Research On The Reliability Of Counterpoised Traveling Bridge-erecting Machine In Construction

Counterpoised traveling bridge-erecting machine is one of the main equipments of the under construction usage of the highway bridge. The thesis is based on the construction item of the SBTJ2 segment of Shangqiu—Bozhou highway grand bridge crossing Longhai railroad and Zhoushangyong River. Combining to the domestic and international interrelated research at present about the counterpoised traveling bridge-erecting machine, researches were done on the reliability of counterpoised traveling erecting mode in this thesis.The thesis evaluates the safety of the counterpoised traveling bridge-erecting machine with an additional weight moves on the bridge, namely, when the bridge-erecting machine works regard the bearing single bridge floor prestressed box beam (uncovered beam) as a simply supported beam, and calculate its strength. It is also the design and calculation of the bridge-erecting machine on varying span construction. Based on the original calculation results, the thesis test the real distortion status of the box beam on load and find out the stress distribution of bearing prestressed box beam under the worst status-varying span in the construction of the bridge-erecting machine.The research uses the block element to simulate the concrete beam body and the truss element for the steel bars and wires, and set up the finite element model of the box beam of the bridge-erecting machine. Considering the loading and boundary conditions of the model finite element calculation is carried out. Both for the working conditions of prestress and load, the finite element model of the box beam is approved to be suitable and correct by the actual test results. Aiming at the dissimilarity of space between crossties in paving tramroad of the moving bridge-erecting machine, some load experiments were did and a reasonable construction project was advanced combining to the finite element computing result.The actual loading test and finite element calculation results indicate: the maximal tension stress is within the range of permissibility and in the proximity of permissible value. Considering the influence of other loads and uncertain factors, the follows should be taken into account if the bridge erecting mode is continue to be used.(1) Strengthen beams of steel structure (the Bere Beam) with orbits, especially second half part of the Bere Beam;(2) Altering the space between crossties and increasing the support in the mid of station weight beam both can enlarge the decentralization function of the load carrying on the trunk beam, but usually the latter way is more effective. When the latter way is chosen, the stiffness of the support should be diminished correspondingly. Furthermore, adjusting the height of the support would help a lot in dispersing load.The results in this study have been applied in the construction of the Shangqiu—Bozhou highway grand bridge crossing Longhai railroad and Zhoushangyong River. Furthermore, they can be used as the reference for the similar engineering projects.