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REPAIR, EVALUATION, MAINTENANCE, AND REHABILITATION RESEARCH PROGRAM
US Army Corps of Engineers TECHNICAL REPORT REMR-CO-1
STABILITY OF RUBBLE-MOUND BREAKWATER AND JETTY TOES; SURVEY OF FIELD EXPERIENCE
by Dennis G. Markle
Coastal Engineering Research Center
DEPARTMENT OF THE ARMY Waterways Experiment Station, Corps of Engineers PO Box 631, Vicksburg, Mississippi 39180-0631
December 1986 Final Report
Approved For Public Release; Distribution Unlimited
Prepared for DEPARTMENT OF THE ARMY US Army Corps of Engineers Washington, DC 20314-1000
Under Civil Works Research Work Unit 32278
The following two letters used as part of the number designating technical reports of research published under the Repair, Evaluation, Maintenance, and Rehabilitation (REMR) Research Program identify the problem area under which the report was prepared:
pe Problem=Afeqeaees ——_—Problem Area CS _ Concrete and Steel Structures EM Electrical and Mechanical GT Geotechnical El Environmental Impacts HY Hydraulics OM Operations Management CO Coastal
For example, Technical Report REMR-CS-1 is the first report published under the Concrete and Steel Structures problem area.
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.
COVER PHOTOS: TOP—Field Research Facility, Duck, North Carolina.
BOTTOM—One layer of 7.5-ton tribars used on 8- to 12-ton toe buttressing stone. Tribar and concrete ribcap rehabilitation of a portion of the Hilo Breakwater, Hilo Harbor, Hawaii.
REPORT DOCUMENTATION PAGE
Ta, REPORT SECURITY CLASSIFICATION 1b. RESTRICTIVE MARKINGS Unclassified
2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION / AVAILABILITY OF REPORT Approved for public release; distribution
2b. DECLASSIFICATION / DOWNGRADING SCHEDULE unlimited
4. PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S)
Technical Report REMR-CO-1
6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION USAEWES, Coastal (if applicable) Engineering Research Center WESCV
6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code)
PO Box 631 Vicksburg, MS 39180-0631
8a. NAME OF FUNDING / SPONSORING &b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (if applicable) US Army Corps of Engineers &c. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS
a ce ELEMENT NO. } NO. NO. ACCESSION NO. Washington, DC 20314-1000 32278
11. TITLE (include Security Classification)
Stability of Rubble-Mound Breakwater and Jetty Toes; Survey of Field Experience
12. PERSONAL AUTHOR(S) Markle, Dennis G.
13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Month, Day) 5. PAGE COUNT Final report FROM Feb 84 TOOct 85 December 1986 82 16. SUPPLEMENTARY NOTATION
Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161.
17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number) SUB-GROUP Armor units Rubble mound Wave stability
(a a a a os yes Toe scour
Jetties Water waves 19. ABSTRACT (Continue on reverse if necessary and identify by block number)
The purpose of this survey of field experience is to present an overview of the coastal rubble-mound breakwaters and jetties built and/or maintained by the US Army Corps of Engineers that have or have had stability problems related to structure toes. Exten- sive discussions with US Army Corps of Engineers division and district personnel, along with review of district office files, revealed that rubble-mound toe stability is a major repair and rehabilitation problem that can be divided into two major design categories: (a) design of buttressing stone placed at the toe of an armor slope to prevent downslope slippage of primary armor, and (b) design of toe berm armor size and geometry that will be stable for incident wave and flow conditions and will prevent, or at least slow down, scour and undermining of a structure's toe. No firm guidance presently exists to aid Corps personnel with these two design problems, and most design work is carried out using
(Continued)
20. DISTRIBUTION / AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION GJ UNCLASSIFIEDUNLIMITED (J) same as RPT. Cloric users | Unclassified
22a. NAME OF RESPONSIBLE INDIVIOUAL 22b. TELEPHONE (Include Area Code) | 22c. OFFICE SYMBOL
DD FORM 1473, 84 MAR 83 APR edition may be used until exhausted. SECURITY CLASSIFICATION OF THIS PAGE All other editions are obsolete. incarcerated
Unclassified SECURITY CLASSIFICATION OF THIS PAGE
19. ABSTRACT (Continued).
limited local field experience on past successes and failures. Design guidance in this
area is urgently needed and will be addressed through the use of coastal hydraulic model tests authorized and funded under the Repair, Evaluation, Maintenance, and Rehabilitation Research Program Work Unit titled "Rehabilitation of Rubble-Mound Structure Toes." field survey was conducted under authority of this same work unit.
This
n¢l ifi SECURITY CLASSIFICATION OF THIS PAGE
PREFACE
Authority to carry out this survey was granted the US Army Engineer Waterways Experiment Station (WES) Coastal Engineering Research Center (CERC) by the Office, Chief of Engineers (OCE), US Army Corps of Engineers, under the Repair, Evaluation, Maintenance, and Rehabilitation (REMR) Research Program Civil Works Research Work Unit 32278, “Rehabilitation of Rubble-Mound Struc- ture Toes."
The survey of field experience, which fulfills one milestone of this work unit, was conducted under the general direction of Messrs. John R. Mikel and Bruce L. McCartney and Dr. Tony C. Liu, REMR Overview Committee, OCE;
Mr. Jesse A. Pfeiffer, Jr., Directorate of Research and Development, OCE; members of the REMR Field Review Group; Mr. John H. Lockhart, REMR Problem Area Monitor, OCE; and Mr. William F. McCleese, REMR Program Manager, WES.
The survey was carried out by personnel of CERC, WES, under general super- vision of Dr. James R. Houston, Chief, CERC, and Mr. Charles C. Calhoun, Jr., Assistant Chief, CERC; and under direct supervision of Messrs. C. E. Chatham, Chief, Wave Dynamics Division, and D. D. Davidson, Chief, Wave Research Branch and REMR Coastal Problem Area Leader. Visitations to the US Army Corps of Engineers division and district offices to acquire survey data were made by Messrs. Dennis G. Markle and Robert D. Carver, Research Hydraulic Engineers; Mr. John P. Ahrens, Research Oceanographer; Messrs. Peter J. Grace, R. Clay Baumgartner, and Frank E. Sargent, Hydraulic Engineers; Messrs. Willie G. Dubose and Maury S. Taylor, Engineering Technicians; Mr. John M. Heggins, Computer Assistant; and Mrs. Lynette W. O'Neal, Engineering Aide, during the period February 1984 through October 1985. Review of the field experience data and preparation of this report were carried out by Mr. Markle. This report was edited by Ms. Shirley A. J. Hanshaw, Information Products Division, Information Technology Laboratory.
CERC would like to thank the personnel of the US Army Corps of Engineers division and district offices contacted and visited during this survey. The timely and thorough completion of this study would not have been possible without the outstanding assistance and information provided by these individuals.
Commander and Director of WES during publication of this report was
COL Dwayne G. Lee, CE. Technical Director was Dr. Robert W. Whalin.
CONTENTS
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PART II: FIELD EXPERIENCE. . 0... ccc cece cc ccc cer c cer er ccc crensssscsees
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3 4 4 4 6 Summary of Contacts and VisitationsS......cscccccccccccccccrcccoss 6 8 13 25)
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 To Obtain feet 0.3048 metres miles (US statute) 1.609347 kilometres pounds (force) 4.44822 newtons tons (force) 8896.444 newtons
STABILITY OF RUBBLE-MOUND BREAKWATER AND JETTY TOES; SURVEY OF FIELD EXPERIENCE
PART I: INTRODUCTION
Background
1. Failure of rubble-mound breakwater and jetty toes is a problem whose solution has plagued the majority of the US Army Corps of Engineers (Corps) divisions and districts responsible for designing, constructing, and main- taining these structures. Instability of a rubble-mound structure's toe directly impacts on the primary armor stability and overall performance of a structure. In most instances, instability (failure) of a structure's toe does not become evident until it has resulted in damage to the primary armor which has progressed up to or above the still-water level (swl). This observable damage can range from a minor slumping or reorientation of a few armor units around the swl to the total disappearance of large numbers of armor units. Left unattended, this type of damage could propagate upslope at a rate depen- dent upon incident wave conditions and severity of the toe and lower slope armor damage. In many cases, it will result in either localized or widespread failure of the structure.
2. No guidance presently exists for the preparation of adequate repair and/or rehabilitation designs for damaged or failed rubble-mound structure toes. A concentrated effort to better understand the various types of toe stability problems and to develop and document effective repair methods is urgently needed. Through the development of sound design guidance, the need for frequent repair work will be minimized which will result in substantial
dollar savings.
Authority, Purpose, and Approach
3. Under the Repair, Evaluation, Maintenance, and Rehabilitation (REMR) Research Program, the US Army Engineer Waterways Experiment Station's (WES's)
Coastal Engineering Research Center (CERC) has been authorized and funded to
carry out a work unit under the Construction, Operation, and Maintenance Research Area titled "Rehabilitation of Rubble-Mound Structure Toes." The prime objective of this work unit is to develop guidelines for repair and/or rehabilitation of rubble-mound structure toes. This will be accomplished through conduct of the following four work phases:
a. Through telephone contacts with design, construction, and opera- tions personnel in the Corps' division and district offices it will be determined where structures exist that have, are felt to have, or have had toe-related stability problems. Once this is accomplished, follow-up visits will be made to the division and district offices to gain a better understanding of the problems, and the steps that were taken (if any) to alleviate the prob- lems, and the relative success or failure of the repair or rehabilitation work.
Once an overall understanding is gained of the various toe stability problems confronting field designers, they will be categorized according to type. Subsequent to this, general experimental model testing programs will be developed to address the various problem types. The goal of these tests will be to experimentally determine and document improved methodologies through which successful toe repair and rehabilitation work can be designed and carried out.
|o
c. The experimental model tests (both two- and three-dimensional) will be carried out over a 2-year period. During this time, the scope of the tests will be subject to periodic changes based on continued information obtained and additional understanding gained on the problems confronting field personnel.
d. A thorough analysis of the data compiled during the model tests will be carried out in an effort to produce general rubble-mound toe repair, and rehabilitation guidelines and a comprehensive report covering the model tests and presenting the experi- mentally developed guidance will be prepared and published.
