Page 335 - Forensic Structural Engineering Handbook
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10.24 CAUSES OF FAILURES
(a)
20 ft
20 ft
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
101
100 29
99 30
98 N
97 31
32 First
96 collapse
95 33
94 34
93
92 35
91 36
37
90
89 Three tiers of tiebacks Note: Soldier beam third tier was not Three tiers of internal bracing 38
88 in the internal support system. 39
87 40
86 41
85 42
84
83 43
82 44
81 Scale : 1" = 30' 45
80
79 46
78 47
77 Two tiers of tiebacks 48
76 75 74 73 72 71 70 6968 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
20 ft
30 ft
Second collapse
(b)
FIGURE 10.3 Washington excavation. (a) Overall view of the collapsed site—look-
ing toward the east. (b) Extent of initial and second collapse. (From OSHA
Investigation of November 19, 1990 Excavation Collapse at 14th & H Streets, N.W.,
Washington.)
