Structural Design of Connections in Precast Reinforced Concrete Structures
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants|
|Research Institution||Tokyo University of Science|
MATSUZAKI Yasuhiro Tokyo University of Science, Faculty of Eng., Professor, 工学部, 教授 (30138979)
NAKANO Katsuhiko Niigata Institute of Technology, Faculty of Eng., Associate Professor, 工学部, 助教授 (80188995)
|Project Period (FY)
2002 – 2003
Completed(Fiscal Year 2003)
|Budget Amount *help
¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 2003 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 2002 : ¥2,400,000 (Direct Cost : ¥2,400,000)
|Keywords||Precast Reinforced Concrete / Connection / Shear transfer strength / Shear slipping displacement / Dowel action / Shear-key / Friction / Adherence / PCa接合部 / 接合筋のダボ抵抗 / シヤキーの直接せん断抵抗 / 圧縮軸力下の摩擦抵抗 / コンクリート面の固着抵抗 / せん断ズレ変形量 / 構成則 / あと施工アンカー|
Shear transfer across a definite interface must frequently be considered in the design of precast concrete connections. As the following various resistances in the effecting shear transfer strength are given : (1) dowel action, (2) shear-key, (3) friction with axial force, (4) adherence on the concrete surface. The purpose of this paper is to reveal the compound effects of the various resistance elements.
Basic experiments on the interface shear transfer at the precast joint faces were carried out. Fifteen panel type specimens with the same dimensions were tested.
The specimens used for investigation of the shear transfer mechanism consisted of two concrete blocks. The dimensions and reinforcement details of all the specimens were identical : the width of 900 mm, the height of 1400 mm, the thickness of 225 mm with an interface of 860 mm × 225 mm at the height of 700 mm from the base. The following parameters were investigated : (a) the kind of shear resistance in concrete connections [fr
iction with axial force, dowel bar, shear-key, and compound of various elements], (b) the direct force acting transverse to the concrete interface [N=0,1500,-220 kN].
The friction with axial force can roughly be evaluated from the hysteresis loop as follows : (a) Friction can be estimated from the first positive maximum strengths of the specimens under different axial force levels, and the force is proportional to the axial force. (b) Friction with axial force under cyclic loading may be taken at the flat level during reloading to the opposite direction until it meets the original displacement.
The dowel action can roughly be evaluated from the hysteresis loop as follows : (a) Substantial stiffness decreases gradually. (b) The maximum shear displacement with cycling increases. (c) The pinching effect is very pronounced, and the area of hysteresis loops with cycling decreases.
The stiffness of the hysteresis loop is high and the displacement of that is minimal until the compressive failure of shear-key. The resistance after compressive failure is constant.
Research results lead to the following : (a) Total shear resistance can be evaluated as the sum total of each shear transfer element at the same shear displacement. (b) Dowel action is not influenced by compressive axial force. (c) Structural performance (resistance and stiffness) of shear-key increases by the compressive axial force.
Basic experiments on concrete connections were conducted on the shear transfer and the shear displacement behavior in concrete connections under shear and axial force. The following conclusions may be drawn.
(a) The shear transfer mechanism and shear slipping displacement behavior in concrete connections is clarified. And the shear transfer mechanism is verified by the structural experiments.
(b) The shear transfer strength can be evaluated as the sum total of each shear transfer element at the same shear displacement. The evaluation equation is also proposed. Less
Research Products (8results)