Item a has been completed and is reported herein. Continued efforts will be made to maintain contact with and to obtain additional information from field personnel faced with rubble-mound toe stability problems. Item b has been completed for the presently available data, and two-dimensional experimental model tests (Item c) have been developed and initiated. A three-dimensional test series (Item c) is being developed based on findings of the two- dimensional tests. As previously stated, Item b and, in turn, Item c are
subject to change as more field experience information becomes available.
PART II: FIELD EXPERIENCE
Summary of Contacts and Visitations
4. During the period February 1984 to October 1985, 9 division and 21 district offices (Table 1) of the Corps were contacted by telephone in order to determine whether any rubble-mound toe stability problems presently exist or have existed on the coastal structures under the jurisdiction of the various offices. The points of contact at each district office were those recommended by the REMR Field Review Group members from the district's division office. Of the 21 districts contacted, 12 responded positively regarding existing or past toe stability problems.
5. Prior to a district office visit, a copy of the district's project index maps was obtained in order to become familiar with the authorized coastal structures and their current status. During the planning stages for a district visit, it was requested through the district point of contact that upon arrival at the district office a meeting be held so that a detailed explanation of the purposes of the visit could be given and so that an over- view of the district's coastal structures and the various problems and repair histories related to them could be obtained. Notably, the Wave Research Branch (WRB) of CERC is funded for three REMR work units other than the one being addressed herein, namely, (a) "Use of Dissimilar Armor for Repair and Rehabilitation of Rubble-Mound Structures," (b) "Repair of Localized Damage to Rubble-Mound Structures," and (c) "Techniques of Reducing Wave Runup and Over- topping on Coastal Structures." In addition to these, the WRB has been autho— rized under the Coastal Program's Research and Development Work Unit titled "Breakwater Stability" to write case histories on all breakwaters and jetties built and/or maintained by the Corps of Engineers. All of these work units require the gathering of field data; and for this reason when WRB personnel visited a district office, data were gathered, when available, for each of the work units. It was requested that, where possible, the meeting be attended by district representatives from planning, design, engineering, construction, and operations. In this way, it was assumed that the data obtained would reflect
all areas of concern relative to a district's coastal structures.
Table 1
Divisions and Districts Contacted
Method of Contact
District/Division Telephone ~=Visitation Problems Honolulu/POD* Yes Yes Yes Alaska/NPD Yes Yes No Seattle/NPD Yes Yes Yes Portland/NPD Yes Yes Yes San Francisco/SPD Yes Yes Yes Los Angeles/SPD Yes Yes No Galveston/SWD Yes Yes Yes New Orleans/LMVD Yes Yes Yes Mobile/SAD Yes Yes Yes Jacksonville/SAD Yes Yes No Savannah/SAD Yes Yes No Charleston/SAD Yes Yes No Wilmington/SAD Yes Yes Yes Norfolk/NAD Yes Yes No Baltimore/NAD Yes Yes Yes Philadelphia/NAD Yes Yes Yes New York/NAD Yes Yes No /NED Yes Yes Yes Buf falo/NCD Yes Yes No Detroit/NCD Yes Yes Yes Chicago/NCD Yes Yes No
* POD - Pacific Ocean Division; NPD - North Pacific Division; SPD - South Pacific Division; SWD - Southwestern Division; LMVD - Lower Mississippi Valley Division; SAD - South Atlantic Division; NAD - North Atlantic Divi- sion; NED - New England Division; NCD - North Central Division.
6. Following the entrance meeting, all available information on the district's coastal structures (design memorandums, plans and specifications texts and drawings, reconnaissance reports, photographs, etc.) were retrieved from the district's files and duplicated. The data were then taken back to CERC for scrutiny by the principal investigators assigned to the various work units.
7. Where representative structures were near the district offices, site visits were made to gain a better understanding of the type of construc- tion used on the district's structure. During these site visits, photographs were taken to document the above-water conditions of the structures. Because of time constraints and remoteness of the structures, site visits were not possible at some of the district offices.
8. Prior to departure from the district office, an exit meeting was held for WRB personnel to summarize their findings to ensure that no miscon- ceptions were drawn from the data gathered. Where possible, the same personnel attended the exit meeting as had attended the entrance meeting.
9. In some instances, the quantity of data contained in the district's files was so massive that time was not sufficient for WRB personnel to dupli- cate the data during the time allotted for the visit. When this situation occurred, a request was made for the district to provide personnel, when and where available, to duplicate data and send it to CERC. In some instances, it was determined that an additional visit to a particular district by WRB
personnel was needed to adequately review the available data.
Pacific Ocean Division
10. The Honolulu District of POD has three breakwaters which have problems and/or design questions that are related to toe stability. Two of the structures, Nawiliwili and Hilo, had a related problem. The head and adjacent 500 ft* of breakwater trunk at Nawiliwili Harbor, Kauai, Hawaii
(Figure 1), were rehabilitated in 1959 using 17.8-ton tribars. Model
* A table of factors for converting non-SI units of measurement to SI (metric) units is presented on page 3.
VICINITY MAP
B HARBOR 10-TON STONE PACIFIC @HANALE!
1/2-TON STONE
1.5 MLLW EL 0.0°
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Figure 1. Nawiliwili Harbor Breakwater, Kauai, Hawaii
tests*, conducted at WES in 1958, revealed that two layers of randomly placed tribars on the head and one layer of uniformly placed tribars on the trunk were the best methods of rehabilitating the storm damaged structure. A survey in 1975 revealed extensive tribar breakage, and later it was found that the toe buttressing stone recommended for placement at the toe of the one layer of uniformly placed tribars had not been incorporated into the construction specifications. It was surmised that in the absence of these buttressing stones the tribar toe slid on the hard bottom which resulted in an en masse slippage and breakage of several tribars. This area was rehabilitated with two layers of randomly placed 11l-ton dolosse onslope and through the use of special placement of the toe dolosse. This latter work was also model-tested at WES.**
11. A repair similar in design to that used on Nawiliwili in 1959 was completed on the Hilo Harbor Breakwater, Hawaii, Hawaii (Figure 2), in 1981. One layer of uniformly placed 7.5-ton tribars was placed on the sea-side slope of the breakwater between sta 11+00 and sta 20+00. Based on knowledge gained through the failure of the Nawiliwili tribar section, a row of 8- to 12-ton buttressing stone was incorporated into the toe repair. No design guidance is presently available to aid in sizing the buttressing stone for an incident wave environment, and no model tests were conducted. For this reason, close monitoring of the repair work should be carried out after storm events. Thus, POD and the Corps as a whole will gain from prototype experience which can be used to complement the data acquired during the experimental model tests on toe buttressing stone design proposed to be carried out under this work unit.
12. Haleiwa Harbor, located on the north side of the Island of Oahu, Hawaii (Figure 3), was modified in 1975 by the addition of a revetted mole and two stub breakwaters. Subsequent to this time, repairs were required on the 80-ft breakwater due to a slippage failure of the primary armor stone. Close
inspection of the structure revealed that the bedding and berm had been
* R. A. Jackson, R. Y. Hudson, and J. G. Housley. 1960 (Feb). "Design for Rubble-Mound Breakwater Repairs, Nawiliwili Harbor, Nawiliwili, Hawaii," Miscellaneous Paper No. 2-377, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.
** D. D. Davidson. 1978 (Jan). "Stability Tests of Nawiliwili Breakwater Repair," Miscellaneous Paper H-78-4, US Army Engineer Waterways Experi- ment Station, Vicksburg, Miss.
10
8 TON STONE
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BREAKWATER (COMPLETED) TYPICAL SECTION A-A
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oo E
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Whe
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| WAIAKEA a HARBOR BASIN
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CONC RIBS DOWELED INTO CREST STONE
OCEAN SIDE
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10% —~ SCALE \N FEET
2000
1 TO 2 TON UMNDERLAVER OME ROW OF & TO i2 TOM ARMOR STONES ALONG BREAKWATER TOE
TRIBARS REPAIR SECTION B-B STA 11400 TO STA 20+00
Figure 2. Hilo Harbor Breakwater, Hawaii, Hawaii
iil
HALEIWA 2 LAYER OF 2 TO 4 HARBOR TON STONES
EXIST GROUND REVETTED MOLE 125° BEDDING STONES TYPICAL SECTION A-A SPALLS TO S0#
LOCATION MAP ISLANO OF OAHU O8466
SCALE IN MILES
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AVE ABSORBER \: 140 FEET LONG
EXISTING ENTRANCE CHANNEL
BOAT SLIPS
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SCALE IN FEET
QUARRY : 1975 DESIGN
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TYPICAL SECTION TYPICAL SECTION 110 BREAKWATER —_ 80’ BREAKWATER
Figure 3. Haleiwa Harbor Breakwaters, Oahu, Hawaii
12
omitted from the construction. Localized scour had undermined the armor stone toe and resulted in the slippage failure. The structure was repaired by ex- cavating around the perimeter of the structure down to firm bottom and over- laying the structure head with an additional layer of 1- to 2- ton armor stone which extended down to the toe. This repair was feasible due to the shallow depth of the sand in the area of the west breakwater. No stability problems
have been observed since the repair was completed.
North Pacific Division
Seattle District
13. The south jetty at the entrance to Grays Harbor, Washington (Fig- ure 4), has sustained severe scour on the channel side toe. The outer 5,600 ft of the jetty are presently below mean lower low water (mllw). It is not known if the toe scour is the cause, or a portion of the cause, of the present deteriorated condition of the jetty. Presently, no repair work is planned for the Grays Harbor Jetties.
14. As of August 1985 plans were being developed for the repair of the rubble-mound breakwaters at Edmonds Harbor, Washington (Figure 5). It is not definitely known that toe stability was a cause of some of the existing damage, but it is thought to be a probable cause. The bottom drops off on a 1V:2H slope to a deep depth just out from the toe of the breakwaters. There is some thought that this deep water adjacent to the structure, which allows large amounts of wave energy to reach the structure, could be initiating toe stability problems. No firm decisions had been made on the repair design when this report was being prepared.
