Optimization for design parameters of highway bridge approach slab

SHEN Yupeng; ZHANG Yaoyu; CHAI Shushan; WEI Qingchao; CHEN Dunchang; NI Yongjun

doi:10.11860/j.issn.1673-0291.2017.03.009

Abstract：Two parameters are applied as control indicators,including the dynamic wheel load fac-tor and the allowable step height between the bridge and the bridge approach.Besides,the vehicle model with seven degrees of freedom and the three-dimensional dynamic model of transition sec-tion are established to analyze the dynamic characteristics of vehicle and approach under different combinations of slab parameters.And the optimum design parameters of bridge approach slab are proposed,including thickness,elastic moduli,length and buried depth of the slab.The results show that when the faulting of slab ends is considered,if the thickness of the slab is no less than 30cm,the elastic moduli is over 2.8×104 MPa,and the length is 8.3m,the slab can meet the re-quirements of a slight bump and reach the dynamic rear wheel load factor standard of the B class road.While the elastic moduli is 2.8×104 MPa,the length is 8.3 m,and the thickness is no less than 45cm,the slab can meet the dynamic rear wheel load factor standard of the A class road.When overlooking the faulting,if the thickness of the slab is 30cm,the elastic moduli is 2.8×104 MPa,and the length is no less than 8.3 m,the slab can meet the dynamic wheel load factor standard of the B class road.However,the buried depth of slab has little effect on the cumulative settlement of subgrade.In order to meet the dynamic wheel load factor standard and the require-ments of a slight bump,we advise to choose C25as the material of bridge approach slab and make sure that the thickness is over 0.3m,the length is no less than 8.3m,and the buried depth is no more than 0.1m.