| During the bridge building, Incremental Launching Construction Method(ILM) has already been one of continuous beam construction methods which has strong competitiveness because of its few occupation of land ,no effect on the headroom under bridge, simple construction equipment, little cost of erection and stable quality . However, comparing assembling pre-cast push with cast-in-site push, the former is safer, faster, more environmental and more inexpensive. Therefore, research of assembling prefabricated push is of great significance.This paper took the Huai Fu railway bridge(18×50m) in the north of HuaiHe Bridge as an example, analysed how to guarantee the safety of the design in the situation of overweight vehicles. Some discussions were studied as follows:Firstly, researching crack status of PC continuous bridge, analyzing the reason for overrun of principal tensile stress at web cracks, the principle tensile stress increasing main factorηand the abolition conception that the longitudinal vertical prestress is replaced by the web is proposed, and demonstrated its feasibility, at last simple design formulas of principle main tensile stress is obtained, which provide the theoretical basis for ILM design.Secondly,research in ILM pre-stress design. First, prestress reservoir need achieving 3MPa in the process of ILM, and the convenience in the lately cable construction is should also taken into account when the prestress stress reaches 3MPa in the operation condition, so that it can ensure the crack can not appear in the early time under the overweight vehicles .Thirdly,research in assembling construction technology. Under the experience in the past, Huai Fu on the railway bridge across L1 900m assembling technology was studied, so that the push task could be completed with safe, fast and save.Fourthly, using the major bridge software MIDAS / CIVIL, the pushing process and the bridged stage (130t considered overweight vehicles) were simulated to validate the validity of new ideas and the reliability of new methods.The purpose of this paper is to provide some technical reference to similar bridges'design and construction, through Huai Fu assembling prefabricated bridge pushing research. |
