The Research On The Overall Performance Of LVL-Concrete Composite Beam Bridge

Timber concrete composite structure(TCC)is a new type of structure,in which the materials are effectively utilised in terms of strength performance where the timber is mainly subjected to tension and bending,the concrete slab is mainly subjected to compression,and the connection system subjected to shear.Relatively,compared with the reinforced concrete structure the TCC has low energy consumption,low emission,and light quality.Although this kind of structure has been widely used in Europe and the United States,it has not formed a complete theoretical system.That is still in its infancy in China.The current research on wood-concrete composite structure mostly concentrate on the destruction test and push-out specimens testing.LVL-concrete composite beam bridge is composed of beams and concrete slab,this thesis studies the mechanical properties from the perspective of the overall performance of the composite beam bridge.This thesis uses the finite element analysis software Midas Civil to establish a solid model for numerical analysis of Laminated wood concrete composite beam bridge.The deformation mechanism and mechanical behavior of composite beam bridge has been researched with the knowledge of statics and dynamics.Through the static and dynamic test about the structure model,analyze and compare of the measured value and the theoretical value to verify the correctness the calculation.It has discussed the mechanism of the interaction between the beams and the concrete slab to provide a theoretical and experimental basis for the design of that composite beam bridge.The thesis puts forward the production process and the construction technology of this kind of bridge.In the static test,loading test was implemented on account of the principle of the equivalent internal force of load effect and calculated load effect in the cross region of bridge.Use the method of sudden unloading to measure the frequency of wood-concrete composite girder bridge.The modal shapes of composite beam bridge were tested with the method of white noise excitation.The static test results show that concrete slabs and glued wood beams can work together effectively,and different support types have great influence on the beam end slip for wood concrete composite beam bridge with notch-stud shear connectors.The load deflection curve shows a linear change,indicating that the overall structure is in an elastic deformation stage.Under the action of 240kN,the concrete plate and the glued wood beam still have a common neutral axis,which can judge that the composite beam bridge approximately satisfies the assumption of flat section.Based on the analysis of the slip,deflection and strain of the composite beam bridge,it can basically meet the load level requirements of highway-class Ⅱ.It is found that the measured values are in good agreement with the theoretical values,which shows that the finite element model used in this thesis is reliable and correct.Learned from the dynamic test results,the theoretical calculation value of frequency of the composite beam bridge is smaller than the measured value,which shows that the actual stiffness of the bridge is better than that of the finite element model.The measured vibration mode is consistent with the finite element model,which verifies the correctness of the theoretical model.