Page 201 - Forensic Structural Engineering Handbook
P. 201
THE ENGINEERING INVESTIGATION PROCESS 6.3
FIGURE 6.2 An example of snow loading far in excess of building code design criteria.
FIGURE 6.3 Lack of adequate temporary bracing caused the collapse of these long-span wood
roof trusses during construction.
It is critical to determine time-dependent effects that have impacted the structure’s per-
formance. These time-dependent effects include environmental loads (which, by definition,
change with time) as well as other live loads, and in-place material properties like deteriorat-
ing concrete compressive strength, various concrete degradation processes, corrosion of steel
elements, creep and rot of wood elements. Fatigue cracks in steel, for example, can propagate
undetected until they initiate a collapse without any other warning signs of distress.
