Development mechanism of plastic hinge in reinforced engineered cementitious composite beams under monotonic loading

摘要

Engineered cementitious composites (ECCs) are materials featuring strain-hardening behavior with the formation of multiple cracks. When ECC is incorporated in structural applications such as beam, it is expected to significantly improve their mechanical performance. In this study, finite element analysis is performed to investigate the characteristics of the plastic hinge in reinforced ECC (RECC) beams. The plastic hinge lengths of RECC beams, involving rebar yielding zone, concrete crushing zone and curvature localization zone, are found to be much larger than those for reinforced concrete (RC) beams. Based on the above results, parametric studies on the plastic hinge lengths in RECC beams are conducted to study the influences of the tensilecompressive properties of ECC, yielding strengthhardening modulusultimate strain of tensile reinforcement, tensilecompressive reinforcement ratio and beam size. This theoretical study has shown that the existing empirical models for RC beams' plastic hinge length are not applicable to RECC beams which exhibit much longer plastic hinge length. A new empirical equation for predicting the plastic hinge lengths of RECC beams is thus proposed.