装配式圆竹结构螺栓连接节点的力学性能

近年来,随着新型结构和绿色建材的推广和发展,竹材作为结构材料用于建造新型竹结构建筑开始得到越来越多的关注。针对装配式圆竹结构螺栓组合节点,采用单螺栓、双螺栓和节点域高强度砂浆强化处理3种形式进行静力加载试验研究,分析其承载力和破坏形态。试验结果表明:装配式圆竹结构螺栓组合节点在保证一定构造条件后,可以有效避免脆性破坏,同时使竹材和螺栓的力学性能均能得到充分发挥并形成延性破坏,节点整体受力性能良好。采用双螺栓节点设计及节点域高强度砂浆强化措施可以明显提高螺栓组合节点的承载能力。基于试验建立了力学模型,并推导出组合节点的理论求解公式。通过结果比较发现,解析值和实测值的平均比值可达0.98,表明解析方法具有可适用性。该理论模型可以作为圆竹结构螺栓组合连接节点承载力计算的参考公式。
Bamboo grows rapidly and matures for structural applications within 5 years, which allows the rotation period of bamboo to be much shorter than that of trees. As a green construction material, bamboo has superior engineering properties compared with those of timber and timber-based products. Bamboo is stronger than some wood species as it is longitudinally reinforced by strong fibers, which are distributed densely in the outer surface region and sparsely in the inner surface region. Moreover, bamboo is an important construction material particularly in rural and remote areas, where the access to steel or reinforced concrete production complemented with heavy machinery is limited. With the development and commercialization of novel structure and green building materials in recent years, a growing number of researches reconsider bamboo as a structural material. In this paper, bamboo-to-steel dowel-type joints were introduced for prefabricated bamboo structures. In order to analyze the bearing capacity and failure mode of the bolted joint of modern prefabricated round bamboo structure, three different joints were employed for a static loading experiment, including single bolted joint, double bolted joint and strengthen joint with high-strength mortar. The experimental results revealed that, under certain connection configurations, the modern prefabricated bamboo joints could effectively avoid the brittle failure and fully utilize the plastic performance of the bolt. The using of the double bolted joint with the strengthen high-strength mortar could significantly improve the bearing capacity of the bolted joint. In order to further understand the load-resistance capacity of the connection, theoretical formulas of the bamboo-steel bolted joint were derived based on the laboratory test results. The comparison between calculated results and tested outcomes was conducted. The average ratio of the calculated values to the experimental values was 0.98, which validated the applicability of the calculation method. This theoretical model can be referred to calculate the bearing capacity of bolted joint of round bamboo structure