Research On Bolt Joint's Mechanical Properties Of Prefabricated Bamboo Structure

With the development and popularization of new architectural structure and green building materials in recent years,a growing number of researches focus on using bamboo as a structural material to build new types of buildings.Also,academia and industry have reached the consensus to explore and improve sustainable and renewable building materials.Taking bamboo as research object,this paper aims to solve the problems of joint connections of prefabricated bamboo structure.It studies the bearing capacity and failure modes of joints and their influencing factors,and proposes optimization schemes to evaluate the improvement.Meanwhile,this paper also analyses and compares the simulated and experimental values by combining finite element simulation analysis.At last,it provides reference formulae for theoretical calculation for the engineering design of these joints in the way of analytical solution.The research status of bamboo structures,and as reference,the application of bolted joints in timber structures in Eurocode5,National Design Specification of America and Chinese specifications have been introduced.Design formulae are deduced and compared,and different hypotheses that each specification relied on are analyzed.By studying the basic material mechanical properties of bolted connection through multiple tests,confirm strength indexes of Mao bamboo and analyze its failure process and final failure mode.Design tests to analyze the relative factors that influence bearing capacity of bolted joints.Creatively study the strengthening effect of joints after high strength mortar strengthening treatment of double bolted joints and node domains,and further study their failure process and final failure mode according to loaddisplacement curves.Apply finite element analysis software named ABAQUS to do node modelling and finite element simulation.Simulate the node loading condition of different tests,analyze the load-displacement curves in the loading process.Meanwhile,quantify the six factors that influence bearing capacity of bolts,evaluate degree of influence on the whole bearing capacity of joints and propose suggestions on design.By analyzing classical mechanics model of timber structure bolted joints by adopting plasticity theory,it is found that mechanics model of bamboo structure bolted joints have fewer limits in hypothesis and is better for theoretical formula to predict and represent actual value.Therefore,the formula for altogether six typical failure modes of non-filled bolted joints and high-strength-mortal-filled joints is deduced.The relative coefficient of computing value and test value reaches 1.01.This theoretical model can be used as a reference formula to calculate the bearing capacity of bamboo structure bolted joints.