Jeong-Hun Won

Behavior of Partially Earth Anchored Cable-Stayed Bridge Considering Construction Phase and Operational Phase

In this study, the behavior of a cable-stayed bridge with a partially earth anchored cable system was studied both for the construction phase and for the operational phase. The recently constructed 3- span cable-stayed bridge with a usual self anchored cable system in Korea was modified into a partially earth anchored cable system. According to the FCM construction method, the construction sequence analysis was performed to find optimal cable stressing forces. Effects of the systems with partially earth anchored cables were examined by comparing the self anchored cable system. The behavior of the partially earth anchored cable-stayed bridge in the operational phase was investigated. The live load analysis was carried out according to the Korean vehicle class. Also, the response spectrum analysis for the seismic load and the buffeting analysis for the wind dynamic load were carried out. From these results, it is shown that the partially earth anchored cable-stayed bridge increases the resistant capacity against the service loads.

Analysis of Design Wind Load Level for System Supports Considering Local Basic Wind Velocity and Construction Period

This study evaluated wind loads considering a local basic wind velocity and construction periods to define the level of applied wind loads for system supports. Structural responses of system supports were examined and compared to those of system supports with the level of wind loads following various standards and specifications for permanent and temporary structures. And, the maximum combined stress ratios were estimated to evaluate the structural safety of a considered system support. From results, it was found that the wind load level should be applied in accordance with construction periods when estimating the safety of system supports. Looking into the response by change of the basic wind velocity according to local regions, it is no need to consider wind loads in regions with the basic wind velocity of 30 m/s. However, it was analyzed that wind loads should be considered in the regions with the basic wind velocity of 40 m/s or above. In addition, wind loads should be considered in designing system supports located at the region with the basic wind velocity of 35 m/s starting from construction period of 1.5 years. The standard specification for temporary work was analyzed as an incorrect standard in evaluating wind loads, since it underestimated the response of system

Analysis of Support Reactions of RC Slab Bridges with Various Skews

The support reactions of two-span RC slab bridges with various skews are studied through the time history analysis for moving vehicles. Dynamic behaviors of bridges are evaluated by using the commercial FEM code and the bridge is modelled using shell elements. The analysis method is verified by comparing measured values and analysis results. Parametric analysis are performed for various skew angles. The bearing below the end slab with an obtuse angle shows the largest reaction forces. As the skew angle is reduced(a skew angle of means a straight bridge without skew in this study), the distribution of reaction force is growing uneven and the largest reaction force is increased. In case of the model having skew angles under , the bearing located near the bearing with the largest reaction force shows the uplift force. Thus, it is concluded that the bearing in RC slab bridges with skew should be selected carefully by considering the variation of reaction force and uplift force.