Recent Approaches to Shear Design of Structural Concrete

It is not correct to state that the collapse of the Wilkins Air Force Base depot building occurred without warning. The structure was known to be extensively cracked in shear well before the collapse, and it is the discusser’s understanding that some beams in the building were already being braced with shoring consisting of various wooden poles. The observer was in fact looking for additional trouble at the time of the collapse, although it must be argued that the fact that the failure occurred while he was present was coincidence. The record of cracking for the particular design at Wilkins was so bad that a revised design had already been prepared and was used in some similar buildings. The January 1957 issue of the ACI Journal had several articles dealing with the failure and with the repairs to other structures of the same group that had not failed but that were showing significant shear cracking.