Analysis and design of FRP composites for seismic retrofit of infill walls in reinforced concrete frames

There is an urgent need to retrofit deficient mid-rise reinforced concrete (RC) frame buildings in Turkey. For this purpose, an efficient FRP retrofit scheme has been developed previously, in which hollow clay brick infill walls can be utilized as lateral load resisting elements after retrofitting. The main premise of this practical retrofit scheme was to limit inter-storey deformations by FRP strengthened infill walls that are integrated to the boundary frame members by means of FRP anchors. Based on the analytical model that was previously verified extensively by comparison with test results, a simplified model was proposed for use in displacement based design of FRPs for deficient RC frame buildings. FRP retrofit design and analysis of an actual deficient RC building located in Istanbul are presented herein both for the local design spectrum and Duzce ground motion. It was observed that the FRP retrofit reduced the damage induced to deficient columns by controlling story deformations. In this way, it was possible to satisfy the collapse prevention performance state in an efficient and economical manner.     

Thermal Transmittance of Porous Hollow Clay Brick by Guarded Hot Box Method

The thermal property of a porous hollow clay brick was determined by measuring the thermal transmittance of the wall made of porous hollow clay bricks. Prior to the production of porous hollow clay bricks, nonporous and porous tiny clay bricks were prepared to determine the physico-mechanical properties by modifying the amount of wood flour and firing temperature. The bricks were produced by uniaxial pressing and then fired in an electric furnace. Their physico-mechanical properties were measured by water absorption, apparent porosity, bulk density, and compressive strength. The porous tiny clay bricks were produced with three types of wood flour: coarse wood flour (1–0.36 mm), medium-sized wood flour (0.36–0.15 mm), and fine wood flour (< 0.08 mm). The thermal transmittance of porous hollow clay bricks was determined through the guarded hot box method, which measures the wall made of porous hollow clay bricks and nonporous cement bricks. The two walls had a thermal transmittance of 1.42 and 2.72 \(\hbox {W}\cdot \hbox {m}^{-2}\cdot \hbox {K}^{-1}\), respectively. The difference in thermal transmittance was due to the pores created with fine wood flour (< 0.08 mm) as a pore-forming agent.     

大时差双倒向爆破拆除七层空心砖混结构楼

待拆七层公寓楼房为空心砖墙和钢筋混凝土构造柱结构 ,具有较小的高宽比。爆前通过预处理 ,切断南、北楼的联系 ,使它们成为独立的建筑物。采用大时差多段别延时爆破方案 ,使两个独立的楼房分别向南、北方向倒塌。文中论述了爆破方案设计、爆破参数确定以及在空心砖墙上进行钻孔和装药的施工工艺。     

高台阶崩落法处理复合采空区的应用实践

采用深孔牙轮钻机、利用高台阶崩落法成功地处理了复合采空区,解决了复合采空区处理难的问题,使技术人员在熟练浅采、深采空区处理的情况下,又探索出复合采空区的处理方法。为矿山的发展消除了安全隐患,扫清了前进的障碍;为同类矿山的空区处理及相关问题的探讨提供了参考依据。     

中国传统建筑营造技术中的砖瓦设计研究

以传统建筑材料的砖瓦为研究对象,基于设计学视野,运用纵向考证与横向比较的研究方法,系统梳理了古代砖瓦的发展脉络及其应用场景。通过对条砖的尺寸进行数据量化分析,明晰了条砖尺度自汉代以降日趋变小并趋于固定,且更具有适人的特征,并逐渐替代大型空心砖成为主流。随着楔形砖与曲尺形砖的创制及大半圆瓦当的普及,至宋代砖瓦制作朝向规范化路径发展。以此探明古代烧造技术与建筑材料发展的相互关系。     

Investigation of kinetics of Cr(VI)-fired brick clay interaction

Fired brick clay is an excellent sorbent for the removal of heavy metal ions from waste water, owing to the availability of pores and interlayer spacing. Consequently, heat treatment of brick clay significantly affects the extent of interaction between the brick clay sorbent and adsorbates. The interaction between Cr(VI), available as Cr(2)O(7)(2-), and brick clay particles fired at temperatures between 200 °C and 600 °C follows pseudo second order kinetics, and the method of initial rates leads to the estimation of the average rate of the interaction process. Kinetics modeling suggests that the mass transfer of the interaction be mainly controlled by time-dependent intraparticle diffusion, as well as immobilization of Cr(VI) species within interlayer structure of the brick clay matrix and interparticle diffusion, both of which are time-independent.     

