木结构设计计算理论关键问题研究

The current design theory of our country for wood structures applies to structures made of traditional round timber or sawn timber, in which strength of wood is determined by the species only. Although wood from the same species is also classified into different quality grades, the strength is not associated to those grades. Yet the strength of modern wood products like dimension lumber and glulam is all determined by the quality grade of wood, strength of wood of the same species is different from different quality grade. This makes our current design theory not suitable to the modern wood products. The following three problems arise-calculation of the stability of members in compression and members in bending, the calculation of load-carrying capbility of bolt connections and nail connections, and the determination of design values of wood products. Modern wood products have already been imported into and manufactured in our country, to solve the three problems scientifically and reasonably is of urgent need of the development of wood structures. This project aims to conduct in-depth invesitigation,both theorectcally and experimentally, to address those problems. The corresponding solutions and design methods will be given, which are compatible with the design theory and methods from the countries with advanced technology in wood structures. The study is expected to provide basis to perfect and develop the design theory and method for wood structures in our country, which is independent and with Chinese characteristics.

我国现有木结构设计计算理论，适用于采用传统的方木、原木制作的木结构，木材的强度等级是仅按树种确定的。虽然同一树种的木材也划分为不同的材质等级，但强度指标并不按这种材质等级区分。规格材和胶合木等现代木产品，都是按材质等级划分强度等级的，同一树种不同材质等级木材的强度指标不同。这就使得我国的木结构设计计算理论体系不适用于现代木产品。问题主要体现在受压和受弯构件的稳定性计算、螺栓连接和钉连接承载力的计算以及木结构产品强度设计指标的确定三个方面。我国已经进口和自行生产现代木产品，科学合理地解决该三方面的问题是我国木结构事业发展的迫切需要。本项目拟就此展开深入的理论和试验研究，提出相应的计算方法，并与世界木结构技术先进国家的计算理论和方法相兼容，以期为完善和发展独立自主的、具有中国特色的木结构设计计算理论，提供依据。

针对面临的木结构设计理论与方法的几个关键问题，主要开展了木结构可靠度分析、受压和受弯木构件杆稳定问题试验研究和计算分析、销连接承载力试验研究和计算分析等三大方面的问题。提出了木材和木产品强度设计指标的确定方法，提出了轴心受压木构件稳定系数的统一算法和计算式，提出了受弯木构件侧向稳定系数的统一算法和计算式，提出了木结构销连接承载力的设计计算式。并且，这些研究成果全部为《木结构设计规范》GB 50005-2017所直接采用。通过该项目研究，解决了我国木结构发展迫切需要解决的几个大问题，继承和发展了具有中国特色的木结构设计理论和方法。