Portland District
15. The north jetties at the mouth of the Columbia River, Tillamook Bay, Yaquina Bay, Siuslaw River, Coos Bay, and Rogue River, the south jetties at Nehalem Bay and Umpqua River, both jetties at the Chetco River, and Jetty "A" at the mouth of the Columbia River have all shown toe stability problems. The problems at these 11 sites (Figures 6-14) are the result of one or a combination of the following: (a) ebb and/or flood flows training on the channel side of the jetties which undermine the jetty toes, displace the toe berm stone or a combination of both, (b) wave- and flow-induced displacement
of toe berm armor and foundation scouring and undermining at the jetty heads,
13
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so
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VICINITY MAP
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10.000
Figure 4. Grays Harbor Jetties, Washington
14
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MEAD OF NAVIGATION
MORIZ. CL. - 92° VERT. CL - 20"
VICINITY MAP °
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wicGhway ELEVATION IN FEET
16 i] To 10 0 10 DISTANCE IN FEET DISTANCE IN FEET
SECTION A-A SECTION B-B NORTH JETTY SECTIONS
3
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EE a; | @SECTIONLC SCs SECTION D-D Federal Project SOUTH JETTY SECTIONS
(EXISTING CONDITIONS SHOWN)
Nehalem
Base Point of mileoge is about 530 feet shoreward from the outer end of the Jet ties.
OREGON
SCALE IN FEET
2090 1500 o 1600 3000
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Figure 7. Nehalem Bay Jetties, Oregon
17
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Sr) 4 SECTION A-A
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Boulder Point
Rock Point : * Dick Point : i MORIZ, CL. - 15"
1 VERT. cL. - 28° Note: ee Bose Point of mileoge is in za
line with shore line north of ir Jetty ond is 4500 feet seaward ‘ (olong range tine) from U.S. Highway No./0/.
\ fa) ‘\0ceanside es are. \ PREF 68 ow
TILLAMOO é
{
TRUE BORTH
MORIZ. CL. - OS" VERT. Ch. - 14.5"
COR
fmol ia een oie oe ae ras =a B moRIE. CL. - 70"
ee aE ee Ee ae ae 20 ° Lr) @
TYPICAL DIKE SECTION
SCALE IN FEET 8000
as] Dara within boxes pertain to Authorized Project
Figure 8. Tillamook Bay Jetties, Oregon
18
° OurmPia
LINCOLN COUNTY
Channel 30 feet deep, 300 feet wide from end of Entrance Channel to McLean Pt,
VICINITY MAP. TN MIL
Dato within boxes pertain to Authorized Project.
Q
Base pointofmileoge is one 8°X 20" Sheeting mile downstream trom U.S.
Highway 101 Bridge. MOORING lighway 101 Bridge.
BASIN
TYPICAL BREAKWATER SECTION Naa) EY SET) AB SCALE IN FEET TYPICAL SECTIONS
10 9 i} SCALE IN FEET
SCALE IN FEET 500 1000
Figure 9. Yaquina Bay and Harbor Breakwater and Jetties, Oregon
19
igs EL. Varies
¢ Stone prior to
: a Stone prior to
Mae Waeeaiinn TYPICAL NORTH JETTY SECTION
rehabilitation
TYPICAL SOUTH JETTY SECTION 25 ° 25 50
25 ° 25 50
NORTH JETTY
EXISTING ENTRANCE CHANNEL 7790 FEET
18 FT. DEEP BY SOO FT. WIDE FROM DEEP WATER TOA POINT 1,500 FT. INSIDE OUTER END OF EXISTING NORTH JETTY.
600' FOOT NORTH JETTY EXTENSION UNCONSTRUCTED
SOUTH JETTY 4200 FEET
EXISTING CHANNEL 200 FT. WIDE BY IGFT. DEEP TO FLORENCE
STONE GROINS (5)
eG
CUSHMAN Va
MORIZ. CL. -110" VERT. CL.-NO LiMiT CHANNEL 2 FT. DEEP uy BY ISOFT. WIDE
PILE DIKE c FLORENCE TO Mi. 16.5 GROINS (6) GCENADE ae
EXISTING TURNING BASIN I6 FT. DEEP BY 400FT. WIDE BY 600 FT. LONG
VICINITY MAP.
SCALE IN MILES
Figure 10. Siuslaw River Jetties, Oregon
20
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PACIFIC
VICINITY MAP “SCALE IN MILES ———
Bonk Protection
5 astcec erm of 3 Federal Project i Gronnat t 13f1. deep Vp 300 ft. Gao y] eee
Am i « Le, preckwater
_—_—— T VE JCM OMIE NCL 200 By Locol interests df
OCEAN
7a 38°
Turning Basin 1341. deep, SOOT. wide & 65011. long
: [7 5 Two Jetties | j GOLD BEACH
PACIFIC
| Ge, Here TYPICAL JETTY SECTION
SCALE IM FEET
Channel 10 ft. deep and (00f!. wide
Dato within boxes pertain to Authorized Project.
Ej,
SCALE IN FEET ° 2p00
2p00_ poo
Figure 13. Rogue River Jetties, Oregon
23)
PROTECTIVE DIKE (781_ FT. LONG, EL./8
DIKE CONSTRUCTED OY LOCAL INTERESTS
Upstreom Limit of Federal Project \ \N
SMALL BOAT ACCESS CHANNEL NORTH 100 FT. WIDE BY 12 FT. DEEP AT MLL.
XN SMALL BOAT BASIN 12 FT. DEEP AT M.L.L.W. PROVIDED BY LOCAL INTERESTS
f HARBOR
| _ th] i VICINITY MAP
I: so ° so '
MILES
BARGE TURNING BASIN 250 FT. WIDE BY 650 FT. LONG
eT AND 14 FT. DEEP AT MLLW ‘ Ea
BARGE SLIP - PROVIDED 8yY LOCAL INTERESTS
BOAT BASIN PROVIDED BY LOCAL INTERESTS
woss r
NORTH JETTY| 8B 1350' LONG
SECTION B-B
& YY
4 OUTH JETTY).
Cheteo Rwe- A’ LSSONLONS: j ENTRANCE CHANNEL On Entrance Light “0 120 FT. WIDE BY 14 FT. DEEP 2 7 ee CUP REEL NOTES: 7 aN © E g DATA WITHIN BOXES PERTAIN TO AUTHORIZED PROJECT.
ML
oo F-14 Gravel Embontmen!
SECTION C-C
BEODING MATERIAL GROUND LINE
SECTION A-A
Ex/sting Stone MLL,
SECTION D-—D
Figure 14. Chetco River Jetties, Oregon
24
and (c) wave-induced displacement of toe berm stone and/or scour of foundation material which results in undermining of the structure's toe. As a result of this displacement, scour, and/or undermining of the structure's toe, the pri- mary armor stone layers become unstable and lead to structural failure. The Portland District carries out repair in these scour areas by filling the scour holes with small stone, core size or smaller, to form a foundation to rebuild the toe and upper portions of the structure. During the repairs and rehabil- itations of the north jetty at Yaquina Bay and Jetty "A" at the mouth of the Columbia River, a sacrificial berm of core-sized material was placed at the structure's toe after the primary armor layers had been placed. It was thought that this material would help stabilize the jetty toes by slowing down the scour rate as well as providing some degree of armoring of the scour hole as the berm stone is displaced into the scour hole. In some instances, scour at the jetty heads has been so severe that it was not economically feasible to try to fill and stabilize the scour holes. The best approach in these cases was to abandon the outer 200 to 300 ft of the jetty heads and rehabilitate the
remainder of the structure.
South Pacific Division
16. The San Francisco District sited the jetties at Humboldt Bay (Fig- ure 15) as being the only area showing obvious toe stability problems. The channel side of the north jetty and exposed side of the south jetty have shown obvious signs of scour and undermining which resulted in instability and slippage of the dolos toe. Condition surveys of the area have revealed the depths of the scour holes appear to have a seasonal fluctuation. An armor stone berm, extending from 70 to 100 ft out from the existing dolos toes, was included in the jetty repair work conducted in 1985. The multilayered berm consists of a 3- to 6-ton primary armor stone overlying two graded filter
layers (Figures 16 and 17).
Southwestern Division
17. Several rubble-mound structures in the Galveston District have experienced toe stability problems. Recent attempts to improve stability
include the construction of toe berms of core sized material at the toe
25
Arcota Whorf GZ “AAbandoned)
i ARCATA CHANNEL 150 FT. WIDE, 18 FT. DEEP : (Not Used)
TURNING BASIN 1000 FT WIDE, IOO FT LONG 35 FT DEEP
SAMOA CHANNEL 400 FT. WIDE, 35 FT. DEEP’ : EUREKA CHANNEL
. 1 4 f MILE 4.29 TO MILE 5.00 400 FT. WIDE, 35 FT. DEEP . Y MILE 5.00 TO MILE 6.30 BAR AND ENTRANCE CHANNEL 1600 FT. TO 500 FT. WIDE, 40 FT. DEEP
E CHANNEL AND GUNTHER /SLAND) zE =
See inset mop for details. |
Of this 0°00 ——y |
CROSS SECTION
NORTH AND SOUTH JETTIES VIEW 1S SEAWARD
TYPICAL
CHANNEL SIDE| OOLOSSE (Not to Scale)
Existing Ground, — A’Stone Fill
: TURNING BASIN CROSS SECTION Too of 42 Ton E00 FT. WIDE, 26 FT. DEEP RS. aa a EGE | 800 FT. LONG NORTH AND SOUTH JETTY HEADS ea te jOTE.
AY BASE POINT OF MILEAGE IS 1800 FT, SHOREWARD OF SOUTH JETTY BEACON,
SCALE IN FEET 5000 10000
Figure 15. Humboldt Bay Jetties, California
26
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28
of the structures. Insufficient data were available to make a judgment on the
success of the berms.
Lower Mississippi Valley Division
18. The New Orleans District has a unique design problem in that the majority of their jetties are constructed on very soft foundations. It is thought that a majority of the repair and rehabilitation work required on the jetties results from the structures sinking into the foundation. The jetties at Southwest Pass and Mississippi River Gulf Outlet (Figures 18-20), have required considerable repair work due to this subsidence, but it is thought that some of the damage on small localized areas of these jetties is the result of toe slippage. Toe slippage in turn results in downslope slippage of the primary armor resulting in loss of jetty design elevations. Efforts have been made to use toe berms to reduce toe slippage and help prevent foundation slip failures caused by the loading of the jetty construction materials. The berms have provided some additional toe stability, but subsidence of the jetties and slippage of the jetty toes and foundations continue to plague the
New Orleans District.
