不同气候条件下预应力木梁柱节点长期转角计算方法  

Numerical investigation on the long-term rotation of post-tensioned timber beam-column connections under different climates

作　　者：郑修知 何敏娟[1] 李征[1] Zheng Xiuzhi;He Minjuan;Li Zheng(Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学,上海200092

出　　处：《土木工程学报》2024年第6期116-126,共11页China Civil Engineering Journal

基　　金：国家自然科学基金优秀青年科学基金项目(52222802)。

摘　　要：梁柱节点长期转角是评估预应力木框架结构长期适用性能的重要指标,过量的梁柱节点长期转角会引起木梁竖向变形的增大,降低结构适用性;因此准确预测预应力木梁柱节点转角的时变规律是保证预应力木结构长期安全服役的重要前提。该文提出了不同气候条件下预应力木梁柱节点长期转角的数值计算方法,该方法包括木材水分传输、时变预应力计算、弹性转角计算、蠕变和环境变形计算、节点长期转角更新五个模块。随后利用长期试验数据验证了计算方法的准确性。最后,基于验证的数值计算方法分析了不同气候条件、木材初始含水率和构件尺寸对预应力木梁柱节点长期转角的影响规律,依据50年服役期内的最大转角蠕变系数评估了节点长期变形的性能等级。结果表明:该文所提出的数值计算方法与试验结果吻合良好;气候年平均相对湿度越大,节点发生中等或严重变形的比例越高;木材初始含水率越高,节点发生中等或严重变形的比例越低;构件理论尺寸越大,节点长期变形越小。The long-term rotation of beam-column connections is an important index of evaluating the long-term serviceability of post-tensioned frame structures.Excessive long-term rotation can lead to an increase in beam deflection,which further degrades the structural serviceability.Thus,reasonable prediction on the long-term rotation of post-tensioned timber connections is vital to ensure the long-term safety of post-tensioned timber structures.In this work,a numerical method for predicting the long-term rotation of post-tensioned timber connections under different climates,which includes moisture transfer,time-dependent prestressing force calculation,time-dependent elastic deformation calculation,creep and environmental deformation calculation and long-term rotation updating.Subsequently,the long-term experimental results were used to validate the numerical method.Finally,the validated method was employed to study the effect of climatic conditions,initial moisture content and member sizes on the long-term rotation of connections.The long-term performance levels were also determined based on the lifetime maximum creep coefficients.The results demonstrate that with the increase of annual average relative humidity,the percentage of moderate or extensive deformation tends to be higher.The higher the initial moisture content,the lower the percentage of moderate or extensive deformation.The larger the notional size,the smaller the long-term deformation of connections.

关 键 词：预应力木梁柱节点 长期性能 节点转角 气候变化 数值计算方法 

分 类 号：TU366.2[建筑科学—结构工程]