The effect of strain lag for the flexural enhancement of RC beams strengthened by HMRE under secondary load

• Published in: Engineering structures Vol. 316; p. 118612
• Main Authors: Wei, Yaoxin, Li, Ke, Xu, Chaoyang, Wang, Ling, Fan, Jiajun, Zhu, Juntao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2024
• Subjects: Engineered cementitious composite (ECC); Flexural performance; High-strength stainless steel wire rope (HSSSWR); Secondary load; Strain lag; Strengthening; Strain lag; Strengthening; Secondary load; High-strength stainless steel wire rope (HSSSWR); Flexural performance; Engineered cementitious composite (ECC)
• ISSN: 0141-0296
• DOI: 10.1016/j.engstruct.2024.118612

This paper presents experimental, numerical and theoretical studies on damaged reinforced concrete (RC) beams strengthened with high-strength stainless steel wire rope (HSSSWR) meshes reinforced engineered cementitious composite (ECC), in order to evaluate the influence of strain lag caused by secondary load on the strengthening effect. Four-point bending tests were first performed to investigate the failure mechanism of HSSSWR meshes reinforced ECC (HMRE) strengthened RC beams under secondary load. Then the parameters were comprehensively studied by finite element (FE) simulation. The results show that even under secondary load, the HMRE can still exhibit good crack-control capacity on concrete and gave significant enhancement in the flexural performance of RC beams. The strain lag of the strengthening layer, which resulted in inadequate utilization of its strength, was intensified with an increase in the initial load level or reinforcement ratio of the longitudinal steel bars, but was mitigated as concrete strength, ECC thickness, reinforcement ratio of HSSSWRs, or HSSSWR ultimate strength increased. Finally, a calculating model was proposed for predicting the bearing capacity of the damaged RC beams strengthened with HMRE, considering strain lag caused by secondary load. •Experimental and numerical studies on RC beams with the initial load strengthened by HMRE were conducted.•The effect of strain lag in HMRE was fully analyzed and discussed.•A calculation model was proposed for predicting the bearing capacity of strengthened beams, considering strain lag.