圓形鋼管橋墩之耐震徑厚比與破壞風險分析
Other Title
Seismic Compactness and Risk Assessments of Circular Steel Bridge Piers
Journal
結構工程
Journal Volume
40
Journal Issue
2
Start Page
67
End Page
96
ISSN
1021-7878
Date Issued
2025-06
Abstract
橋墩為橋梁之韌性構件，當橋梁遭逢極端地震時，可藉塑鉸消能降低橋梁整體結構之損壞。因此，使其展現足夠強度對於橋梁之耐震設計極為重要。我國相關耐震規範中對鋼橋墩設計著墨甚少，使實務設計上無明確可遵循之依據，僅能參考他國耐震設計流程進行設計，惟各國耐震設計規範之精神及性能要求不盡相同，應進一步檢討後方可採用。此外，過往鋼橋墩之相關研究多以斷面性質、加載方式等因素探討其非線性行為，然對於真實地震下之鋼橋墩，地震強度與其引致之結構反應均具不確定性，需利用機率式分析，完整評估鋼橋墩之震災風險及耐震能力。有鑑於此，本研究以圓形空心斷面單柱式鋼橋墩為研究對象，探討不同徑厚比、長細比、軸壓比等關鍵參數對韌性容量及破壞風險之影響。首先以擬靜態分析求取鋼橋墩之韌性容量，以此定義後續非線性歷時分析之破壞基準，並提出斷面性質之建議公式。而鋼橋墩之破壞行為分兩部分進行討論，其一，假設鋼橋墩工址位於台北二區，分析圓形單柱式鋼橋墩之50年破壞風險；其二，假設台北山腳斷層之地震情境，計算符合該情境之近斷層地震歷時下破壞機率。最後，依據破壞行為分析之結果，檢視建議公式之適宜性，對圓形斷面單柱式鋼橋墩之斷面性質提出耐震設計建議。
Bridge piers, which are ductile components of bridges, need to exhibit sufficient energy dissipation under earthquakes. However, there is little emphasis on the compactness requirements for steel bridge piers in Taiwan seismic design codes. Structural engineers can only refer to seismic design guidelines from other countries, but the difference in the seismic design concept makes them potentially inappropriate for Taiwan. To address this shortcoming, this study investigates single-column steel bridge piers with varied compactness and axial load levels. The ductility capacity of each pier is determined by quasi-static analysis and considered as the failure criteria in the subsequent risk assessment. Assuming located in the Taipei basin zone II, the seismic risk of steel bridge piers is evaluated using the failure probability during the 50-year lifespan and under the seismic scenario of the Shanchiao fault. Based on the results of ductility capacity and risk assessment, the seismic compactness requirements are proposed for single-column steel bridge piers.
Subjects
單柱式鋼橋墩
徑厚比限制
有限元素分析
韌性容量
破壞風險分析
近斷層地震
single-column steel bridge piers
compactness requirements
finite element analysis
ductility capacity
risk analysis
near-fault ground motions
Type
journal article