The Study On Anchor Bar Connection Of External Steel Braces And Concrete Frame Joints

Steel braces reinforcing is an effective component to resist lateral force, it plays an important role in the improve the seismic performance of structure under seismic action. External strengthening as a new kind of structure system, it use the overall substructure work together with the original structure to increase the integral rigidity of structure, to change the the stress state of structure, to reduce interlayer displacement of the structure, so as to improve the overall seismic performance of structure.In experimental research and practical application, the connection is complex between the external steel braces and beam-column joint, and structure under bending moment, shear force at the same time, the force mechanism is complex. Ensuring the reliable connection between steel braces and the reinforced concrete frame structure is the key to the realization that steel braces can strength the reinforced concrete frame effectively. In order to research the dynamic properties of frame joints with post-installed chemical anchor bolt, four test specimens were tested under reciprocal horizontal loads. Concrete research content including following:(1) The destruction of post-installed fastenings connection is due to one of the anchor bolt reaches its ultimate tensile strength, ultimate bearing capacity of post-installed fastenings connection is slightly different theoretical calculations of built-in fitting. Reinforced concrete substrate core area severely damaged, concrete of both sides of the anchor plates occur "trapezoid" failure surface, and where stirrups of column occur yield, cracks at end of beams.(2) The specimen of anchor asymmetrical arrangement occur serious twist in the loading process, from ultimate bearing capacity of post-installed fastenings we can see, bearing capacity of the specimen of anchor asymmetrical arrangement reduce by10.68%, indicating that the anchor asymmetrical arrangement tied a greater impact on the carrying capacity of the anchorage system connection.(3) As we can see from the experimental phenomena and results, ultimate bearing capacity of post-installed fastenings connection spacing240mm raised6.1%than spacing180mm, because of the greater distance between anchor bolts, at the same moment the stress of a single anchor bolt is smaller.(4) From the experimental results, ultimate bearing capacity of post-installed fastenings connection can’t increase as buried depth increases of anchor bolts after buried depth longer than15d.(5) The experimental results were simulated by means of the finite element software, bonding-slip of planting-bar anchorage glue and anchor bolts at the range of buried depth was simulated by nonlinear spring element SPRING2. Both of ultimate bearing capacity is near and loading location displacement is significant differences by comparing the skeleton curve of tese and finite element results...