In situ experiment on retrofit of school buildings by adding sandwich columns to partition brick walls

Many significantly strong earthquakes have occurred over the years in Taiwan, which have caused tremendous damage to primary and middle school buildings; the 921 Chi‐Chi earthquake was particularly devastating. According to statistics, 786 schools (1,958 classrooms) were damaged on September 21, 1999 during this earthquake event. The devastation showed that a lack of seismic performance is a common problem for existing school buildings in Taiwan. Therefore, the retrofit of existing school buildings has become an urgent issue in the prevention of possible damage in the future. The retrofit technique of adding sandwich columns to partition brick walls is proposed in this paper, and the feasibility of the proposed method was verified by in situ pushover tests of two real school buildings, one without and one with retrofit. The experimental and analytical results show that the sandwich column itself contributes significantly to the seismic capacity of the examined school building. Moreover, the analytical results yielded conservative capacity curves when compared with the experimental results. Copyright © 2013 John Wiley & Sons, Ltd.     

带构造柱混凝土多孔砖墙体的抗震性能试验研究

通过4片带构造柱混凝土多孔砖墙片在低周反复荷载作用下的试验研究,分析了该种材料墙体的破坏特征及其强度、滞回曲线、延性等抗震性能.试验结果表明:墙片两端设置构造柱后,即能较大幅度提高极限荷载,又能改善其变形,延性等性能.另外分析了墙片的高宽比、轴向压力、构造柱等对抗剪承载力的影响,对<抗震结构设计规范>(GB5001-2001)中抗剪承载力计算公式提出补充建议,得出这类墙体的抗剪承载力计算公式.     

Experimental study on the seismic performance of new sandwich masonry walls

Sandwich masonry walls are widely used as energy-saving panels since the interlayer between the outer leaves can act as an insulation layer.New types of sandwich walls are continually being introduced in research and applications,and due to their unique bond patterns,experimental studies have been performed to investigate their mechanical properties,especially with regard to their seismic performance.In this study,three new types of sandwich masonry wall have been designed,and cyclic lateral loading tests were carried out on five specimens.The results showed that the specimens failed mainly due to slippage along the bottom cracks or the development of diagonal cracks,and the failure patterns were considerably influenced by the aspect ratio.Analysis was undertaken on the seismic response of the new walls,which included ductility,stiffness degradation and energy dissipation capacity,and no obvious difference was observed between the seismic performance of the new walls and traditional walls.Comparisons were made between the experimental results and the calculated results of the shear capacity.It is concluded that the formulas in the two Chinese codes(GB 50011 and GB 50003) are suitable for the calculation of the shear capacity for the new types of walls,and the formula in GB 50011 tends to be more conservative.     

碳纤维布用于砖砌体抗震加固的试验研究

通过4片碳纤维布加固砖砌体在周期反复荷载作用下受力性能的试验，研究了粘贴碳纤维布来增强砖砌体抗震能力这种加固方法的有效性。本文研究了碳纤维布加固砖砌体的受力特性，分析了碳纤维布的用量以及贴布方式等因素对砖砌体抗震加固效果的影响。在此基础上，本文提出了碳纤维布加固砖砌体抗剪承载力的简化计算方法，可以满足实际工程设计的要求。     

芦山地震中校舍建筑的震害特点与分析

本文对芦山地震中的校舍建筑震害进行调查和分析.调查发现,汶川地震后重建的框架结构,由于按照新的抗震规范进行设防,大多数没有出现结构性损伤,震害集中在填充墙等非结构构件上.建于汶川地震前的框架结构,当不符合规范的强制条文时,破坏严重,特别是单跨框架,个别发生首层柱端破坏.砖混结构校舍中的宿舍楼,由于开间小,横墙多,多设置了构造措施,虽有结构破坏,但均可修复.砖混结构教学楼采用砖墙-框架柱混合承重的结构体系,大多在汶川地震后得到加固,未加固的教学楼有严重的结构破坏,而加固后的校舍建筑则表现较好,但是这些结构体系多采用预制空心板,整体性较差,已经被规范禁止用于校舍建筑.场地对结构震害有重要的影响,密实的持力层、妥善的地基处理和整体性好的基础形式,可以大幅度减轻结构的震害.本文建议:应加强校舍建筑基于性能设计的研究,进一步明确其设防目标;研究填充墙与框架的相互作用,设计新型的填充墙体系以实现校舍建筑在不同地震水平下的功能要求.     

Experimental evaluation on seismic performance of sandwich box columns

This paper presents experimental information on the behaviour of sandwich box columns subjected to combined bending and axial loading. The sandwich box columns consisted of double thin-walled steel tubes with concrete between them. Owing to the interaction between steel and concrete, the composite members performed in a ductile manner during testing. Test results show that high strength/mass ratio characteristics were maintained, and the goal of obtaining significant member ductility was also achieved. The contribution of concrete to member performance was found to be more significant for members with higher steel width/thickness ratios. Copyright © 1999 John Wiley & Sons, Ltd.     

