Study On Bearing Capacity Of RC Rib Arch Bridges Strengthened With Prestressed High Strength Steel Wire Mesh

The prestressed steel wire in the circumferential direction can effectively improve the compressive strength of the core concrete.The application of the prestressed steel wire to strengthen reinforced concrete rib arch bridges which are dominated by compression pressure have a very realistic engineering significance.However,the study and application in this field are less at present.The thesis aims at studying the bearing capacity of reinforced concrete rib arch bridges which were strengthened with prestressed high strength steel wire mesh.The calculation formula of the bearing capacity of reinforced concrete members after reinforcement was put forward to some extent based on the study of properties of the concrete axial compression and eccentric compression member with square cross section.The strengthening effect of this technology was verified through the test of reinforced concrete arch ribs.The main research contents and achievements of this paper is outlined as follows:(1)The tensile property test of high strength steel wire mesh and the development of a device which is used to stretch and anchor steel wire mesh in the circumferential direction.The tensile property parameters and stress-strain relationship curve of high strength steel wire mesh were achieved in this test.Meanwhile,a set of device which was used to stretch and anchor steel wire mesh was designed,the application and maintenance of prestress were realized by it and the feasibility of this device was confirmed by practical application.(2)Experimental study on axial compression property of square concrete members confined with circumferential prestressed steel wire mesh.11 concrete menbers in 4groups were designed,the effects of concrete strength,reinforcement pitch and prestressing level on the axial compression property of confined concrete were studied.The results showed that the brittle failure characteristics of the reinforced specimen were obviously weakened,the development period of the crack was prolonged significantly,and the bearing capacity and ductility of the reinforced specimen were also greatly improved.At the same time,the stress-strain relationship formula of confined concrete members was established based on the Mander model.(3)Experimental study on eccentric compression property of square reinforced concrete members confined with circumferential prestressed steel wire mesh.A total of6 specimens in 3 groups were designed and the eccentric compression properties of confined concrete were studied.The results showed that the prestressed steel wire had a significant effect on the concrete in compressive zone and hindered the development of the vertical cracks in the specimen.The increased range of the bearing capacity of the reinforced specimen declined with the increase of the eccentricity.The relative depth of the confined members compression zone ξb was increased and the calculation formula of the bearing capacity of the reinforced concrete members confined with prestressed steel wire mesh was established to some extent.(4)Experimental study on reinforced concrete arch ribs confined with prestressed steel wire mesh in the circumferential direction.Two reinforced concrete arch ribs were designed and the mechanical properties of them were compared.The results showed that the method of reinforcement of the prestressed steel wire mesh effectively improved the overall stiffness of the arch ribs and slowed down the stiffness reduction.The reinforcement method had a good effect on the improvement of bearing capacity of the arch ribs.The calculation formula established in this paper of the bearing capacity of the specimens confined with prestressed steel wire mesh in the circumferential direction had a reference value in some degree.