体内预应力胶合木梁短期受弯性能试验研究

为研究体内预应力胶合木梁短期受弯性能，对15根胶合木梁进行了受弯试验研究，包括1组未增强试件、1组直线形有黏结预应力筋增强试件、2组抛物线形有黏结预应力筋增强试件以及3组抛物线形无黏结预应力筋增强试件。试验结果表明：为布置抛物线形预应力筋，该文首次提出的胶合木梁中抛物线形孔道的开槽方案效果良好，注胶密实性较好；预应力筋增强试件中，摩擦系数?的试验均值为0.0030，?的试验均值为0.10；相比未增强试件，直线形有黏结预应力筋增强试件的受弯极限承载力提高了33.2%，抗弯刚度提高了27.2%，抛物线形有黏结预应力筋增强试件的受弯极限承载力分别提高了29.9%和50.1%，抗弯刚度分别提高了28.9%和30.8%，抛物线形无黏结预应力筋增强试件的受弯极限承载力分别提高了23.7%、32.3%和7.9%，抗弯刚度分别提高了17.3%、18.8%和20.4%；抛物线形预应力筋增强试件相对于直线形受弯极限承载力略有降低，有黏结预应力筋试件相对于无黏结短期受弯性能更好；增大张拉控制应力能有效提高构件受弯极限承载力，但对抗弯刚度的提高贡献不大。

Experimental study on short-term flexural behavior of internal prestressed glulam beams

A total of 15 glulam beams, including a group of unreinforced glulam beams, a group of straight-bonded prestressed glulam beams, two groups of parabolic-bonded prestressed glulam beams and three groups of parabolic-unbonded prestressed glulam beams, were tested to study their short-term flexural behaviors. The experimental results showed that the curved slot manufacturing method and gluing process were effective and strong strand-laminate bonds were realized. For prestressed glulam beams, the average value of friction coefficient ? was 0.0030, and the average value of ? was 0.10. Compared to the unreinforced glulam beams, the ultimate bearing capacity of straight-bonded prestressed glulam beams increased by 33.2%, the flexural stiffness increased by 27.2%. For parabolic-bonded prestressed glulam beams, the ultimate bearing capacity may be increased by 29.9% and 50.1% respectively, the flexural stiffness increased by 28.9% and 30.8% respectively. For parabolic-unbonded prestressed glulam beams, the ultimate bearing capacity increased by 23.7%, 32.3% and 7.9% respectively, the flexural stiffness increased by 17.3%, 18.8% and 20.4% respectively. The ultimate bearing capacity of curved prestressed glulam beams was slightly lower than that of straight prestressed glulam beams, and the bonded prestressed glulam beams showed better flexural behavior than the unbonded ones. Moreover, it was found that the increase of tensioning stress effectively improved the ultimate bearing capacity but contributed little to the improvement of flexural stiffness.