外部接触装药爆破拆除空心墙楼房

在复杂环境下 ,利用外部接触爆破成功地拆除一空心水泥砖承重墙结构的五层楼房。本文介绍了爆破方案的确定 ,装药设置和爆破参数选取 ,较详细地阐述了爆破网路和起爆延时的设计以及安全防护措施。为类似结构楼房的拆除提供了一种可行的方法     

Schubtragfähigkeit von Mauerwerk aus Wärmedämmziegeln

Der Beitrag berichtet über zentrische und exzentrische Schubversuche an Mauerwerk aus Wärmedämmziegeln. Die Ergebnisse werden mit den aktuell gültigen Bemessungsansätzen in DIN 1053‐1 verglichen. Es wird gezeigt, dass die Versuchsergebnisse immer eine ausreichende Sicherheit gegenüber den Bemessungswerten nach DIN 1053‐1 aufweisen. Auch für Mauerwerk aus Wärmedämmziegeln mit allgemeiner bauaufsichtlicher Zulassung können somit die vereinfachten Bemessungsregeln der DIN 4149 ohne Abminderungen angewendet werden. In plane shear resistance of thermal insulating vertically perforated clay brick masonry. In plane shear tests on thermal insulating vertically perforated clay brick masonry are presented. The results are compared with the design rules from DIN 1053‐1. The test results exceeded the design predictions of DIN 1053‐1 by a significant safety margin. The simplified design rules from the German earthquake standard DIN 4149 can be applied to thermal insulating clay unit masonry with technical approvals without any reduction.     

外部接触装药爆破拆除空心墙楼房

在复杂环境下 ,利用外部接触爆破成功地拆除一空心水泥砖承重墙结构的五层楼房。本文介绍了爆破方案的确定 ,装药设置和爆破参数选取 ,较详细地阐述了爆破网路和起爆延时的设计以及安全防护措施。为类似结构楼房的拆除提供了一种可行的方法     

GFRP复合材料与砖界面粘结性能的数值模拟

纤维复合材料(Fiber Reinforced Polymer,FRP)加固砌体结构剥离破坏是一种常见的破坏形式。对玻璃纤维复合材料(GFRP)和砖粘结界面进行数值模拟,用Solid65单元和Shell41单元分别模拟砖和GFRP,采用接触单元的方法,用"接触对"将砖实体单元和GFRP单元连接在一起,研究粘结界面的应力、应变分布特点和破坏过程。分析结果表明用有限元模拟分析粘结界面应力状态具有一定的可行性。     

Design thermal values for unfired clay bricks

This paper reports on a laboratory and theoretical method for determining the design values for thermal conductivity and thermal resistance of unfired clay masonry bricks from both experimental and theoretical design point of view. The paper describes the methodology of obtaining these values using the measured lower and upper lambda limits. In order to determine the basic design thermal value and the design thermal resistance, a Laser-comp FOX 200 thermal conductivity meter equipped with WinTherm32an software package was employed for the laboratory data collection and analysis. Lime or Portland cement (PC)-activated Ground Granulated Blastfurnace Slag (GGBS) binder was used to stabilise Lower Oxford Clay (LOC) for unfired masonry brick specimen production. The major influence of the design values on the thermal conductivity and thermal resistance are illustrated in this study, using two different types of unfired clay bricks (LG and PG) at 2% moisture content prior to test. This paper covers conductivity test for each unfired clay bricks within the temperature range 2.5–17.5 °C. The measured thermal properties of the unfired clay bricks were compared to the design thermal properties of fired bricks. The results were used to predict the design thermal values of unfired clay masonry bricks at varied density and moisture contents prior to testing. A comparison of the measured thermal values for the unfired bricks to the design thermal values of fired clay bricks can also be seen. The results demonstrate that the unfired clay bricks were able to comply with the design thermal requirements for clay masonry units, suggesting that the unfired clay bricks can be used for low-medium cost housing and energy efficient masonry structures.     

Application of Effective Media Theory for Determination of Thermal Properties of Hollow Bricks as a Function of Moisture Content

The effective thermal conductivity and effective specific heat capacity of hollow brick blocks are investigated as a function of moisture content. While the effective specific heat capacity as a heat storage parameter is calculated using the linear theory of mixtures, the effective thermal conductivity as a heat transport parameter is analyzed using the effective media theory. At first, the effective thermal conductivity of the dry hollow brick block is calculated using a combination of properties of the brick body and air cavities, and verified using experimental data. Then, the effective thermal conductivity of the brick body is analyzed as a function of moisture content both theoretically and experimentally, and appropriate homogenization formulas are identified. Finally, the effective thermal conductivity of the whole hollow bricks is expressed as a function of moisture content from the dry state to water saturation.     

Microstructural Characterization of Fired Clay Bricks in the Chontalpa Region, Tabasco, Mexico

In the Mexican state of Tabasco, clay-like materials are of particular interest in the handcraft and construction industries. Combining both and due to the abundance of clay on this region, fired clay bricks are commonly used in construction. These are done in an artesian way without proper quality control. We present a chemical content analysis study for three particular areas in the Chontalpa region in Tabasco, where the mud used to produce the fired clay bricks is obtained. It is found that the mineralogical composition and firing temperature influence the brick porosity promoting textural and physical changes.     

