Main Design Parameters Optimization and Experimental Research on UHPC Box Deck System
The reasonable ranges of primary design parameters of the deck system consisting of UHPC box girders,UHPC panels and UHPC stitching joints between panels are studied.An existing simply-supported UHPC box girder bridge spanning 102 m is used as a case.The parameters,including UHPC panel thickness h1,the diaphragm depth h2,diaphragm thickness b,and diaphragm interval L,were optimized based on the single parameter influential effect analysis and design optimization simulated in ANSYS.A 1:2 scale-down mockup of the UHPC deck after optimization was prepared for tests,and finite element analysis was conducted.The parameters associated with the anti-cracking performance of the UHPC deck(diameter of tension rebars in the diaphragms and diaphragm depth)were analyzed.It was concluded that the reasonable ranges of h1、h2、b and L are 1/40-1/35,1/10-1/8,1/37-1/31,and 1/2.8-1/1.4 of the transverse spanning of the top plate(exclusive of flanges)of the single-cell UHPC box girder,respectively.The values of h1,h2 and b should not be less than 14,55 and 15 cm,and L should not exceed 4 m.The optimization in ANSYS basically agrees with the optimization of the indexes of the mechanical property of the UHPC deck,resulting in 11.0％saving of the UHPC used for the whole bridge.The diaphragms are prone to lateral bending failure(in the surface),which are considered the components under most adverse loading condition.The stresses causing cracks are 2.14 times of the design values,indicating large safety margin.Enlarging the diameter of tension rebars in the diaphragms and increasing the depth of diaphragms can effectively improve the anti-cracking performance of the UHPC deck system.
UHPC box girderdeck systemdesign parameteroptimization designanti-cracking performancemodel testfinite element method
万方数据
维普
