COMPRESSIVE MEMBRANE ENHANCEMENT IN TWO-WAY BRIDGE SLABS

THE RESULTS OF A STUDY OF THE ULTIMATE STRENGTH OF ISOTROPICALLY REINFORCED, CONTINUOUS TWO-WAY BRIDGE SLABS, SUBJECTED TO CONCENTRATED WHEEL LOADS, ARE REPORTED. A THEORY IS PROPOSED FOR PREDICTING THE ULTIMATE STRENGTH OF SUCH SLABS, WHICH INCLUDES THE ENHANCEMENT IN STRENGTH DUE TO COMPRESSIVE MEMBRANE ACTION. THE THEORY WAS CONFIRMED IN TESTS DONE ON DIRECT BRIDGE MODELS. THE MAIN VARIABLES CONSIDERED ARE REINFORCEMENT PERCENTAGE, SHEAR SPAN, AND BOUNDARY CONDITIONS. IT IS SHOWN THAT THE PRESENT ELASTIC DESIGN PROCEDURES ARE TOO CONSERVATIVE, AND THAT THE PROPOSED METHOD IS A MUCH MORE ECONOMICAL ONE, WHICH CAN BE SAFELY APPLIED. /ACI/