedared SOG CNW taadoy to Almaddd G'98S DdAL BW? [P Sa) LavalL- sain goa ay¥d ff Walsavrvaag BBL nino ABzBS SOM 72 BAD Cag i we ne We QO 0 = 0 Z Va \— 0) 0 : ty mM ; $ e B j x 1. cea We ee ee BEC ROOT. Lee eel aiveD \OAST ANID -JOHS IVYOD HSU) sea ALITIDYS Sbvactca oo AYNoW aay NEO M¥@xOo" FENCE UNCER FRANG TogeTHeR, wo To 4" woe TING CONVEYOR, B H Gq __ | tae i { DOC DETAIL ZeCTION LO\- BOAIN ACBALE Ya''=|'-0 Sau =25 BUNOLE PONG TRUcK TIRES ZN LS FINGEA PIEA SECTION 40' LONG FINGER FieGR BREAAWATEA BECTION (2! WIDE MAIN Doc 13 The tires are tied with conveyor belt edge trimming 4%" to 4%" thick, 2" to 4" wide, with a wide range in quality. They are bolted with 5/16" galvanized bolts, using corrugated washers. Conveyor belt edge trimming was supplied by a tire and rubber company in Cincinnati. Our assembly took place in a heated shop where the tires were vacuumed, filled with foam as required (partially or fully filled) and assembled into modules before being dragged by their belts 1200 feet down the road to the construction site. There they were arranged into the layout as designed, bolted into the complete breakwater and dock attached to the top as needed. Once the dock was floating, we added additional anchors and 4" used well casing spiles to hold it in place. There are now about 150 anchors and 50 spiles holding it in place. COSTS: Project costs for the breakwater and docks are summarized in Table l. PERFORMANCE : The Floating Tire Breakwater has now been in service six summers and shows promise for six more. There have been no major problems. There have been changes made to the docks over the years, but in general the Floating Tire Breakwater has been very successful. We find that the effectiveness of the Floating Tire Breakwater is quite adequate. It does not stop a sea entirely. We have observed a reduction of a 30" to 36" incident wave, with a period of 2.5 to 3 seconds to a 6" to 10" transmitted wave with a very tolerable boat motion. I have watched the boats many times lying peacefully and rocking gently while to the north and south of the breakwater, waves were breaking with a roar on the beach. Having been warned of this potential motion, we had designed the harbor to orient the boat's bow and stern into the seas. At no time have the cleats jerked out or lines broken, except from shear wind force. The consensus of our customers is to choose this dock over our fixed structure at our adjacent site. EXPERIENCE AND PROBLEMS : We encountered some resistance from neighbors and residents who felt we were in effect making a junk yard of old tires in their lake. We countered this with photographs of existing Floating Tire Breakwaters that looked neat and orderly. We have experienced some anchor dragging. The surge of the dock together with the pull of 50 tons of boats does have an effect on the anchors. With one anchor for every two modules of tires there is an anchor supposedly for every nine linear feet of dock. In addition, the spiles locate the dock so it doesn't drift far. 14 FLOATING TIRE BREAKWATER COSTS TABLE ONE PROJECT COSTS (1978 - 1979 PRICES) Welding Supplies $305.00 Urethane Foam and Equipment 92-1b density (10,000 cu.ft) $18,200.00 Pipe 4" used well casing (Spiles - 100) $3,008.00 Conveyor Belting % - % " thick 2"-4" wide $3,140.00 Tires Sal 54) 510.0) Nails and Tex Screws S2F 237 0.0 Nuts and Bolts $3,020.00 Steel 12" I Beams, Re-Rod, Gussets etc. $32,650.00 Electrical $20,534.00 Lumber - Decking SS) DOO Styrofoam Buoyancy Billets - Finger Piers $4,746.00 Vinyl Dock Bumper $999.00 Cleats and Brackets $475.00 Water $651.00 Cable \" 1x7 Galvanized $968.00 Anchors - 120 $600.00 Miscellaneous $1,871.00 MATERIAL TOTAL $110,700.00 Dredging $14,000.00 Labor (7,500 man-hours in design, fabrication, and anchoring) $43,700.00 Other Site Improvements (Sewer, Plumbing, etc.) $26,000.00 TOTAL COST $194,400.00 Excluded From Total: Restrooms and Office $29,750.00 Total cost of $194,400.00 divided by the number of slips of 62 equals a cost per slip of $3,135.00. 15 If the spiles were all removed, as they are in the fall, the dock will move about 6 feet in any direction. We find it necessary to send a diver down once a year to tension cables. On occasion we will relengthen and reposition the anchor and cable. The noise of spiles squeaking is annoying to some people, particularly on a quiet summer evening. When the wind is screaming, then the noise is lost in the general noise of the storm. Several alternative designs have been tried but we have yet to arrive at a good solution. Waste foam ("flashing") breaking off the exterior of the tires and floatation foam eroding and loosening within the tires is common. We find a trio around the breakwater by small boat with a minnow net is an effective way to pick up the small pieces of foam, as well as other debris. The floatation foam loosening may be a problem in a few years and at that time we will replace foam as necessary with "Ethafoam". Broken conveyor belts and resultant loose tires are not a problem, but as a good neighbor, if someone complains of a stray tire, we go and pick it up. Ours are branded so that we may identify them. 16 ENGINEERING EVALUATION OF ALTERNATE MATERIALS FOR REDESIGNED MOORING SYSTEMS Anthony Franco Abstract The load-carrying capacity of four types of conveyor belts was investigated to test their applicability for use in both navigational aids and boat moorings. Different methods of fastening the belt to itself were also investigated. Control sample and six-month exposure test results are presented. One-year test samples are still in the water. Introduction The purposes of this research were to: 1- Obtain strength data for conveyor belting in a systematic way. 2- To develop an alternate material which is cheaper initially and would have longer service life than the materials being used presently, and still have adequate strength. 3- To make this information available to people responsible for the maintenance, installation, and replacement of navigational and boat moorings. Consequently, the author dealt primarily with marina owners and townships on Long Island and in Westchester. The choice of conveyor belt size to test was dictated by the hardware these people use in their marinas. Since the marina owners that the author had dis- cussed fastening techniques with preferred to bolt the belting together, a simple bolt pattern was tried as well as glueing the belt together with various compounds. Their main concern was that the fastening should be easy to fabricate and cheap. Test Plan To test the actual strength of the belt, three test specimens were made up from each of the conveyor belts according to the drawing shown in Figure 1. Then a tensile test Wi, was performed on a specimen of each material, while the two other specimens were set aside to be tested after exposure to the working environment for six months and one year. A comparison of the three load-deflection curves of each material would then show the deterioration of the material as a result of the exposure. When performing these tests, the outer rubber covers were not stripped away since in actual practice, the marina owners wouldn't do this before using the belt. The failure criteria used was either: 1- When either the top or bottom rubber cover separated from the inner synthetic careass fabric or 2- When the synthetic carcass broke, whichever occurred first. The particular tensile test specimen's geometry was obtained after consideration of Figure 802.1 in the Conveyor and Elevator Belt Handbook. This book is published by the Rubber Manufacturers Association, located in Washington, D.C. If one calculates the ratios of * = and = they will be constant regardless of the die number. Since a 2-inch-wide belt was decided upon for testing, making A=2.0, the other dimensions came out as shown in Fig. 1. The second phase was to test the strength of various forms of connections. Five concepts were used. In order to eliminate any steel in the connection, a fastening concept was designed that used only chemical compounds. It is shown in Figure 2 and is called the first concept. The two compounds used were cold vulcanizing compound and Flexane 80 putty. This particular geometry was chosen for a number of reasons: 1- The belt is easily bent into loops. 2- Looping is the simplest way to bring the belt through shackles and rings. Therefore, this would be a very simple and cheap way to fasten the belt to itself if it was found that the joint formed would have sufficient load- carrying capacity. 18 Figure 1. First concept CoLl ViicAn(2E texan 80% TTY S- | 4° 3” Z" | Ss Figure 2. Cold vulcanization and Flexane 80 putty IL) 3- 4- By forming the loops shown, there was no eccentric load in the connection. The loops were made large to eliminate the chafing I had seen in similar connections that were tightly fastened to rings. In order to see which was stronger, one loop was fastened to the centerpiece using cold vulcanizing compound, the other using Flexane 80 putty. The cold vulcanizing compound is made up of a cement and an accelerator that is mixed together. It is compounded for bonding rubber to rubber. After mixing, the pot life is approximately 3 hours, and the mixture is very easy to work with. It was applied using the following technique: 1- q- Use a stiff wire wheel attached to a bench grinder to roughen the surface of the belt. Surface should feel rough to fingers. Wash down the area using alcohol until it is clean and free from dirt and grease. Prepare the cold vulcanizing compound according to instructions given on can. With a small nylon paint brush apply two coats to each surface. The initial coats should be allowed to dry thoroughly. The third coat was applied, and when it felt tacky the parts were assembled. The two parts of the end piece were sandwiched over the center section at the 4-inch overlap, one piece of aluminum sheet metal was placed on each side of the joint and the entire assembly placed in a vise and tightened to firm pressure. Coat the aluminum with a very light coat of grease to prevent it bonding to the rubber. Leave the assembly in the vise for approximately 48 hours. The entire procedure from step 1 through 6 took about three hours and half the amount purchased would have sufficed. 