The 1996 seismic design specifications of highway bridges

This paper describes the revised Seismic Design Specifications of Highway bridges in 1996 as well as the background of the revision. Damage features of bridges in the 1995 Hyogo-Ken Nambu Earthquake is first described with an emphasis on the lesson learned from the earthquake. Seismic performance levels and design method as well as the seismic design force introduced in the 1996 Design Specifications are then described. (AU)

Current research efforts in Japan for passive and active control of highway bridges against earthquake

This paper presents current research activities on passive, active and hybrid control for application to bridge structures conducted at the Public Works Research Institute.(AU)

Seismic response control of highway bridges by variable damper

This paper presents analytical and experimental studies on the dynamic characteristics of a variable damper developed at the Public WorksResearch Institute. Effectiveness of the variable damper for seismic response control of highway bridges is analytically investigated. A small-size model of the variable damper is developed and the dynamic characteristics through the dynamic loading tests is also presented.(AU)

Menshin design of highway bridges in Japan

This paper presents the back ground of seismic isolation of highway bridges in Japan. The Menshin Design which emphasis to reduce deck response by increasing energy dissipating capability and to distribute seismic lateral force of deck to as many substructures as possible is presented. Design guidelines for the Menshi Design and its implementation are described. A new joint research program on Development of New Materials and Passive and Active Control of Long-span Bridges is introduced.(AU)

Seismic response control of highway bridges by variable stiffness control

Presented is a concept of the variable stiffness control bridge response against an earthquake. The proposed concept is to shift the instantaneous natural period of bridges using the variable dampers by avoiding the resonance with ground motions. The effectiveness of the variable stiffness control through the analytical simulation is presented.(AU)

Application of electro-rheological fluid for variable damper

This paper presents the potential application of electro-rheological (ER) fluid for the seismic response control of structural systems. Variable damper systems using ER fluid and the trial design are presented. The applicability of the ER damper for the seismic response control of structural systems are discussed.(AU)

Hybrid protective systems for seismic-excited bridges

Recently, several hybrid protective systems have been explored for applications to seismic excited bridge structures. In particular, two types of aseismic hybrid protective systems have been shown to be quite effective: rubber bearings and variable dampers (or actuators), and sliding systems. The control methods are based on the theory of variable structure system (VSS) or sliding mode control (SMC). Emphasis is placed on the direct output feedback controllers using only a few sensors. Sensivity studies are conducted to evaluate and compare the effectiveness of passive sliding isolators and hybrid protective systems for reducing the response of seismic-excited bridge structures. The advantages of each protective system are demonstrated by simulation results for a wide range of earthquake intensities.(AU)

Response of on-netoh bridge during Kushiro - Oki earthquake of January 1993

On-netoh bridge is being constructed in the East of Hokkaido for the replacement of the existing bridge. Menshin design using lead rubber bearings is employed for the On-netoh bridge. In January, 1993, the Kushiro-oki earthquake with magnitude of 7.8 occurred and it was the first time that a Menshin designed bridge experimented a major earthquake. This paper presents earthquake response characteristics of a Menshin designed bridge during the Kushiro-oki earthquake. The analysis of acceleration records measured close to the On-netoh bridge and the simulation analysis using the measured record are made.(AU)

Menshin design example of a highway bridge

This paper presents a Menshin design example of a highway bridge based on the Japanese design specification. The design of Yama-age Bridge which was completed in May 1993 in Tochigi Prefecture is presenetd as an example. The Yama-age bridge is of 6-span continuous concrete box girder with length of 246.3m. High damping rubber bearings were adopted as Menshin devices.(AU)