Development of an energy-based redundancy evaluation method for steel bridges

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K14718
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Structural engineering/Earthquake engineering/Maintenance management engineering
• Research Institution: Gifu National College of Technology
• Principal Investigator: Mizuno Yoshinori 岐阜工業高等専門学校, 環境都市工学科, 准教授 (90585093)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: リダンダンシー評価 / エネルギー / トラス橋 / 桁橋 / 崩壊挙動

Outline of Final Research Achievements

Experiments performed on the collapse of a truss bridge model due to the sudden failure of the lower chord have confirmed that brittle fracture of the bolted connections of the lower chord of the opposite panel can lead to instantaneous large-scale collapse. In addition, it was determined that the collective system could not be expected to absorb the energy generated by the collapse through a chain of member failures, as is seen in so-called progressive failures. Therefore, this study investigated the applicability of a collapse prevention system using cables that could be easily installed as a method for preventing the large-scale collapse of an entire system as a result of sudden member failure. A numerical study was also carried out to investigate the collapse behavior of minimized girder bridges with insufficient redundancy when the lower flange and web plate were suddenly fractured at the center of the span.

Free Research Field

構造工学

Academic Significance and Societal Importance of the Research Achievements

トラス橋の大規模崩壊は甚大な被害をもたらすので，大規模崩壊を回避する何らかの方策を講じることが必要である．大規模崩壊しないようにするための本質的な方策は部材補強などにより構造系のロバスト性を向上させ構造系の吸収エネルギーを大きくすることであるが，設計荷重に対する安全性・使用性の照査を再度行うことも必要となり，工期・工費の面で適当でないといえる．そのため，施工が容易な崩壊防止策として汎用的なケーブルを用いた崩壊防止装置の適用性を検証した．