20 The Flexane 80 putty is a room-temperature curing urethane, made up of flexane resin and a curing agent that must be mixed together. After mixing, it has a pot life of about 15 minutes and once the two ingredients are mixed together, the mixture thickens and further mixing is extremely difficult. The manufacturer advised the investigators that new belts were more difficult to bond than used ones and that proper belt preparation was critical. The compound was applied using the following technique: 1- 4- The area to which the Flexane putty was to be applied was roughened by a wire wheel attached to a bench grinder. Using a paper towel and special cleaner provided in the kit, the area was scrubbed clean. Then an abrasive pad (3M Scotchbrite pad) saturated with cleaner was used to scrub the area. Area was then washed again with a paper towel saturated with cleaner and this was repeated until no black transferred to the paper towel. Then let the belts dry. This portion was very long and tedious. Approximately four hours were spent cleaning the surfaces. While the belts were drying the special mold boxes that the investigators had fabricated for this part of the operation were set up and the mold release agent applied to all inside surfaces. While step 4 was being performed, the rubber primer that was supplied with the kit was applied to all surfaces to be bonded. Once this primer is applied, the Flexane putty should be applied within 10 to 60 minutes to insure full bond strength. The Flexane was mixed and poured into the molds to form a half-inch thick layer between the rubber being bonded, to form the section shown in Figure 2. 21 T- The sections were left in the molds for approximately two days. Room temperature was about 65° to 70°F. The very short working time for the Flexane 80 putty made spreading the material out and building up the layer difficult. One has to work very rapidly or he will lose the entire batch within 15 minutes. The two bolted concepts, called the second and third fastening concepts, were based or discussions with marina owners about methods being currently used to connect chain and conveyor belts to the anchor and to the buoys on boat moorings. These two concepts are shown in figures 3 and 4. The bolts were 4" diameter by 24" long steel bolts with oversize washers on each side. The bolts were torqued down until the conveyor belt just started to protrude above the washer surface. The second concept used the first concept geometry. The object was to compare the first and second techniques to see which was stronger. The third concept would be the simplest to fabricate in the field. The belt is simply looped over onto itself and bolted. Also, a comparison could be made between the two bolting techniques to see which was stronger. In order to determine whether the material by itself had any load-carrying capacity at all once the carcass had been cut or drilled through, a fourth concept was tried. It is shown in Figure 5. Shackles were placed through the 3/8" drilled holes and no other preparation was,done. Since the water would now be able to quickly penetrate the inner carcass, a measure of how quickly the water deteriorates the fibers could also be obtained. The first three fastening concepts have one thing in common - they require the belt to be looped around a steel shackle or ring at both ends of the mooring. An attachment method 22 Figure 3. Second concept Figure 4. Third concept Figure 5. Fourth concept 24 was designed that would eliminate the metal-torubber connection and the possible chafing problem this creates. This fifth fastening concept is shown in figure 6 and is made up of a central core of Flexane 80 putty, the conveyor belt on one end and a steel plate on the other. This concept has another advantage also. Since rubber is buoyant, there is the possibility that it would be cut by the propeller of a passing boat. This attachment would allow the use of a few feet of chain first to get the belt out of the propeller's way and still eliminate any chafing. The following technique was used: 1- All steel plates were ground on a bench grinder according to the adhesive manufacturer's instructions until white metal showed. 2- Clean steel parts with cleaner provided in the kit, let dry and apply the Flexane Primer for Metal. 3- 3/8-inch-diameter holes were drilled into the belts. Since drills don't cut through the belt cleanly, the holes were then burned out with a heated steel rod. 4- The belts were cleaned and prepared as explained previously. o- Prepared mold boxes with a release. 6- Flexane 80 putty was mixed and poured into each mold, then the steel and belting were placed in the mold and the putty forced through the drilled holes. Then more Flexane was poured over the steel and conveyor belt. 1- The fastenings were left in the molds for two days at a temperature of 65° to 70°F. Conveyor Belts Used Four conveyor belts were used. 1- Uniroyal UsFlex Straightwarp belting. The word "straightwarp" describes a particular type of carcass construction, and is shown in figure 1-7 of the Conveyor and Elevator Belt Handbook. The particular belt used had a single ZS Figure 6. Fifth concept polyester carcass covered by top and bottom RMA Grade 2 rubber covers. The belt measured 2-3/8" x 1/2". 2- Uniroyal Royalon. This is a multiple-ply belt. The belt tested was a three- Ply belt, i.e. it had three layers of a synthetic polyester carcass fabric, and an RMA Grade 2 top and bottom cover with an ASTM compound specification SBR. The belt measured 2" x 30/64" and had a conventional or plain weave. 3- Goodyear. This is also a multiple-ply belt, a two-ply nylon belt, with RMS Grade 2 covers. The material measured 2-1/8" x 7/32''. The rubber covers were ASTM compound specification SBR, and the nylon was woven in a plain weave. 4- Empire State. The belt that was tested was a multiple-ply belt, with a two- layer synthetic fabric carcass. The fabric is woven in a plain weave. The rubber covers are RMA Grade 2, with an ASTM compound specification SBR. The belt was supplied by Empire State Belting and Hose company and manufactured by B.F. Goodrich. The material measured 1-61/64" x 3/8". The Uniroyal UsFlex and Goodyear samples were immersed in salt water in Port Jefferson Harbor on the North Shore of Long Island. To test these concepts, the belting samples were tied together to form two long rubber belts. One belt held a 36-foot sail boat in the inner harbor, and the other held a 33-foot Silverton power boat in the outer harbor. The chain in the inner harbor showed heavy barnacle growth. The rubber was not damaged by this growth. The typical arrangement used is shown in Figure 7. In addition to being in the water for approximately seven and one half months, these belts were exposed to the environment in the marina yard as any ordinary chain used in moorings would be. They were exposed to snow, ice, rain and sun for approximately two and one half months before being tensile tested. Dif Buaey wae lla Si 2 CHAIN LEADER BELT FO SCKAHCE, SYSTERED AV77/ Chie CHAN 75 2° LONGER THAN BELT, SO 777 GEL7 FPAES LOR CB7KER FRAN CLP°771M Figure 7. Typical arrangement 28 The Uniroyal Royalon samples were in salt water in Hempstead Harbor. A long rubber chain was made up using the first, second and third fastening concepts, and this chain was used to hold a navigational buoy in place. A schematic is shown in Figure 8. The fourth and fifth concepts took no service load but were immersed in the water for a longer period of time. Tensile testing began the day after the specimens were removed from the water. The Empire State samples were exposed to salt water in Long Island Sound off Mamaroneck in Westchester County. None of the pieces had any marine growth on them. All of these specimens saw an entire winter in the water starting in November and were then exposed to the environment for approximately one month prior to testing. They took a light service load since they ran alongside a length of chain between the mooring and the anchor. Essentially, the load was split between the rubber and chain. Results In order to establish a basis of comparison, tensile tests were performed on one sample of unexposed fastening concepts and tensile test specimens from each material. In order to avoid stress concentrations when testing the first three fastening concepts, a steel pipe 3- 1/2 inches in diameter by 8 inches long with a 3/16-inch wall thickness was placed inside each loop. This tube beared against the upper and lower crossheads of the tensile tester, and then one end of the particular fastening concept was pulled against the other end. After one end failed, jaws were placed in the lower crosshead and the remaining connection was tested to failure. To test the fifth concept a special jig was made up to hold the steel at the lower crosshead, while jaws were used to hold the conveyor belt in the upper crosshead. The table showing failure loads and mechanisms for the connection control samples is shown in Figure 9. The table showing failure loads and mechanisms for the connections after approximately six months’exposure is shown in Figure 10. 