Approximate Calculation Of Design Indices For High-Performance Lightweight Composite Bridge Decks

At present,flexible asphalt concrete pavement,such as asphalt concrete,has been under adverse conditions of high temp erature,pavement crack,rut,and interlayer failure,etal.And because of its low stiffness it is prone to fatigue cracking.For the the long-span steel bridge which is sensitive to its own weight,we have to reduce its weight as much as possible in satisfying the mechanical performance requirements of steel bridge deck at the same time.To this end,this paper proposes a "steel-UHPC-TPO" ultra-thin pavement system of 41~48 mm thickness.we have studied mechanical properties of the pavement system and conclu ded the key parameter of mechanics performance index.Then,the approximate calculation formula had been fitted out.This paper mainly completed the following work:(1)The deficiency of traditional flexible and rigid orthotropic steel bridge deck pavement were expounded.The "steel-UHPC-TPO" ultra-thin pavement system was proposed.(2)Finite element model of "steel-UHPC-TPO" ultra-thin pavement system was established.The orthogonal experiment design of related parameters of tensile stress of UHPC and TPO layer,local deflection span ratio,UHPC-TPO interlayer shear stress,and shear stress of stud were finished.According to the parameter selection in orthogonal table,the finite element calculations were completed.And then,a maximum of all indexes were got.Extreme analysis and variance analysis of calculation results of the orthogonal experiment w ere completed to get the key factors of various indexes.(3)According to the Latin hypercube sampling of key factors,we get the approximate calculation formulas of maximum tensile stress of UHPC and TPO layer,maximum local deflection span ratio,maximum UHPC-TPO interlayer shear stress,and maximum shear stress of stud.(4)The reliability of formulas of maximum tensile stress of UHPC and TPO layer,maximum local deflection span ratio,maximum UHPC-TPO interlayer shear stress,and maximum shear stress of stud were tested,such as statistical tests,experience tests,and experiment tests,etc.The results show that the linear correlations and regression effects of the formulas were significant.The maximum deviations between the finite element results and the fitted values of maximum tensile stress of UHPC and TPO layer,maximum local deflection span ratio,maximum UHPC-TPO interlayer shear stress,and maximum shear stress of stud are less than 10%.The qualitative analysis were consistent with the general engineering experiences.Deviations between the formula calculations of maxi mum tensile stress of UHPC and maximum local deflection span ratio and the measu red values of the indoor tests are less than 10%.Formula calculation of maximum shear stress of stud is greater than 9.6% of the measured value in the laboratory.