South Atlantic Division
Mobile District
19. The Mobile District has a problem with jetty subsidence but, unlike the New Orleans District's problem, theirs is not thought to be related to low-density foundations. It is generally thought that toe scour is the significant problem after major storms. Bedding layers slough off into the scour holes, and this damage migrates back to the toe of the primary armor. The resulting instability of the armor stone toe leads to downslope migration of the onslope armor and eventual deterioration of the structures.
20. During the period 1937 to 1938 attempts were made to alleviate toe scour problems on the Panama City Harbor Jetties (Figures 21 and 22) by encas- ing the jetties with asphaltic concrete. Asphaltic concrete mats (2 in. thick) were anchored on the channel side of the jetties and extended over the jetties to a point 24 ft seaward of the existing jetty toe. A hot asphaltic
concrete was poured over the matting in an effort to bond the mats together
29
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31
PARIS ROAD. HIGHWAY BRIDGE
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PROJECT LOCATION
GEE Inorovements completes
= Improvements outnorized
< 5 u 3 we 3 =9 Xo S
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TYPICAL SECTION MILE 160 To MLE 202
° DISTANCE IN FEET
100
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ctee Swtoce E100
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32
MEXICO
1siana
River Gulf Outlet Jetties, Loui
ississippi
M
Figure 20.
DEPTHS ARE IN FEET AND REFER TO MEAN LOW WATER.
MILEAGE ON GULF INTRACOASTAL WATERWAY |S FROM HARVEY LOCK, NEW ORLEANS, LA
_\_
© MEMPHIS T ENN CnaTranoos
--prascacoury , wad yy wos {| New \c 3
ORLEANS" 4
tpowt Pensa’
—-- s-= q
37 CULE OF
(\s
PROJECT MEXICO
VICINITY MAP
SCALE 1@MiLES
AUTHORIZED |\~ TURNING BASIN |...
;
‘SS 2a
GUL INTRACOASTAL >
WATERWAY. (FOR DETAILS SEE foes SHEET 9-2) CE CEHED
TS AUTHORIZED CHANNEL Inside (Bay) 40° x 300° Gulf Approach 42x 450°
GRAND LAGOON CHANNEL 8° x 100°
"S ST. ANDREWS STATE PARK &
WEST. JETTY
EXISTING CHANNEL, Inside (Bay) 32 x 300
FOR JETTY DETAILS SEE SHEET 9-/
MEX/1CO
PLAN
SCALE IN MILES
CHAN 38 x Fee D> Wz
—— NEL 300
Gulf Approach 32 x 450 :
<} PANAMA
AUTHORIZED ANCHORAGE AND LOADING BASIN FOR LASH TYPE INTERMODAL CARRIERS - DEPTH 40
A WATSON BAYOU | CHANNEL 10'x 100
ieee [ |
BAY HARBOR
BEACON BEACH
Figure 21.
33
Panama City Harbor Jetties, Florida
19+65N 14+89N
COUNT ¥
10+ 25N
ROCK JETTY EXTENSION
ST. ANDREWS
: BAY Ki STEEL SHEET fj PILING 5 To: ASPHALT
‘
2+ 30S oe ROCK JETTY EXTENSION ahaa nN STEEL SHEET PILING \ Ween i >, WE wy —— 9+99E
N
(©) 7T+O4E
) AY s—— ce CA O+00€ G24 <3. +005 0+00 1+ 00N 40s
“EAST JETTY Bis
PLAN
SCALE IN FEET 500 1000 1500
SECTION A-A
Cap Stone Riprap Stone
i<«—Stee! Sheet Piling
SECTION C-C
SECTION B-B
Figure 22. Details of Panama City Harbor Jetties, Florida
34
as well as stabilize them to the existing armor stone structure. This design proved to be unsuccessful. Scour initiated at the toes of the mats and, as the mats subsided into the scour holes, they pulled the mats and armor stone off the upper slope which resulted in general deterioration of the jetties. Subsequent repairs were carried out by placing a toe berm of 100- to 200-1b stone and, where needed, overlaying the old structure with additional armor stone.
21. Toe scour also has been noted as a problem with the jetties at East Pass Channel and St. George Island, Florida, and Perdido Pass Channel,
Alabama (Figures 23-25, respectively). Scour on the channel side of the east jetty at East Pass is so severe that it is thought that portions of the jetty may slide into the channel at any time. In the past, this type of slippage failure has caused severe damage to the west jetty at Panama City.
22. Jetties at St. George Island have suffered cover stone loss result- ing from the undermining action of toe scour. The west jetty at Perdido Pass presently has significant amounts of toe scour on the channel side, and Hurri- cane Frederick produced significant amounts of toe scour on the east jetty. The overall condition of the Perdido Pass jetties was said to be good; there- fore, it is assumed that the toe scour has not caused any obvious damage above the waterline.
Wilmington District
23. The 3,650-ft-long rubble-mound north jetty located at Masonboro In- let, North Carolina (Figure 26), was constructed between August 1965 and June 1966. The north jetty required extensive repair on the channel-side toe of the outer rubble-mound structure in 1969 and to the channel-side toe of the inner weir section in 1973. This was prior to construction of the south jetty (14- to 22-ton armor stone) in 1980. It was thought that ebb and flood flows had caused the channel to move adjacent to the north jetty, creating the scour problem. In both repairs, a 2- to 3-layer protection of bedding mate- rial and riprap (25 to 2,000 1b) was used. This toe protection butted against the existing armor stone toe or sheet-pile weir. The berm width varied from 30 to 50 ft. It is thought that this work had limited success because the jetty has not totally deteriorated, but it is presently in need of repair work in several areas. Presently it is unknown whether the deteriorated appearance
of the north jetty results from a toe scour problem or from the possibility
35
DESTIN Ee iY
MORENO POINT
FIXED BRIDGES HOR. CL.78' VERT. CL. 38°
SAND DIKE STONE JETTY SECTION 5
WEIR SECTION / DEPOSITION BASIN: 7
OPEN WATER DISPOSAL SITE PLAN
SCALE IN FEET 1000
GULF OF
DEPTHS ARE IN FEET AND REFER TO MEAN Low water. S/OME JETTY SECTION
MEMPHIS T ENN CHaTTANOOGA“ AS Y) Le 7 ' T Columbus. * JeiRMINGHAM Ce RATLANTA ¢ iy PY \ cla € \ | Symmetrico/ obout € MONTGOMERY ¢ Ry = S i ~ Existing ground surface z (Elev vories) ~"yRescacout PROJECT © TYPICAL JETTY SECTION RIVER, ae LA: ) ‘ FLA \C Gul!port BRA CACHIC OLA! . Cees ge mqoce yom" TALLAHASSEE
ORLEANS'
mw? GULF OF MEXICO
VICINITY MA
SCALE INMILES so 9 50 100
Florida
Figure 23. East Pass Channel Jetties,
36
E N N CHATTANOOGA
APALACHICOLA
‘> ‘ é No s Sir 4 ST. GEORGE f me SIP Nec alGereyty 24 ci] s ey CHANNEL 3 WS Ss z . 4 3 =) 10'x 100' TO 200 aS at § MISs li WALA & YAGKSON 3G Meridian AWER ls : MONTGOMERY Py fle Nl s : AGE ya ey > news z N. fines) AZ S \ a | MOBILE =
~-prascacoury ae Dv aver {woae
“a,
NITY MAP
SCALE INMILES ° 50 100
VICI
GULF INTRACOASTAL WATERWAY /2°X 125°
EASTPOINT CHANNEL 6 x/00
APALACHICOLA AIRPORT
~NSWING BRIDGE S BULKHEAD SHOAL \ MOR.CL Me, CHANNEL 10'x 100", i ——— 1 5 (NOT MAINTAINED) Mee ST VINCENT TWO MILE BREA WATERS | \ ra TWO MILE CHANNEL CLUECINE \\ i SOUND 6x100' CHANNEL fi ee AINNER BAR CHANNEL 10 x 100
awe” (MAINTAINED TO 12'X 125’ UNDER te PROJECT FOR GULF INTRACOASTAL WATERWAY.)
=—eRWAY ; a= WATE _-t FIXED BRIDGE «=, ee i 388 =cut a HOR.CL 125° =
“s.._ VERT. CL. 50°
ST. GEORGE ISLAND CHANNEL 10'x 100' TO 200° TWIN RUBBLE MOUND JETTIES _.”
en"
os DEPTHS ARE IN FEET AND REFER TO MEAN LOW WATER.
MILEAGE ON GULF INTRACOASTAL WATERWAY 1S FROM HARVEY LOCK, NEW ORLEANS, LA
PLAN
SCALE IN MILES
1 oO U 2 3 aaa
TYPICAL JETTY SECTION
Figure 24. St. George Island Jetties, Florida
37
N TERRY COVE
WALKER ISLAND)
PERDIDO BAY
STA. 32+00 ong —Q ISLAND a
FIXED BRIDGE CLEARAN TO COTTON BAYOU ee HORI
VERT. 29° TO PERDIDO BAY HOR. 80 VERT, 35°
FLORIDA POINT
€@ UNM
GULF OF MEXICO PLAN SCALE IN FEET 800 oO 800 1600 SESE TR DEPTHS ARE IN FEET AND REFER TO MEAN LOW WATER. Ca
MEMPHIS T(E NUN} CHATTANOOGA
CORESTONE CAPSTONE 25 To 2 TONS
8 TO12 TONS, FOUNDATION BLANKET
3 Geen .) \ r
MONTGOMERY
TYPICAL SECTION THROUGH JETTY
« x é 5S N = = $
= psseaaouy t S SCALE IN FEET Yama 10 oO 10 20 Ss )=SE
APALACHICOLA RIVER
= _ Poromq PROJECT *X" GULF OF MEXICO
Figure 25. Perdido Pass Channel Jetties, Alabama
38
aN NORTH 7T90.< > CORE CREEK BRIDGE is SIDE CHANNEL Ca CAROLINA - & BASIN AT Y & JACKSONVILLE SWANSBORO Whe, = a 6] ‘ CHANNELS TO S. aNGe aS JACKSONVILLE & > Z; 2/0 NEW RIVER INLET Ye \ G oe SZ Bocue \PELTIER CREEK oad Ld INLET N
= ZA S. WA a2 CHANNEL TO p Bi % BOGUE INLET € ~ hy 0 iG
CONNECTING CHANNELS
CG MASON BORO INLET a are OSI) LG AND CONNECTING iy SOUTHPORT f CHANNELS Pang f/ CAROLINA BEACH INLET p
CAROLINA BEACH HARBOR
—— | “342 CAPE FEAR END A.1.W.W. SOUTHPORT HARBOR WILMINGTON DISTRICT
NEW HANOVER COUNTY
SCALE OF FEET
Figure 26. Masonboro Inlet Jetties, North Carolina
39
that the original 7- to 12-ton armor stone may have been an inadequate design
for the incident wave environment.