双层打包带加固窗间墙抗震性能试验研究

地震时砌体结构窗间墙易发生破坏,为了提高其抗震性能,对高宽比为1的2组共4片墙体,其中:2片为双层打包带加固墙体,2片为原墙,进行了拟静力试验,研究墙体的破坏形态、水平承载力、滞回曲线和耗能等抗震性能。试验发现原墙发生剪切破坏,加固后墙体发生摇摆破坏,加固改变了墙体破坏模式,加固后墙体滞回曲线饱满但有捏笼,破坏荷载、延性和耗能能力都有提高,破坏时未发生剥离,表明双层打包带加固法有效地提高了窗间墙体抗震性能,对承受较大竖向应力墙体效果更好,建议加固时要加强加固层与窗下和窗上墙体的连接。     

钢管高强混凝土柱抗震性能的试验研究

本文对钢管高强混凝土柱进行低周反复水平荷载作用的试验,得到了不同轴压比情况下的滞回曲线及骨架曲线,讨论了钢管高强混凝土柱压弯承载力计算公式的适用性。结果表明,钢管高强混凝土柱具有很高的承载力及良好的抗震性能。     

钢管混凝土叠合柱边框内藏钢桁架核心筒抗震性能试验研究

为进一步改善混凝土核心简的抗震性能,本文提出了钢管混凝土叠合柱边框内藏钢桁架组合核心筒.进行了2个1/6缩尺的核心筒模型在低周反复荷载下的抗震性能试验研究,1个为钢管混凝土叠合柱边框毛组合核心筒,1个为钢管混凝土叠合柱边框内藏钢桁架组合核心筒.通过试验,对比分析了2个核心简的承载力、延性、刚度及其衰减、滞回特性、耗能能力及破坏特征,给出了钢管混凝土叠合柱边框内藏钢桁架组合核心筒的承载力计算模型,计算结果与实测值符合较好.研究表明,钢管混凝土叠合柱边框内藏钢桁架组合核心筒与钢管混凝土叠合柱边框组合核心筒相比,其抗震性能明显提高.     

超高强混凝土短柱抗震性能的试验研究

通过对12根剪跨比λ=2．0的超高强混凝土短柱在低周反复荷载下抗震性能的试验研究,分析了其破坏形态,并研究了轴压比和配箍率对试件滞回特性和抗震延性的影响,提出了满足一定延性要求（μ△≥3．0）超高强混凝土短柱的轴压比限值和箍筋加密区的最小配箍特征值的建议值。该值可为现行规范的修订提供参考。     

土坯墙体抗震加固的试验研究

通过对4片西北地区传统土坯墙体在低周往复荷载作用下的抗震性能试验研究,对比分析了竹胶板及木柱木梁加固墙片的破坏形态、水平承载力、变形性能、骨架曲线、刚度退化曲线、滞回曲线与耗能性能。试验研究表明:加固墙片可有效提高墙体的抗震性能。在此基础上提出用竹胶板加固既有且在用的村镇土坯墙体房屋,该加固方式经济有效,又能在一定程度上保存建筑原始风貌,满足实际工程的设计要求。     

两结构高效阻尼控制体系试验研究

本文通过模拟地震动振动台试验，研究了两个相邻结构模型的地震响应，结构模型采用一种高效阻尼装置(High Efficient Damper for Multi—Structure System即HEDMS)连接。非线性时程分析与振动台试验结果都证明了该阻尼装置能高效发挥软钢阻尼器的耗能能力，从而显著减轻两结构模型的地震响应。同时，研究还指出了进行阻尼装置设计时应该注意的一些问题。     

型钢高强混凝土柱抗震性能的试验研究

通过14根型钢高强混凝土柱的低周反复加载试验，得到了型钢高强混凝土柱在压、弯、剪共同作用下的主要破坏形态，并探讨了剪跨比、配箍率、混凝土强度对型钢高强混凝土柱滞回曲线、耗能能力以及延性的影响。试验结果表明，型钢高强混凝土柱具有抵御二次地震作用的能力，其抗震性能优于钢筋混凝土柱。     

Experimental study on the seismic response of braced reinforced concrete frame with irregular columns

A 15-storey K-braced reinforced concrete model frame with irregular columns, i.e., T-shaped, L-shaped, as well as +-shaped columns, was constructed and tested on the six-degree-of-freedom shaking table at the State Key Laboratory for Disaster Reduction in Civil Engineering in Tongji, China. Two types of earthquake records, El-Centro wave (south-north direction) and Shanghai artificial wave (SHAW) with various peak accelerations and principal-secondary sequences, were input and experimentally studied. Based on the shaking table tests and theoretical analysis, several observations can be made. The failure sequence of the model structure is brace→beam→column→joints, so that the design philosophy for several lines of defense has been achieved. Earthquake waves with different spectrums not only influence the magnitude and distribution of the earthquake force and the storey shear force, but also obviously affect the magnitude of the displacement response. The aftershock seismic response of previously damaged reinforced concrete braced frames with irregular columns possesses the equivalent elastic performance characteristic. Generally speaking, from the aspects of failure features and drift ratio, this type of reinforced concrete structure provides adequate earthquake resistance and can be promoted for use in China.     

