为了研究北京市传统村落住宅结构的抗震能力,选取北京市门头沟区某传统村落住宅为研究对象,利用通用有限元软件MSC.MARC进行弹塑性时程分析。计算结果表明:北京传统村落住宅在结构布置上存在前后纵墙刚度差异大、山墙中部平面外约束弱的问题,可能出现砌体墙与木构件的连接破坏和山墙的开裂破坏,结构抗震能力弱,不能满足"中震可修,大震不倒"的抗震设防要求;采用前墙设置钢门窗框的加固措施,能提高前纵墙刚度,前檐口最大层间位移角可降低20%左右。

为了检验北京市既有单层大开间砌体砖木结构农宅的抗震加固效果,选取一座北京市既有典型单层四开间砌体砖木结构农宅作为研究对象,制作了1∶2缩比结构模型,模型按照北京市DB11/T 1199-2015《农村既有单层住宅建筑综合改造技术规程》的相关要求,采取增设钢门窗框、钢板圈梁、钢丝网水泥砂浆加固砖柱,以及在房屋四角砖墙、屋架间设置拉杆等抗震加固措施.对加固后结构模型进行了振动台试验,得到模型在不同水平地震波激励下的动力响应与损伤情况.试验研究结果表明:北京既有单层农宅在结构布置上存在沿纵向前后墙抗侧刚度差异大、木屋顶面内刚度小、结构整体性差、屋架抗倒塌能力弱等问题;随着山墙间距的增加,其抗倒塌能力愈弱;采用规程DB11/T 1199-2015建议的抗震加固方法能显著提高前纵墙抗侧刚度与前檐砖柱的变形能力、结构的整体性和屋架的抗地震倒塌能力.加固后结构整体达到“小震不坏、中震可修、大震不倒”的抗震设防目标.

本文以北京地区为例,探讨如何建立适合传统村落保护和发展的措施体系,并建立长效机制,确保传统村落得到修缮保护和传承发展.

传统村落有着悠久的历史文化渊源,但也存在着局限性,其民居建筑的格局、功能已不能满足现代生活的需要,其丈量尺度也不和现代建筑的300mm模数相吻合;其空间布局、院落、建筑形式及细部装饰充满着建造工匠的精湛技艺,彰显着人文、地理、历史文化和地域特色.本文从修缮等级划分研究入手,对传统村落内院落(含建筑物)按照保存完好程度及历史文化重要性等,进行等级划分;进而对其修缮保护方法包括材料的使用等等,进行分门别类的有针对性的研究,以确保传统村落的修缮从专业技术方面来说,既保存和维护了村落的环境、人文、历史、建筑的原真性,又有所发展,体现活态传承的理念.

砌体墙开设门窗洞口会导致其平面内的刚度及抗剪承载力降低,而开洞砌体墙的分布不均衡又使得地震作用下整体结构出现扭转变形,从而加大地震震害.以3片开洞砌体墙的拟静力试验为原型,采用ABAQUS有限元程序对3个模型(未加固的开洞砌体墙A-1、单面钢筋网加固的开洞砌体墙A-2、单面钢筋网和钢窗框同时加固的开洞砌体墙A-3)进行建模和非线性计算,得出了在低周反复水平荷载作用下砌体墙的荷载-位移滞回曲线,并通过对滞回曲线的处理,对比分析了应力云图、应变云图、滞回特性、砌体墙耗能、骨架曲线和刚度退化曲线,验证了有限元模型的合理性和有效性,同时也验证了加固措施的有效性.

根据北京地区既有农村住宅典型砖木结构(木柱支撑,木屋盖,外砖墙)的抗震性能特点以及农宅砖木结构未抗震加固模型的振动台试验损伤特征,结合北京地区8度抗震设防的要求,提出以下加固结构方案:①配筋砂浆带圈梁、②前檐加设钢门窗框、③房屋四角钢丝网砂浆加固,并设计2/3大比例缩尺模型,进行了8个工况振动台试验,研究了北京地区既有农村住宅单层砖木结构房屋上述抗震加固方法的有效性.通过与未加固模型的振动台试验损伤结果、动力特性、动力反应和频谱分析比较,验证了提出的加固方案的抗震性能和可行性.振动台试验结果表明:加固后模型达到了“小震不坏、中震可修、大震不倒”的抗震设防目标,为制定这类结构的抗震加固方案提供了依据.