North Atlantic Division
Baltimore District
24. The south jetty at Ocean City Inlet, Maryland (Figure 27), is the only structure within the Baltimore District that was reported as having significant toe stability problems. The original north and south jetties, both rubble mound, were constructed in 1934 and 1935, respectively. The crown elevation on the shoreward end of the north jetty had to be increased in 1937 to stop flow of sand into the inlet. The landward end of the south jetty required extensions in 1956 and 1963 to repair flanking caused by erosion. The south jetty has suffered major deterioration along its outer leg caused by ebb flow induced scour and undermining of the structure's inlet side toe. During major repair of the south jetty in 1963, the center line of the struc-— ture's repair section was offset outward from the inlet (Figure 27). This was done to alleviate the need to fill the massive scour hole that existed where the inlet side of the structure was originally constructed. The ocean side of the existing structure that remained was used as a base against which the in- let side toe of the jetty repair section was positioned. By 1982, the 1963 repair section of the south jetty was once again very deteriorated. Like the original, this damage was only on the converging portion of the jetty and was caused by ebb flow induced undermining of the structure's inlet side. In order to prevent failure of the outer end of the south jetty, which would lead to severe inlet shoaling, the scour hole adjacent to the structure was filled with dredge material and capped with stone. The lower portion of the inlet side of the jetty was overlaid with an intermediate stone size, and the remainder of the inlet side slope was covered with primary armor stone. This work was completed during 1983 to 1984, and a typical repair cross section is shown in Figure 27. The majority of the south jetty's original repair section still shows considerable deterioration and is highly overtopped. It is unknown how well the scour protection is performing. It appears that scour on the north side of the inlet has slowed down, and the north jetty is in good condition; however, the overall scour in the throat of the inlet shows no
signs of stabilizing.
40
HOR. CL. 70° VERT. CL. 18° -DRAWBRIDGE
S. STNEPUXENT MARYLAND . [-
O.65Mi -€ PC RR. 6OR/W. _-N. HARBOR ROAD [7 = = = —F— =
10.
fo} ey
», W. HARBOR
CESTERj# fF COUNTY
12° ke | +4.N. JETTY, +6 S. JETTY
SCALE OF FEET 500 fo} 1
OCEAN SIDE
CAP STONE; 6TON MIN. ABOVE -9.0; 1 500# MIN. BELOW -9
15 #TO 2 TON 1
ORIGINAL JETTY
FILTER, RUN OF CRUSHER STONE
1956 NORTH JETTY REPAIR
OCEAN SIDE
CAPSTONE; 9 TON MIN
“ELEVATIONS IN FEET REFERRED TO MLW
1’ FILTER; RUN OF CRUSHER 1 TON” 1963 SOUTH JETTY REPAIR
150° EXISTING
6.0 TO 10.0 TON STONE
MIN EL FOR TOP OF ARMOR STONE (-3.0) ~a,
0.6 TO 1.0 3 OCEAN SIDE TON STONE 1
SAND A Se
Co EXISTING GRADE —™ ~~ -
ee
FT
1983 SOUTH JETTY REPAIR
Figure 27. Ocean City Inlet Jetties, Maryland
41
Philadelphia District 25. The most common problem occurring on the Philadelphia District's
coastal structures is subsidence of structures below design elevation. It is thought that toe scour contributes to this, but the primary cause is poor foundation conditions in the areas where most of the structures have been built. This is especially true for those structures located in the Delaware Bay area.
26. The jetties located at Reedy Point, where the Chesapeake and Dela- ware Bay Canal intersects the Delaware River, were originally constructed prior to 1938 (Figure 28). Both structures were of rubble-mound construction. In the 1960's the existing south jetty was removed, and a new south jetty was constructed farther south. This was done to increase the entrance size to accommodate larger vessels and improve navigation safety. The present jetties are both 2,095 ft long, and it was reported that the north jetty has problems with toe scour, loss of armor stone, and overall subsidence.
27. The rubble-mound and sheet-pile composite jetties at Indian River Inlet, Delaware, were completed in 1939 (Figure 29). The jetties required storm damage repairs in 1956 and 1957. At that time, the north jetty was extended inshore a distance of 320 ft. At present both jetties are 1,566 ft long. Both jetty heads have deteriorated significantly from a combination of toe scour, armor stone slippage and displacement, and overall subsidence. Because of the success of the Manasquan River Jetty repairs, dolosse are being considered for inclusion in the repair and rehabilitation designs for the
structure slopes. No details on the proposed toe repair design are available.
New England Division
28. Based on review of historical repair data, it appears that three project sites within the New England Division that contain rubble-mound jetty structures have exhibited stability problems which could be related to in- stability of the structure toes. Both jetties at the mouth of the Kennebunk River, Maine (Figure 30), have a history of extension and repair. The latest jetty rehabilitation work was completed in 1982. Recent inspections show that both jetty heads are damaged and that 250 ft of the channel side of the east jetty have been undermined. The most recent inspection reports (1973-74),
indicate that the north and south jetties at Newburyport Harbor, Massachusetts
42
Tf Peo Pac ‘stand
evancn cnannes > envaance Delawa . >
\ SURAT BRIDGE
Ucn Neen
Oy aie | . COUNTY IN | = KO Teese ign
Pr
, he 5 Gity =
Baie!
Sal
ce) sy x OG -
CMESAPEAKE CITY> “US Engineer
ery BR (GH LEVEL) , Resident Office rou, Chesepeate City sy . Oy Aacheroge @ Meermg Basin 2 £ (@ece Crees! g 2
&
,
ST GEORGES (HIGH LEVEL) AR BR (VERTICAL LIFT)
© H
5 oj $s SE = fy ad s IS
AEEOY PT OR d (HIGH LEVEL)
MARYL O€L aw
Te Delewere Bey =
LEGEND
u S Reservetion Boundery
,
SCALE OF FEET
3.0c0 ) S 10 ic} 2c 2500¢ [SS=S5=c —- == 2:
& ¢
2
‘Steed Bultnecd 45
HEALTH CENTER
wary OR. (FIXED) 2 LANES ya
SCALE OF FEET
Figure 28. Reedy Point Jetties, Delaware
43
REHOBOTH BAY
To Rehoboth Beach.
INDIAN RIVER NECK
\
DELAWARE SEASHORE STATE PARK
+;
CHANNEL SIDE
Prevent bottom tobe axceraied to 0 depth of -3.0 Fe permit o min secton of patty 08 shown
Stee! ance! poling Ihrw
Mi core @ Cop stone
u
TYPICAL SECTION “TS.
() ©, rire ANY) : a
OCEAN
BOTTOM HILLS DRAIN US COAST GUARD STATION
2 ag \\se'J INDIAN RIVER ——= INLET FIXED
BRIOGE ELEV 35'MHW
ATLANTIC
——ro Bethony Beoch
TYPICAL SECTION OF REHABILITATED BULKHEADS
to conus! of 0 graced
(qwarry run stone, proces Mor stone{3'-0" deep) 10 conniet of preces exighing n Win! rrom notions tnon «07 1484 (ham /3 bs @ nol more than 200 D4 TNS OE Tho/! be placed for Iho tui! wi81h of 1he jally of
25% ibs 16 200 ioe Jea1t 200' in adrence of placing the Core stone 35% 200108 ro 2/008
HALF SECTION-OUTER 300! OF JETTY NTS
MTS
SCALE OF MILES
' ° ' _——— ———)
Figure 29. Indian River Inlet Jetties, Delaware
44
Behe entSee | SWING 8B
SEEDEAL See heer KENNEBUNK ~
RIVER 4
LOCATION MAP
SCALE IN MILES 10 oO 10 zo 30 [es es | 6-FT. CHANNEL @ GUERTIN
6-FT. ANCHORAGE 2 ACRES
100'7|
oh MONASTERY
6-FT. ANCHORAGE 4 ACRES
NONANTUM HOTEL \\
6-FT. CHANNEL
KENNEBUNK RIVER CLUB
SEVERANCE r) TOWN LANDING
= ‘ = OCH BEACH VT: 7 8- FT. CHANNEL
SAND FENCE
WEST JETTY =~ sep ge
& EXTENSION
Figure 30. Kennebunk River Jetties, Maine
45
(Figure 31), which have an extensive repair and rehabilitation history, are showing considerable damage. This damage appears to result primarily from subsidence. Damage on four areas on the channel side of the south jetty most likely result from undermining of the rubble toe. The jetties at Hampton Harbor, New Hampshire (Figure 32), were originally constructed by the State and were turned over to the Corps in 1964. During 1965 to 1966, considerable work was done on both jetties. Since that time the south jetty has remained in good condition, while the north jetty has required continuous maintenance. Most of the repair and rehabilitation work has been needed on the seaward por- tions of the north jetty. The last rebuilding of the north jetty was com- pleted in 1980, and it is thought that part of this recurring damage can be
attributed to scour and undermining of the jetty toe.
