Exploration On New Technology Of Prefabrication Of Standard Span Steel-concrete Composite Beams

This article relies on the construction technology project of the Ministry of Transport under the auspices of the Ministry of Transportation “Integrated/Half-width assembled steel-concrete composite simply supported beam bridge construction technology”(2018-MS1-019).For the widely used small and medium span bridges,the on-site operation of the existing assembly and construction technology is affected by human factors,environmental changes,material uncertainty,etc.,resulting in low work efficiency and difficult to control the quality of the project.The concept of the whole plant prefabricated cross-section steel-concrete composite beam is proposed.In this paper,the structural design principle of the whole-span precast steel-concrete composite beam,the process flow and equipment of the whole factory construction are systematically explored.The main research work is as follows:1.The conceptual design of pre-casting cross-slab-concrete composite beams is proposed.Analyze and compare the technical and economical characteristics of steel plate composite beam and steel box composite beam.It is proposed to use steel plate composite beam for the structural form of composite beam.2.Using the elastic analysis method,the steel beam floor stress and the flange stress on the bridge deck are taken as the control indexes.Based on the moment balance equation,the height of the full-factor prefabricated steel-concrete composite beam and the estimation formula of the floor area of the steel beam are proposed..Based on the comparative analysis of structural static characteristics,dynamic characteristics and economy,this paper discusses the cross-section selection of transverse joints of prefabricated steel-concrete composite beams.Based on the comparative analysis of the stress distribution,deflection variation and construction convenience of the bridge deck in the direction of the bridge and the transverse bridge,the section form of the bridge deck is discussed.3.Propose the production process of the whole factory prefabricated steel-concrete composite beam.Proposed to set the card slot device to automatically guide the steel main beam accurately in place.Exploring the adaptive height adjustment device of the bridge deck side formwork to achieve one-time pouring of concrete.Propose a feasible scheme for steam curing of bridge deck.