表层嵌贴CFRP板条加固混凝土梁抗剪性能的研究

STUDY ON SHEAR RESISTANCE OF CONCRETE BEAM STRENGTHENED WITH NSM CFRP STRIPS

为研究采用表层嵌贴法加固后钢筋混凝土梁的抗剪性能,推导加固梁抗剪承载力设计公式。本文基于Abaqus软件,构建表层嵌贴CFRP板条的T型梁模型,研究混凝土强度、配箍率、剪跨比、嵌贴角度、嵌贴间距对加固梁抗剪性能的影响,通过回归得到相关影响因素下的CFRP板条的有效应力表达式,建立表层嵌贴法的加固梁抗剪承载力表达式。研究表明:混凝土强度、剪跨比、板条的嵌贴间距和嵌贴角度对加固梁抗剪性能影响较大,配箍率对加固效果有一定的影响。表层嵌贴法对加固梁的挠度和极限承载力均有提高。将采用本文抗剪承载力表达式计算的结果与相关试验值对比,吻合较好。

At present,most of the research methods for the shear strengthening of concrete beams with near-surface mounted FRP strips(NSM-FRP strips)are experimental research,few of which use finite element analysis,and there is no corresponding code to guide the design.In the relevant design formulas put forward by most scholars,most of the effective strain for FRP are obtained through the direct reduction of its ultimate strength,and some scholars have considered the influence factors on the effective strain Ring,but the calculation result is too large.In order to study the shear behavior of concrete beams strengthened by NSM CFRP strips,and derive the expression of shear capacity of reinforced beams.Based on Abaqus,a T-beam model with NSM CFRP strips was constructed to study the effects of concrete strength,stirrups ratio,shear span ratio,embedding angle and interstitial spacing on the shear resistance of reinforced beams.The effective stress expression of CFRP strip considering the related influencing factors is obtained by regression.And the expression of the shear capacity of the beam strengthened with NSM CFRP strips is established.The results show that the strength of concrete,the shear span ratio,the spacing between the battens and the angle of the battens have a great influence on the shear performance of the strengthened beams,and the ratio of stirrups has a certain influence on the strengthening effect.The results calculated using the shear bearing capacity expression are in good agreement with the relevant experimental values.