North Central Division
29. There are 38 project sites within the Detroit District which have breakwater and/or pier (jetty) structures that have exhibited stability prob- lems related to the structure toes. At 14 of these sites problems are associ- ated with rubble-mound structures, while at the remaining 24 sites toe prob- lems occur on other structure types. Table 2 is a listing of these 24 sites and the types of breakwater and/or jetty construction associated with each site. The remainder of this section on the Detroit District deals strictly with those 14 sites which are having and/or have had toe stability problems with rubble-mound structures. At some of these sites, toe stability problems have occurred on areas of the structures that are not rubble mound.
30. Structures at Black River Harbor, Cheboygan Harbor, Hammond Bay Harbor, Harrisville Harbor, New Buffalo Harbor, and Point Lookout Harbor, Michigan, are purely rubble-mound construction (Figures 33-40). Charlevoix Harbor, Michigan; Duluth-Superior Harbor, Minnesota and Wisconsin; and Leland Harbor, Muskegon Harbor, Pentwater Harbor, Port Washington Harbor, and Traverse City Harbor, Michigan (Figures 41-55), have structures that are com- posed of a combination of rubble mound, timber cribs, timber piles, steel sheet piles, concrete caissons, steel cells, concrete caps, and concrete superstructures. The head of the east jetty on the north end of the Keweenaw Waterway, Michigan (Figures 56 and 57), is an old timber crib which is encased
in rubble. For this reason, its response is very similar to that of a purely
46
9.0 FOOT CHANNEL
(12-FT. DEPTH NOT DREDGED-|NACTIVE)
Figure 31.
@ANCHESTER
LOCATION MAP
SCALE IN MILES
paease
NORTH JETTY ~~
SHORE REVETMENT
12 FOOT CHANNE
(15-FT. DEPTH NOT DREDGED- INACTIVE)
CROSS SECTION OF NORTH JETTY
TOP OF MOUND EL.12° RIVER SIDE
7——\_ _M.H.W. EL. 7.8' aprii on U.L.w. EL. 0.0 hl od = EXISTING BOTTOM
CROSS SECTION OF SOUTH JETTY
SCALE IN FEET 1000 2000
Newburyport Harbor Jetties, Massachusetts
47
NEW HAMPSHIRE
i @ cCoNcoro é LOCATION MAP SCALE Im MILES
ganting ground surtoce - E110 9-90 (vores) 7
NORTH JETT Y— SECTION
SCALE im FEET . o >
STONE JETTIES
ry
HAMPTON® HARBOR
8-FT. ENTRANCE CHANNEL
=) Ore
Inner Sunk Rocks
SOUTH JETTY SECTION
SCALE m FEET * ° 3
SEABROOK
SCALE IM FEET
Figure 32. Hampton Harbor Jetties, New Hampshire
48
Table 2 Project Sites in Detroit District with Toe Stability Problems
on Other Than Rubble-Mound Structures
Types of Structures at
Location Project Site* Algoma Harbor, Wisconsin TP** and TC w/CS Areadia Harbor, Michigan SC and TC w/SSP Big Bay Harbor, Michigan RM, SC and SSP Frankfort Harbor, Michigan G5 WP, SP5 SGy SSR25 CS ema Ger Grand Haven Harbor, Michigan Se5 IH, GS eimel EGP Harbor Beach, Michigan TC and CS Holland Harbor, Michigan SSP, TC, RM, TP, CS and CCP Kenosha Harbor, Michigan G5 SSP, SG5 GEP emma CS Kewaunee Harbor, Wisconsin TP, CC, RM, SSP, SS, CCP and CS Lac La Belle Harbor, Michigan SC and SSP Ludington Harbor, Michigan TC Lee SOSP RM, (CGR and ics Manistee Harbor, Michigan Soe, ING, IWe5 ame CS Manitowoc Harbor, Wisconsin We, G65 Woy SSP5 IM, emal ES Menominee Harbor, Michigan and Wisconsin S125 6, GG, Ca? aml CS Milwaukee Harbor, Wisconsin TC, SSP, CC, RM, CCP and CS Portage Lake Harbor, Wisconsin TC, TP and CS Racine Harbor, Wisconsin WG, WP, IMI, SSP, CG, Gee ame GS Saugatuck Harbor, Michigan WG, 12, SSP5 amal CS Sheboygan Harbor, Wisconsin WG, WP, SSP, smal CS South Haven Harbor, Michigan SSP, TC, CCP, and CS St. Joseph Harbor, Michigan AG, S25 GIP ehial CS Sturgeon Bay, Wisconsin TP, TC, SSP, and CS Two Rivers Harbor, Wisconsin TP, TC, SSP and CS White Lake Harbor, Michigan WP, IEC, emal CS
* Not all structure types at each site are experiencing toe problems; how- ever, tabulation presents all structure types existing at each site.
*x TP-timber piles; TC-timber cribs; CS-concrete superstructure; SC-steel cells; SSP-steel sheet pile; RM-rubble mound; CC-concrete caisson; SP-steel piling; CCP-concrete cap; SS-steel sheeting
49
-—\7 =f je f
yi
Note
Projec! depths ond soundings are referred to LWD 600.0 feet | above MWL at Father Point, Quebec (IGLO 1955) (International VICINITY MAP Great Lokes Datum 1955).
"99 'p 2 30 40 S0 Op 70 eo SCALE IN MILES
GOGEBIC COUNTY (Gl eRseeraree
ies 2 MICHIGAN BOAT RAMP=——=P (reel)
; hoe == Suspen Foot Bridge 18 ft. clearance B@LAC K RIVER
CLORURINIE any. Poy O03 Parking Area
eo
SCALE IN FEET
Figure 33. Black River Harbor Breakwaters, Michigan
50
Lakeward End to -5 Ft. Contour
-5 Ft. Contour to +2Ft. Contour
SCALE 10 io) 10 20 FT =
+2Ft. Contour to Landward End
RUBBLE MOUND - BUILT 1957 EAST AND WEST BREAKWATERS
Eos! Breokwoter-825 FI. +
UOTE u es, Breokwoter-555 Ft. +
Figure 34. Details of Black River Harbor Jetties, Michigan
51
LAKE HURON 8 / =I / 7, 16.1.0. EL 576.8' /),’ 0 G o r 0 ” 2 ty! Ue : > STRAITS OF “M AC KIN LA C2 / 2 3 / G2 / & ‘4 s\n S ” 7) Cheboygon Crib Lt Ws \ #L/ Nos N w 40 ° 25 10 o 22 hl 27 2 0 D 2s Little ee SS Sa 10 SS 10 PROJECT DEPTH 2/ FT. ¥ Qs, 2 5 F : -= == ’ oF > As A = a = a = A -~ = - us = - -_ > _ a > -_ -_ sie eae WM we An A
104 P g ae x Atl, 3 TURNING BASIN
PROJECT DEPTH 2/FT.
— = R g z isin & MICHIGAN E y oS S oer ho oR = ‘ 37 soszen fen PROJECT DEPTH (ave INDIANA onIo _ \ VICINITY MAP. “| SCALE OF MULES a s 16 0 PRI h 4 | el a OTE CTs DEPTH 8.5F. 3 3 la] COVER STONE a 5 CHANNEL SIDE WEST
CHANNEL CINE I-TOE STONE
WEST PIER ‘o| 4 TON MIN
LAKE si0g 2TONMIN RUINS OF OLO Ss fae
two EL 576.8"
CORE STONE
MATTRESS STONE
TLEVELARD
EXISTING coma
f>—Lwwc. tock SECTION A-A TYPICAL SECTION OF RUBBLE-MOUND BREAKWATER
SCALE OF FEET
= 5 4
Figure 35. Cheboygan Harbor Breakwater, Michigan
52
COVER STONE PROJECT DEPTH ENTRANCE CHANNEL /2 FT HARBOR BASIN IO FT
_ CHANNEL WIDTH VARIES
EXISTING BOTTOM
TYPICAL SECTION
SCALE OF FEET
VERTICAL
HORIZONTAL
MICHIG
ENTRANCE CHANNEL PROJECT DEPTH 12’
MICHIGAN
MICHIGAN
INDIANA
VICINITY MAP SCALE OF Bai
MICHIGAN STATE HIGHWAY PARK AREA
HIGHWAY les
PUBLIC ACCESS AREA FOR HARBOR
Project depths, saundings ond elevations are referred to
Internationa! Great Lakes Datum (1955) for Lake Huron , elevation Scale of Feet
700
576 6ft above Mean Water Level (MW.L.) at Father Point, Quebec ""p o tao 200300400800 800
Figure 36. Hammond Bay Breakwater, Michigan
53
NOTE: Cover stone 5 ton minimum in types 1 and 1 3 ton minimum in types II ond I
oe Toe stone 7 ton minimum in types I ond I; 5 ton minimum in types If ond I t ee I] wacxway FA ee BB
HARBOR SIDE LAKE SIDE
o TYPES Row
* D> ' G.L.0. El 5768" Ro ——} ae) uy “ 3 ;) CORE STONE Y_ } ia R roe stonk ¢
A
——MaTTRESS STONE a
AKE BOTTOM
TYPICAL GROSS TI
Scole of Fest VICINITY MAP SCALE OF WiLeD
ALCONA COUNTY | A
NOTE Project depths, soundings and elevations are referred to International Great Lakes Datum (1955) for Lake Huron, elevation 576.8f1. above Mean Water Level (MW.L.) at Father Point , Quebec.
