2007 Fiscal Year Final Research Report Summary
Seismic Performance and Soil Structure Ineteraction effects of Earth quake Response of Cable-Stayed Bridge Towers
| Project/Area Number |
18560459
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Structural engineering/Earthquake engineering/Maintenance management engineering
|
|---|
| Research Institution | Hokkaido University |
|---|
Principal Investigator |
HAYASHIKAWA Toshiro Hokkaido University, Grad. School of Eng, Professor (90002302)
|
|---|
| Project Period (FY) |
2006 – 2007
|
| Keywords | Cable-stayed bridge / Seismic performance / Dynamic interaction / Dynamic response analysis / Lever 2 earthquake / Energy dissipation system / Fiber elements / Initial imperfection |
|---|
| Research Abstract |
A nonlinear dynamic analysis including soil structure interaction is developed to assess the effects of soil-structure interaction on the seismic response and dynamic performance of the cable-stayed bridge steel towers. Numerical results indicate that considering soil foundation interaction and soil nonlinearlities can reduce response of the tower model. The soil yielding below the foundation and uplift at the interface have significantly contribution to foundation rocking response.
Passive control techniques are aimed at reducing and possibly eliminating plastic deformations of structures under strong earthquakes, by exploiting a predetermined favorable behavior of special devices inserted in the tower to provide a more flexible rocking or uplift of the bridge pier foundation. The numerical results show that allowing of limited rocking can reduce demands on the bridge structure, effectively acting as an isolation mechanism. The consideration of rocking as an acceptable mode of response can impact design costs by reducing the required footing size. In addition the simultaneous rocking of a properly designed foundation and flexural deformation of the supported-column is expected to eliminate or substantially reduce damage in the column and residual displacements in the bridge following a major earthquake.
Anew challenge to the earthquake engineering community is to develop new technologies that could improve the seismic performance of bridges. These new technologies consist of new construction materials (smart materials) and protective system. Shape memory alloy material concepts to improve the bridges seismic performance, are suggested by providing base plate anchor bolts at the tower base. The calculated results prove the effectiveness of using shape; memory alloy bolts in reducing structural element forces and control tower displacement for seismic design.
|