接触爆炸下黏土砖砌体墙的抗爆性能

为了研究接触爆炸下黏土砖砌体墙的抗爆性能，采用LS-DYNA有限元软件，以传统单面黏土砖砌体墙为例，建立了黏土砖砌体墙三维分离式细观模型，分析了不同强度接触爆炸载荷下墙体的毁伤和破坏特征。使用两种不同质量的TNT炸药对普通黏土砖墙体在单方向支撑条件下进行了对应的接触爆炸试验验证，并研究其工作机理及响应特性。分析结果表明，随着爆炸载荷的逐渐增加，接触爆炸对墙体的破坏形式主要由中央爆坑以及水平、竖直方向的十字形裂纹的形成，转化为灰缝的层裂、崩落、贯穿以及墙体的错位和倒塌。     

Strength and chemical resistance of mortars containing brick manufacturing clays subjected to different treatments

This paper presents the results of an investigation of the properties of mortar in which a calcined clay was employed as a pozzolan. Mortars were prepared using either heat treated clay or ground waste clay bricks (from the same clay subjected to 1000 °C calcining) as a pozzolanic partial replacement for cement at replacement levels of 10%, 20% and 30%. The compressive strengths of the mortars were monitored up to 90 days and the resistance to sodium sulphate solution and synthetic seawater was monitored up to 300 days. The specimens were also monitored for weight changes. Partially replacing cement by ground brick or heat-treated brick clay gives early strengths that are lower than that of the control. At 90 days, however, the strengths are the same as or are greater than that of the control. Heat-treated clay is effective in reducing expansion during exposure of the mortar to sulphate solution and synthetic seawater. The rapidly cooled clay gives better performance, in terms of strength development and resistance to harmful solutions, than the slow cooled clay.     

Creep of clay masonry exhibiting cryptoflorescence

To determine creep of clay masonry in the laboratory, total time-dependent strain readings are recorded from a wall subjected to a constant load and from a corresponding control wall not subjected to load. Creep is then calculated by subtracting the moisture movement strain of the control wall plus the elastic strain from the loaded wall, from the total strain recorded on the loaded wall. It is assumed that the moisture movement behaviour is the same in both the loaded and the control walls. The paper questions that assumption for certain types of clay brickwork. Small control walls built from low strength bricks having high water absorption can undergo an enlarged moisture expansion. The enlarged expansion is greater than the irreversible moisture expansion of the unbonded clay brick and is thought to be the result of crystallization of salts at the brick-mortar interface, a process known as cryptoflorescence. In a loaded wall, cryptoflorescence is suppressed or restrained so that the effect of an enlarged expansion of the control wall is to overestimate creep and considerably so in some cases. The paper demonstrates the problem by examining the effect of enlarged expansions when ascertaining creep of masonry built from different types of clay bricks. Experimental and design recommendations are made for more reliable methods of determining creep.     

多点空气耦合爆破拆除空心砖结构楼房

介绍了采用多点空气耦合爆破拆除技术对空心砖结构实施定向爆破.通过多次实体试验,合理选取各爆破参数,在起爆顺序及网络联结中,采用交叉复式非电导爆系统组成的微差起爆网路.爆破结果表明,拆除空心砖结构建筑群所采用的多点空气耦合爆破拆除技术和选取的参数是合理可行的.     

废玻璃再生利用制备长余辉蓄光釉面砖及其性能的研究

利用传统陶瓷制备方法合成了SrAl2O4:Eu,Dy长余辉发光粉体,该磷光体主发射波长位于520nm,余辉时间长达20h以上,将发光粉掺入适量的低熔点玻璃料,经780℃烧成30min合成了性能较好的低温发光釉料,以废玻璃,粘土为主要原料添加其它少量助剂,经过成型,预烧,将低发光釉料涂覆在其上,在一定温度下烧成,制得长余辉蓄光釉面砖。     

基于安徽地域特色的博物馆文创产品设计研究

目的 针对安徽省博物院现存文创产品的状况和问题,以其馆藏砖雕精品——百子图砖雕为例,研究和创新富有安徽地域特色的文化创意产品,为安徽省博物院的文创设计提出建设性的方案。方法 通过分析百子图砖雕的文化价值、艺术特色,进行产品的定位分析和主题构建,梳理百子图砖雕图案寓意,进行百子图砖雕文创产品的设计实践。结果 在造型提炼、色彩选择、字体构成的设计实践基础上,开发以青少年为消费主体的文化创意文具系列。结论 通过探索百子图砖雕在文创产品上的设计应用,进一步挖掘安徽地域文化之美,传承发展徽州砖雕艺术。设计具有地域性、文化性、实用性的文化创意产品,促进安徽省博物院文创产品设计的发展和创新,同时对地域性特色文创设计和实践具有启发性意义。