- 期刊
鋼筋混凝土二元系統剪力牆之剪力強度設計
Shear Strength Design for Reinforced Concrete Shear Walls of Dual System
摘要
歷年來的震後勘災均顯示鋼筋混凝土剪力牆系統有極佳的耐震能力，其中合併使用韌性立體剛構架與特殊剪力牆的二元系統尤其優越。例如二元系統具有剪力牆與構架兩道耐震防線，其對餘震有額外之安全保障。從地下室連續施作至屋頂的剪力牆可以排除軟弱層破壞之可能，而剪力牆勁度高、強度大的特性也可以有效保護非結構桿件不致於提前損毀。新版鋼筋混凝土設計規範要求特殊剪力牆作剪力容量設計，在引入超額強度係數與動剪力效應係數後，剪力牆之剪力強度設計需求被放大2至3倍。若按新版規範設計，如此高額之強度需求會要求非常厚的剪力牆，這造成建築使用上的困擾。此不利於優良耐震系統之推廣應用，實需有效之解決對策。若能善用二元系統之特性並配合壓拉桿設計方法，其應可解決上述困境。其設計構想為利用二元系統之梁柱框架，束制樓層間之牆體使其出現低矮型剪力牆之傳力行為。再以壓拉桿方法估計低矮型剪力牆較高之剪力強度，此可有效降低剪力牆之厚度，排除建築使用困難之不利限制。本文內容包含新版規範設計需求、壓拉桿設計方法、二元系統框架剪力牆之傳力機制、日本振動台試驗驗證、剪力牆設計建議，並配合案例比較說明。希望透過本文之努力，鋼筋混凝土二元系統之優越抗震性能可獲得肯定與廣泛之應用。
並列摘要
Past earthquake reconnaissance already demonstrated that the reinforced concrete dual system, which consists of ductile moment resisting frames and shear walls, is one of the most effective earthquake resisting systems. A dual system can provide the 2nd line of defense when shear walls are coupled with frames. In seismic design, the 2nd line of defense is a secure protection against impulsive earthquakes. The shear walls of the dual system provide a continuity over height, which effectively prevent the story sway mechanism and provide uniform and reduced lateral drift resulting in a better damage control. The new building design code of Civil 401-110 requires the shear capacity design of the special shear wall. After the inclusion of the over-strength effect and the dynamic amplification factor, the shear strength demand can be doubled or even tripled, which leads to the shear walls with highly improbable thickness. This strict demand will hamper the application of the dual system in seismic design. This problem should be resolved. A feasible solution to overcome this difficulty is to adopt the dual system with the shear walls designed by the strut-and-tie method. The structural walls of the dual system are equipped with substantial boundary members appearing as both beams and columns, which create a special shear force transferring mechanism within the framed squat walls. The framed squat walls possess very high shear resisting capacities, which can effectively reduce the thickness of shear walls, if well designed by the strut-and-tie method. The objective of this paper is to demonstrate the merits of the dual system and to promote its application in seismic design. The content of this paper includes the requirements of the new building design code, the softened strut-and-tie model, the shear strength design of framed squat walls of the dual system, design verification using Japanese shaking table tests, design suggestions for shear wall and the related case study.