A rural building in Beijing is a typical single-story brick-timber structure built in 1980 's.There aren't any aseismic measure in the building. The building by aseismic strengthening could achieve the design target of operational after minor earthquake,repairable damage under middle earthquake,and collapse prevention under rare earthquake. The structural aseismic key strengthening technologies against seismic fortification intensity in Beijing are introduced.

Considering the front longitudinal wall of rural housing built by mud masonry as an object of study,three windowed walls reinforced by different methods are designed through the quasi-static test of windowed brick masonry.These three walls are analyzed from the aspects which include destruction,ultimate load and cracking displacement,and the weaknesses of windowed walls are summarized in the earthquake.At the same time,the reinforcement effects and damage characteristics are analyzed for the steel mesh and cement mortar reinforcement and the steel sash reinforcement.In addition,reinforcement recommendations about two reinforcement methods are proposed.

The investigation and seismic reinforcements of typical rural dwellings in Beijing have been sped up since Wenchuan earthquake in 2008.Based on the investigations of the seismic performances of typical rural dwellings in 13 districts of Beijing,the information of structure system,construction time and construction materials were summarized.Based on seismic damage characteristics of similar rural dwellings in Wenchuan earthquake,the actual seismic performances of rural dwellings in Beijing were analyzed and security risks as well as countermeasures were proposed.The research provides reference for design,construction and research of seismic reinforcements of rural dwellings in Beijing.

This paper presents seismic retrofit for the single-story brick-wood structure representative of existing rural buildings in Beijing.The retrofitting effectiveness was examined through large-scale shaking table tests on the unretrofitted and retrofitted specimens.The test results indicate that,for the unretrofitted specimen,the front brick columns deform and damage severely when subjected to the longitudinal motions,because large of lateral stiffnesses difference exists between the front and back longitudinal walls.The brick gables experience significant out-of-plane deformation,resulting in diagonal cracks.The unretrofitted specimen is cracked under minor earthquakes,significantly damaged under design basis earthquakes,and approaches to collapse under rare earthquakes.The method of seismic retrofit was proposed based on the test results of the unretrofitted specimen,including the addition of a steel doorframe,steel window frames and steel plate collar beams,and the strengthening of the brick gables and columns by cement mortar reinforced with steel mesh.Shaking table test results show that the retrofit method significantly improves the earthquake-resistant capacity of the brick-wood building structure,and the retrofitted specimen can achieve the design objective of 'operational under minor earthquakes,repairable damage under design basis earthquakes,and collapse prevention under rare earthquakes'.

In order to investigate the seismic resistant capacity of typical brick-timber structures in rural areas of Beijing,a 2/3 scaled typical brick-timber structure model with timber columns,wood roof and brick peripheral walls was designed and tested on a shaking table,which is a single-story brick-timber structure with three bays.According to the national seismic design code GB50011,the seismic precautionary intensity is 8 for most rural areas in Beijing.Different dynamic base excitation levels,such as design small earthquake with PGA=0.072g,design middle earthquake with PGA=0.2g and great earthquake with PGA=0.4g respectively,were input to the model.Dynamic responses and cracking characteristics on the brick walls were recorded.Based on the test results,the seismic resistant capacity of the model was obtained and analyzed.It was found that due to different lateral resisting stiffness of the front wall and the back wall for different door or window openings,the response of the front wall was far greater than that of the back wall in the longitudinal direction.This leads to out plan flexure of the end brick wall,some key technologies for how to strengthen and retrofit the existing rural brick-timber structure in Beijing are pointed out.