29 SUoy CAYTIN — 1 FURST, SECOND, £ THRO CONCEP IS SHACKCED TOGETHER SINCAOR Figure 8. Schematic LASTENING| GoasyenRe | CAavfroyre CATROYPL Concer WNMeCH8LR cea pie LMaccanize ——__ P/E RE AT CeNWECTION 399slas | 2920 Las r4 AM Jae: <— AZ Ss SSLO WPOLKgIY TOLT- oLe Woywiow CS ALEX CO am Seo PELE L SIILED FHROQCGNW 0.10 and fp < O67 [tk and the corresponding second-order regression curve. There is good data coverage for 0.2 < L/B < 0.8. This range has been extended in Figure 8 by plotting results for the two values of frequency (at 0.04—Hz intervals) for each record that are just smaller than the smallest frequency meeting the criterion Sj(F)/S; (fp) > WolO. The corresponding second—order regression curve is also shown. This provides good data coverage for 0.8 < L/B < 1.4. The data plotted in Figures 7 and 8 is from 118 records obtained between October 8 and November 13, 1982. Characteristic wave heights vary from 12 to 66 cm with peak frequencies from 0.32 Hz to 0.64 Hz. The data in Figures 7 and 8 has been combined in Figure 9. The curve through the data is the curve from Figure 7 for 0.2 < L/B < 0.6, from Figure 8 for 1.0 < L/B < 2.2, and a transition by eye for 0.6 SLB < 10. Some of the scatter in results is probably due to variability in the direction of the incident waves. Under oblique attack, the effective beam of the FTB is increased but this has not been taken into account. A constant value of B = 18.9 m was used to determine values of L/B. 77 ce d 7H 190 > “+ pue oro < (°4)!s/c4y's 404 ShInse4 uosssiwsue44 eney *2 eunB! 4 a1 o2 st 9% wt 2@t ot - 80 SINIOd 808 S800 = u/'q s6z ='d/a @AINO UOISSaIBe! JEPIO PUDDSS 90 Ae) re) Wuvd ATIVS V1 78 AA ZOO. > ea Ove Of°O > ay!ec4yts JO} SL|[NSe4 UO!SS|wSUeI, SAeM *g e4nbl4 af oz 81 oy ra Zt oy go 90 +0 #20 SINIOd O€2 sg00 =u/'q éz ='0/a @AINO UOISSeuBel JEps0 cae WaVd ATIVS V1 79 co Oc 8 y4eq a1 jes 21 42 *Z861 “Z| 4equisAoN Pue B 4840490 usemMLeq peule1go Sp4ooe4 gi | WO44 S4{|Nse4 UO!SS|WSUeIL SACM "6 e4nbl4 a/1 oy rl ral Ol 80 90 v0 #2Oo SINIOd 80! ss00 =u/'d Gézc ='d/a (N)'sro>()'s + (N)'stoz)'s x Wud 3TIVS V1 80 Comparison With Model Results Prototype-scale wave transmission tests of Goodyear FTB's were conducted by Giles and Sorensen (1978) with car tires of 64 cm diameter using monoperiodic waves with heights up to 1.4 m. The tests were done on two different beam widths, four and six modules at two water depths, 2 and 4 m. Their results are referred to as the CERC results in Figure 10. Model—scale tests of Goodyear FTB's were conducted by Nelson (1978) using monoperiodic waves and tires of 15 cm diameter. The tests were done on three different beam widths, three, four and six modules at two water depths, 46 and 84 cm. Results for the six-module beam tests agree well with the CERC six-module results and these data sets have been plotted in Figure 11. Only those points with wave steepnesses H/L in the range 0.02 - 0.06 are included. The results are easily distinguishable because the CERC data is for L/B > 0.81 and the Nelson data is for L/B < 0.82. The curve through the data is from second-order regression, modified slightly by eye for L/B > 2.0. Model—scale tests of Goodyear FTB's were conducted by Harms and Bender (1978) using mostly monoperiodic waves and tires of 8.4 and 15 cm diameter. The tests were done on four different beam widths, two, four, eight and twelve modules at water depths from 31 to 120 cm. Their results are referred to as the Harms results in Figure 10. Model-scale tests of Goodyear FTB's were conducted by McGregor (1978) using pseudo-random waves and tires of 15 cm diameter. The tests 81 co 0X4 St S8AIND UO!SS!WSUE4YL SAeM JO UOS!4UedWwOD *O| Seunb!l4 98/1 oy vl rAll oy go 90 +0 #4=2zo QHIO-UOSION—~» J0BaIN OW X 2 Ryep jo sbuey \\ eR . ci €€0-810 900-200 UOS/jON ci 900 sv00 sJODaINOW 9° z€0-9'0 O'0-S0OO OH39D Gi ‘v80" zS0-200 ¥00 swiey (w)'ig u/'g /H_ eaunog Ol cl [3] 39 82 co (SL61 ) USSUSLOS pue Sso| iS) pue (8Z6| ) UOS | Sy $0 st| nse UOISS!WSUBIL SACM nal | eunb! 4 a/1 OZ gt ey yl ral Ol 80 90 v0 #£2zo @AIND UOISSAIHBAl JOPIO PUDDIS £609} 910 = y/'q €1Z2 1 941 = 'G/g Wvs8 JINGOW 9 900 5 1/H 5 200 83 were done on six different beam widths, 2, 3, 4, 5, 6 and 7 modules at a constant water depth of 240 cm. Results were presented graphically in the form of transmission coefficients versus frequency for each beam width (McGregor 1978, Figure 7). All tests were run with the same incident wave spectrum with a peak frequency of 0.67 Hz. Values of Cy versus Lp/B have been obtained by measurement from McGregor's Figure 7. Results agree very well with those of Harms and are shown in Figure 10. Unfortunately, there is no data for Lp/B < 0.99. As seen in Figure 10, the results of the present field study agree quite closely with earlier model test results. For practical purposes, the most important part of Figure 10 is for values of Cy less than 0.5. In this range the Harms curve shows the best agreement with the field results. For values of C, larger than 0.4, the Harms and McGregor results underpredict Cy- The field results indicate a levelling-off or residual value of Cy of approximately 0.15, while the model results tend towards zero for small values of L/B. This may be attributable to viscous scale effects causing more attenuation in the model than in prototype. It may also be due to reflected and diffracted wave energy contributions in the field. Unfortunately the prototype-scale CERC model tests do not include data for values of L/B less than 0.8. 84 Application Wave energy spectra for the largest recorded wave height event are shown in Figure 12. For a known incident spectrum the transmitted spectrum can be predicted using values of Cy from Figure 10. Using the La Salle Park curve, this has been done for pressure transducers 3 and 5 in Figure 4; results are provided in Table 1. The predicted transmitted characteristic wave height is 0.193 m while the value calculated from the pressure measurements is 0.184 m, giving an overprediction of 4.9 percent. A simpler approach to predicting the transmitted wave height would be to use a single value of Cy corresponding to the peak frequency. For the example in Table 1, fp = 0.36 Hz giving Cy 0.355. The predicted transmitted wave height would be 0.638 x 0.355 0.226 m, giving an overprediction of 25 percent. In general, the simpler approach will be less accurate than the spectral approach. Whenever the incident spectrum is multi-peaked, only the spectral prediction method should be used. For practical purposes, a breakwater is seldom required unless wave attenuation of 50 percent or more is needed. From Figure 10 it can be seen that to obtain Cy < 0.5 the ratio L/B must be less than 0.85. Therefore, a rule of thumb for Goodyear FTB's would be that the beam must be at least 1.2 times the design wavelength. For another type of FTB, the Pipe-Tire floating breakwater (Harms et al. 1981), a comparable 85 (sunoy LIII1 *ZI/il/Z8) +U¥EeAS pepsose jsebue| eyt soy eupoeds ABueuse eaem “Z| e4nb!4 ZH9E =S+ce ZH9E =S ZHO9E =€ ‘OSHA MVAd ----- ZH9E ==C+l ZHOE =c ZHOE =t Odes WWAd — wo Est =G+c wo 16 =G WO QOZ9=E LHOISH YVHO ----- WO PGQO=E+lL WO GJtE=c WO BE9=! LHOISH YVHO —— Ol 6) Ol O SSAVM SSAVM SADVYESAV G31 LINSNVYL INAGIONI Ol Ol Ot ZH/,W9 SGOZ = SIeUIPIO “XeI/\ ZU - oul cl/t/Z8EL :e7eg WHLOAdS YSMOd SONVINWA NOLWAATA SOVSHNS YSWM YSIVMYVSHE SHYIL ONIVO1S VNIYVW Mevd ATIVSV) 86 TABLE 1. Comparison of Transmitted Wave Energy Spectral Values (1982/11/12, 1117 hours) (1) (2) (3) (4)* (5)* (6)* freq & S,(f) S,(f) C, C,7-S.(f) (Hz) B (cm2/Hz) (cm? /Hz) (cm? /Hz) 24 1.43 3.5 2.3 .795 Do 28 1.05 46.3 24.4 .675 Doi 32 .81 424.6 83.9 515 112.6 36 64 2054.8 273.2 355 259.0 .40 52 1581.1 78.0 .260 106.9 44 43 870.5 23.5 215 40.2 48 36 457.0 is? 185 15.6 52 31 242.0 eu 175 7.4 56 26 256.1 5 165 7.0 60 123 122.9 4.6 155 Dei) 64 .20 163.4 4.2 150 Sol 68 18 143.7 WS 7.5, 150 WeSR2 H_(m)*: .638 .184 .193 (4) Spectral values calculated from measured pressure fluctuations on leeward side. (5) From Figure 10 (6) Predicted spectral values from (3) and (5) (7) The values of H. differ slightly from those in Table 4 due to a simplified manual method of computation here. 87 rule of thumb would be that the beam must be at least 0.8 times the design wavelength. Mooring Loads - Empirical Mooring load signals from the largest recorded wave height event are shown in Figure 6. It can be seen that the mooring load fluctuates with the passage of each wave. There is a well-defined minimum load on each gauge during a record, and local maxima which appear to be correlated with wave groups. Dimensional analysis of wave-induced mooring loads (Harms et al. 1981) has shown that [6] Fy = o(L/D,, H/D,, D4/h, B/D,) where Fg is the dimensionless peak mooring load, Dy is the outside tire diameter (approximately 64 cm) and 77 Fats is L egD, where Fae is the maximum measured load (Newtons) at a gauge during a record ) density of fresh water in kg/m? g gravitational acceleration (m/sec*) 88 gL is the length in metres of breakwater frontage restrained by the mooring line (10.72 m for the central line, 5.36 m for the corner line). ) is the angle between the mooring line and a perpendicular to the front face of the FTB. (0 degrees for the central line, 45 degrees for the corner line) The formulation of Equation 6 neglects current or ice-induced mooring loads; it is appropriate for the La Salle Park FTB during the boating season. Model tests of Goodyear FTB's (Harms and Bender 1978) and of Pipe-Tire floating breakwaters (Harms et al. 1981) revealed that Fy does not vary substantially with B/Dy- Mooring loads increase with increasing values of L/D, H/D, and D,/h. Preliminary analysis of the dimensionless parameters Fg versus H-/Dy showed that the use of tires with diameters larger than 0.64 m would result in the prediction of smaller mooring loads for the same incident wave height. This disagrees with expectations. More data is needed to aueataey the effect of tire diameter on mooring loads. Accordingly, the analysis of mooring loads has been done dimensionally. The dominant variable affecting mooring loads at the La Salle Park FTB is He. There are 65 records in which H. > 30 cm (see Tables 2-4). For these records, the dimensional peak mooring loads per unit length (Fms,cose)/z have been plotted against He in Figure 13. 