Table 15 



Grand Traverse Bay Harbor Structures 



Grand Traverse Bay, Michigan 



Date(s) Construction and Rehabilitation History 



1949- Construction of two piers at the site (Figure 39) progressed during 

 1951 this time. The north pier was 707 ft long, and the south pier was 



567 ft long. The shoreward portions of the piers (Figures 39 and 40, 

 Sections D and E) were built with steel sheet pile at an el of 

 +6.5 ft Iwd. They were backfilled with sand except at the top where 

 a rock surface was installed. The 111-ft-long section of the north 

 pier at the water's edge (Figures 39 and 40, Section C) was a sand- 

 filled sheet-pile structure. It was 12 ft wide with an el of +8 ft 

 Iwd. The structure was capped with 2-ton (minimum) stone and 3-ton 

 (minimum) stone placed on the lakeside to an el of approximately 

 +4.5 ft Iwd. A 307-ft-long section of the north pier, and the lake- 

 ward portion of the south pier (Figures 39 and 40, Section B) were 

 built with steel sheetpiling. The structure was sand filled with a 

 concrete cap installed at an el of +6 ft Iwd. The pier was 11.5 ft 

 wide, and stone toe protection was included. The outer end of the 

 north pier (Figures 39 and 40, Section A) was of similar construction 

 except it was capped with 2-ton (minimum) stone at an el of +8 ft Iwd 

 and was 14.5 ft wide. 



1964 Construction of a 164-ft-long north pier extension was completed 

 (Figures 39 and 40, Section F) . Cellular steel sheet piles with 

 diameters of 37.3 ft were used. These cells were sand filled with 

 2-ft-thick rock (filled with grout) caps. The el of the cellular 

 structures was +8 ft Iwd, and stone toe protection was installed on 

 the lakeward side. 



1975 A 180-ft-long cellular sheet-pile north breakwater extension was com- 

 pleted (Figure 39) . 



1979 An inspection of the piers indicated that repairs were needed on the 

 cap of the north pier at the intersection of the cell and Section A. 

 Additional repairs were needed on the outer three cell caps. 



1981 The north pier caps. Identified in need of repair in 1979, were 

 repaired. 



1983 An inspection of the structures revealed that the cap on the south 

 pier had settled as much as 6 in. in some areas. The outer cell of 

 the north pier also had settled (up to 14 in.) and had several large 

 cracks. Additional riprap stone also was required at Section C. 

 Repairs to the structures were subsequently made. 



1986 The piers presently are in good condition. An aerial view of Grand 

 Traverse Bay Harbor structures is shown in Figure 41. 



71 



