基于改进MCFT的GFRP-RC梁抗剪承载力分析  

ANALYSIS OF SHEAR CAPACITY OF GFRP-RC BEAMS BASED ON IMPROVED MODIFIED COMPRESSION FIELD THEORY

作　　者：宋博[1] 金浏[1] 陈凤娟 杜修力[1] SONG Bo;JIN Liu;CHEN Feng-juan;DU Xiu-li(The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市减灾与防灾防护教育部重点实验室,北京100124

出　　处：《工程力学》2023年第8期36-46,共11页Engineering Mechanics

基　　金：国家重点研发计划项目(2018YFC1504302);国家自然科学基金项目(51822801)。

摘　　要：通过三维细观数值模拟方法,建立了大尺寸GFRP筋混凝土(GFRP-RC)梁剪切破坏力学分析模型,研究了剪跨比、纵筋率和梁深对GFRP-RC梁裂缝倾角及荷载-位移曲线的影响规律。并以修正压力场理论(MCFT)为基础,根据剪切裂缝宽度沿梁深变化的特点,建立了考虑裂缝宽度沿梁深变化的平均裂缝宽度计算模型,提高了修正压力场简化公式的计算精度。鉴于此,提出能考虑剪跨比及大尺寸影响的无腹筋GFRPRC梁抗剪承载力计算方法,并通过213组试验和模拟数据验证其合理性及准确性。与规范计算结果相比较,结果表明,本文所建立的平均裂缝宽度计算模型合理有效,基于此得到的MCFT简化公式能较好的预测大尺寸无腹筋GFRP-RC梁的抗剪承载力,为GFRP-RC梁的抗剪设计提供了理论参考和方法。Through a 3D meso-scale numerical simulation method,the shear failure mechanical analysis model for large-sized GFRP reinforced concrete(GFRP-RC)beams was established.The influences of parameters of major importance on the crack angle and on P-Δcurve of GFRP-RC beams was discussed through this model,such as shear span ratio,longitudinal reinforcement ratio,and beam depth.Based on the modified compression field theory(MCFT),a calculation model for the average crack width was established,considering the variation of crack width along the beam depth,which improves the calculation accuracy of the simplified formula for MCFT.A design method was proposed for shear bearing capacity of GFRP-RC beams without stirrups considering the influences of the shear span ratio and size effect on the crack angle and on shear capacity.The model proposed is validated by comparing with the corresponding experimental measurements of 213 GFRP-RC beams,and with the consideration of the average crack width and size effects,utilizing the model proposed will garner the satisfactory results with remarkable higher accuracy compared to current used design codes.Therefore,the improved MCFT model proposed provides a theoretical reference for the shear design of GFRP-RC beams.

关 键 词：大尺寸GFRP筋混凝土梁 改进MCFT 抗剪承载力 细观模拟 尺寸效应 

分 类 号：TU375.1[建筑科学—结构工程]