边距对扩底型预埋吊件抗拉承载力影响研究

Study on the effect of edge distance on anti-pull bearing capacity of bottom-enlarged lifting anchor

预埋吊件在使用过程中,边距效应是影响其抗拉承载力的主要因素。采用有限元分析与试验研究相结合的方法,研究边距对扩底型预埋吊件抗拉承载力的影响。整理国内规范《混凝土结构后锚固技术规程》(JGJ 145—2013)、美国规范ACI 318-05、英国规范CEN/TR 15728中预埋吊件受拉破坏模式及抗拉承载力计算公式,比较其异同。建立三组试验,预埋吊件边距100mm,埋深分别为70,85,90mm。建立三个与试验对应的有限元模型,通过试验结果与模拟结果的对比,证明有限元模型可以用来研究边距对预埋吊件抗拉承载力的影响。在此基础之上建立混凝土强度为C20,C30,C40以及预埋吊件埋深为90mm的三组模型,每组6个模型,模型边距为100,110,120,130,140,150mm。有限元分析结果表明扩底型预埋吊件受拉时均发生混凝土锥体破坏,锥角约40°。预埋吊件抗拉承载力与英国规范CEN/TR 15728的计算值最为接近,且随边距增大而增大。

In the process of using the lifting anchor,the effect of edge distance is the main factor on the influence of the antipull bearing capacity.The combination method of finite element analysis and experimental research was used to study the effect of edge distance on the anti-pull bearing capacity of the bottom-enlarged lifting anchor.The tensile failure modes and the corresponding anti-pull bearing capacity calculation formulas of lifting anchor were sorted out in the Chinese standard After anchoring technical regulations for concrete structures(JGJ 145—2013),American standard ACI 318-05,and British standard CEN/TR 15728 to compare their similarities and differences.Three test groups were established,the edge distance of the lifting anchor is 100mm,and the embedded depths are 70,85,90mm respectively.Three finite element models corresponding to the experiment were established,and the comparison of the test results with the simulation results proves that the finite element model can be used to study the influence of edge distance on the anti-pull bearing capacity of lifting anchor.On this basis,three groups of models with concrete strengths taken as C20,C30,C40 and embedded depth of the lifting anchor as 90mm were established.Each group has 6 models,with 100,110,120,130,140,150mm in edge distance respectively.The results of finite element analysis show that the concrete-cone breakage occurs when the bottom-enlarged lifting anchor is tensioned,and the cone angle is about 40 degrees.The anti-pull carrying capacity of the lifting anchor is closest to the calculated value of British standard CEN/TR 15728,and it increases with the increase of the edge distance.