Large Curvature Continuous Curved Steel Box Girder Bridge Ultimate Load Analysis And Experimental Research

The curved steel box girder has many advantages such as good torsion performance, best stess performance , light weight, succinct and beautiful appearance, made simply and construction in short time. The application of continuous steel box girders with large curvature is used widely in construction of city viaducts and crossroad. Especially, it is very convenient to cross some special occasions as the ground crack, over lines, etc.. The curved lines of this bridge are smooth and the artistic conception is vivid, so it can give people the beautiful feeling, and the curved bridge can well meet the demand of the topography, surface feature limit. In addition, the continuous curved steel box girders which joined in the form of welding is made simply, and its construction is convenient, so the cost is not very high generally. So whatever from geometry, aesthetics or economy, this bridge will have development prospect. So, there are important realistic meanings in the study on this kind of bridge.In this paper, the ultimate load carrying capacity of continuous steel box girders with large curvature is studied in full. First of all, according to space size, material characteristic, connection way of the original bridge, make the 1/10 of the proportions model bridge. Then, carry on space finite element analyse to model bridge by finite element procedure Ansys7.0, and confirm the ultimate load carrying capacity of model bridge in different load condition. Basing on analysis above it can be known:Load of model bridge in corresponding with control load which is guache-120 of original bridge is 11.62kN; The load carrying capacity of model bridge under the control of allowable stress is 63kN; It can be known from steady bucking analysed that the least load which made the first step of lost steadily is 208.04kN ; The ultimate load carrying capacity when model bridge is destroyed is 162kN; Also this text includes the study of shear lag effect of the model bridge in elasticity, elasticity and plasticity , complete plasticity. The analysis above can confirm that the model bridge is very safty, and will not lose the steady in the whole course. On this basis, according to the condition of the laboratory, choosing one named loading in two middle sections of middle spans of model bridge which can be realized in laboratory and have representative, it can ensure through the comparing and analysing of the result of the test and that of space finite element calculation of every load grades that the analysis of above-mentioned is reliable. In the course of testing, the worst section of model bridge is the middle section of five meterspan, and when the load had been added to 156.7kN. the inside web and the weld of floor and outside web of this section had cracked. Finally, according to the resemblance between original bridge and model bridge, the analysis result of model bridge can reflect the performance of original bridge. Thus it can confirm the security performance of the original bridge and the destruction shape that may appear finally. This text can offer reference in calculating of design for similar bridge and offer the technical data for criterion revision of steel bridge.