Experimental Research On Mechanical Properties Of Larch Glulam Columns Under Axial Compression

The guled laminated timber is popular as a kind of green building materials. While most standard in "Technical code of guled laminated timber structures"are drawn up in reference to foreign standards,which is not adapted to domestic fast-growing wood. In order to seek and modify technical standard of the behavior of domestic fast-growing larch under the compression parallel to grain. Experimental study and capacity analysis were carried out on seven group of prcessing formed Larch Glulam columns. Finite element analysis (ANSYS) is finally applied to check experimental and theoretical conclusions. All the results are expected to provide references for structural design and application in timber engineering. The paper completed the following work:(1)The material characteristic parameters of the formed Larch Glulam specimens, such as density, modulus of elasticity parallel to grain, poisson’s ratio for direction of LT and LR, bend elastic modulus of cemented surface and Non-cemented surface, were tested;(2)Two group of experimental study on mechanical properties of Larch Glulam short Columns under compression parallel to grain was carried out. The test results for the compressive strength, peak strain, the range of stress proportional limit are 45.98MPa,4009,0.50-0.7 respectively. The stress-strain curve and failure pattern of short columns under compression parallel to grain were analyzed. The results shows that three phases are divided for the stress-strain curve of Larch Glulam short Columns, meanwhile the empirical formula of stress-strain curve for each phases was given out. The Larch Glulam short Columns belongs to strength failure,4 typical failure pattern were given out;(3)Experimental study on mechanical properties of Larch Glulam long columns with five different slenderness ratio were carried out. The difference of failure pattern for each specimen was analyzed. Variations of experiment data with slenderness ratio changing such as Vertical strain, Lateral strain, Lateral deflection, Ultimate bearing capacity etc were comparatively analyzed. Furthermore, calculation results based on the stability coefficient between three design code of timber structure at home and abroad was comparatively analyzed. The experimental results are analyzed by the method of nonlinear regression. The empirical formula of stability coefficient for the Larch Glulam Columns was given out, which is in good agreement with the experimental results. The critical buckling load formula for the Larch Glulam Columns has been modified, which is more suitable for predicting the ultimate bearing capacity of Larch Glulam long Columns;(4)The finite element (ANSYS) is performed so as to check the material nonlinearity behavior between experimental and theorital results. The results showed that the stress and strain are approximately in agreement with those of experiment respectively. The eigenvalue bucking of Larch Glulam long Columns was analyzed. The experimental result basically tallies with the finite element analysis. Meanwhile buckling is most likely to occur at the Mid-height of the specimen. The nonlinear buckling FEM analysis was carried out for two group of Larch Glulam long Columns. The results indicated that when the load is greater than 1.1 Pcr, the error between theory results and finite element results are less than 1%. This shows that the method of finite element analysis on Larch Glulam Columns is feasible.