Experimental Investigation And Numerical Simulation On Seismic Behavior Of PVA Fiber-reinforced Concrete Columns

The reinforced concrete frame structure of the architectural form is widely used in China. The frame column as an important seismic member of a frame structure, its damage may lead to failure and even collapse of frame structure. In order to overcome the poor ductility of concrete column which causes the damage of structure, mixing amount of fiber into concrete is one of the main measures. It can significantly improve the ductility of concrete and improve the seismic performance of concrete structural members.Engineered Cementitious Composites is one kind of fiber reinforced concrete with super high ductility, showing obvious pseudo strain- hardening and fracture crack characteristics under the actions of tensile load and bending load. Fiber as reinforced materials, can improve the tensile strength, shear strength, toughness,impact resistance, crack resistance, impermeability, wear resistance and durability of concrete. The excellent mechanical properties make the concrete column under high axial compression ratio still exhibit excellent seismic performance.This paper mainly makes a deep research on the seismic performance of the PVA fiber reinforced concrete column based on the domestic and foreign achievements,and the concrete work is as follows:(1) The performance of ductility, deformation and energy dissipation capacity of the PVA fiber reinforced concrete column can be got under low cyclic loads by the pseudo-static test. The study finds that in the condition of high axial compression ratio and PVA fiber reinforced concrete column damaged, the crack develops slowly and fiber bridging effectively control the crack. The fiber reinforced concrete column is mainly manifested as ductile failure mode and ultimate displacement angle is about times of the ordinary concrete column 1.47~1.53, which shows it has a good plastic deformation and damage tolerance. The energy dissipation ratio of PVA fiber enhanced reinforced concrete column is the times 1.82~1.95 of common concrete columns, suggesting that the energy dissipation capacity significantly improved, and the seismic performance is superior.(2) The force performances of the fiber model of PVA fiber reinforced concrete columns and ordinary reinforced concrete columns are simulated under low cyclic loading based on the finite element analysis software OPENSEES. A comparison withnumerical simulation results and the test results are made from the column lag back curve, skeleton curve, bearing capacity, ductility and energy dissipation.(3) The parameters of shear span ratio and axial compression ratio are analyzed by finite element analysis software OPENSEES. The influence of shear span ratio and axial compression ratio on the ductility of columns are evaluated in terms of the ultimate displacement angle and displacement ductility factor. The ultimate displacement angle of column increases with the increase of the shear span ratio, and displacement ductility factor represents a tendency of first increased and then decreased, reaching the maximum when the shear span ratio is equal to 3. The ultimate displacement angle and the displacement ductility coefficient increase with the increase of the axial compression ratio.The above investigations show that the doped fiber can improve the seismic performance of reinforced concrete frame structure. The advised values of design parameters of the PVA fiber reinforced concrete frame structure are given based on the experimental and simulation results, which provides a reliable basis for the structural design and engineering application.