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体外预应力混凝土连续梁的弯矩重分布试验研究
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(北京交通大学桥梁工程系 北京 100044)

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杜进生

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TU378.2

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Experimental study on moment redistribution of external prestressed concrete continuous beams
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(Department of Bridge Engineering, Beijing Jiaotong University, Beijing 100044)

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    摘要:

    进行了3根体外预应力混凝土两跨连续梁受力全过程试验。试验表明,自加载至受拉区混凝土开裂前,连续梁处于弹性阶段,边支座、中支座反力、跨中截面和中支座截面弯矩的实测值与采用弹性理论计算值接近。受拉区混凝土开裂后至非预应力受拉钢筋屈服,边支座反力及跨中截面弯矩实测值开始向大于弹性理论计算值的方向偏离;而中支座反力及中支座截面弯矩实测值则向小于弹性理论计算值的方向偏离。当梁内受拉非预应力筋屈服后,边支座、中支座反力的实测值以及跨中截面弯矩和中支座截面弯矩实测值与弹性理论计算值的偏差进一步增大,这种偏差在试验梁破坏时达到最大。3根试验梁中支座截面弯矩重分布值分别为12.8%、16.9%及14.6%。试验实测值还与4个不同设计规范的弯矩重分布计算值进行了比较。结果表明:采用美国ACI 318-95规范及中国GB 50010-2010规范计算的中支座截面弯矩重分布值均小于试验实测值;除一根编号为B5的梁外,加拿大A23.3-M84规范的预测值与试验值最为接近;而英国BS8110规范则偏于不安全。实际设计中,可按中国规范公式来计算体外预应力混凝土连续梁的弯矩重分布,但必须合理确定体外预应力筋的极限应力。

    Abstract:

    The whole load test of 3 external prestressed concrete two-span continuous beams was carried out. The test results show that the continuous beam is in the elastic stage before the concrete cracks in the tension area under self-loading, and the measured values of the side support, the reaction force of the middle support, the bending moment of the middle span section and the middle support section are close to the calculated values using the elastic theory. The measured values of the side support reaction and the moment of the mid-span section start to deviate to the direction larger than the calculated value of the elastic theory. The measured values of the reaction force of the middle support and the bending moment of the section of the middle support deviate to the direction less than the calculated value of the elastic theory. When the tensile non-prestressed tendons in the beam yield, the deviations between the measured reaction force of the side support and the middle support and the measured bending moment of the middle span section and the middle support section and the calculated values of the elastic theory increase further, and the deviations reach the maximum when the test beam is damaged. The bending moment redistribution values of the three test beams are 12.8%, 16.9% and 14.6%, respectively. The measured values are also compared with the calculated values of bending moment redistribution in 4 different design codes. The results show that the bending moment redistribution values calculated by ACI 318-95 and GB 50010-2010 are both smaller than the measured values. The predicted values of the Canadian A23.3-M84 code are the closest to the test values, except for a beam numbered B5; The British BS8110 specification is not safe. In practical design, the bending moment redistribution of external prestressed concrete continuous beams can be calculated according to the Chinese standard formula, but the ultimate stress of external prestressed tendons must be reasonably determined.

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Jinsheng Du, Yipeng Zhao Experimental study on moment redistribution of external prestressed concrete continuous beams. Prestress Technology 2015,19(05):26-38. 10.59238/j. pt.2015.05.003

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  • 在线发布日期: 2023-08-06
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