Parameter Sensitivity Analysis On Construction Error Of Three Main Trusses Continuous Steel Truss Bridge

Double-deck steel truss bridge structure have many advantages:it can meet traffic demand of upper layer and lower layer, take full advantage of river way, land and space, has a board vision. it not only has good conomic benefits, but has significance in technique. As the economic developing, increasing traffic and the ipmroving level of bridge technology in China, the application of double-deck steel truss bridge will be a trend in some economically developed areas or special natural areas. Due to a number of structure members and points in closure, the space of points in closure is difficult to control, and during construction, construction errors will have effect on structure linear, resulting in the structure members difficult closure and install. Therefore, by analyzing construction error parameter sensitivity, the changes of internal force and linear and the impact of construction errors on the structure is studied, which have a important engineering significance in safety construction and successful closure.In this paper, double-layer steel truss highway bridge-Dongjiang Bridge as the background. The construction error impacting on steel truss bridge and stiffening string closure is described, and Midas/Civil finite element analysis of full-bridge model is established. Using Midas/Civil, main parameters of the bridge model, the construction boundary conditions and construction phase is simulated. by calculating parameter sensitivity analysis of the main error effect on closure with construction, mechanical characteristics and linear of steel truss beams effected by error parameters under different condtruction phase is got.The analysis results show that error parameters of the load and stiffness play a small part in the main trusses stress, but have great effect on structure linear. the main trusses stress and the structural linearity is large impacted by forced closure, so it should be avoided in construction and make full use of temperature difference to closure.The error parameters of lateral and longitudinal internal force adjustment have a great effect on main truss stress, during construction monitoring, these error parameters should be payed much attention. a variety of negative error parameters same produced, impact the main truss stress, which make the maximum combined stresses of upper and lower chord in some parts greater than the value of allowable stress.Construction error stress have a negative impact on the main barThe change of on struction error parameters have great effect on the largest cantilever state, the main truss closure, internal forces and the linear in bridge phase by comparing the calculation error parameters under changing condition with the result of ideal design, which should be given adequate attention in construction.