Composite behavior of wall-beam structure

Abstract

Load bearing masonry wall supported over lintels, grade beams, floor beams etc. when subjected to superimposed vertical load act compositely with the supporting member. The wall contributes in stiffening the structure, the effect of which is reduced dimension and saving in material of bottom beam. An experimental investigation has been performed to study this composite action between wall and the supporting beam. In this experimental program a total of twelve specimens under four groups are tested. Out of these twelve specimens nine are composite wall-beam and the remaining three are reinforced concrete beams which are identical to the bottom beams of the composite wall-beam of the test series. Different height to length ratio of the wall beam has been considered in the study by varying the length of wall, while keeping the height of wall and beam constant. Different bond pattern in the brickwork of wall-beam structures and the provision of reinforcement in the brickwork are also considered in this study. From the analysis of the test results, the effect of bond pattern of brickwork, inclusion of vertical reinforcement in the wall and H/L ratio on the failure load and deflection of composite wall-beams are discussed. The test results along with the analysis using existing formulae are also reported in this study. Load carrying capacity of composite wall-beam structure is predicted by considering the wall-beam section uncracked and ultimate state of failure. The formulae for reinforced concrete' beam and deep beam have been used with slight modification for prediction of the load. An analytical method is also suggested for the prediction of load carrying capacity of composite wall-beam. The predicted load using this suggested method is compared with the experimental loads.