SOUTH BREAKWATER EXPANSION OF
STATE BERTHING ~ FACILITIES
3. 15.7 HARGOR BASIN / 10 FEET OEEP on 12.0 15.2 ‘ g ’ Bs ENTRANCE CHANNEL Wo YF te Ob 12 FEET DEEP 1.G.L.0. El. 576.8" Scale of Feet
100 0 100 2 3 5 6 7 6 9 1000 SS
Figure 37. Harrisville Harbor Breakwaters, Michigan
54
(WISCONSIN
rm n Vo w °
EXPERIMENTAL VICINITY | MAP "a" FRAME
BREAKWATER REACH -F
' SCALE OF! MILES REACH-A 480'+
300 40
VILLAGE
PROJECT DEPTHS AND SOUNDINGS ARE REFERRED
TO LOW WATER DATUM 576.8 FEET ABOVE MEAN SCALE OF FEET WATER LEVEL AT FATHER POINT, QUEBEC. |.G.L.D. =Ss=o=————r (1955) (INTERNATIONAL GREAT LAKES DATUM) ° 200 400
Figure 38. New Buffalo Harbor Breakwaters, Michigan
55
12-0" AVERAGE |2 TON COVER STONE ¢
( RANGE 10 TO 16 TONS)
EXISTING —=LAKE BOTTOM
CORE STONE (100-LB. TO1 TON PLACE LARGER STONE ON OUTSIDE)
2-0" BEDDING STONE (I-LB. TO 50-LB QUARRY SPALLS )
16 TON TOE STONE
REACH-A BUILT 1975
¢
AVERAGE 6 TON COVER STONE (RANGE 5 TO 10 TONS )
EXISTING ZLAKE BOTTOM
CORE STONE (I-LB. TO 1,000-LB PLACE LARGER STONE ON OUTSIDE)
2-0" BEDDING STONE (1-LB. TO 50-LB. QUARRY SPALLS )
10 TON TOE STONE
REACH-B BUILT 1975
AVERAGE 4 TON COVER STONE ¢ Leo!
(RANGE 3 TO 5 TONS )
EXISTING LAKE BOTTOM
ra a aor
5 TON TOE STONE 2'-0" BEDDING STONE (1-LB. TO 50-LB. QUARRY SPALLS )
CORE STONE (1|-LB8. TO500-LB PLACE LARGER STONE ON OUTSIDE )
REACH-C BUILT 1975
fe) (e) 10 20
CORE STONE (I* TO 500°) PLACE LARGER STONE OUTSIDE
AVERAGE 3 TON COVER STONE (2 TO 4 TON)
SCALE OF FEET
EXISTING LAKE
2-0" BEDDING STONE (1° TO 5O0°QUARRY STONE)
REACH-D BUILT 1975
Figure 39. Details of New Buffalo Harbor Breakwaters, Michigan
56
1/4 TON MIN. VARIES +9° TO+I2
rors! COVER STONE aac tan
ey \/4 TON MIN 2/3 TOMMIN
ccs TONMIN j Zee: STONE \
Yi 172 TON MIN 11/2 TON MIN,
11/2 TONMIN: 1/2 TON MIN- H { TOE STONE TOE STONE TOE STONE TOE STONE
MICHIGAN
2 MATERIAL TO BE EXCAVATED
LAKE
vote
re
SECTION A-A on Leute NO SCALE ‘VICINITY MAP SCALE
10 0 100 Mi =
SAGINAW
OF CULVERT 8+00
18+00 "2 : ~ : DOWNSTREAM : : LIMIT OF FEDERAL PROJECT-
WEST ng j JETTY /OFT. PROJECT DEPTH : 12 FT. PROJECT DEPTH:
NOTES:
Project depths, soundings & elevations are referred to International Great Lakes Datum (1955) for Lake Huron;
Elev. 576.8 ft, above Mean Water Level at Father Point, Que.
Figure 40. Point Lookout Harbor Jetties, Michigan
57
ueSTyotTW ‘Ssetaqer Aoqzey xPoneTseyD “1H ein3tq
oe 08) Gaim 40 av2s NTOONIT dV¥M ALINIDIA
wo
4 VNVIGNI >
ey 0
m ce :
PCED
ei
ine qunH
| vOH
2901N8
NVOIHIIN INT
EPEDEDSED) 331Sinvn Y
agnviqsi
> Ae OILS 7 a7rg7
“2907 ONN0H¥
NOLNIT9
os
NvaYor 1Sv3}H > ee Gem br
Lo3dSO0ud
4IVHD TIVNS YOF VIAY IOVYOHINY SNVAU3HLVIM
oz «OF 0 1334 40 3195
d¥W NOILV907 : NVOlLHIOIW"”
STOHIIN
4s
A3NSOL3d
58
SAFETY L 33.0° € RAILING r | zh , x as | 46.75!
Z-27STEEL SHEET PILING
Z-27 STEEL SHEET PILING pis P T- SUBSTRUCTURE 1079-80 Hposr
STEEL
SUPERSTRUCTURE 1078-9,1007-9 Bh oag =25.17' PILING 25125) REHAB 190!
35.01' DIA SECTION—-AI -38.75" = = =| SS
| ye ceELL NORTH PIER
_+7.0' BUILT: SUBSTRUCTURE 1679-80 i a F SUPERSTRUCTURE 1676,1667-9
are 7 45.25" REBUILT 1966 bs 1G.L.0._ 5 Bei 76.80 _j—$-28
s-28 |
| STEEL PILING STEEL PILING 1
lJ a | 1 o | i ‘ f | I | | | el eee —--}---- eg ee al HER Kelop SIE Cum hOUNi—vANe NORTH PIER BUILT i966 FE icd SAFETY RAILING icGuo 576 8°
WALKWAY
SECTION-B
NORTH PIER
BuILT 1897 REHAB 1981
SER al : : 276.8"
| e210 z-27 STEEL PILING—\-
STEEL PILING
CHANNEL
-9.5'
Scale of Feet
"B % 2 on 30 40
arpa SECTION-—F SOUTH PIER
ACBUILT 1930 PEPAIRED i966
Figure 42. Details of Charlevoix Harbor Jetties, Michigan
59
uTSUODSTM pue eJOSeUUTW ‘SteqeMYeeIg pue set ef Joqiey AOTAedns-yan[ng “Ey eANsTy
alee
Oboe ae oo
4334 i_31¥95
a
BG «| : S500
ODE
OD Qy Q “e; Lp o Xs "Vos ye = =| = (ol "7 Lal il Oo [oa eel aa
cma)
e LQ A raga Sere
® Q i (| [oa] (es) le) ea} CO onthe! 0
Ol (onl)
0 ON
¥ kL er Ss: Z osh
oS & J Gsose ‘ J 5 ¢/ Vl I ss
60
pay citya fh a -PSacinaw °-
VICINITY MAP SCALE OF MILES 100 50 100
D CAUTION Y sicn
Va ©
MICHIGAN
1.6.4.0. EL. 576.8’
NOTES:
Project depths, soundings and elevations are referred to International Great Lakes Datum (1955) for Lake Michigan, elevation 576.8 ft. above Mean Water Level (M.W.L.) at Father Point, Quebec.
Scale of Feet “€bap 100 ° 100 200 ————————_———S=_—SSSSSSSSS==SS=)
Figure 44. Leland Harbor Breakwater and Jetty, Michigan
61
je DIA 17.5' = 2
eae 3 oO re a ES he ‘ (one fe | Neale YU Sa : Re AGGREGATE (ARIE re = CELL FILLY hal £2. Jo >): 3 ive | | ee
—SP-6 STEEL SHEET PILE
=21.5°
SECTION-B
BUILT: 1936 REPAIRED: 1952 REHABILITATED: 1966
€ 250-1000L 8.! STONE |
S-28 STEEL SHEET PILING —+ ER eee oe = el uJ oO = SECTION-A i¢p) CONSTRUCTED: 1968 8'-0" [sa BS 576.8 a ot Hs ; IPRs a bGLO,
CLOSE PILING
STONE MATTRESS
SECTION-C BUILT: SUBSTRUCTURE: 1936 CONSTRUCTED: 1968
COVER STONE 5 TON MIN.
LAKE
SECTION I -10' SECTION I-8'
1G6.L.D.
STONE MATTRESS
SECTION-D
RUBBLE MOUND BUILT: 1941-3
TOE STONE 7 TON MIN.
EXISTING BOTTOM ~
TYPICAL CROSS SECTION-RUBBLE MOUND BREAKWATER
CONSTRUCTED: 1968
576.8'
LAL.0.
STEEL SHEET PILING
SECTION—E
stv! vn SHORE CONNECTION QUILT! 1946
Figure 45.
62
Scale of Feet
ee
Details of Leland Harbor Breakwater and Jetty, Michigan
SIDE
HARBOR
35
UPSTREAM LIMIT OF
TAT! SUMS Galas FEDERAL PROJECT
32 PROJECT DEPTH USK EGON 35 LAKE > 44 NAVAL ” - be —. @ s \ % 2 %, By a 6 XY 98 CANADA 30 MUSKEGON . 3 w) ra COUNTY 2 Ce) /GLO ELEV 576.8" # 7 2 v q MANISTEE 2 bd iS = S = ww x x s INDIANA VICINITY MAP r SCALE OF MILES A NOTES ; Project depths, soundings and elevations are referred to NORTH Isternational Great Lakes Datum (1955) for Lake Michigan, elevation
MUSKEGON 576.8 ft above Mean Water Level (MW.L.)at Father Point, Quebec.
