Table 37 (Concluded) 



Date (s) Construction and Rehabilitation History 



1965 The lakeward end of the shore arm extension (Figure 97, Section B3) 



was capped with a concrete superstructure. The breakwater included a 

 parapet installed at an el of +7.0 ft Iwd (Figure 97, Section B3) . 

 Rubble (7-ton average) was added on each side of a portion of the 

 inner breakwater (Figures 97 and 98, Section P) , and the north pier 

 (Figures 97 and 98, Section J) was repaired. The north pier and por- 

 tions of the inner breakwater (Figure 98, Sections J, M, and N) were 

 modified by the Metropolitan Sanitary District of Greater Chicago. 

 This modification included the creation of wider structures by con- 

 structing a wall, filling voids with clay, and installing stone 

 (Figure 98) . 



1979 A site inspection of the structures indicated cracks in the parapet 



walls of the shore arm extension (Figure 97, Sections A, Bl, and B3) . 

 In Section B2 of the shore arm extension fill stone had settled; and 

 cap stone was either settled, broken, or missing in some areas. 

 Spalling at construction joints and along the edges of the exterior 

 breakwater (Figure 97, Sections C, D, and E) was observed. Along 

 Section E the timber structure in some places had deteriorated, and 

 fill stone was missing. Cover stone was missing and/or deteriorated 

 along Sections F and G (Figure 97) of the exterior breakwater 

 southerly extension. Spalling at construction joints and along the 

 edges of the inner breakwater (Figure 97, Sections M, N, P, and S) 

 was noted. Maintenance of the breakwaters was performed subsequent 

 to this inspection. 



1981 A condition survey of the structures indicated that the shore arm 



extension (Figure 97, Sections A, Bl, B2, and B3) were in good con- 

 dition. The exterior breakwater (Sections C, D, and E) was also in 

 good condition except for an area in Section E where failure of the 

 crib substructure resulted in the superstructure's caving in. The 

 exterior breakwater southerly extension was in good condition at 

 Section H; however, in many locations along Sections F and G concrete 

 fill between the armor stone had been lost. Also, many of the stones 

 were split in pieces and disintegrating. In many locations stone was 

 low (either lost or subsided) . The north pier was in good condition 

 except for minor spalling and weathering of concrete. The inner 

 breakwater (Sections K, L, M, N, U, 0, P, R, and S) was in good con- 

 dition except for Sections N, U, and where the concrete base slab 

 was severely spalled and eroded with reinforcing bars exposed at the 

 edges in many locations. 



1983 Rubble-mound areas of the southerly extension (Figure 97, Sections F 

 and G) were rehabilitated, and maintenance of the other faults noted 

 in the condition survey of 1981 was performed. 



1986 The structures are presently considered to be in good condition. 



(Sheet 3 of 3) 

 162 



