| Title |
Effects of Post-Tensioning Tendons and Vehicle Speeds on Dynamic Response of Concrete-Filled Steel Tubular Tied Arch Girder |
| Keywords |
CFTA girder;FEM analysis;post-tensioning tendon;tendon quantity;moving vehicle load;dynamic amplification factor;korea highway standard specification;CFTA 거더;유한요소해석;외부긴장재;긴쟁재양;이동차량하중;동적증폭계수;도로교설계기준 |
| Abstract |
The CFTA girder developed is a concrete filled steel tubular system with arched shape and external post-tensioning (PT) tendons which control the initial camber and the bending stress of the girder. In the present study the effects of the PT tendons on the dynamic behavior of the girder subjected to a moving vehicle load are numerically investigated. Various levels for the tendon quantity and the tendon forces are considered, using the existing FE model of the girder. The vehicle considered is a DB-24 truck and is modeled with two tracks-three axles. Equivalent-load pulse time histories are applied to each node to simulate the moving vehicle, depending on the time of arrival and the discretization. The vehicle speeds are varied from 40 ㎞/hr to 100 km/hr with increment of 20 ㎞/hr. The analysis results show that the tendon forces do not produce any influences on the dynamic responses of the girder. However the dymamic deflection of the girder increases when a smaller amount of tendons is used. The Dynamic Amplification Factors (OAF) are evaluated based on the static and dynamic responses. Much lower values of the OAF are obtained, even no tendons applied, than those provided by the design criteria of the AASHTO LRFD and the Korea Highway Standard Specification. |