应用三维有限元法探讨RC梁柱节点的破坏机理

为了探究节点加强后RC梁柱节点的抗剪承载力、延性提高以及节点破坏模式由剪切破坏转变为梁弯曲破坏的实质,本文在RC节点的三维有限元分析的基础上探讨RC梁柱节点加强后的破坏机理。通过详细考察加固前后节点内部不同位置混凝土的应力-应变发展规律,探讨加强前后节点混凝土的宏观损伤发展过程;同时,通过考察核心混凝土的应力-应变关系及发展过程定量探讨加强钢板、梁柱主筋及箍筋对核心混凝土的约束作用。基于上述混凝土损伤过程的宏观分析,可以得出由于梁主筋的粘结加强、加强钢板以及箍筋对混凝土约束作用,使节点核心混凝土的实际强度增大、损伤延迟,RC节点由加强前的节点剪切破坏模式转变成梁端的弯曲破坏模式,从而提高RC梁柱节点的抗剪承载力和延性。

Studies on failure mechanism of reinforced concrete beam-column joints using three-dimensional finite element method

In order to study the essentials of the increases of shear resistance and ductility of RC beam-column joint,and the change of failure mode from joint shear failure to beam-end flexural failure,the failure mechanism of RC joints are investigated before or after being strengthened based on three-dimensional finite element analysis in previous paper.Through deeply investigating the developments of stress-strain relationship of core concrete in joints,the damage growths of concrete in different zones are studied.Simultaneously,according to the stress-strain relationships of concrete,the confined effect from hoop steels,tie plate for bond strengthening is discussed.Seen from above researches,it can be concluded that the factual strength of core concrete is increased and the its damage is weakened,and then the failure mode is changed from joint shear failure to beam-end flexural failure,because of bond linking strengthening and the confined effect of tie plate,anchor plate and hoops.As a result,the shear resistance and ductility of RC joint are increased by strengthening.