ABSTRACT
An anomaly was found during this exercise which led to exhaustive checking of these calculations. A loadcase had been found which gave a stress of 6kN/mm in the weld connecting the smaller infill member to the top boom. However the maximum stress in the weld connecting the same member to the arch was only 2kN/mm. It was eventually established that the three components of force causing a moment on the weld were additive at the top, while one component had a relieving effect at the bottom. Detailed checks on problems of this nature are vital for a structure where it is impossible to do simple hand calculations to validate the computer analysis.