89 TABLE 2. Summary Data Table for Mooring Force Results When Ho > 30 cm TS abana ueenetl alia awl callg erica pict line line (hr/min) (s) (m) (cm) (N/m) (N/m) Oct. 20 UY 1.92 5.75 36.4 52.6 (72.5)* 9/8 2.08 Gof BWaoll 64.8 (85.4) 10/8 oll 8.06 54.3 166.0 (223.2) 11/7 2.50 1/5 Bo) (25) 2 255.6 N27) Zo Cll 8.06 49.2 W572 68} 389.1 13/8 2.08 6.77 33.8 158 98 .4 14/8 2.08 6.77 36.9 113.4 201.7 15/8 oll 8.06 44.1 161.2 367.7 16/8 Boik}s N20) 48 .6 159.6 374.8 17/8 Botksh tol) 49.0 192.8 435.9 18/8 2.08 Oo/7 So 93.2 207.5 19/8 2.50 9.75 40.0 106.1 316.7 20/8 2.50 of Uoll 123} oil 285.7 21/8 do all 8.06 39.9 116.7 322.4 22/8 2.50 OFy/ Sea Srl 140.9 356.8 23/8 2.50 Vos LOZ 123.9 380.6 Oct. 21 0/8 2 oll 8.06 30.8 (277.0) 213.9 1/8 2.50 Jo BWolll 108.5 295.1 2/8 2.50 5/5 Soh! 69.6 193.9 3/8 2.50 9.75 34.4 Vol 196.7 4/8 (2 oll SoH. Soil 82.6 ZO 5/7 2otll 8.06 30.2 51.8 121.4 * Brackets signify an outlying point. 90 TABLE 3. Summary Data Table for Mooring Force Results When He > 30 cm Fea oi ll a ma 6 line line (hr/min) (s) (m) (cm) (N/m) (N/m) Nov. 5 11/30 2.50 oS Bi/o8 79.3 129.9 12/30 Qe 8.06 32.3 64.0 133.6 14/30 2.50 Ve . Bots} 7/ of) 150.1 15/31 2.50 9.75 41.9 85.8 257.0 16/31 Boil 8.06 33.0 61.6 NB 62 18/31 2o2l 8.06 33.0 Vouk 162.9 19/31 2.08 Oo// | SoS 60.8 155.8 20/31 2.2/7 8.06 36.5 ORS 139KS 21/31 2.50 Bos 87/08 93.2 207.5 23/31 2.50 Qos Sod} 85.8 NBS Nov. 6 0/31 2.08 OSU S58 74.5 183.8 WAS Zolli S05 Shh 7/ Vol 219.0 2/31 stil 8.06 45.1 90.7 213.9 3/31 2.50 9.75 44.5 99.7 SAWS 7/ 4/31 Bo@ll S50 Gimmes Sh 77.0 150.8 5/3 2.08 OsHY 85083 69.6 135.8 6/31 1.92 Ho Biloi/ 44.6 99.8 Uh 2.08 O50 Soil 52.6 105.6 8/31 2.08 6.77 34.9 72.1 133.6 9/31 2.08 (AW 1 TPL 0) 68.8 139.3 10/30 BoBl/ 8.06 32.4 68 .8 WES 11/33 2.08 ORI) leere 53.4 109.9 12/33 eval] 8.06 36.2 72.9 MIS 7/ 13/33 Boll 8.06 38.1 69.6 147.1 14/33 1.92 H6I/9, 38306 60.8 117.8 15/33 2.2/7 8.06 41.2 Soll i358} 91 TABLE 4. Summary Data Table for Mooring Force Results When H. > 30 cm ee ar a eae Am line line (hr/min) (s) (m) (cm) (N/m) (N/m) Nov. 12 0/11 1.92 Ho/5 Woe 47.8 (268 .5)* if ils 1.92 Bo/5 3208 60.8 114.1 Udy 2.08 6.77 42.4 195.2 220.4 8/17 Coll 8.06 46.4 237.3 336.7 9/17 2.50 o/s Bios 290.0 503.3 10/17 2o30) oI do? 321.6 812.1 11/17 Dols NA ol) 65.4 504 .6 835.1 12/17 Boll 8.06 44.7 214.7 355.4 ESAT, 2.50 9.75 42.4 (61 479.6 14/17 2.08 Golf Ghitail 179.0 (601.7) 16/17 2.78 W260) esol 353.1 657.0 La 2.78 W260 © SS) 406 .6 545.4 18/17 2.78 12.0 42.4 131.2 414.3 19/17 Soils} W562 S68 81.0 188.8 20/17 2.50 9.75 43.9 154.7 319.5 21/17 2.27 8.06 30.7 46.9 108.5 22/19 Bol) S06 eee S0l2 42.1 99.1 * Brackets signify an outlying point. 92 LA SALLE PARK FTB October - November 1982 D, =0.64m B=189 192s <¢ Tp < 3.85 LEGEND @ CORNER 4 CENTRAL 0,4 OUTLIERS H, (cm) Figure 13. Dimensional plot of peak mooring load versus characteristic wave height data 93 After removing several outlying points from the data set, second-order regression curves were determined and are also shown in Figure 13.* Some of the scatter in results is probably due to Lp varying from 5.75 m to 15.2 m. However, there is insufficient data at overlapping values of H. to determine a relation similar to that between Fy and Lp/Dt as done for Pipe-Tire floating breakwaters in Harms et al. (1981). Results from the 6-module-beam two-dimensional prototype-scale tests by Giles and Sorensen (1978) in 4 m of water are compared with the La Salle Park results in Figure 14. For the Giles and Sorensen (1978) data, the height H of regular waves has been substituted for H-- Agreement is surprisingly good. A second-order regression analysis of the 64 field test points and 39 model test points gives S86 2 [8] (F axc0S8)/2 346 + 8.76 Ho + 0.0798 (Ho) where (Fma,cose)/g is in Newtons per metre length and H. is in centimetres. The corresponding value of the square of the correlation coefficient is 0.96. Equation 8 should only be used for values of Ho > 40 cm. It is very similar to the relation proposed by Harms and * A plot of (Fmaxcose)/eg versus H. where H. was calculated according to linear wave theory (i.e., N = 1.0) showed almost no difference in the regression curve over the range of data. 94 Fp KS (N/m) 1400 GOODYEAR FTB MOORING FORCE DESIGN CURVE Fnax (N/n)=-346+8,76H, + 0.0798 He” (R= 0.96) for 40cm < H, S$ 120cm and D; /h s 0.18 4 La Salle Park FTB, central mooring line e Giles and Sorensen (1978), 6-—Module- Beam h=4m 20 40 60 80 100 120 = 6140 H, (cm) Figure 14. La Salle Park peak mooring load data from central mooring line and 6-module-beam data from Giles and Sorensen (1978) 95 Westerink (1980) from an analysis of the 6-module-beam data of Giles and Sorensen (1978) in 4 m of water which gave F,ja,/2 = .140 (H.)?. A striking feature of Figure 13 is that the mooring loads on the corner line (Dy/h =~ 0.18) are significantly greater than those at the central line (Dy/h = 0.085). Prototype—scale model tests of Pipe-Tire floating breakwaters (Harms and Westerink 1980) showed a large increase in mooring loads when D,/h changed from 0.22 to 0.51. Prototype-scale model tests of Goodyear FTB's (Giles and Sorensen 1978) showed a slight decrease in mooring loads when D,/h changed from 0.16 COMO R Sr This latter trend, however, disagrees with the results of other model studies (Harms 1979) and with theoretical expectations. At La Salle Park, the increase in Dy/h from 0.085 to 0.18 is not expected to cause a large increase in mooring loads. A more likely reason for the increase in mooring loads from central to corner mooring lines is that waves diffract around the corner of the breakwater, essentially doubling the frontage restrained by the corner line. Clearly more data is needed on the influence of relative draft D,/h on mooring forces. Meanwhile, for design purposes, it is suggested that the mooring load (in a direction perpendicular to the FTB length) of the corner line be estimated as twice the central mooring line load. Mooring Loads - Analytical The preceding empirical approach can be compared with an analytical method. A floating body which reflects or dissipates wave 96 energy is subject to a mean horizontal force, F. The existence of a horizontal momentum flux, or radiation stress, has been demonstrated experimentally by Longuet-Higgins (1977). For non-breaking waves of low amplitude (obeying linear wave theory), the mean horizontal force per unit length has been shown by Longuet-Higgins (1977) by conservation of momentum to be [9] Poe Cle sa! Sa ey oe Ci ia ial IP t sinh2kh where o = density of water g = gravitational acceleration a. = the amplitude of the incident wave Cie the amplitude of the reflected wave aes the amplitude of the transmitted wave ke = Bare Le L = wavelength h = water depth Floating tire breakwaters characteristically dissipate wave energy through internal friction rather than reflection. Therefore, as a first approximation, F has been calculated by assuming ay = 0. The wave amplitude is assumed to be half the wave height. For the water depths and wavelengths present at La Salle Park, the factor (1 + 2kh/sinh kh) equals unity. In Figure 15, the predicted loads (for a 5-module 7) (LL61) SU!6H1H-4enbuo7 JO Uuolpe|;eu Bulsn suolso1peud Of speo| Hul4oow yeed peunsesw jo uosiuedwog “*G| eunbl4 JNIT SNINOOW TWHIN3O Iv GAYNSVAW (N) GVO XWW 10,0,014 OOOE 0002 OOo! Go v (Gy) - (44) x ZL01 X Ge POY MeVa ATIWS VI (N) GVO1 GaLOIdSud 98 frontage of 10.72 m) are compared to the peak loads measured at the central mooring line. Equation (9) tends to overpredict for loads less than 2000 N and to underpredict for larger loads. It should not be used for design purposes, contrary to some evidence presented in Galvin and Giles (1979) which gave F = Fray/2- This lack of agreement can be attributed to the following reasons: The theory predicts a mean load in non-breaking waves but steep and breaking waves were present at La Salle Park. Furthermore, the comparison of mean loads estimated by Equation (9) is made with the peak measured loads (a comparison of F to F,r,,/2 is also unsatisfactory). The theory is valid for sinusoidal waves. In irregular waves, the wave amplitude has been approximated by one-half the characteristic wave height. The peak prototype mooring loads are dependent on the elasticity of the mooring lines and on the dynamic interaction between the waves and the structure. Wave grouping and the structure's natural period of oscillation will affect the peak mooring loads, while the mean horizontal load is essentially independent of wave-structure dynamics and mooring line elasticity. 