To increase together damping force and horizontal force of constraint, by comprising a lead cylindrical damper containing a steel rod in a manner that a steel rod having approximately the same length as the height of a lead cylinder, is inserted in a hole opened in the center part of the lead cylinder.
In this damper 8a, a steel rod 14 having approximately the same length as the height of a lead cylinder 13, is inserted in a hole opened in the center part of the lead cylinder 13 comprising a large diametral mounting lead cylindrical part 12 formed at both upper and lower ends of a main lead cylindrical part 11. In this damper 8a, the mounting lead cylindrical part 12 is inserted in, fitted and fixed to upper and lower damper mounting hardwares 15a, 15b which are respectively fixed on a beam 4 and an abutment 1. When an earthquake occurs, the abutment 1 responses to the vibration of a ground so that relative movement in a horizontal direction occurs between the abutment 1 and the bean 4 thereby, positioning relation between the upper and lower damper mounting hardwares 15a, 15b is shifted. Hereupon, the damper 8a is plastically deformed as shown by an imaginary line 22 thereby, most vibration energy in the horizontal direction can be absorbed and amplitude of vibration can be diminished. At the same time, the steel rod 14 increases horizontal force of constraint so as to control the horizontal displacement of the beam 4 therefore, the steel rod 14 can be prevented from being fallen from the abutment 1.
TSUCHIYA HIROYUKI
SAKUMIYA KAZUYOSHI
NOYORI TOKIHIKO
TOHO ZINC CO LTD
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