| With the introduction of"One Belt One Road"strategy,the urgent need for marine infrastructure construction has become increasingly prominent.At present,the construction of marine infrastructure is facing two problems:First,most of the islands lack the fresh water,river sand and gravel aggregates required for concrete.Secondly,the marine environment is a complex corrosive environment.In the construction of marine engineering,although sea water,sea sand and coral aggregate can be used as local materials to configure concrete to solve the problem of raw materials.For traditional reinforced concrete structures,the chloride salt in sea water and sea sand will accelerate the corrosion of steel bars and affect the use life.Therefore,there is an urgent need to develop a new structural system suitable for the marine service environment.Fiber Reinforced Polymer(FRP)has the advantages of light weight,high strength,corrosion resistance,and good fatigue resistance,has been extensively studied in domestic and foreign engineering structures.Concrete Filled FRP Tube(CFFT)formed by filling concrete in FRP tube.Compared with plain concrete structure,CFFT structure has higher strength and deformation ability.At the same time,FRP tube can protect core concrete from harsh environment Erosion.In view of the above research background,this paper proposes a new type of Basalt-FRP(BFRP)tube reinforced Seawater Sea-sand Coral Concrete(SSCC)arch bridge structure.Based on the innovative technology,a new type of integrated BFRP tube with pre-bonded BFRP longitudinal bars has been developed.The axial and eccentric compression performance of the new SSCC-filled BFRP tube string was tested and analyzed;and on this basis,the mechanical properties of the new SSCC-filled BFRP tube arch structure were studied.A total of 49 specimens were tested in the test,including 10 BFRP tube-constrained SSCC arch specimens,3 unconstrained SSCC axial compression stubs,18 BFRP tube-constrained SSCC axial compression stubs,and 18 BFRP tube-constrained SSCC eccentric compression stubs.Test variables include:BFRP pipe wall thickness,whether the inner wall is pre-bonded with BFRP longitudinal ribs,eccentricity,and arch’s rise-to-span ratio.The results showed that:(1)Axial compression column specimen.Based on the BFRP tube restraint,the existence of BFRP bars further enhances the ultimate bearing capacity of BFRP tube restraint members,and the effect of BFRP bars on the ultimate bearing capacity of thick BFRP pipe wall restraint members is more obvious.(2)Eccentric compression column specimen.Generally speaking,the influence of eccentricity on ultimate load P_u and ultimate axial displacementΔ_u is:the greater the eccentricity,the smaller P_u andΔ_u.Increasing the thickness of the BFRP pipe wall and the BFRP bars can promote the increase of P_u andΔ_u.(3)Arch specimen.For part of the arch specimen without BFRP bars,after the initial failure of the middle span,the force form develops from the hingeless arch to the three-hinged arch.The load drops during the initial failure of the middle span,and then the force form changes,and the load continues to rise.For the arch specimens with BFRP bars,the reinforcement of BFRP reinforcement significantly improves the ultimate bearing capacity of the test arch.At the same time,the existence of BFRP reinforcement changes the force form of the arch.Among non-reinforced members,the greater the ratio of rise to span,the lower the ultimate bearing capacity of the arch specimen.The effect of the BFRP bars on the member with a central angle of 150°is most obvious.On the basis of the above-mentioned experimental tests,this paper also simulates and analyzes the experimental results based on the ABAQUS finite element software.Based on simulation and test results,this paper proposes a design method for the new type of FRP tube concrete solid-web catenary arch bridge with longitudinal FRP bars and carries out trial design work to verify the effectiveness of the design method. |
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