Experimental and analytical investigations on tension stiffening of reinforced engineered cementitious composites members

Abstract

Experimental and analytical investigations on the performance of reinforced ECC members in tension were studied in this paper through direct tension load. The applied load and elongation of members were measured during testing. The number and width of major cracks in specimens were determined at failure. The influences of the cross-sectional dimension and steel reinforcement diameter on the tension stiffening of members were investigated. Comparisons were made among reinforced ECC members with different cross-sectional dimensions or reinforcement diameters in terms of the cracking load, ultimate load and ultimate strain. Experimental results showed that the load-deformation relationship of reinforced ECC members could be divided into three stages, namely, initial elastic stage, multiple cracking stage and major cracking stage. In addition to experimental tests, an analytical model for the tension stiffening behaviour of reinforced ECC members was proposed. The interaction between ECC and steel reinforcement was considered at different stages in this model. Comparisons with experimental data suggest that the analytical model could accurately predict the relationship between load and deformation of reinforced ECC members. The cracking load obtained by this model is conservative as compared with test data. Based on the validated analytical model, a parametric study was carried out on the effects of reinforcement ratio and bond stress on tension stiffening of reinforced ECC. The direct tension tests and analytical results in this study can be used to predict the load and deformation behaviour of reinforced ECC members in tension.