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试验中设计了2根足尺木梁,包括1根未加固对比木梁和1根粘贴钢板加固木梁,进行了1200 d的长期持荷试验。试验结果表明:加固木梁与对比木梁均有明显的初始蠕变阶段和稳态蠕变阶段,但加固木梁的跨中挠度和跨中曲率增量明显小于对比木梁,说明加固钢板对木材蠕变具有约束作用;木材应变总体上随温度和湿度的升高而增加、随温度和湿度的降低而减小。采用老化理论、Burgers模型和五参数模型对对比木梁的跨中挠度-持荷时间曲线进行了参数拟合和预测,验证了五参数模型可满足初始与稳态蠕变阶段的计算精度,能够较好地进行木梁蠕变的预测。采用ANSYS中的蠕变方程,并基于所提出的蠕变参数分时段线性化的方法对粘贴钢板加固木梁的长期挠度进行了模拟,计算结果具有较好的精度。
In the experiment, two full-size wooden beams were designed, including one unreinforced contrast wood beam and one glued steel reinforced timber beam. The long-term load test was carried out for 1200 days. The experimental results show that both the initial and the steady state creep phases of the reinforced timber beam and the comparative timber beam are obvious, but the mid-span deflection and the increment of the mid-span curvature of the reinforcement beam are obviously smaller than those of the comparative timber beam, Wood creep has a binding effect; wood strain generally increases with temperature and humidity, decreases with decreasing temperature and humidity. Aging theory, Burgers model and five-parameter model are used to fit and predict the mid-span deflection-hold time curve of the comparative timber beam. The five-parameter model can meet the calculation accuracy of the initial and steady creep phase, Better prediction of wood beam creep. The creep equation in ANSYS was used to simulate the long-term deflection of the steel beams strengthened with bonded steel plate based on the proposed method of time-varying linearization of creep parameters. The calculated results have good accuracy.