Table 37 



Chicago Harbor Structures 



Chicago, Illinois 



Date(s) Construction and Rehabilitation History 



1874 Construction of the 4,338-f t-long northern portion of the inner 



breakwater (Figure 97, Sections K, L, M, N, 0, and U) was completed. 

 The breakwater was constructed of stone-filled timber cribs on a 

 stone base. It was 30 ft in width (Figure 98, Sections K through 

 and U) . 



1876 Construction of the 960-ft-long north pier (Figure 97) was completed. 

 The pier was of stone-filled timber crib construction (Figure 98, 

 Section J). It was built on a stone base and was 30 ft in width. 



1880 The 2, 544-f t-long southern portion of the inner breakwater (Fig- 

 ure 97, Sections P, R, and S) was constructed. These structures also 

 were stone-filled timber cribs built on a stone base (Figure 98, Sec- 

 tions P, R, and S) . The southern 2,244 ft of breakwater was 16 ft in 

 length (Sections R and S) , and the remaining 300-f t portion (Sec- 

 tion P) was 30 ft in width. 



1889 Construction of a 5, 321-f t-long extension breakwater (Figure 97, Sec- 

 tions C, D, and E) was completed. This was a stone-filled timber 

 crib breakwater (Figure 99, Sections C, D, and E) built on a stone 

 base with a 30-ft width. 



1908 The north pier was capped with a concrete superstructure (Figure 98, 

 Section J) with a crest el of about +11 ft Iwd. 



1917 A 2, 250-f t-long shore arm extension (Figure 97, Sections A, Bl , B2 , 

 and B3) and a 2, 227-f t-long southerly extension (Figure 97, Sec- 

 tion F) of the exterior breakwater were constructed. The shore arm 

 extension was constructed with stone-filled timber cribs (Figure 99, 

 Sections A, Bl , B2 , and B3) built on a stone base. The shoreward 

 750-ft-length (Section A) was 24 ft in length, and the remaining 

 breakwater (Sections Bl , B2 , and B3) was 30 ft wide. The southerly 

 extension was a rubble-mound breakwater with 1V:1.5H side slopes 

 (Figure 99, Section F) . Its crest el was +8.44 ft Iwd, and armor 

 stone sizes were 3 tons (minimum) from el +1.72 ft Iwd to the lake 

 bottom and 7 tons (minimum) from el +1.72 to +8.44 ft Iwd. 



1920 An additional 1 ,532-f t-long portion of the southerly extension (Fig- 

 ure 97, Section G) was constructed. The extension was a rubble- 

 mound structure with a crest el of +6.1 ft Iwd and 1-V:1.5-H side 

 slopes (Figure 99, Section G) . Armor stone sizes ranged from 3 tons 

 (minimum) from el 0.0 ft Iwd to the lake bottom to 7 tons (minimum) 

 from el 0.0 ft Iwd to +6.1 ft Iwd. 



(Continued) 



(Sheet 1 of 3) 



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