The Mechanical Properties Analysis Of Steel Expansion Joints In Continuous Rigid Frame Aqueduct With Long-span

Due to the water supply needs in distant mountain area increasing much,the form of aqueduct with high pier and long span continuous rigid frame appears.The length of the expansion joints is extended as well,which makes the traditional aqueduct expansion joints fail to meet the requirements in the force,deformation and durability,etc.Thus,a new form of steel telescopic joints,setting at the junction of the continuous rigid frame aqueduct and the end of simply supported aqueduct,is proposed in this paper.This paper takes steel structure expansion joint of XuJiaWan that the water conservancy hub of central Guizhou as the research object.Structure geometric nonlinear analysis model is established to calculate and analyze the stress levels of the telescopic joints in the case of the internal water pressure,axial relative displacement,lateral relative displacement,and vertical relative displacement.According to the results of finite element analysis,the mechanical properties of the joints are evaluated and the parameters are optimized.The results can be used as reference for the relevant engineering design,construction and applicationThe main contents include the following aspects:(1)Combined with the structural characteristics and stress characteristics the aqueduct expansion joints,the preliminary design of the expansion joint for aqueduct is carried out.(2)Considering structural geometric nonlinearity,finite element analysis of the aqueduct that includes the force distribution and value of the stress under the internal pressure,displacement load and combined load.And compared with the calculated values of American Society of Expansion Joint Manufacturers' standards(EJMA),it can be seen that the value calculated with the EJMA agrees well with finite element solution.(3)The parametric analysis of the expansion joints is carried out to explore the variation of the stress of the large-scale expansion joints.The parameters include radius,height,thickness.Then the telescopic joint is optimized.At the same time,two independent models are established,which are applied with axial pull and internal pressure,respectively.Taking the telescopic wave height,wall thickness and ripple radius as the design variables,taking the stress as the result variable and the unit volume as the objective function,the optimal value of the weight is obtained.(4)The contact element is used to simulate the interaction between the hoop and the telescopic joint under internal pressure.Moreover,the stresses at the troughs were extracted,compared with the stress of trough of telescopic joints without hoop.The results indicate that the hoop can effectively reduce 50% to 70% of the stress value.