Ultimate strength of pre-tensioned I beams in combined bending and shear

This paper summarizes conclusions drawn from tests on pre-tensioned I beams without web reinforcement. The factors that govern the ultimate strength of such beams in combined bending and shear, and their influence on the mode offailure, cracking, and the ultimate load are studied. A simple theoretical analysis is presented for evaluating the ultimate strength of I beams failing by crushing of the web. The theoretical expression is compared with the test results of the author and of other workers and shown to result in a fairly safe and reasonably accurate estimate of the ultimate load. An empirical equation is suggested to determine the inclined cracking load and the collapse load for diagonal tension failures.