Analytical modeling of reinforced concrete beam column connections for seismic loading

Reinforced concrete beam column joints are critical members in frame structures since they can be subjected to high shear forces under earthquake loading. As a consequence, they can experience high shear and bond slip deformations that contribute significantly to the story drift. Moreover, the joint capacity may be exceeded leading to a joint shear failure that can have a major impact on the overall stability of the entire structure. This condition is particularly pronounced in lightly reinforced concrete structures where the beam column joints are typically the weakest link in the lateral load resistant frame. There is a persistent need to develop an analytical model that accounts for their shear and bond slip deformations in order to predict realistically their response and assess their safety.; A finite element based analytical model is developed in this thesis for the beam column connection region. The model overcomes the need of using refined meshes of simple elements by using high power elements in the critical regions of the joint panel and the plastic hinge zones in the beams and the columns. The proposed model takes into account the shear and bond slip deformations in the joint panel as well as flexural and shear deformations in the plastic hinge zones in the beams and the columns. Material non-linearities associated with the concrete and steel behavior are taken into account. Bond slip relationship between the beam reinforcement and concrete in the joint panel is considered. The material models developed in this thesis are verified at the element level before the verification is made to the entire beam column connection model. The predictions of the model are compared with experimental data for beam column subassemblies experiencing high shear and/or bond slip deformations. The success of the proposed model is demonstrated by the good correlation achieved with the experimental data. The model is then used in the analysis of a three story reinforced concrete frame structure designed without consideration of earthquake loads. The structure is analyzed using different joint detailing schemes using pushover and time history analyses to investigate the effect of the joint detailing on the response of the structure.; It is concluded that the proposed beam column connection model can be used successfully for the dynamic analysis of a complete multistory structure.