自由拉拔植筋系统的粘结滑移受力机理分析

Analysis on Bond-Slip Performance and Load Transfer Mechanism of Bonded Rebars

自由拉拔植筋系统破坏时发生复杂的混合界面拔出型破坏,为了研究其粘结滑移受力机理,对该植筋系统进行了考虑粘结滑移的非线性有限元分析。根据植筋自由拉拔试验结果,建立了混合界面的粘结滑移本构关系。该本构关系考虑了有效锚固深度、钻孔直径和植筋胶等植筋参数对混合界面粘结强度和滑移的影响,全面反映了混合界面的粘结滑移性能。并进一步采用该粘结滑移本构关系,代入特定的植筋试验参数,对自由拉拔植筋系统进行了考虑粘结滑移的ANSYS有限元分析。根据有限元分析结果与试验结果的对比,证明了所建立的混合界面的粘结滑移本构关系是合理的,认识了自由拉拔植筋系统的粘结滑移受力机理并建立了相应的承载机理简化模型,认识了自由拉拔植筋系统的裂缝分布及发展规律,并进一步建立了针对自由拉拔植筋系统的承载能力极限状态设计计算公式和正常使用极限状态验算公式。

To study the load transfer mechanism of bonded rebars failed on combination interface, the bonded rebars systems of concrete block which are failed on combination interface are studied by nonlinear FE analysis method. According to the results of the pull-out tests of concrete block, the bond-slip constitutive relationships of combination interface are formed, in which the three main factors including effective embedment length, diameter of hole and the fixing adhesive are taken into account. The bond-slip behavior on the combination interface is all-sided described by these formed bond-slip constitutive relationships. Then by specifying the parameters＇ values of these constitutive relationships based on the given tests, the bonded rebars systems of concrete block are studied by the FE analysis based on the ANSYS program considering slip of interface. According to the analysis results, the bond-slip constitutive relationships of combination interface are reasonable, and the load transfer mechanism of bonded rebars failed on combination interface is understood, and also corresponding simplified model of load transfer mechanism is formed, also the development and distribution of crack of bonded rebars failed on combination interface are understood, and the design and calculation formulas in bearing capacity limit condition and normal limit condition of the bonded rebars system failed on combination interface are formed.