| Prestressed steel-concrete composite structure is a new type structure，in whichthe steel and concrete are integrated to take advantage of their properties in tensionand compression．The mechanical properties of the structure are affected by thematerials, the structural response in different stages and the performance of shearconnectors. The inclined steel-concrete composite pylon of the Dongguan LichuanBridge employs the PBL shear connectors to transfer longitudinal shear forces acrossthe steel–concrete interface. Due to the complexity of the structural mechanism andlong-term creep effect of the pylon and the shortage of the guideline and specificationfor the design of the pylon. Hence it is necessary to conduct the study through modeltest and numerical simulation.(1) The3D FEM analysis according to the standard code is conducted to checkwhether the structural index satisfies the requirements of specification or not.(2) The ultimate load capacities of perfobond strip used in the Lichuan Bridgeare analyzed according to the6methods proposed by Leonhardt, Hosaka, Nishiumi,Oguejiofor, Zong Zhouhong, Hu Jianhua and other researchers. The forcetransmission performances of6kinds of perfobond strip in the elastic stage arestudied. The diameter of the holes and the distance between them have effect on thethe shear capacities, whearas the effects of the reinforcement bars are not obvious.(3) Parameter analysis for4concrete creep models are conducted. Based on theassumptions of plane section and deformation harmony, an age adjusted effectivemodulus (AEMM) method is presented to deduce the creep model of the prestressedsteel-concrete composite structure considering the content of steel rebar and elasticmodulus ratio. The effectiveness of the creep model is verified via FEM-basedparametric analysis. By using the user-defined algorithm, the constitutive relation ofthe materials and the creep criteria via ANSYS,4creep models, the TEST-AI209-92model deduced in the paper and the elastic creep equation are introduced to ANSYS toachieve the finite element solution of the prestressed steel-concrete composite pylon.(4) According to the structural characteristics of the prestressed steel-concretecomposite pylon of Lichuan Bridge, a segmental model of the key area of the pylon isselectde to conduct a one-year creep test. An observation on the environmenttemperature, humidity, prestressed tendon force, strain of the steel plate and concretewas lasted for a period of one years. The measured time-history curve of these experimental data indicates that the TEST-ACI209-92model is valid for creepcalculation. |
PDF Full Text Request