Experimental Study On Shear Properties Of Bamboo Aggregates By Side Compression

With the improvement of people’s living standards and the worsening of the environment,China is implementing the policy of "low carbon environmental protection,energy saving and emission reduction",vigorously advocating the development of green building materials,resolving overcapacity and promoting the optimization and upgrading of bamboo structure industry.Bamboo composite is a kind of engineering composite bamboo with modern processing technology,high strength and quality ratio,environmental protection and beauty.It is also a kind of green building material with sustainable development.It is widely used in engineering field because of its superior performance.The manufacture and application of bamboo composite timber will help to solve the current environmental situation.However,the study and application of bamboo-assembled wood started late in China,an d the related research on its mechanical properties is still a blind area,and the related manufacturing and design specifications are not perfect.In order to investigate the shear behavior of bamboo aggregated beams,this paper mainly carried out three parts of work:the experimental study on the shear strength of side-pressed bamboo aggregated beams,the experimental study on the interlaminar shear strength and the experim ental study on the influence of shear capacity of side-pressed bamboo aggregated beams by shear span ratio.The following research results were obtained:（1）To four groups,a total of 60 lateral pressure bamboo integrated timber material small shear strength test specimens,discusses four direction clear material small damage form,the shear strength of the specimens,paths of the load-displacement relationship,and the grain direction of shear strength compared with glulam,puts forward the lateral pressure bamboo integrated timber shear strength standard values and the calculation method of design value,The allowable stress,standard value and design value of the shear strength of the side pressed bamboo composite are given.（2）Interlaminar shear strength tests were carried out on 21 bamboo laminated beams in 7 groups to study the effects of span height ratio and overextension length on the failure modes and interlaminar shear strength of bamboo laminated beams.The experimental results show that the interlaminar shear strength is mainly related to the ratio of span to height.When the ratio of span to height is less than or equal to 5,the failure mode is interlaminar shear failure.When the span height ratio is greater than 5,the failure form is bending failure.In addition,the shear stress calculated from the measured strain is in good agreement with the measured one.（3）Taking the shear to span ratio as the change parameter,the four-point bending test was carried out on five groups of 3 bamboo composite beams with shear to span ratios of 0.75,1.0,1.5,2.0 and 2.5,respectively,to study the deformation characteristics,failure modes and the influence of shear to span ratio of side-loaded bamboo composite beams.The results show that the shear to span ratio has an important influence on the failure mode of bamboo composite beams.When the shear to span ratio is less than 1.5,the interlamellar shear failure occurs,and when the shear to span ratio is greater than or equal to 1.5,the bending failure occurs.（4）The formulas for calculating the flexural bearing capacity,shear bearing capacity and elastic deformation of bamboo composite beams are put forward,which are in good agreement with the measured values.