99 Mechanical Load Gauge A mechanical load gauge was installed on each of four windward anchor chains (Figure 4). The load gauges produce scratches on brass disks that rotate as the scratch is being made. After retrieving the disks at the end of the field season the scratches were measured using a microscope. This provided estimates of the largest loads but did not give the load-time history. The gauges were designed for a maximum load of 5000 lbs (22250 N). They were calibrated in the lab and showed a linear relationship between the load and the length of the scratch up to 22250 N. The gauges were deployed September 24 - November 12, 1981 and June 15 - November 15, 1982. The largest measured loads were much smaller than the design load of 22250 N, and therefore, the resolution of the scratches was sometimes difficult. The maximum estimated loads (N + 20 percent) for gauges 1 to 4 for 1981 and 1982 respectively were: 1 2 3 4 1981 4900 3400 3700 3900 1982 - 5900 4400 5400 These estimates compare well with the maximum loads measured in 1982 with the electronic load cells: 5400 N at the central anchor chain between gauges 2 and 3, and 6300 N at the corner anchor chain beside gauge 4. These loads were probably induced by characteristic wave heights of 65 cm or less. 100 Storm of April 30, 1984 A severe storm occurred over the Great Lakes on this date. A fishing boat sank near the end of Long Point in Lake Erie, taking three lives. Several sailboats moored at offshore buoys beside the La Salle Park Marina broke their mooring lines and sunk or were badly damaged. One of these breakaways became grounded on the 9-module— wide southwest-facing section of FTB; the boat safely rode out the storm without damage to itself or the FTB. Although the FTB was not equipped with measuring instrumenta- tion during this storm, its performance was observed under these extreme wave conditions. Environment Canada wind measurements at Hamilton Airport, located 14 km south of La Salle Park, recorded a peak southwest gust of 30.9 m/s at 1555 hours, with a corresponding one-minute average speed of 21.6 m/s. At the L.B. Pearson (Toronto) International Airport, the peak of the storm occurred at 1422 hours with a southwest gust of 27.8 m/s and a one-minute average speed of 19.6 m/s. Using the average of these two one-minute speeds, 20.6 m/s, the resulting hindcast wave conditions at La Salle Park are H_ = 1.0 m and Tp = 3.5 s. The FTB successfully rode out the storm without any apparent damage. Minor damage occurred to the floating docks in two locations. The FTB mooring system had been designed for waves of the magnitude and period hindcast for this storm. However, the transmitted characteristic wave heights were not expected to meet the standard of being less than 0.3 m. 101 The transmitted wave height at the peak of the storm has been estimated by obtaining a value of C, from Filguneunel Ons fom sey B corresponding to Tp = 3.5 s; the resulting value of H, is 0.66 m. Visual estimates of the transmitted wave height at the peak of the storm were 0.6 - 0.9 m. An estimate of the peak mooring load can be obtained by using Equation 8 for H. = 1.0; the resulting peak mooring load on a central mooring line is 14240 N or 1330 N/m. Conclusions The Goodyear-design floating tire breakwater at La Salle Park Marina has performed successfully from its installation in May 1981. It survived extreme wave conditions estimated at H. = 1.0 m and Tp = 3.5 s with no damage, during a storm on April 30, 1984. It appears that an FTB of this type can be designed with confidence using the prototype results in this report and field-proven construction guidelines reported elsewhere (Bishop et al. 1983). An 129 m x 19 m section of FTB was monitored during parts of 1981 and 1982. Wave transmission characteristics were determined by measuring incident and transmitted waves with underwater pressure transducers. The wave transmission results (Figure 10) are in close agreement with earlier results from model tests. Mooring load characteristics were determined by measuring the loads exerted on several anchor lines using electronical and mechanical 102 gauges. For the central anchor line the peak mooring loads per unit length were found to be in good agreement with those measured in earlier prototype-scale model tests (Figure 14). The peak loads measured on the corner anchor line were found to be significantly greater than those measured at the central anchor line. Acknowledgements Thanks are expressed to the City of Burlington for cooperation in the monitoring program, to Messrs. J. Valdmanis and M. Pedrosa for their help with the electronic system, to Mr. H. Savile for his work on the mechanical load gauges and in the field, and to Drs. T.M. Dick and M.G. Skafel for their continued support of this project over three years. References BilShOpeuaGellic 1981. Drag Tests on Pipe-Tire Floating Breakwater. National Water Research Institute, Burlington, Ontario. Bishop, C.T. 1982. Floating Tire Breakwater Buoyancy Requirements. National Water Research Institute, Burlington, Ontario. BijShoOpemnGrulis 1984. Measuring Waves with Pressure Transducers. National Water Research Institute, Burlington, Ontario. 103 Bishop, C.T. and Gallant, B.A. 1981. Construction of Goodyear Floating Tire Breakwater at La Salle Marina, Burlington, Ontario. Proceedings of the 2nd Floating Breakwaters Conference, Dept. of Ocean Engineering, University of Washington, Seattle, Washington, 190-207. Bishop, C.T. DeYoung, B., Harms, V.W. and Ross, N.W. 1983. Guidelines for the Effective Use of Floating Tire Breakwaters. Information Bulletin 197, Cornell University Cooperative Extension, Ithaca, New York. Bruno, R.O., Dean, R.G. and Gable, C.B. 1980. Longshore Transport Evaluation at a Detached Breakwater. Proceedings 17th Coastal Engineering Conference, American Society of Civil Engineers, 2:1453-1475. Candle, R.D. and Piper, D.R. 1974. The Proposed Goodyear Modular Mat Type Scrap Tire Floating Breakwater. Goodyear Tire and Rubber Co., Akron, Ohio. Draper, L. 1957. Attenuation of Sea Waves with Depth. La Houille Blanche, Vol. 12, 6:926-931. Galvin, C. and Giles, M. 1979. Mooring Forces on Rafts from In-Line Radiation Stress. Proceedings Civil Engineering in the Oceans, American Society of Civil Engineers, 487-503. Giles, M.L. and Sorensen, R.M. 1978. Prototype Scale Mooring Load and Transmission Tests for a Floating Tire Breakwater. Technical Paper 78-3. U.S. Army Corps of Engineers, Coastal Engineering Research Center, Fort Belvoir, Virginia. 104 Grace, R.A. 1978. Surface Wave Heights from Pressure Records. Coastal Engineering, 2:55-67. Harms, V.W. 1979. Design Criteria for Floating Tire Breakwaters. Journal of the Waterway, Port, Coastal and Ocean Division, ASCE, WW2:149-170. Harms, V.W. and Bender, T.J. 1978. Preliminary Report on the Application of Floating Tire Breakwater Design Data. Water Resources and Environmental Engineering Research Report 78-1, Dept. of Civil Engineering, State University of New York at Buffalo. Harms, V.W. and Westerink, J.J. 1980. Wave Transmission and Mooring Force Characteristics of Pipe-Tire Floating Breakwaters. Report LBL-11778, University of California, Berkeley, California. Harms, V.W., Bishop, C.T. and Westerink, J.W. 1981. Pipe-Tire Floating Breakwater Design Criteria. Proceedings of the 2nd Floating Breakwaters Conference, Dept. of Ocean Engineering, University of Washington, Seattle, Washington, 47-86. Kowalski, T. and Candle, R.D. 1976. Scrap Tire Floating Breakwater. Proceedings Oceans '76, 886-894. Longuet-Higgins, M.S. 1977. The Mean Forces Exerted by Waves on Floating or Submerged Bodies with Applications to Sand Bars and Wave Power Machines. Proceedings Royal Society of London, A352:463-480. 105 McGregor, R.C. 1978. The Design of Scrap-Tyre Floating Breakwaters with Special Reference to Fish Farms. Proceedings Royal Society of Edinburgh, 76B:115-133. Nelson, W.L. 1978. An Investigation into the Scaling Confidence of Floating Tire Breakwater Model Tests. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Engineering, University of Washington, Seattle, Washington, 79 p. Shooter, J.-A. and Ellis, G.E. 1967. Surface Waves and Dynamic Bottom Pressure at Buzzard's Bay, Massachusetts. Defence Research Laboratory Accoustical Report 292, University of Texas, Austin, Texas. Valdmanis, J. and Savile, H.A. 1984. Hardware for 1982 Monitoring of Floating Tire Breakwater at La Salle Park Marina. National Water Research Institute, Burlington, Ontario. 106 FTB LIST OF SYMBOLS amplitude of the incident wave amplitude of the reflected wave amplitude of the transmitted wave beam width of FTB transmission coefficient = H,/H. tire diameter frequency corresponding to the peak of the wave spectrum frequency floating tire breakwater mean horizontal force per unit length dimensionless peak mooring load maximum measured load during a record gravitational acceleration water depth wave height characteristic wave height = four times. the deviation of the water surface elevation record incident wave height wave pressure head transmitted wave height International Great Lakes Datum én /L pressure response factor wavelength 107 energy standard wavelength corresponding to the frequency at the peak of the wave energy spectrum length of breakwater frontage empirical correction factor for pressure records water surface variance spectral component of incident waves water surface variance spectral component of transmitted waves water surface variance spectral component wave pressure head variance spectral component wave period = 1/fp depth of submergence of pressure transducer density of fresh water angle between the mooring line and a perpendicular to the front face of the FTB 108 FLOATING BREAKWATER PROTOTYPE TEST PROGRAM Eric Nelson ABSTRACT Due to increased interest in the use of floating breakwaters to provide wave protection, the US Army Corps of Engineers initiated the Floating Break- water Prototype Test Program in February 1981. The program, which utilizes