Experimental Study On Compression-bending Of CLT Wall Components

Cross laminated timber is a new kind of engineering wood product,made of three or more layers of sawn timber vertical orthogonal group blank,adjacent layers along the grain direction orthogonal form can effectively overcome the defect of anisotropy of wood mechanical properties.At present,the CLT is mainly used for shear wall structure,during construction,considering the the influence of bending and eccentric,standards from different country give the corresponding calculation formula but there are differences between different specifications.To check the applicability of the specification and to explore the factors influencing the bearing capacity,this article has carried on the bending test of CLT component,the specific research results are as follows:1.Carry out the basic mechanical property test and rolling shear test of CLT material to obtain the tensile strength,compressive strength and bending strength along the grain and rolling shear strength and modulus of CLT.2.Taking the eccentricity as the control factors,the axial and eccentric compression and bending tests of CLT wall components are carried out.The test results show that:(1)the failure mode of axial compression members is mainly characterized by extreme point instability failure.(2)The failure modes of the eccentric compression component include compression failure of the laminated plate on the compression side,tensile failure of the laminated plate on the tension side and shear failure of the cross layer.(3)The rolling shear failure of the cross layer occurs simultaneously with the overall failure of the component,and the cross layers can maintain their joint efficient until failure occurs..(4)The greater the eccentricity,the lower the bearing capacity of the member,the greater the lateral displacement of the span,compared with the axial compression member,even the smaller the eccentricity will significantly reduce the bearing capacity.3.Combined with the test results,the calculation theories of CLT bending stiffness in different specifications in the world are compared,and the applicable calculation formulas of different blank assembly methods are determined.The results show that when checking the safety of three-layer CLT,the formula of GB 51226 is more appropriate,and the safety of CSA O86 is poor;When checking the five-layer CLT,CSA O86 is more applicable,while GB 51226 is more conservative.4.The simulation test is carried out by using the finite element software ABAQUS,and the simulation results are in good agreement with the test results,which can reasonably predict the stable bearing capacity of CLT compression bending members.The stable bearing capacity of seven-story CLT members under different eccentricities is predicted.