| In recent years,with the rapid increase of urban traffic load,the bridge faces a lot of problems of demolition and replacement and new expansion.Steel-concrete composite bridges have increasingly become an important choice for bridge engineers.This paper elucidates the advantages and disadvantages of the steel-concrete composite bridges system applied to small and medium span bridges.It is found that the cracking of concrete bridge decks has become a major challenge restricting the rapid development of composite beams,and it is urgent for engineers to solve them.In order to provide new ideas for solving traditional bridge diseases and problems,a new sustainable steel-UHPC waffle composite beams is proposed,in which highperformance materials UHPC are attached to the high-strength steel beams from the material level.In this paper,the steel-UHPC waffle composite beam is taken as the research object.The reasonable shear design methods are recommended based on the experimental,finite element and theoretical results to achieve the performance-oriented shear design.The main results of this paper are as follows:1.An innovative steel-UHPC waffle composite beam system was proposed in this paper.The influences of shear span,depth of the rib,and width of the UHPC waffle slab on shear performence were studied in this testing program.The test results reported the typical failure modes of the composite beam,and their respective ultimate strength behaviours in terms of load versus deflection(or strain)curves and load-transferring mechanism.2.Three-dimensional finite element models were developed for the steel-UHPC waffle composite beams using the commercially available softwarepackage ABAQUS.The accuracy of the FE models were verified by comparison with the experimental results.The load-transferring mechanism on shear behavior of the composite beam was analyzed deeply.The main factors of the shear performence of the beam were investigated.The difference on the normal working state and the overall working state between the original composite beam and the composite haunch beams was compared.Finally,the grade of steel beam and the height ratio between top plane and ribs of waffle slab were recommended in the design of practical engineering.3.The theoretical formula of composite beams based on the test results was modified to meet the calculation of shear resistance of steel-UHPC composite beams.Through extensive parametric studies using the finite element method,the influence coefficient of shear bearing capacity of the plane of the waffle slab and the ribs of the waffle slab were gived.The bending and shear interaction formulas based on the test results and the FE predictions of the composite beam were suggested.The accuracy and feasibility of the formula was verified by comparison with the observed experimental results. |
PDF Full Text Request