Analytical investigation of hybrid composite precast beams with modified strain compatibility for entire history of nominal flexural capacity

Abstract

SummaryThe strain compatibility documented in Chapter I of the American Institute of Steel Construction 360‐10 (AISC, 2010) was modified to provide accurate analytical solution for hybrid composite precast beams. In the proposed method, locations of neutral axis of the section are investigated to formulate all possible equilibrium equations of stress fields of composite sections. The only neutral axis satisfying all stress fields is then found for composite sections for entire loading history including yield and maximum load limit state and between those limit states. Finally, the nominal moment capacity of hybrid composite precast beam is calculated based on the correct neutral axis. Experimental study was conducted to verify the accuracy of the proposed method. The test results for hybrid composite precast beams agreed very well with the analysis results. The capacity difference between them is less than 4.8%. This study also compares the proposed design method with the conventional strength addition method, showing that the conventional method underestimated structures leading to over‐design. It was found that the new approach predicted the behaviors of hybrid composite precast beams more accurately than the conventional methods. Copyright © 2015 John Wiley & Sons, Ltd.