Experimental Stress Analysis

3

Fixed Beams

3.1 INTRODUCTION

Fixed or built-in beams are commonly used in building construction because they possess high rigidity in comparison to simply supported beams. When a simply supported beam of length, L, and flexural rigidity, EI, is subjected to a central concentrated load W, the maximum bending moment (BM) in beam is (WL/4), maximum deflection in beam is WI³/48EI, and maximum slope in beam is ±WL²/16EI but if the ends of the same beam are fixed (i.e. built in walls), maximum bending moment is reduced to (WL/8), maximum deflection is reduced to WL³/192EI, and maximum slope is reduced to ±WL²/32EI, If the allowable bending stress for the fixed beam is taken to be the same as for simply supported beam, then the load carrying capacity ...