砖石质文物建筑结构安全稳定性能提升措施研究

Research on safety and stability performance design of masonry historical building structures

砖石质文物建筑历经百余年环境因素产生劣化损伤后,多数存在安全隐患。国家现行相关规范标准中所提供工程常用的结构安全性能提升措施与文物建筑的保护原则之间,存在诸多难以协调的矛盾。而新的修缮措施中又缺乏对文物建筑整体稳定性能提升有效性的分析评价方法。为此,以清华大学图书馆老馆Ⅰ期为例,在其结构现状分析的基础上,提出增设内钢框架和外拉索的修缮方案。新增结构基本不侵入文物建筑本体,不改变原结构传力路径,基本实现了“不改变文物原状、最低限度干预、措施可逆”的文物保护原则。正常使用极限状态的承载力分析表明:采取性能提升措施后,随着原结构材料逐步劣化,原结构承载能力进一步降低,荷载才将逐渐转移至新增结构。建立了与文物建筑材料连接界面相适应的离散体结构力学模型,抗倒塌分析结果表明:8度罕遇地震作用下,各部分主体结构最大层间位移角小于1/100,新增结构可大幅提升防震性能,实现了预防地震倒塌的结构稳定性能目标。

After hundreds of years of deterioration and damage caused by environmental factors,most brick and stone cultural relics have potential safety problems.There are many contradictions that are difficult to coordinate between the measures to improve the safety of structures commonly used in engineering provided by the current national codes and the principles for the protection of cultural relics.For new measures,there is a lack of analysis and evaluation methods for their effectiveness in improving safety and stability performance of historical buildings.Taking Phase 1 of Tsinghua University\s old library as an example,the repair measures of additional internal steel frames and external cables are proposed.The newly added structures basically do not invade the building body,do not change the force transmission path of the original structure,and basically achieve the cultural relic protection principle of not changing the original state,minimum intervention,and reversible measures.The analysis results of bearing capacity in normal use limit state show that after performance improvement measures are taken,with the gradual deterioration of the original structural materials,the bearing capacity of the original structure is reduced,and the load will be gradually transferred to the new structure.A mechanical model of the discrete structure is established to adapt to the interface between cultural relics and building materials.Under the 8-degree rare earthquake effects,the maximum inter-story displacement ratio of each part of the main structure is less than 1/100.The new structure has greatly improved the seismic performance and achieved the goal of structural stability to prevent earthquake collapse.