與柱外緣切齊之鋼筋混凝土梁鋼筋細部對耐震性能影響之探討

Discussion on Influence of Reinforced Concrete Beam Reinforcement Detail with Flush Outside Faces of Beams and Columns on Seismic Performance

李台光(Tai-Kuang Lee) ； 陳正誠(Cheng-Cheng Chen)

《結構工程》 38卷1期 (2023/03) Pp. 5-30

https://doi.org/10.6849/SE.202303_38(1).0001

摘要

國內建築普遍存在RC梁與RC柱外緣切齊偏心接合的情況，偏心接合RC梁之韌性尚未獲得實驗驗證。本研究針對此類國內工程實務問題，規劃4座大型鋼筋混凝土梁試體，並於內政部建築研究所材料實驗中心進行實驗驗證。本研究共製作R試體（梁主筋不偏移，箍筋為正常尺寸）、RH/SU試體（梁主筋向內偏移且箍筋為縮小尺寸，側面配置U形橫向輔助筋並以2根縱向輔助筋固定）、RH試體（梁主筋向內偏移且箍筋為縮小尺寸），以及SH/SLB試體（梁主筋向內偏移且箍筋為正常尺寸，箍筋增加2根縱向輔助筋固定）等4座試體，其中R試體做為本研究耐震性能之比較基準。研究結果發現：（1）所有試體（含3種外緣切齊的梁鋼筋配置細部）均可發展4%弧度的梁端轉角，皆能達到規範耐震要求。負方向韌性表現，以RH/SU試體為最優，RH試體次之，R試體再次之，SH/SLB試體為最差。SH/SLB試體上、下層梁主筋，皆僅有1根被箍筋角落束制，梁箍筋之角落配置縱向輔助筋，對於RC梁之耐震性能可能會造成不利的影響，因此建議RC梁箍筋之角落應配置梁主筋；（2）RH試體之一側混凝土保護層達85 mm，惟RH試體之側向強度及耐震性能皆不亞於R試體，因此實務上採用RH試體之型式，應為可接受的作法；（3）RH/SU及RH等2座試體之耐震性能皆優於R試體，惟RH試體裂縫寬度較寬且混凝土保護層剝落程度明顯較RH/SU試體嚴重，因此實務上建議採用RH/SU試體之型式。

關鍵字

鋼筋混凝土梁 ； 柱 ； 外緣切齊 ； 耐震性能

並列摘要

In domestic buildings, the eccentric beam-column connections with the flush outside faces of beams and columns are common, and the ductility of RC beams with eccentric connections has not been experimentally verified. In view of such domestic engineering practice problems, this study plans four large-scale reinforced concrete beam specimens, and conducts experimental verification at the Materials Experiment Center of the Architecture and Building Research Institute, Ministry of the Interior, Taiwan. In this study, the R specimen (the main reinforcement of the beam is not offset, and the stirrups are of normal size), the RH/SU specimen (the main reinforcement of the beam is offset inward and the stirrups are reduced in size, the side is equipped with U-shaped transverse auxiliary reinforcement and two longitudinal auxiliary reinforcements are fixed), the RH specimen (beam main reinforcement is shifted inward and stirrups are reduced in size), and the SH/SLB specimen (beam main reinforcement is shifted inward and the stirrups are normal size, and two longitudinal auxiliary reinforcements are arranged at the corners of the stirrup) are fabricated. The research results show that: (1) All specimens (including 3 beam reinforcement details with flush outside faces) can develop beam end rotation angle of 4% radian, which can meet the seismic requirement of the specification. For the seismic performance in the negative direction, the RH/SU specimen is the best, the RH specimen is the second, the R specimen is the third, and the SH/SLB specimen is the worst. There is only one top and bottom main reinforcement of the SH/SLB specimen, which is surrounded by the corner of the stirrup. The longitudinal auxiliary reinforcement is arranged at the corner of the stirrup of the beam, which may have an adverse effect on the seismic performance of the RC beam. Therefore, it is recommended that the corners of the stirrups should be equipped with the main beam reinforcement. (2) The concrete cover on one side of the RH specimen is 85 mm, but the results of this study show that the lateral strength and seismic performance of the RH specimen are not inferior to the R specimen. It is acceptable to use the type of the RH specimen in practice. (3) The seismic performance of the RH/SU and RH specimens is better than that of the R specimen, but the RH specimen has wider crack width and the degree of spalling of the concrete cover is obviously more serious than that of the RH/SU specimen. Therefore, it is recommended to use the type of the RH/SU specimen in practice.

並列關鍵字

reinforced concrete beams ； columns ； flush outside faces of beams and columns ； seismic performance

參考文獻

內政部營建署 (2021). “109 年營建統計年報 ” ，內政部營建署網站 http://www.cpami.gov.tw/。

內政部 (2021). “混凝土結構設計規範”，臺北。

ACI-ASCE Committee 352 (2002). “Recommendations for design of beam-column connections in monolithic reinforced concrete structures (ACI 352R-02)”, Michigan, USA.

李宏仁、林克強、紀凱甯、林明志 (2019) “鋼筋混凝土柱梁偏心接合之耐震抗剪強度檢討”，內政部建築研究所委託研究報告。

ACI Committee 318 (2019). “Building code requirements for structural concrete (ACI 318-19)(SI) and commentary”, Michigan, USA.