應用高強度鋼筋混凝土於斷層近域橋梁之耐震性能設計

Seismic Performance Design of New RC Bridges subjected to Near-Fault Earthquakes

劉光晏(Kuang-Yen Liu) ； 吳振揚(Chen-Yang Wu)

《結構工程》 36卷3期 (2021/09) Pp. 71-92

https://doi.org/10.6849/SE.202109_36(3).0004

摘要

本研究採用本土化之高強度鋼筋混凝土受圍束之應力應變關係，探討高強度混凝土取代一般強度混凝土後，在相同的上部結構載重作用下，對於橋柱斷面尺寸與鋼筋用量縮減之影響。案例分析顯示，因材料強度提升後使橋柱斷面縮小，造成結構周期延長與地震力下降，進一步達到橋柱主筋減量的雙重目標。此外，當橋梁工址位於斷層近域，如採用一般強度或高強度鋼筋混凝土材料，並納入速度脈衝引致高應變率來提升材料強度之貢獻，亦可有效縮減橋柱斷面及節省主筋量。設計成果採用ATC-40容量震譜法與Fu-R-T強度韌性折減法，耐震性能檢核均符合，驗證高強度混凝土橋柱之斷面尺寸與鋼筋量更具經濟性。

關鍵字

高強度鋼筋混凝土 ； 橋柱 ； 近斷層地震 ； 應變率 ； 耐震性能檢核

並列摘要

This study adopts the stress-strain relationship of localized high-strength reinforced concrete to explore the effect of replacing general-strength concrete with high-strength concrete on the reduction of the cross-sectional dimensions of the bridge column and the amount of steel under the same superstructure load. Case analysis shows that the increase in material strength reduces the cross-section of the bridge column, resulting in an extension of the structural period and a decrease in seismic force, which further achieves the dual goal of reducing the main reinforcement of the bridge column. In addition, when the bridge site is located near the fault, if conventional and high-strength reinforced concrete materials are used, and the contribution of the speed pulse to the high strain rate and the enhancement of the material strength is incorporated, it can also effectively reduce the cross-section of the bridge column and save the amount of main reinforcements. The design results adopt the ATC-40 capacity seismic spectrum method and the Fu-R-T strength and ductility reduction method, and the seismic performance assessment are consistent, verifying that the cross-sectional size and the amount of steel reinforcement of the high-strength concrete bridge column are more economical.

並列關鍵字

high-strength concrete ； bridge column ； near-fault earthquake ； strain rate ； seismic performance assessment