Development of a bridge pier foundation structure that simultaneously realizes high earthquake resistance and excellent economy

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K18144
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Geotechnical engineering
• Research Institution: Hokkaido University
• Principal Investigator: Isobe Koichi 北海道大学, 工学研究院, 准教授 (70452084)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 杭基礎 / 橋脚 / 耐震 / 損傷制御設計

Outline of Final Research Achievements

A multiple steel pipes bridge pier integrated by pile foundation without a footing has been proposed to design a rational foundation of the bridge pier structure. The proposed substructures possess an excellent advantage of reduction of strain at the column through strain decentralization at footing point. In addition, reduction in footing weight contributes to decrease pile strain. The seismic performance of the proposed bridge pier structure grounded in dry sand and liquefiable sand is evaluated based on the large-scale shaking table tests and numerical simulation. As a result, the proposed structure has advantages of strain reduction of column by strain decentralization at footing point. It is recognized that it has high seismic performance and high toughness in view of the fact that the main members hold a large residual strength after yielding of the shear panels.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

フーチングの省略と杭本数の削減による大胆なスリム化橋脚基礎構造は，高い耐震性と優れた経済性を同時に実現可能であることを明らかにした．特に，初期コストと地震ライフサイクルコストの両面から大幅なコスト縮減の達成が可能で，その経済的波及効果は大きい．また，当該構造の設計には，地上部と地中部を分離して設計していた従来設計手法とは異なり，上下部基礎工を一体で計算し，高精度に地盤と構造物の相互作用，地震時応答挙動を把握する必要があり，それを実現する高度な数値解析手法を確立した点は学術的・工学的にも大変意義深い．