Research On The Seismic Performance Of Existing Concrete Structures Reinforced With Externally Attached Precast Beams And Columns

At present, there are a large number of concrete structures that don’t meet the seismic requirements in China, which are badly damaged in the earthquake. However, nowadays, the reinforcement of the components such as columns or beams of the buildings, can not achieve the desired effect, what’s more, the need for indoor work affects the normal use of the buildings. This paper sums up various types of seismic reinforcement with attached external substructures at home and abroad, combine this seismic reinforcement method with precast technology, and puts forward a new method of attaching external precast beams and columns to structures for seismic reinforcement. The components of the attached external framework can be prefabricated in factories, then transported to the construction site, and tied to the buildings by anchor bolts and bonding material, which can speed up the construction, reduce pollution and meet the direction of industrialization of architecture.This paper mainly introduces the design method and construction technology of seismic reinforcement with externally attached beams and columns for concrete structures and the finite element analysis for it. The main results obtained are as follows:(1) Propose a new reinforcement method of attaching external precast beams and columns to structures for seismic reinforcement and systematically introduce the design process, calculation method, preparation process of the precast components, construction process and the matters needing attention of this reinforcement method based on Chinese building codes.(2) The effect of the reinforcement method is simulated by using the seismic analysis software PERFORM-3D and five story concrete frame models are established with four kinds of reinforcement scheme respectively. Based on time history analysis method, with and without reinforcement frames are analyzed under frequently occurred earthquake and seldom occurred earthquake. The analysis results show that the reinforcement method can reduce the inter-story drift and shear of concrete structures and lower the internal force of the important beams and columns of the structures reinforced, protecting them from destruction.(3) To validate the feasibility and validity of the reinforcement method proposed in this paper,3 concrete frame models are designed and made. One of them is not reinforced and the other two are reinforced using this reinforcement method. All the 3 models are tested under low cyclic loads. The test results show that the reinforcement method has the advantages of easy construction, significantly improving the bearing capacity of the frames reinforced, and reducing the structural damage and displacement.