Title: Studies in the Reinforcement of Bridge Seats Against Earthquake

Author(s): Y. Shioi, Y. Mitsuie, and T. Shimizu

Publication: Symposium Paper

Volume: 70

Issue:

Appears on pages(s): 587-623

Keywords: bridge foundations; bridges (structures) ; cracking (fracturing); earthquake resistant structures; loads (forces) ; load tests (structural); reinforced concrete; structural design; substructures.

DOI: 10.14359/17429

Date: 1/1/1981

Abstract:
As earthquakes often occur in Japan, the dimensions of the substructures of bridges and their supports are mainly depending upon seismic load. In order to prevent the fall of superstructure or breaking of bridge seat concrete, the 'Substructure Specifications for Highway Bridges' published in 1968 has defined the necessary distance from the edge of a bearing to the edge of a bridge seat in proportion to span length. Various types of damage to supports resulted from the Miyagiken-oki Earthquake in 1978. In consequence of a detailed investigation, the damage found among substructures could be classified into breakage of bearings and anchor bolts, cracking of bridge seat concrete, and slight damage to supports. The authors have undertaken a series of loading tests on bridge seat concrete to confirm the safety of structures built to present specifications and to examine more effective reinforcements, and have analysed the measured data. They have thus been able to confirm the validity of the specifications and have been able to propose some effective reinforcements.