Erection stresses, allowable

AISC specifications for the design fabrication and erection of structural steel for buildings shall govern the design of these steel structures (for AISC specifications, see the current edition of Steel Construction Manual of the American Institute of Steel Construction). Only Part I of the AISC manual, the portion commonly referred to as elastic design, shall be used in determining allowable unit stresses use of Part II, which is commonly referred to as plastic... 

For AS ME Code vessels the allowable compressive stress is Factor B. The ASME Code, factor B. considers radius and length but does not consider length unless external pressure is involved. This procedure illustrates other methods of defining critical stress and the allowable buckling stress for vessels during transport and erection as well as equipment not designed to the ASME Code. For example, shell compressive stresses are developed in tall silos and bins due to the side wall friction of the contents on the bin wall. 

This e( uatiou may lie modified to fit erection and other coiulitions not <-ovenMi by the liini tat ions above. To del ermine. V, the ilistance at which the induced tensile slres.s is equal to the allowable stress. /gUo . may lie subsliiuled... 

Suppose a designer is asked to design a shelf that is required to withstand a continuous load for 1000 hr. If after 1000 hr of continuous loading, the deformation is not to exceed 2 percent, what should be the maximum allowable stress To solve this problem, the designer hrst needs to erect an ordinate on the basic creep strain versus time curve at 1000hr, as shown in Figure 2-29. From this curve, the designer can determine the strain value at different stress levels. These values allow the... 

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