| The composite box girder bridge with corrugated steel webs not only has the technical advantages of concrete box girder and steel box girder,but also makes full use of the mechanical properties of concrete compressive strength and steel plate tensile strength.It has the advantages of light weight and good durability.The sectional prefabrication method is introduced into the construction of corrugated steel web box girder bridge,which gives full play to the characteristics of short construction period and high efficiency,and can further improve the technical advantages of corrugated steel web box girder bridge from the aspects of economy and convenient construction.It has broad application prospect.In order to further study the mechanical properties of precast corrugated steel web box girder,the shear properties of this type of bridge were systematically studied by static test,numerical simulation and theoretical analysis.The main research contents and conclusions are as follows:(1)Two sections of prefabricated continuous corrugated steel web proportional test beams with variable section were designed and manufactured,with span arrangement of(2.5+5+2.5)m.The test beam section adopts precast assembly construction,and the test beam floor concrete section adopts monolithic pouring construction.Through static tests and numerical analysis,the difference of shear performance between precast segmental continuous beams and integral cast continuous beams was studied.The failure mode,crack behavior,deflection variation,shear capacity and web shear strain of test beams were analyzed.The results show that the shear ratio of corrugated steel webs at 1/4 of the span of Segway beam is 80%,which is 5% higher than that of the whole beam.From 1/4 of the span to the intermediate support,the shear ratio of the corrugated steel web gradually decreases to 50%.Under symmetrical mid-span load,the shear stress of corrugated steel web at 1/4 span position of segmental beam is slightly greater than that of full beam at elastic stage,but no more than 3MPa.After entering the plastic stage,the shear stress growth rate of segmental beams at this position is obviously higher than that of integral beams.When the load value is 1100 k N,the shear stress of section beam increases by 24% relative to the whole beam.(2)A numerical model is established according to the scale test beam,and the rationality of the numerical model is verified.On this basis,the effects of different thickness of rubber layer,thickness of bottom plate and number of segments on shear properties of segmental beams are calculated and analyzed.The results show that the shear stress and shear ratio of corrugated steel webs do not change obviously with the rubber thickness.The shear stress and shear ratio of corrugated steel web increase with the thickness of bottom plate.With the increase of the number of sections,the additional shear stress caused by torsion increases during unloading.(3)Based on classical beam theory,the shear stress calculation method of segmental precast box girder with variable section corrugated steel webs is established.Considering the bending moment and axial force of the box girder with variable section,the shear stress will be generated.The effect of forced displacement on shear stress during assembly is considered.(4)Finite element method was used to analyze the parameters of joint shear capacity,and the influence of joint form,horizontal pressure and other factors on the joint shear capacity was discussed.The results show that the key way joints have the highest shear capacity,followed by rubber joints and dry joints.The shear capacity of rubber joints is 20% higher than that of dry joints,and the shear capacity of keyway joints is 15% higher than that of rubber joints.Under horizontal pressure,the shear capacity of rubber joint,dry joint and key joint increased by 23%,30% and 18%,respectively. |
PDF Full Text Request