Study On The Mechanical Properties And Key Technology Of Prestressed Concretecontinuous Bridge

ABSTRACT:As an essentially important part in the construction of transportation,prestressed concrete beam bridge has been rapidly developed. In the range of span from40m to200m, either from the aspect of the structure mechanical properties or from that of economic requirements, prestressed concrete continuous beam bridge is always ahypothetical selection. Therefore, it also shows the significance of researchingprestressed concrete continuous beam bridge from the aspects of both the design and construction techniques.In this paper, a three span prestressed concrete continuous girder bridge (65m+100m+65m) was the research example, the key technology for design and construction was researched. And based on the current construction technology and research experience, the construction technologies ofupper structure for this kind of bridge, including some issues in construction, are further studied and analyzed after calculation.The main research works can be drawn as follows.(1) The development situationof prestressed concrete continuous girder bridge in both domestic and foreign countries including Afghan, is investigated and discussed, the characteristic and developing trend of this kind of bridge is introduced, the key content, design calculation and analysis methodologyare presentedin this paper.(2)According to the current design code and experience, design parametersof the prestressed concrete continuous girder bridge is drawn up, and the calculation model was established based on finite element analysis software Midas Civil, and the change of internal forces and deformation valuesof the whole bridge are computed and analyzed, including that of cross section in different T structuresduring cantilever construction stage. Effects of different construction closure schemes on thestress and linear of whole bridge are analyzed,together with the change of3years’and10years’shrinkage and creep of the concrete,and based on the advantages and disadvantages of different schemes, useful conclusions are drawn.(3) Temperature loads in design codesof Chineserailway bridge and highway bridge are elaborated simply, combined with that in American, British, Australia, New Zealand. Based on the above specification, stress and deformation of prestressed concrete continuous girder bridge under temperature loads are carried out and researched, and the tendency of the continuous girder bridge under different temperature loads aresummarized.(4) Construction method of continuous girder bridge is studied, includingbracket casting method,prefabricate installation method, cantilever construction method and incremental launching constructionmethod, erection by swing method, etc. And studied the cantilever construction technology of prestressed concrete continuous girder bridge, including the cantilever construction technology in hanging basket construction cast-in-site segments, bracket cast-in-site segments in side spanand closure section, and including various stage in the mass concrete casting, thebracket construction, the template installation, steel bar construction,prestressed tensioning construction and the prestressed pipe construction and so on.What’s more, the structure measures and construction method of temporary locking measuresin closure segmentis also studied.