小剪跨比格构式混凝土墙体抗震性能试验

文章旨在研究不同剪跨比的格构式混凝土墙体抗震性能.将生产车间预制成EPS保温模块拼接成墙体模板,在横向和纵向孔洞中分别布置钢筋,然后在孔内浇筑自密实混凝土,形成“EPS新型节能”格构式混凝土墙体,然后对6个参数不同的试件进行低周反复水平荷载作用的试验.结果,墙体破坏形态为:首先墙体相邻格构柱间的连梁出现环状裂缝和“X”...     

免蒸压免烧结粉煤灰多孔砖砌体力学性能试验研究

免蒸压免烧结粉煤灰多孔砖是一种新型承重墙体材料,为使其在地震区村镇建筑中得到推广应用,进行了多孔砖砌体抗压强度和抗剪强度试验,分析了砌体裂缝开展及破坏过程。试验结果表明:免蒸压免烧结粉煤灰多孔砖砌体的受压、受剪破坏过程及特征与普通黏土砖砌体类似,但具有更大的脆性;抗压、抗剪强度均小于普通黏土砖砌体;采用6次多项式的受压本构关系数学模型,反映了免蒸压免烧结粉煤灰多孔砖砌体受压应力-应变全过程,计算值与实测数据比较接近。     

钢筋混凝土带暗支撑核心简体抗震性能试验研究

本文在带暗支撑剪力墙研究的基础上,进一步提出了带暗支撑核心筒体,通1/6缩尺的1个带暗支撑筒体结构和1个普通筒体结构的低周反复荷载试验,比较分析了它们的承载力、刚度、延性、滞回特性、耗能能力及破坏机制。试验表明,带暗支撑筒体比普通筒体的抗震性能明显提高。     

水平嵌筋加固砖砌体墙抗震性能试验研究

以嵌缝胶泥作为嵌缝材料,针对不同高宽比和不同配筋率的6片墙体进行了拟静力试验,探讨了嵌筋加固砖砌体墙的破坏特征、变形能力、承载能力、耗能能力、滞回特征及刚度退化等抗震性能,建立了以试验为基础的嵌筋加固砖砌体墙的抗剪承载力计算公式。研究结果表明:高宽比为1.8的试件,嵌筋墙体较无筋墙体水平抗剪极限承载力提高了17%~31%,延性提高了54%~83%;高宽比为0.5的试件,嵌筋墙体较无筋墙体水平抗剪极限承载力提高了13%~17%,延性提高了17%~20%,嵌筋加固墙体滞回环饱满,耗能能力有较大幅度提高,破坏形式由脆性破坏转变为延性破坏,嵌筋对墙体初始刚度的影响较小,给出的抗剪承载力公式计算值与试验值接近,为工程应用奠定了基础。     

低层装配式钢筋混凝土水平坐浆墙体抗震性能试验研究

为了研究低层装配式钢筋混凝土水平坐浆墙体的抗震性能,对3个不同剪跨比的低层装配式钢筋混凝土水平坐浆墙体进行了低周反复荷载试验。根据试验结果,分析了剪跨比对墙体的破坏形态、承载力、变形能力、刚度退化和耗能能力的影响。结果表明:随着剪跨比的减小,墙体的破坏形态由弯曲破坏转为剪切破坏;试件SW2和试件SW3的承载力相对于试件SW1分别提高68%和110%,延性分别降低21.8%和37.5%;试件SW1的耗能能力最好,刚度退化速度最缓慢;预制钢筋混凝土墙板与现浇边缘构件协同合作,连接处无竖向裂缝,墙体整体性较好,具有良好的抗震性能,可用于我国城镇建设中的低层住宅结构。     

不同延性条件下框架柱塑性铰区箍筋抗剪能力试验研究

允许钢筋混凝土框架柱端出现塑性铰但又不形成柱铰破坏机构是一个十分现实而又未得以很好解决的课题。通过10个钢筋混凝土框架柱构件抗震剪切抗力的试验研究,明确了加载全过程骶架柱构件中箍筋与混凝土的抗剪贡献及比例,分析了框架柱塑性铰区抗剪机理,为框架柱基于延性的抗震设计提供了试验依据。