Research And Application Of Bridge Deck Pavement Technology For Steel-Concrete Composite Girder Bridge

The steel-concrete composite girder bridge has the advantages of both steel structure bridge and cement concrete bridge.It has the characteristics of reasonable force,moderate cost,rapid construction and so on,and was especially suitable for the construction of small or middle span bridge in highway and urban roads.At present,China doesn’t proposes relevant standards and specifications for steel-concrete composite girder bridge deck pavement.In order to adapt to the wide promotion and application of steel-concrete composite girder bridges in the future in China,this paper relies on the bridge deck pavement project of the South-to-North Water Transfer Bridge in the Qugang Expressway to study mechanical properties of the pavement structure of the steel-concrete composite girder bridge,the optimization design of the pavement material,the construction technology and quality control of the bridge deck pavement and so on.Firstly,this paper establish the mechanical model of the steel-concrete composite i-beam approach bridge of the Qugang Expressway South-North Water Transfer Bridge by using the finite element analysis software,and calculates the pavement structural layers following reasonable basic assumptions and parameters;According to conclusions of invsetigating and analyzing the bridge deck pavement disease,it builds relationship between common disease of the deck pavement layer and the stress or strain of the pavement structure,the maximum tensile stress and the maximum shear stress in the pavement layer,the maximum shear stress between the deck and the pavement layer are used as the design control index;under the standard load,the longitudinal most unfavorable charge position of the bridge span and the lateral most unfavorable charge position of the cross bridge to the load I are determined;under the variation of the thickness and modulus of the pavement layer,The mechanical response law of the pavement layer is obtained,and the design requirements of the modulus of the pavement material and the thickness of the pavement layer are proposed.Secondly,based on the structure type of hot rolled asphalt mixture and the strength theory of asphalt mixture,it is determined that the modified asphalt of hot rolled asphalt concrete is prepared by SBS+HRA composite modified matrix asphalt;the SBS of different sets of HRA is set up.For the asphalt samples,the conventional performance test and microscopic observation methods such as penetration at 25 ℃,softening point,and 5℃ ductility were used to determine the reasonable dosage of the special modifier HRA was 8.0%;the special modified asphalt was 135℃,Brookfield viscosity test at 155 ℃ and 175℃,comprehensive consideration of engineering practice experience,to obtain hot rolled asphalt mixture mixing and compaction temperature;based on the British standard BS 594 recommended grading range,consider China’s climate and the traffic conditions,adjust the key mesh pass rate to obtain the HRA-13 grading range applicable to the underlying layer of the steel-mixed composite girder bridge;adopt the Marshall design method and supplement the high and low temperature performance test to obtain the HRA-13 design gradation.And the best oil-stone ratio OAC=6.2%;finally,the designed hot rolled asphalt concrete HRA-13 adopts 60℃ rutting,-10℃ and-15℃ low temperature bending,freeze-thaw splitting,water-immersed Marshall and 750με four points bending labor and other laboratory tests were used to verify the performance of the road.Thirdly,based on the performance requirements of the upper layer SMA of the bridge deck pavement,in order to improve the asphalt viscosity as the research entry point,it is proposed to prepare the high performance modified asphalt for SMA by SBS and high viscosity modifier HVA composite modified matrix asphalt;The regression relationship between the 60℃ dynamic viscosity of high performance asphalt and the high temperature stability,low temperature crack resistance and water stability of SMA mixture,and the high performance asphalt should meet the design requirements of high performance SMA mixture.60℃ dynamic viscosity ≥300000Pa.s,combined with technical economy,construction workability,etc.to determine the high viscosity modifier HVA reasonable dosage is 8.0%;reference SMA-13 specification grading range,using Marshall method for SMA-13 designed with the best ratio of oil to stone,OAC=6.6%;finally,the performance of the designed high performance SMA-13 was verified by the 60℃ rutting test,-10℃ low temperature bending test and water stability test.Fourthly,the three types of commonly used waterproof bonding materials for cement bridge decks are selected for basic performance tests such as impermeability,drawing and drawing.Considering the technical advantages of waterproof adhesive layer and construction workability,water is preferred.Epoxy modified emulsified asphalt is used as waterproof adhesive layer material for steel-mixed composite beam bridge;multiple sets of emulsified asphalt samples with different waterborne epoxy content are set,and the indoors are obtained under the mechanical requirements of deformation,shearing and drawing resistance.The reasonable content of waterborne epoxy in the self-made waterborne epoxy modified emulsified asphalt is 30～40%;the composite test pieces with different sets of different waterproof adhesive layers are formed,and the construction of waterproof adhesive layer is determined by interlayer drawing and oblique shear test.The reasonable dosage range is 0.8～1.4kg/m2;the curing state of waterborne epoxy modified emulsified asphalt material under different dosages and different curing temperatures is observed and recorded,and the recommended time for waterproof adhesive layer under different conditions is proposed.Fifthly,based on the comprehensive indoor research results,considering the actual situation of the project,the implementation plan of the steel-concrete composite girder bridge pavement of the South-to-North Water Transfer Project is proposed.Based on the implementation of the project,the steel-mixed composite girder pavement construction technology and quality control technology are expounded.