RC梁扭力簡化分析法

A Simplified Analytical Method for RC Members Subjected to Torsion

彭晨軒(Chen-Hsuan Peng)

指導教授 ： 鄭全桓

國立暨南國際大學/科技學院/土木工程學系/碩士(2008年)

https://doi.org/10.6837/NCNU.2008.00167

摘要

論文摘要
本研究論文主要是將近年來最新的鋼筋混凝土梁受純扭力(pure torsion)之分析模式SMMT(Softened Membrane Model for Torsion) (Jeng et al. 2008)予以簡化，在該模式分析開裂(crack)點與極限(ultimate)點的演算過程中，發展出一套快速而有效的RC梁扭力簡化分析法。本研究也蒐集更多實驗試體，以檢核SMMT在開裂點與極限點之扭矩與扭轉角的值之正確性與適用性。
在求開裂點的簡化分析過程中，利用鋼筋未降伏之特性推導出一方程式，並簡化開裂點軟化係數及Hsu/Zhu ratio，可推導出開裂點之簡化分析法。由分析結果可知，開裂點簡化分析之扭矩與扭轉角分別與SMMT分析值及實驗值比對，皆相當吻合一致。
由SMMT在最大扭矩的分析值中，找出有規律的應變簡易關係式，因材料組成律的關係，修正關係式中的變數，並簡化平均剪應變，可推導出最大扭矩點的簡化分析法。由分析結果可知，最大扭矩點簡化分析之扭矩與扭轉角分別與SMMT分析值及實驗值比對，皆相當吻合。

關鍵字

鋼筋混凝土；扭力；開裂點；極限點；扭矩；扭轉角

並列摘要

ABSTRACT
This thesis concentrates on a simplified analytical method for calculating torques and twists at cracking and ultimate for RC members under torsion. The simplified analytical method is derived from the Softened Membrane Model for Torsion (SMMT) (Jeng et al. 2008). This study collected 128 tested specimens to examine the accuracy of the SMMT and the simplified method.
A set of equations is derived by utilizing the linear characteristic of steel prior to yielding, and simplified softening coefficient and the Hsu/Zhu ratio at cracking state are obtained. Then a simplified algorithm for calculating the cracking torque and cracking angle of twist is developed. Calculated results show a good agreement with the experimental data.
Simplified strain compatibility equations are derived from the analytical maximum torques calculated by the SMMT. Based on these simplified equations, a simplified solution algorithm for calculating the ultimate torque and ultimate angle of twist is developed. The calculated ultimate torques and ultimate angles of twist also agree with the SMMT and experimental data reasonably well.

並列關鍵字

Reinforced concrete ； torsion ； cracking ； ultimate point ； torque ； twist angle

參考文獻

參考文獻

1. ACI Committee 318, “Building Code Requirements for Structural Concrete（ACI 318-05）and Commentary（ACI 318R-05）”American Concrete Institute, pp. 147-191.

2. Ashour, S. A., Samman, T. A., and Radain, T. A., (1999), “Torsional Behavior of Reinforced High-Strength Concrete Deep Beams” ACI Structural Journal, Vol. 96, No. 6, Nov.-Dec., pp.1049-1058.

3. Belarbi, A. and Hsu, T. T. C., (1994), “Constitutive Laws of Concrete in Torsion and Reinforcing Bars Stiffened by Concrete” ACI Structural Journal, Vol. 92, No. 5, Sept.-Oct., pp.562-573.

4. Bradburn, J. H., “An Investigation of Combined Bending and Torsion in Rectangular Reinforced Concrete Members” Doctoral Dissertation, Department of Civil Engineering, North Carolina State University at Raleigh, (1968), 174 pp, (under the supervision of Prof. Paul Zia).