Study On Seismic Behavior Of Reinforced Concrete Piers With Basalt Fiber Sheets

All the major earthquakes at home and abroad will lead to extensive damage or even collapse of Bridges in the disaster area,thus delaying the relief and post-disaster reconstruction,resulting in huge economic losses.With the continuous development of bridge ductility seismic design concept,a large number of existing Bridges reinforcement ratio to low or performance degradation(such as reinforcing bar corrosion,concrete cracking,etc.)and their poor ductility,cannot meet the requirements of the current specification on seismic performance of its.Fiber Reinforced Polymer(BFRP)due to its good mechanical properties and more economic price,make it have potential application prospect in bridge seismic reinforcement.Therefore,in this thesis,the seismic behavior of typical viaduct piers before and after reinforcement based on continuous basalt fiber distribution constraint is systematically analyzed and experimentally studied.The main research contents and conclusions are as follows:(1)According to the Guidelines for Seismic Design of Highway Bridges Bridges(JTG/T B 02-01-2008),the influence of reinforcement ratio(stirrup),reinforcement corrosion,axial compression ratio and basalt fiber reinforcement parameters on seismic performance of typical elevated bridge piers is analyzed.The results show that the axial compression ratio and stirrup reinforcement ratio can affect the ultimate failure curvature and ultimate bending moment of the pier and change the ductile deformation capacity and bearing capacity of the pier.Basalt fiber reinforcement can improve the allowable Angle and displacement of the pier and the seismic performance of the pier.(2)Standard reinforced concrete circular section piers with reinforcement reinforcement,low reinforcement reinforcement and corroded reinforcement were designed respectively,and basalt fiber cloth was used for reinforcement,and low-cycle reciprocating pseudo-static test was carried out,and anti-seismic performance parameters such as hysteresis curve,stiffness,bearing capacity,damping ratio and energy dissipation of the piers and columns were condensed.The results show that the bearing capacity,ductility and energy dissipation capacity of the piers are reduced by low reinforcement ratio and corrosion of reinforcement.The seismic performance of the low-reinforced and corroded columns strengthened by basalt fiber cloth is improved.(3)The finite element software ABAQUS was used to establish the refined finite element model of typical circular section piers and columns for numerical analysis and comparison with the experimental results.Then,the influence laws of BFRP strengthened layers,height,axial compression ratio,reinforcement corrosion rate and other factors on the seismic performance of typical circular section piers and columns were studied.The results show that the numerical simulation results are basically consistent with the experimental results.BFRP reinforcement and moderate increase of axial compression ratio can improve the seismic performance of pier and column.The improvement of steel corrosion rate will reduce the seismic performance of the pier.(4)Finite element software ABAQUS was used to process the refined finite element models of rectangular piers,hollow piers and double-column piers respectively,and numerical simulation of BFRP seismic reinforcement for piers and columns of different cross-section types was conducted.The results show that the load carrying capacity,ductile deformation capacity and energy dissipation capacity can be effectively improved by strengthening the piers with different sections with BFRP.