Design of Slender Webs Having Rectangular Holes

Abstract

The ultimate shear capacity of a plate girder having a central rectangular web‐hole is shown to be the sum of three contributing factors: (1) The elastic critical load of the web; (2) the load carried by the membrane tension in the web in the post critical stage; and (3) the load carried by the flanges. The elastic critical load in shear is evaluated by using an approximate formula derived from a finite element analysis. The load carried by membrane tension is calculated using the Von Mises criterion and a suggested mean value for the angle subtended by it with the longitudinal axis of the girder; the contribution of the flanges is calculated from their plastic moment capacities. The proposed method is shown to be satisfactory by comparing the predictions obtained from it with the corresponding test observations. An ultimate load method of designing flat strip reinforcement is proposed and is aimed at restoring the strength of the web to a value that would have been obtained had the hole not been cut. The suggested design procedure is shown by a worked example.