Experimental Research Of New Type Of Beam-column Connection For Post-tensioned Precast Frame

Precast technology is the key issue of building industrialization. The behavior of connection joint determines the development and application of precast concrete frame, which is very practical and common in China. Based on the relevant literature at home and abroad, a new type of post-tensioned concrete frame joint is proposed, bolted angles are used in the connection as energy dissipation component, and corbel is designed for the assembly and construction of the joint. In order to test the seismic capacity of such structure, the experimental study on the behavior of the bolted angles is carried out first, together with the finite element analysis. On the basis of the result of the analysis of bolted angles, the experimental study on the behavior of such joints is continued, besides, comparative study and finite element analysis is also conducted combining with the experimental results. The main contents as follows:(1) Different kinds of connection modes of precast concrete structure are thoroughly introduced, together with their respective advantages and disadvantages. A new type of post-tensioned concrete frame joint is proposed on the basis of improving the previous connections studied by our research group.(2) In order to study the property of bolted angles,12 sets of angle specimens were subjected to reversed low-cyclic load and monotonic load. Several parameters which have a significant impact on the behavior of bolted angles were analyzed, such as length, thickness and the location of the bolts. The experimental results show that bolted angle is of good capacity of energy dissipation. The experiment also results in a restoring force model and a conclusion about the mechanical behavior of the bolted angles.(3) Finite element software Abaqus is used to carried out numerical simulation for bolted angles. Results show analysis model based on Abaqus can be applied to non-linear analysis and of good precision. Based on the results, numerical simulation of bolted angles with stiffener is completed by Abaqus. The comparison between the bolted angles with and without stiffeners is studied and illustrated. The simulation shows that bolted angles with stiffener are of better stiffness, bearing and energy dissipation capacity.(4) 3 full-scale connection subassembly specimens were subjected to reversed low-cyclic load. Several parameters which have a significant impact on the behavior of connection subassembly were analyzed, such as initial stress of post-tensioned strand and type of bolted angle. The experimental results show that the joint is of good self-center and energy dissipating ability. After the experiment, the damage concentrate in the bolted angle and the area between beam and column. As the column and beam remain elastic, this kind of connection joints are easy to repair.(5) Finite element software OpenSees is used to carried out numerical simulation for such connection joints. The restoring force model is used and the results show that the analysis is of good precision. Finite element method is tested to be good in study of this kind of connection joints.