EXPERIMENTAL STUDY ON BOND BEHAVIOR OF INTERFACE BETWEEN OLD AND NEW CONCRETE COMPOSITE BEAM UNDER PRE-STRESSING FORCES
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摘要: 新老混凝土界面之间能够很好地传递界面间剪力，是人们普遍关心的一个问题。为研究在预应力作用下新老混凝土界面之间的力学性能，该文进行了施加预应力后新老混凝土组合梁在静载作用下界面间粘结性能的试验研究，试验梁变化的参数为箍筋间距。试验结果表明：新老混凝土组合梁在预应力作用下，粘结面无明显滑移，在静载作用下，荷载达到极限荷载的72%时，剪跨区局部发生粘结破坏，界面间滑移较明显。在Girrhammar给出的组合梁微分方程的基础上，考虑粘结面滑移、箍筋直径和间距，建立了新老混凝土组合梁界面应力、应变及滑移的计算方法。计算结果表明：该文建立的考虑滑移的新老混凝土组合梁界面分析方法与试验值吻合良好，计算结果可靠。Abstract: How the shear force is transmitted between old and new concrete is of common concern. To study the mechanical characteristics of the interface between old and new concrete under pre-stressing forces, the bond behavior of the interface was experimentally investigated through loading tests of composite beams. The considered parameter is the space between the hoop bars. It is observed that, under pre-stressing forces, there is no slip on the interface of the old and new concrete. When the static loads increase to 72% of the ultimate loads, the slip occurs in sheer span region and the local bond failures are observed. A calculated method about stress, strain and slip of the interface is proposed based on the differential equations proposed by Girhammar. The calculated results are in good agreement with the experimental results.
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Keywords:
- old and new concrete /
- composite beam /
- slip /
- bond /
- interface
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