two types of breakwaters--a concrete box and a pipe-tire mat--was designed to answer several important engineering questions which include the following: determining the most efficient breakwater for a particular wave climate, pre- dicting the forces that act upon structures and anchoring systems, determining the optimum construction materials, and providing a low-cost means of connect- ing or fendering the individual breakwater modules. After construction and mooring at an exposed site in Puget Sound, the breakwaters were monitored relative to performance and structural response, and the results are being consolidated to aid designers of future floating breakwaters. INTRODUCTION In February 1981, the US Army Corps of Engineers (USACE) initiated a 3-1/2-year prototype test program to establish design criteria for floating breakwater applications in semiprotected coastal waters, lakes, and reservoirs. The test was designed not only to obtain field information on construction methods and materials, connector systems, and maintenance problems but also to measure wave transmission characteristics, anchor loads, and structural forces. Program planning, engineering, and design work were completed in September 1981, and construction and placement were completed in August 1982. Monitor- ing and data collection were concluded in January 1984. The Office of the Chief of Engineers (OCE) had overall program responsibility, which included funding of the total program and reviewing and approving all major actions and reports. Guidance regarding site selection, breakwater design, and monitoring 109 was provided by the Floating Breakwater Prototype Test Working Group comprised of representatives from OCE, the US Army Engineer Waterways Experiment Station (WES), the Coastal Engineering Research Center (CERC) (now at WES), the Seattle District (NPS), and the North Pacific Division (NPD). The Seattle District had primary responsibility for carrying out all major facets of the program except data analysis, which is the responsibility of CERC. The breakwater test site was in Puget Sound off West Point at Seattle, Washington (Figure 1). The site was in an exposed location, assuring that, within the period available for testing, wave conditions would approximate de- sign waves normally associated with sites currently considered suitable for floating breakwaters. Water depth at the site varied between 40 and 50 ft at mean lower low water (MLLW), and bottom materials consisted of gravel and sand. The diurnal tide range at the site was 11.3 ft, and the extreme range was 19.4 ft. The prototype structures that were built and monitored were of two types: a concrete box design (Figure 2) and a pipe-tire mat design (Figure 3). The concrete breakwater was composed of two 75-ft-long units, each 16 ft wide and 5 ft deep (draft of 3.5 ft). The pipe-tire breakwater was composed of nine 16-in.-diameter steel pipes and 1,650 truck tires fastened together with con- veyor belting to form a structure that was 45 ft wide and 100 ft long. DESIGN AND CONSTRUCTION The concrete structure design was based on field and design experience from numerous floating structures now in use, available model test data, and detailed structural analysis of similar structures (Adee, et al., 1976; Carver, 1979; Davidson, 1971; and Hales, 1981). The pipe-tire mat breakwater was based on a sea grant-funded design by Professor Volker Harms (Harms and Westerink, 1980) and modified based on local site conditions and personal dis- cussion with Professor Harms. Other types of floating breakwaters, such as log bundles and twin pontoons, or A-frames, were considered; but either high construction costs, lack of broad applicability, or overall test program bud- get limited testing to the box-type concrete float and the pipe-tire mat structures. Based on available design information, the breakwaters were sized to provide acceptable wave attenuation under conditions typical of sites where the future use of floating breakwaters is anticipated (i.e., He = 2 to 4 ft, 110 40'- 60' FIGURE 2. BRITISH COLUMBIA Sy ay oe CE © ee es @ OOD 0) ae : \ UNITED “STATES l N nea ! 43 | S ; ee W A prenr ire 15 4 Peget Seund | Ais WASHINGTON COLYMPIA avert)... poe congue ail OREGON Scale in miles FIGURE 1. VICINITY MAP “ag WG. 2000 Ibs. CONCRETE BREAKWATER (NOT TO SCALE) 111 v WII AURUUERERRETLELLE 1 Wag. 45 TIN SY G Te af FIGURE 3. PIPE-TIRE BREAKWATER (NOT TO SCALE) T = 2 to 4 sec). However, the structures and anchor systems were designed to withstand the maximum wave predicted for the West Point site CH. 26 fit, I = 5 sec). Pipe-Tire Breakwater Construction The tire breakwater was assembled one bay at a time on a construction platform located adjacent to a waterway. As each bay was completed, the break- water was moved (one bay at a time) into the waterway (Photograph 1). Con- struction of the breakwater closely followed the sequence described by Harms. The tires were brought to the assembly platform (Photograph 2) where they were arranged as shown in Figure 4. The matrix of 1,650 truck tires depended on the loops of 5-1/2-in.-wide, 3-ply conveyor belting for structural integrity. A special tool fabricated from a car jack was used to tension the belting (Photo- graph 3) before the loop ends were joined together with five 1/2-in.-diameter by 2-in.-long nylon bolts. The ends of the bolt thread were melted with a welding torch to prevent the nuts from working off the bolts. After 12 rows of 11 tires had been fastened together, additional tires were forced into the open spaces ("free" tire spaces). The breakwater was then ready to have a I UIT LL LL 5 oa EE | 16" STEEL PIPES pg Ht HH] rH gauge ~~ (45' long, 12' apart) FcWas terse iscwerac Det ifsc aaa 10 oea0 pao LOooP ouB 1ano Gao 12 ROWS (il tires each) TIRE RETAINER wa “FREE TIRES (typical) —_———— 4s FIGURE 4. PIPE-TIRE BREAKWATER MODULE (NOT TO SCALE) pipe inserted into the beam-wise row of tires. Because the tires were not perfectly aligned, a "nose cone" was placed on the end of the pipe. The pipe was moved into place with a large overhead crane and was shoved through the row of tires with a forklift (Photograph 4). A tight structure was produced by compressing one additional tire onto each end of the pipe before the keeper pipes were installed (Photograph 5). This procedure brought the total number of tires on each pipe to 66. The completed bay was dragged into the adjacent waterway by using the overhead crane and a small tugboat (Photograph 6). This process was repeated for each of the eight bays (nine pipes). After construc- tion procedures had been perfected, assembly time for each bay was approxi- mately 8 hours for two men. Adding the free tires, inserting the pipe, and moving the completed bay off the assembly platform required an additional two men and took approximately 4 hours. Construction time was considerably re- duced by the use of heavy equipment and the special tools fabricated by the contractor. Concrete Breakwater Construction The two 75-ft-long concrete breakwater units were cast in Bellingham, Washington. Work on these units began with the erection of steel forms. Welded wire fabric (3/8-in.-diameter) was then placed on the sides, ends, and bottom of the breakwater, with the top left open to allow placement of styro- foam blocks during the casting process. All small pieces of reinforcing steel were epoxy coated, and the larger welded wire parts were galvanized for corro- sion protection. Prior to casting, 16 rebar strain gages were fastened into 113 the deck, sides, bottom, and corners as part of the monitoring system. The concrete pour began at dawn; by sunrise the 4-3/4-in.-thick bottom had been completed. The styrofoam blocks that served as the interior forms were then dropped into place (Photograph 7). Wood two-by-fours and PVC pipe were used as spacers to keep the reinforcing steel located properly between the foam and the forms. Steel beams were placed across the deck; then wedges were hammered in between these beams and the foam to keep the foam from floating up as the sides of the float were poured. After the sides of the floats had been poured to within 1 ft of the deck surface, the spacers and steel holddown beams were removed, leaving friction to keep the foam from rising out of the forms. The deck reinforcing steel was placed, and the final stage of the pour was begun (Photograph 8). Pouring and finishing of the deck completed the casting pro- cess (Photograph 9). Test samples of concrete were taken throughout the pour. The concrete weight varied between 131 and 134 pcf, with an average /-day strength of 4,000 to 5,000 psi and a 28-day strength of 5,000 to 6,000 psi. After the concrete had cured for 7 days, each of the 10 cables composing the SiX post-tensioning tendons was tensioned to 25,000 1b (Photograph 10). On May 28, 1982, the 140-ton units were lifted from the casting area and lowered into the waterway (Photograph 11). The longitudinal strain gages in the lower center edges of the B-float were monitored during the launching. A maximum strain of 1,700 microstrains was recorded, indicating that loads were about two-thirds of the yield strength of the reinforcing steel. After both units were launched, they were joined end-to-end with two flexible connectors (Photograph 12) and towed approximately 90 miles south to the West Point test site. Anchoring The concrete breakwater was anchored in place by ten 30-ft-long steel H- piles (HP 14 by 102) (Photograph 13) embedded their full length. The pilings were driven using a Vulcan 010 hammer with a 10,000-1b ram weight and an 8,000-1b mandrel (Photograph 14). A special fitting was attached to the mandrel to hold the piling in proper alignment while it was being driven. Anchor lines consisted of 1-3/8-in.