New RC梁撓曲剪力設計研究

Flexural Shear Design of New RC Beams

廖于興(Yu-Xing Liao)

指導教授 ： 王勇智

國立中央大學/工學院/土木工程學系/碩士(2015年)

摘要

國家地震工程研究中心自從2010年以來推動之台灣新型高強度混凝土結構系統研發計畫(簡稱Taiwan New RC)，時至今日，已進入設計及施工概要研擬階段。本研究藉由收集、整理、歸納已完成之研究資料，進而設計兩組矩形長梁(a/d=4.4)試體，分別配置SD-420及SD-785箍筋，依照ACI374-1.05規定進行反覆載重測試，驗證是否與傳統ACI 318耐震設計規範相符。
由試驗結果得知，梁撓曲鋼筋超額強度因子會隨著鋼筋強度種類不同而有差異，以本研究SD685螺紋節鋼筋研究結果為1.13，而傳統SD420竹節鋼筋為1.25。在層間變位角DR=3.5%左右，塑鉸區混凝土仍有貢獻量，平均可達規範值之一半，即0.085√(f_c^' )(MPa)剪應力值。高強度箍筋(SD785)應力發展，在層間變位角DR=3.5%左右，可量得箍筋應力600MPa以上，與其他學者研究結果相近。本研究亦針對規範ACI 318-11之梁剪力耐震設計規定作基礎，根據實驗結果，建議出New RC梁剪力設計方針。

關鍵字

新型鋼筋混凝土 ； 鋼筋超額強度因子 ； 塑鉸區混凝土貢獻 ； 剪力設計

並列摘要

The National Center for Research on Earthquake Engineering (NCREE) devoted to developing new type structural system called as “Taiwan New RC Project” from 2010. The project now is drafting the structural design guideline. This research focuses on how to design the shear strength in the plastic hinge zone of New RC beams. Not only are the experimental results collected from the previous studies, but also two more rectangular cantilever beams (a/d = 4.4) with SD-420 and SD-785 stirrups, respectively, are tested to confirm the drafted design guidelines.
According to experimental results, the overstrength factor of beam flexural reinforcement is different from the grades of steel reinforcement. That is, the overstrength factor of SD-685 rebar is 1.13 whereas the SD-420 is 1.25 as the traditional specification. The concrete in plastic hinge zone at drift ratio of 3.5% can still resist the shear up to 50% of the value required in ACI-318-11. That is, the residual shear strength in beam plastic hinge zone can be designd to 0.085√(f_c')(in MPa) as suggestion. The average stress of SD-785 stirrups is measured up to 600 MPa at the drift ratio of 3.5%, similar to previous researches. Finally, the flexural shear design guideline of New RC beams revised with reference to ACI 318-11 is proposed in study.

並列關鍵字

Taiwan New RC ； Overstrength Factor of Steel Reinforcement ； Shear Contribution of Concrete in Plastic Hinge Zone ； Shear Design

參考文獻

[1] ACI Committee 318, Building Code Requirement for Structural Concrete, ACI318-11 & Commentary, American Concrete Institute, 2011.

[3] Architectural Institute of Japan, Design Guidelines for Earthquake Resistant Reinforced Concrete Buildings Based on Inelastic Displacement Concept, Tokyo, 1999.

[4] NIST GCR 14-917-30, Use of High-Strength Reinforcement in Earthquake-Resistant Concrete Structures, National Institute of Standards and Technology, 2014.

[6] N.J. Brooke, “The Effect of Reinforcement Strength on the Overstrength Factor for Reinforced Concrete Beams,” Pacific Conference on Earthquake Engineering, 2011.

[11] ACI Committee 363, State-of-the-Art Report on High-Strength Concrete, American Concrete Institute, 1997, pp. 23-24.