Experimental Study On Mechanical Performance Of Continuous Glulam Beam Connected With Steel Splints And Bolts

In order to solve the problems of poor spanning capasity and large deformation exists in glulam bridges,steel splints-bolts connector is introduced into extensions of glulam beams,and a new type of continuous glulam beam connected with steel splints and bolts is propoesd.By utilizing such new type of composite beam,the purpose of reducing the mid-span deformation and bending moment,improving the bearing capacity and normal service performance of bridges,realizing the breakthrough of glulam bridge in spanning capacity is achieved,so as to lay a foundation for the engineering application of continuous glulam beam structures.On the basis of the previous studies,4 classes(cross-section height were 78mm,106mm,119mm and 133mm)and 24 groups of 72 specimens with span-depth ratio of 18 were designed.Besides,4 groups of continuous glulam beams,1 group of pure continuous beam and 1 group of pure simply suppored glulam beam inclued in each kind of specimen were tested under mid-span loadings.At the same time,the loading processes of each specimen was simulated by ANSYS finite element software based on the orthotropic elastoplastic constitutive model and isotropic strengthening constitutive model of glulam,and the simulation results were compared with the experimental results.The main completed works are as follows:(1)4 classes and 24 groups of 72 specimens were tested under mid-span loadings.And the stiffness,failure mode,stress distribution and ultimate bearing capacity among continuous glulam beams connected with steel splints and bolts,pure continuous glulam beams and pure simply supported glulam beams were compared and analysed.(2)Based on the experimental results,the influence of bolt spacing on the mechanical performance of continuous glulam beams connected with steel splints and bolts is revealed,and the reasons of steel splints-bolts connector could significantly improve the local stiffness and intefral stiffness of the specimens is clarified.(3)A nonlinear finite element models of each specemen were established by using the FEM software ANSYS,in which the geometric nonlinearity and material nonlinearity were considered,and the orthotropic elastoplastic constitutive model and isotropic strengthening constitutive mode were adopted in glulam.The results of finite element analysis were consistent with the test results.