-diameter galvanized bridge rope with 15 to 30 ft of 1-1/4-in. stud link chain at each end. Anchor line lengths were sized to provide a minimum slope of 1 vertical to 4.5 horizontal. A 2,000-1b concrete clump weight was attached near the upper end of each anchor line. The purpose of this design was to produce a more even anchor line tension over 114 the full range of tides and thereby to reduce the horizontal excursions of the breakwater, particularly at lower tide elevations. Initial anchor line ten- sions were 5,000 + 1,000 1b. Four months prior to the termination of the field test, the clump weights were removed. During this 4-month period, the effects of this clump weight removal on float motions, anchor forces, and wave attenuation were monitored. The pipe-tire breakwater was anchored alongside the concrete breakwater (Photograph 15) with ten 20-ft-long steel H-piles (HP 12 by 53). Anchor lines, which consisted of 1-1/4-in.-diameter, three-strand, nylon rope with 10 ft of 3/4-in. stud link chain at each end, were attached to both ends of each pipe. Minimum Slope for these anchor lines was about 1 vertical to 4 horizontal. The center and end H-piles had one anchor line each, while the remaining four anchor piles were attached to three anchor lines apiece. The four end pilings were offset at an outward angle to counteract the opposing longitudinal com- ponent of force from the adjacent anchor lines. TEST CONDITIONS The prototype breakwater test site at West Point was selected for its ex- posed location. This choice proved to be more than adequate for providing the desired wave conditions. During the 16-month test period more than 20 storms moved through Puget Sound. One storm brought winds in excess of 60 knots and generated waves over 4 ft high. But most often storm winds were in the 20- to 40-knot range with wave heights between 2 and 3.5 ft (Photograph 16). Access to the breakwater was difficult when winds exceeded 10 knots; 15-knot winds made working conditions potentially hazardous. Advantage was taken of calm periods to make repairs and to conduct addi- tional tests. Four boat wake tests and an anchor line stiffness (pull) test were conducted at various points in the program. For two of the boat wake tests, 41-ft Coast Guard cutters were used to generate waves (Photograph 17). The other two tests used large (75-ft and 110-ft) tugboats. Boat-generated waves were in the 2- to 3-ft range. For the anchor stiffness test, a 4,000-hp tugboat was used to pull on the breakwater with varying loads, while surveying instruments measured displacements, and load cells in the anchor lines moni- tored anchor forces (Photograph 18). This test was conducted to obtain simul- taneous measurements of breakwater lateral displacement and the resisting i115) anchor force, properites of the anchor system that affect overall float mo- tions and internal loads. OBSERVATIONS OF PERFORMANCE AND DURABILITY Visual comparisons of incident and transmitted wave height indicated that, under all observed wave conditions, the pipe-tire and the concrete breakwaters provided an adequate and very similar degree of wave protection for both wind waves and boat wakes (Photograph 19). Readily apparent was the fact that the concrete breakwater reflected the wave energy, but the pipe-tire breakwater dissipated it through viscous damping. As a result of wave reflection, the windward side of the concrete breakwater was always noticeably rougher than the windward side of the pipe-tire breakwater (Photograph 20). Overtopping of the concrete breakwater by waves was quite pronounced (Photograph 21). Sheet flow 3 to 4 in. deep was common. As a result, a lush crop of algae thrived on the deck of the structure, making the surface treach- erously slippery. The actual freeboard of the concrete breakwaters was about 13 in., 4 to 5 in. less than anticipated in the original design. The reduced freeboard undoubtedly contributed to the amount of overtopping. The relatively high tension in the anchor lines of the concrete break- water (5,000 1b with the 2,000-1b clump weights and 1,500 1b without the clump weights) appeared to minimize the lateral travel of the floats even during low tides and fast tidal current flows (2 knots). Lateral displacements were esti- mated to be less than 2 ft even when the clump weights were removed. Lateral displacement of the pipe-tire breakwater did not appear excessive (about 5 ft), but tidal currents running at a 45° angle to the anchor lines tended to carry the pipe-tire breakwater in a longitudinal direction to the near end of the concrete breakwater, a distance of about 30 ft. Water leakage into the hollow end compartments of the concrete breakwater was a serious problem throughout the test. Primary leak points were the "watertight" access hatches and the 2-in.-diameter post-tensioning bolt holes that were used when making the rigid connections between the two floats. Be- cause calculations indicated that the breakwater could sink if the end compart- ments filled, emergency pumping operations were carried out on several oc- casions. Eventually, reworking the hatch covers and filling the bolt holes with sealant reduced the leakage rate to manageable levels. 116 One of the major goals of the test program was to investigate various methods of connecting (or fendering) the two 140-ton floats. Several different connection methods were tested: rigidly bolting the units together, using three types of flexible connectors, and disconnecting completely (with fender- jing). Both the rigid connection and the fendering (Photograph 22) were suc- cessful. None of the flexible connector designs survived their test period undamaged, although considerable progress was made toward a viable flexible connection design. Upon completion of the field test, diver inspections of the anchor lines and the concrete floats were made. No significant damage, wear, or cracking was found on the floats. The galvanized steel anchor lines were visibly cor- roded, and the shackles used to attach the clump weights to the anchor lines were worn; otherwise the anchor line hardware, including the chain, was found to be in excellent condition. For nearly a year, the pipe-tire breakwater proved to be remarkably dur- able. Except for minor repairs to the keeper pipes, it withstood the winter storms of 1982 without any maintenance (Photograph 23). But in June 1983, almost a year to the day after the pipe-tire breakwater was installed, the first problem of any consequence developed. After a minor storm, routine in- spection revealed that one of the longitudinal pipes had broken (Photograph 24). Further scrutiny revealed that the 45-ft pipe had been fabricated from a 40-ft section and a 5-ft section. A poor weld between the two sections had finally failed because of a combination of corrosion and fatigue, allowing the two pipe sections to pull out of the tires. One month later, when a second pipe failed in exactly the same manner, a decision was made to terminate test- ing of the pipe-tire breakwater. The pipe-tire breakwater anchor lines were inspected during the removal process, and no major problems were found in either the nylon anchor lines or the connecting hardware. After the break- water was removed, it was eventually reinstalled at a private marina in southern Puget Sound. Monitoring of the long-term durability of this unit is planned. While the Floating Breakwater Prototype Test Program was under way, two projects using floating breakwaters were designed and constructed by NPSSin 1983, a 600-ft-long breakwater was constructed for the 800-boat East Bay Marina at Olympia, Washington (Photograph 25). A year later, another floating break- water, 1,600 ft long, was anchored at Friday Harbor, Washington (Photograph 26). 117 As originally planned, the prototype test breakwater was refurbished and incor- porated into the Friday Harbor Project. Throughout the test program, informa- tion obtained from the construction and operation of the prototype breakwater was used to refine the East Bay and Friday Harbor designs. Preliminary proto- type test data were used to confirm float sizing. Construction specifications were broadened to allow the use of either lightweight or standard weight con- crete, with appropriate adjustments in float draft. Details of the East Bay connector system were changed to reduce maintenance, and the Friday Harbor fen- der system is a direct spinoff of the one developed during the prototype testing. 118 REFERENCES ADEE, B. H., RICHEY, E. P., AND CHRISTENSEN, D. R. 1976. "Floating Break- water Field Assessment Program for Friday Harbor, Washington," Final Report. Ocean Engineering Research Laboratory, University of Washington, Seattle, Wash. CARVER, R. D. 1979. "Floating Breakwater Wave-Attenuation Tests for East Bay Marina, Olympia Harbor, Washington," Technical Report HL-79-13. US Army Engineer Waterways Experiment Station, Vicksburg, Miss. DAVIDSON, D. D. 1971. "Wave Transmission and Mooring Force Tests of Floating Breakwater at Oak Harbor, Washington," Technical Report H-71-3. US Army Engineer Waterways Experiment Station, Vicksburg, Miss. HALES, L. Z. 1981 (Oct). "Floating Breakwaters: State-of-the-Art Literature Review," CERC Technical Report 81-1. US Army Engineer Waterways Experi- ment Station, Vicksburg, Miss. HARMS, V. W., AND WESTERINK, J. J. 1980. "Wave Transmission and Mooring- Force Characteristics of Pipe-Tire Floating Breakwaters," Report LBL- 11778, Lawrence Berkeley Laboratory, University of California, Berkeley, Calif. Il) PHOTO 1. PIPE-TIRE BREAKWATER PHOTO 2. ASSEMBLY AREA (AS EACH BEING ASSEMBLED (FOUR MODULES MODULE IS COMPLETED IT IS MOVED HAVE BEEN COMPLETED) INTO THE WATERWAY ) PHOTO 3. TENSIONING OF BELTING PHOTO 4. STEEL PIPE BEING SHOVED USING A MODIFIED CAR JACK THROUGH TIRES (TIRES AROUND PIPES WERE NOT FOAMED) i ee) ic - PHOTO 5. KEEPER PIPES BEING PHOTO 6. LAUNCHING OF SECURED (WELDING OF KEEPERS PIPE-TIRE BREAKWATER IS REQUIRED TO PREVENT LOOSENING) 120 PHOTO 7. CONCRETE BREAKWATER POUR (PLACEMENT OF INTERNAL FOAM BLOCKS) PHOTO 9. POURING AND LEVELING DECK PHOTO 11. LAUNCHING OF CONCRETE BREAKWATER PHOTO 10. POST-TENSIONING OF CONCRETE UNITS E PHOTO 12. JOINING UNITS WITH FLEXIBLE CONNECTORS somes : > aac As PHOTO 13. H-PILE WITH CHAIN AND PHOTO 14. ANCHOR PILES STEEL ROPE ATTACHED (NOTE ANCHOR BEING DRIVEN AT TEST FORCE CELL IN CHAIN) SIME PHOTO 15. FINAL ANCHORING OF PHOTO 16. WAVES REFLECTING FROM BREAKWATERS AT TEST SITE THE CONCRETE BREAKWATER (SENDING SPRAY 20 FT INTO THE AIR) PHOTO 17. 