Scale of Feet 500 o 500 1000 1500 2000 nt
LOCATION MAP
MICHIGAN ‘ SCALE OF FEET 4 ° 3,000 10,000 5,000 ul
Figure 46. Muskegon Harbor Breakwaters and Jetties, Michigan
63
=— 255' TO 195! A -aquarry RUN B -1 To 5 Ton C- 4 TO 5 TON D - 8 To 10 TON _ _576.8'_
IGLO
SECTION -—A NORTH BREAKWATER
out 1930-1
3 veal SECTION-B | NORTH BREAKWATER
BuILT 1930-1
SAFETY malenas| OUTER 54 LINEAR FEET OF
SECTION "C" CONSISTS OF 2 RECTANGULAR CAISSONS
Wow We WNW
SECTION — SOUTH BREAKWATER But SUBSTRUCTURE 1927-30 SUPERSTRUCTURE 1927-30
10. i i. it ne 3 3 3 —+71' - P
SAFETY RAILING
[4 fo} a a < : Lye = VS NY oH coRECTION TE. SECTION — O ovicT suastmucture 1927-30 SOUTH BREAKWATER SUPERSTRUCTURE (3877/39 i ounT BUOSTRUCTURE 1927-30 . % ° . SAFETY RAILING tT gupERSTRUCTURE 1027-30 liam 1
SAFETY RAILING
LAKE SIDE
ene Toe STONE SEGTION=G
SOUTH BREAKWATER
BUILT SUBSTRUCTURE 1926-30 SUPERSTRUCTURE 1930 UNDER CONSTRUCTION 1966
MATTRESS STONE
SECTION-F
SOUTH BREAKWATER BUILT: SUBSTRUCTURE 1926-30 SUPERSTRUCTURE 1930 UNDER CONSTRUCTION 1966
SAFEVY RAILING Scale of Feet 10 ° 10 20 yo 40 576.8' eee —$—— ees: }
SECTION-H SOUTH BREAKWATER
BuILT SUBSTRUCTURE 1920-30 SUPERSTRUCTURE 1930
Figure 47. Details of Muskegon Harbor Breakwaters, Michigan
64
HARBOR
OR
CHANNEL
SAFETY RAILINGS (TYP.) + 8.5'
Z IML, i
PRS
Scale of Feet 10 te} 10 20 30 40
TYPICAL SECTION
NORTH PIER
BUILT: SUBSTRUCTURE 1906 SUPERSTRUCTURE 1933-4 REHAB. 1980
S.R 1904 SECTION - N LOS) SOUTH PIER BUILT: SUBSTRUCTURE 1875 SUPERSTRUCTURE 1932-3 REHAB. 1966
-45.5
TYPICAL SECTION - O SOUTH PIER
BUILT: SUBSTRUCTURE 1668,96°99 SUPERSTRUCTURE (932-3 REHAB 1966
Figure 48. Details of Muskegon Harbor Jetties, Michigan
65
1GL.D EL. 576.8"
CHARLES MEARS STATE
DUMP GND. 1-1/4 HI, & E
@ 270° AZ
MAINTAINED TO 12FEET
SUBM. CABLE
UPSTREAM LIMIT OF FEDERAL PROJECT
LIMITS OF APPROVED PROJECT-
NOTE: Work remaining to be done shown thus:
Project depths,soundings,and elevations are referred to International Great Lakes Datum (1955) for Lake Michigan, elevation 576.8 ft. above Mean Water Level (M.W.L.) at Father Point, Quebec.
Scale of Feet
500 ———
INDIANA '
VICINITY MAP
Scole of Miles CONCORD ‘90 5 !
N T WA
EOWELIE STREET
STREET
FIRST STREET
il
SECOND STREET
THIRD STREET
Figure 49. Pentwater Harbor Jetties, Michigan
66
SIDE
CHANNEL
2470 28°
+7"
SECTION— A
NORTH PIER BUILT SUBSTRUCTURE 1872,99 SUPERSTRUCTURE 1938 BUILT
SECTION—- D
NORTH PIER
SASBNAR|
SECTION— B
SECTION
ar 576.8" (esmore= = — FH
SZLERGE
SECTION — C
N. 8S PIER NORTH PIER NP SP BUILT SUBSTRUCTURE 1870,98899 SUBSTRUCTURE 1870,98499 869,99 SUPERSTRUCTURE 1938 SUPERSTRUCTURE 1938 1938
=JE SECTION -G
NORTH PIER SOUTH PIER BUILT SUBSTRUCTURE 1870,98 6 99 BUILT SUBSTRUCTURE 870,898 BUILT SUBSTRUCTURE 1887,9 SUPERSTRUCTURE 1938 SUPERSTRUCTURE (938 SUPERSTRUCTURE 1938
+7 576.8" SOUTH PIER SOUTH PIER BUILT SUBSTRUCTURE 1870,99 BUILT SUBSTRUCTURE 1868,99 SUPERSTRUCTURE 1938 SUPERSTRUCTURE 1938 10-0" 4 TOE STONE ‘ 9 TON MIN a i 2 es LINE 1 Scale of Feet MATTRESS STONE ad 10 0 10 20 30 a0 / \ (2820-82828 = ————— —— ——
TYPICAL RUBBLE MOUND SECTION
BUILT 1959
Figure 50.
Details of Pentwater Harbor Jetties, Michigan
67
ST.
UPSTREAM LIMIT OF FEDERAL PROJECT 6
WISCONSIN ST. FRANKLIN
GRAND AV
U.S.141 & ST HWY. 32 : Y
RIVER STATES
(o}
IPSTREAM LIMIT OF FEDERAL PROJECT
MICHIGAN
27
27 PROJECT DEPTHS AND SOUNDINGS ARE REFERRED TO LOW WATER DATUM 576.8 FEET ABOVE MEAN WATER LEVEL AT FATHER POINT, QUEBEC. 1.GL.D. (1955) (INTERNATIONAL GREAT LAKES DATUM )
SCALE OF FEET I =
i = 200 400 600 600 1000
VICINITY | MAP
SCALE OF NILES CoAT 1 MILWAUKEE o = ct
4
Figure 51. Port Washington Harbor Jetty and Breakwaters, Wisconsin
68
SIDE
HARBOR
SUPERSTRUCTURE ON SOUTH BREAKWATER 1-6 BELOW TOP OF CAISSON.
NOTE: OUTER 54 LINEAR FEET OF SECTION A, NORTH BREAKWATER, CONSISTS OF TWO RECTANGULAR CAISSONS.
N NORTH & SOUTH BREAKWATER NB SB BUILT’ SUBSTRUCTURE 1934 1936
SUPERSTRUCTURE 1934 1936
CAP STONE GROUTED IN PLACE
+7.5'
PILES ARCH CELL TYPE
cd ro oop 9, P0004 aw 2Naa0.60-7--S8sle
i} -19'To-27' SECTION-B SECTION-D NORTH BREAKWATER NORTH BREAKWATER BUILT: SUBSTRUCTURE 1934 BUILT: 1934 SUPERSTRUCTURE 1934 +7.0'
STEEL SHEET PILES
BUTTRESS, SINGLE WALL TYPE Lw.o 13:1 SLOPE t1 SLOPE i gl ig LUA = To-17 FRO PPPOE PPS SECTION-E NORTH SHORE CONNECTION SES VOWS Quit 34 NORTH BREAKWATER SCALE OF FEET BUILT: SUBSTRUCTURE 1934 SUPERSTRUCTURE 1934 L} ° 0 20 %»
Figure 52. Details of Port Washington Harbor North and South
Breakwaters, Wisconsin
69
KF 2
teres wig
7 7 SAND & EARTH ty FILL
Beye ™ en ee) i =| (i an H Sy a j | N Nu
uJ (2) 7) SECTION-F SECTION=-G
x NORTH STUB PIER NORTH STUB PIER
BUILT: 1940 BUILT: 1940 (eo) ao a ‘
6 < +8.7- lr a x= —_ —L.W.D. 576.8 53% Sa a eS J G NY > fo) & e, ‘a> 0 Ce 4 £ON Aptech OF erSZ Orn
oc) eat TH by YB Weamleat.aet 4 WJ SECTION-I z Zz WISCONSIN ELECTRIC POWER CO. < x U
SECTION —J
SOUTH BREAKWATER BUILT: 1936
SCALE OF FEET [=o 50S eS Se ee SS) $ [*) Le) 2 30 4
Figure 53. Details of Port Washington Harbor North Jetty and South Breakwater, Wisconsin
70
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rubble-mound structure. The remainder of the structures at Keweenaw are tim- ber crib with some rubble and steel sheet piles.
31. In general, the rubble-mound structures in the Detroit District that show toe stability problems have shown the results of this problem through damage to the upper slope and crown armor. It is not known defi- nitely, but it is expected that the toe damage is a combination of toe armor instability combined with foundation scour and undermining of the structure toes. Repair to a structure is carried out by filling the scour holes with stone and then reshaping and repairing the structure's armor stone layer(s). Some repairs have been successful thus far, while other areas require frequent
repair work.
75
PART III: DISCUSSION
32. In general, there appear to be three major problem areas with rubble-mound coastal structure toes. One of these pertains to the proper sizing and placement of toe buttressing stone. The purpose of the buttressing stone is to stabilize the onslope armor by preventing downslope slippage of the armor layer. For these stone to function properly, they must be of suf- ficient weight and placed in such a way that they are stable in a wave and/or flow environment. The second major problem area concerns toe berms. A toe berm's primary function is to protect a structure placed on an erodible bottom from being undermined by wave- and/or flow-induced scour and to resist down- slope slippage of the armor. For a toe berm to function properly it, like the toe buttressing stone, must be composed of materials and be constructed in a geometry that will be stable in the incident wave and/or flow environment. Thirdly, toe buttressing stone and toe berms are susceptible to damage and failure when placed on an erodible bottom material. The stone may be sized adequately for the level of energy to which they are exposed, but the exposed bottom material at the outer perimeter of the structure may readily erode and/or an inadequately designed bedding material may allow the foundation material to migrate through it and the toe berm armor. Either one or both of these factors can result in the undermining and displacement of stone that were otherwise able to withstand the wave and flow environment but failed because of undermining induced displacement.
33. In summary, a toe failure may be the result of any one or a combi- nation of the above. Guidance exists for proper design of bedding (filter) layers based on soil types, but very little guidance is available for the siz- ing and geometries needed for the proper design of toe berms and buttressing stone for incident wave environments. Most work done by the districts in these areas is based on field experience and engineering judgment. A scouring bottom is a problem in itself. No matter how well a toe is designed, if the local bottom materials (sands, silts, clays, etc.) are exposed to sufficient energy levels for scour to occur, the toe of the structure is doomed to fail- ure unless the toe berm is extended out to a point where the energy levels are below those which will initiate scour. In most cases this is not practical or feasible. In these instances, sufficient toe berm material, that in itself is
stable for the wave and/or flow environment must be placed so that as the
76
structure toe undermines, the berm material can slough off into the scour hole. This will provide some armoring to reduce the rate of scour and thus
increase the usable, or functional, life of a structure.
77
PART IV: CONCLUSION
34. Based on extensive discussions with Corps division and district personnel and after the review of prototype experience relative to rubble- mound toe stability problems, it is concluded that design guidance is seriously needed on the proper sizing and placement configurations needed to provide adequate buttressing stone and toe berms for rubble-mound coastal breakwaters and jetties. Once it is understood how to design toe berms and buttressing stone for a range of water levels and wave conditions, these designs need to be incorporated into a test series that addresses the way in which varying toe geometries influence localized scour. The latter will pro- vide some qualitative insight into how a toe berm can be configured or
positioned to reduce the quantity and/or rate of localized foundation scour.
78
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