套筒灌浆连接受力失效机理与有限元仿真验证

FINITE ELEMENT SIMULATION VERIFICATION AND FAILURE MECHANISM OF GROUTED SLEEVE CONNECTIONS UNDER LOADING

针对套筒灌浆连接的传力机理尚未完全明确,从理论上分析了受拉时接头的荷载传递路径与方式,提出了基于拟合系数、组合系数、整体系数的套筒灌浆连接受拉承载力计算方法与失效模式识别依据。进一步通过收集国内外试验数据的拟合分析,明确了单调递增受拉、反复拉压作用下拟合系数的取值分别为0.203、0.158。结合高温后套筒灌浆连接反复拉压作用下试验数据的分析结果,建议组合系数、整体系数均取1.2(400℃高温作用后,后者取1.0)。最后,开展高温后套筒灌浆连接反复拉压作用有限元仿真,明确了套筒灌浆连接失效模式转变、承载力明显下降的临界温度分别为400℃、800℃。此外,还发现新建的套筒灌浆连接承载力计算方法的结果与模拟值最大偏差不超过8.2%,表明二者均能较好地反映高温后套筒灌浆连接承载力演变规律,为套筒灌浆连接设计方法的形成提供了理论依据。

The force delivering mechanism is unclear in the grouted sleeve connection,so the load transmission path and method are analyzed.Then considering three coefficients,namely,fitting coefficient,combination coefficient and integral coefficient,methods for bearing capacity calculation and failure mode identification are proposed for grouted sleeve connections under tensile force.Moreover,the fitting coefficient is determined by fitting analysis on the collected date at home and abroad,i.e.,0.203 and 0.158 for the connection under incremental tensile and cyclic loading respectively.According to the analysis result from heat-damaged connections under cyclic loadings,it is suggested that the value of combination coefficient and integral coefficient should be 1.2 but the integral coefficient should be 1.0 after the connection’s exposure to a heating more than 400℃.Finally,a finite element simulation is performed to analyze the heat-damaged grouted sleeve connections under cyclic loadings.It is found that the crucial temperatures of the connection are 400℃for the failure mode changing and 800℃for obvious decrease in bearing capacity.In addition,the maximum difference of the bearing capacity is 8.2%between calculation results and simulation results,which means that both methods show same developing trend of the connection’s bearing capacity under cyclic loading.All of these findings and propositions will benefit the forming of design method of grouted sleeve connection.