41-FT COAST GUARD PHOTO 18. 4,000-HP TUGBOAT CUTTER PASSING THE BREAK- PULLING CONCRETE BREAKWATER WATERS (DURING A BOAT WAKE TO DETERMINE ANCHOR LINE NES) STIFFNESS 122 ESS sees PHOTO 19. BOTH BREAKWATERS PHOTO 20. REFLECTING WAVES PROVIDING GOOD PROTECTION OBVIOUS ON WINDWARD SIDE OF FROM STORM WAVES CONCRETE FLOAT Se PHOTO 21. 1.5-FT WAVES OVERTOP- PHOTO 22. CONCRETE UNITS IN PING THE BREAKWATERS (JOINT DISCONNECTED AND FENDERED BETWEEN RIGIDLY CONNECTED UNITS CONFIGURATION IS VISIBLE) PHOTO 23. PIPE-TIRE BREAKWATER : PHOTO 24. AFTER BREAKING, AFTER HAVING WEATHERED NUMEROUS LONGITUDINAL PIPE PULLS STORMS OUT OF TIRES 123 S ee Bead Ye PHOTO 25. THE 16-FT-WIDE BY 600-FT-LONG EAST BAY BREAK- WATER MOORED WITH PILINGS PHOTO 26. TEST UNITS NOW PART OF THE FLOATING BREAKWATER AT FRIDAY HARBOR, WASHINGTON 124 DATA RESULTS, FLOATING BREAKWATER PROTOTYPE TEST PROGRAM Laurie L. Broderick INTRODUCTION The monitoring program for the prototype test was conducted by the Civil Engineering Department of the University of Washington under contract with the US Army Corps of Engineers. The purpose of the monitoring program was to col- lect data that would serve as a basis for establishing and evaluating the fun- damental behavior of the two breakwater types under study. The University de- signed a system to measure and record pertinent environmental and structural variables that are involved in the design and mathematical modeling of the test breakwaters and similar structures. The parameters that were measured included incident and transmitted waves, wind speed and direction, anchor line forces, stresses in the concrete units, relative float motion, rotational and linear accelerations, pressure distribution on the concrete breakwater, water and air temperatures, and tidal current data. "Off the shelf" transducers for measuring many of the parameters were not available. A major effort was required to design and fabricate anchor force load cells (Photograph |), wave measuring spar buoys, a relative motion sen= sor (Photograph 2), pressure sensor housings, and embedment strain gages, By the end of the monitoring program, approximately 60 transducers had been in- stalled in and around the breakwater. Over 3 miles of underwater electrical cable was required to feed signals to the data acquisition system that was housed on the concrete breakwater (Photograph 3). Using large lead-acid bat- teries for power, the system was completely self-contained. In addition to the input transducers, the system included a microprocessor-controlled data logger and special purpose signal conditioning electronics, which were de- signed and built by the University (Photograph 4). The data acquisition IL 2S) system was programmed to sample selected transducers for 1 min on an hourly basis. When either wind speed, current speed, anchor force, or significant wave height exceeded a preset threshold value, an 8-min record of al] trans- ducers was made at a sampling rate of 4 Hz. The microprocessor was capable of a limited amount of data processing, including calculations of maximum, mini- mum, mean, and standard deviation of selected channels of transducer data. After each data tape was retrieved from the breakwater, it was processed at the University. Selected statistics and data plots were analyzed to determine whether all critical components of the data acquisition system were operating properly. When problems were detected, repairs were made as soon as the breakwater was safely accessible. Keeping this complicated and extensive sys- tem operational in such a hostile environment proved to be a challenging enter- prise. Salt water flooded instrumentation, waves and tidal currents broke transducers and tore out electrical leads, and logs, fish nets, and other de- bris caused damage continuously. Despite these difficulties in the 16 months of data collection, 130 data tapes were recorded, representing approximately one-quarter billion measurements. After initial processing at the University, the data were transferred to CERC for detailed analysis. DATA ANALYSIS Analysis of the data has been initiated, with the major effort being di- rected toward the transmission characteristics and anchor forces of the break- waters. These two parameters are being looked at initially because they ap- pear to be key factors in the effort to optimize the cost effectiveness of floating breakwater design. Other parameters, i.e., the internal concrete strains and wave pressures, have been checked to ensure the reliability of the data; but detailed analysis has not been initiated. Figures 1 and 2 are wave transmission characteristics and mooring forces, respectively, for the concrete breakwater. The data plotted in Figures 1 and 2 constitute a partial data set for the 150-ft pontoon with clump weights on the anchor lines, one of the configurations tested for the concrete breakwater. In Figure 1 the prototype data are plotted versus a laboratory curve of a model of a 16-ft-wide pontoon (Carver, 1979). From Figure 1 the prototype wave transmission data seem to follow the laboratory trend. The mooring line loads shown in Figure 2 are much lower than calculated using simple wave force 126 — (=) TRANSMISSION COEFFICIENT, CT ANCHOR LINE FORCE, LB/FT S -) S a S = S RS LEGEND LABORATORY PROTOTYPE 2 3 4 H) RELATIVE WAVELENGTH, L/W 30 3.04 4.33 WAVE PERIOD, T , SECONDS FIGURE 1. WAVE TRANSMISSION FOR CONCRETE BREAK- WATER (150-FT PONTOON WITH CLUMP WEIGHTS) 100 F LEGEND 80 e CONCRETE LOAD CELL 60 40 e oS Mo 20 8 2° 0 Seen ser 0 1 WAVE HEIGHT, FT FIGURE 2. MOORING LOADS FOR CONCRETE BREAK- WATER (150-FT PONTOON WITH CLUMP WEIGHTS) 127 analysis. This was definitely shown in the design of the anchor force load cells, which for the concrete breakwater were designed for a maximum load of 50,000 1b (approximately 1,670 lb/ft of breakwater) which is more than forty times larger than the loads experienced by the breakwater. Figures 3 and 4 show the wave transmission characteristics and the moor- ing line loads, respectively, for the pipe-tire breakwater. In Figure 3, the prototype wave attenuation does not appear to be as effective as the model data predicted (Harms and Westerink, 1980). There are several possible explanations for this discrepancy between the prototype and the model data such as relative depth effects, long period wave energy, background noise, and diffraction around the breakwater. Figure 4 presents a plot of the mooring loads versus wave height for the pipe-tire breakwater. The prototype data show that the mooring loads are less than predicted. The laboratory data show mooring loads increasing with wave heights; whereas the prototype data are nearly constant for any given wave height. The model data used in Figures 3 and 4, the best available for comparison, are based on two-dimensional labora- tory studies conducted using prototype materials (Harms and Westerink, 1980). When mooring loads experienced by the tire breakwater and the concrete break- water are compared on a per linear foot of breakwater basis, the tire break- water has on the average larger loads for wave heights 2 ft or smaller. These are only preliminary results for the prototype breakwaters, and a detailed analysis of the data is currently under way. Future projects utilizing floating breakwaters (Section 107 studies for Oak Harbor, Washington, and Juneau and Saxman, Alaska, are presently under way) will benefit greatly from the test data, and even more cost-effective and lower maintenance designs are anticipated. 128 —_, (—) © 0.8 — co Oo = 0.6 3 S04 LEGEND Z D/d = 0.14 (LABORATORY) = © —-D/d = 0.10 (PROTOTYPE) = 02 ce a 0 0 I 2 3 i! RELATIVE WAVELENGTH, L/W tS) 0 2.96 4.19 9.13 9.93 WAVE PERIOD, T, SECONDS FIGURE 3. WAVE TRANSMISSION FOR PIPE-TIRE BREAKWATER LEGEND (LABORATORY) LOWER LOAD CELL w= UPPER LOAD CELL HG ANCHOB LINE FORCE, LBS/FT 2 WAVE HEIGHT, FT FIGURE 4. MOORING LOADS FOR PIPE-TIRE BREAKWATER 129 REFERENCES CARVER, R. D. 1979. "Floating Breakwater Wave-Attenuation Tests for East Bay Marina, Olympia Harbor, Washington," Technical Report HL-79-13. US Army Engineer Waterways Experiment Station, Vicksburg, Miss. HARMS, V. W., AND WESTERINK, J. J. 1980. “Wave Transmission and Mooring- Force Characteristics of Pipe-Tire Floating Breakwaters," Report LBL- 11778, Lawrence Berkeley Laboratory, University of California, Berkeley, Calif. 130 PHORM URPERSLOADRCEELE PHOTO 2. RELATIVE MOTION SENSOR IN ANCHOR LINE IN USE DURING TEST OF FLEXIBLE CONNECTOR PHOTO 3. DECKHOUSE PROTECTING PHOTO 4. TWO HERMETICALLY SEALED EQUIPMENT FROM ELEMENTS (NOTE CASES CONTAINING THE ON-BOARD WAVE BUOY IN FOREGROUND) COMPUTER 131 al ikem i) ti