The Study On The Flexural Performance Of Glulam Beams Strengthened With Bamboo Scrimber Based On The Creep Behavior

Modern wooden structures are widely used in developed countries such as Europe and the United States due to their green,environmental protection,low carbon,energy saving,and beautiful texture.And in recent years,China has also restarted the study of modern wooden structures due to the implementation of corresponding policies.Due to the limited tensile strength,low elastic modulus,and large deformation defects of ordinary wood,researchers at universities and research institutes have proposed a variety of reinforcement methods.Compared with the reinforcement forms of many ordinary glulam beams,most of them have increased Beams’ cross-sectional dimensions without fully utilizing the compressive properties of wood.In response to this problem,the research team previously.proposed a new type of composite member-glulam beams strengthened with bamboo scrimber,and verified the flexural performance of the beams through experimental research.It is concluded that the flexural performance of the test beams with the replacement ratio of 2/6 is better and more economical and reasonable.However,if you want to put glulam beams strengthened with bamboo scrimber into engineering practice,you still need to consider the huge impact of the creep which is one of the basic characteristics of wood on the long-term mechanical performance.This paper supplements the research teams’research on the long-term mechanical performance of the glulam beams strengthened with bamboo scrimber under the influence of creep,fills the gap,provides theoretical basis,has practical value.Based on the above research background,this paper has carried out the following work:Firstly,according to the replacement rate and loading level of the glulam beams strengthened with bamboo scrimber,it is divided into four groups A,B,C,and D.Group A is the ultimate load measurement group to determine the long-term loading level.Groups B,C,and D are three groups of long-term test beams when the loading levels is 20%,30%,and 40%of the estimated ultimate load respectively(Each group includes one each of ordinary glulam beams and two kinds of glulam beams strengthened with bamboo scrimber with replacement ratios of 1/6 and 2/6,a total of three test beams).The test puts 9 test beams in two batches in a indoor normal using environment for a 90 days long-term loading test.During the test,the data was recorded in an offline collection mode.The analysis and summary results showed that the creep deformation of the test beams varies with the replacement rate and loading level,and based on the law of change,a power law model of glulam beams strengthened with bamboo scrimber for predicting long-term deflection was established.The power law model gives the long-term deflection calculation formula and the range of the creep variation coefficient.After the end of the long-term test of the B、C、D groups,short-term load destructive tests were conducted.Compared with the test beams that did not undergo creep,the bearing capacity of the glulam beams strengthened with bamboo scrimber with a replacement rate of 1/6 decreased by 15.3%～45.8%,the bearing capacity of the glulam beams strengthened with bamboo scrimber with a replacement rate of 2/6 decreased by 7.9%～30.2%,and the stiffness of the test beams has been slightly reduced.The effects of replacement rate and loading level on the creep of glulam beams strengthened with bamboo scrimber were explained,and the test beams with a replacement rate of 2/6 had the better long-term bending performance relatively,which was economical and reasonable.Besides,the results are consistent with the previous research team’s conclusions.