Abstract:In order to save the land and reduce the construction period, the double-layer viaduct structure type co-built for urban expressway and rail transit is adopted in an airport expressway project. Its substructure is a Y-type pier. The co-built viaduct of urban expressway and rail transit is a new bridge structure to save the space, improve the efficiency and beautify the environment, and but also faces the complex force and seismic problems. In order to meet the requirements of highway and railway specifications, the lower crossbeams and piers are designed with the dual control of allowable stress method and limit state method. In the seismic design, the influence of the long steel rail restraint of the seamless line of the track girders should be considered, and the influence of the incorporated foundation and the succeeding structure are also considered, which can be calculated more accurately and reasonably. The calculation results show that the static and dynamic properties of the bridge can meet the code requirements. The basis is provided for the design and construction of this type of bridge.
