Safety evaluation of cracked concrete structures with crack length index

Abstract

Cracks always pose a great threat to the heath of concrete structures, and safety evaluation becomes an essential task during the life cycle of these cracked structures. In this study, a new safety evaluation method of cracked concrete structures is proposed based on the Boundary Effect Model (BEM). Firstly, the fracture theory is introduced to predict the constant fracture properties of concrete materials regardless the effect of specimen size and crack length. Then, the non-linear relationship between bearing capacity and crack length of cracked concrete beams is established. Next, the established equation is verified by three groups of three-point bending test results with different specimen sizes and crack lengths. Finally, combined with relevant standard, the safety evaluation method is proposed using crack length as an index. Comparing with the traditional methods adopted in standard, the newly-developed methods which use crack length as a safety evaluation index appears to be more convenient and accurate.