【摘要】 研究了预应力FRP增强胶合木梁的预应力损失,其中:FRP采用先张法施加预应力,并采用胶合与机械相结合的方式锚固于胶合木梁。分析表明:先张法FRP板的预应力损失主要包括垫块变形和木材弹性变形,FRP应力松弛、季节温差引起的预应力损失和木材蠕变引起的预应力损失。该研究基于平截面假定,通过胶合木梁的受力平衡与变形协调及材料本构模型,建立了每项预应力损失的计算公式,以及预应力损失后的胶合木梁反拱挠曲线方程,确定初始预应力限值范围;计算并分析了3组预应力CFRP增强胶合木梁的预应力损失值,应用反拱挠度实测值验证该研究计算理论。研究成果可为预应力FRP增强胶合木的设计与安全性评估提供理论参考。更多还原

【Abstract】 This study analyzes the prestress loss of the pre-tensioned prestressed glulam beam reinforced with Fiber Reinforced Polymer(FRP), in which the prestressing FRP is fixed with both bonding and mechanical methods. The analysis results show that the prestress loss results from the deformation of the cushion block, elastic deformation of wood, stress relaxation of FRP, temperature difference and wood creep. Assuming that plane sections remain plane, the formulas to estimate each type of the prestress losses as well as the precamber after prestress loss, are put forward according to the force equilibrium and deformation compatibility of the beam and the constitutive model of each material. The prestress limits are further proposed. The prestress losses of three groups of glulam beams reinforced with prestressing CFRP plates were calculated and analyzed. Their computed precamber values were were used to verify the effectiveness of the proposed formulas. The research achievements can provide a theoretical reference for the engineering design and safety evaluation of the prestressed glulam beam.更多还原