The Effect of Core Eccentricity on the Structural Behavior of Concrete Tall Buildings

The main purpose of this paper is to investigate the effect of core eccentricity on the structural behavior of concrete tall buildings.Concrete buildings of 55 floors with plan dimensions 48.0×48.0 m2 were investigated.Three cases of main core locations are studied:centric(A),eccentric by one sixth(B)and one third(C)of building width.The three-dimensional finite element method has been used in conducting structural analysis through ETABS software.Gravity and lateral(wind and seismic)loadings are applied to all building cases.It has been concluded that the core location is the prime parameter governing the structural behavior of tall buildings.Although the first two cases(A,B)have acceptable and similar structural behaviors conforming to code limits,in the third case(C),the building behavior came beyond code limits.The author introduced remedial action by adding two secondary cores in the opposite direction of the main core(C-R)to restore the building behavior to the code limits.The results of this action were satisfactory.

Weathering Characterization and Degradation Analysis of Landscape Wooden Buildings in Semi-Arid and Sandy Area

Wooden buildings play a very important role in China’s construction and landscape architecture industry.In order to explore the weathering characteristics of the surface layer of landscape wooden buildings,the main causes of weathering were analyzed on the basis of summarizing the common types of weathering characterization.The results showed that the weathering characterization was mainly reflected in the surface defects of wood structures,such as cracking,discoloration,peeling,wind erosion wear,and so on.The coating technology on the surface of constructions was the main artificial factor affecting the surface defects of constructions.In the case of similar surface decoration conditions,sunlight and moisture were the main natural factors affecting the weathering of wooden buildings,which will promote the process of weathering.

FUZZY MATHEMATICAL EVALUATION FOR MASONRY STRUCTURE BUILDINGS' DAMAGE GRADE CAUSED BY COAL MINING

Coal mining under buildings certainly causes surface movement and deformation, therefore, it brings about deformation even fracture for buildings. It is an important task to evaluate correcly the buildings’ damage grabe caused by coal mining. Fuzzy comprehensive evaluation,considering some factors of buildings’ fracture, has been applied to analyze the masonry structure buildings’ damage grade affer coal mining in this paper. It provides a scientific basis for buildings’reidercement before mining and maintenance or compensation after mining.

Earthquake induced pounding between adjacent buildings considering soil-structure interaction

Many closely located adjacent buildings have suffered from pounding during past earthquakes because they vibrated out of phase. Furthermore, buildings are usually constructed on soil; hence, there are interactions between the buildings and the underlying soil that should also be considered. This paper examines both the interaction between adjacent buildings due to pounding and the interaction between the buildings through the soil as they affect the buildings＇ seismic responses. The developed model consists of adjacent shear buildings resting on a discrete soil model and a linear visco- elastic contact force model that connects the buildings during pounding. The seismic responses of＇ adjacent buildings due to ground accelerations are obtained for two conditions： fixed-based （FB） and structure-soil-structure interaction （SSSI）. The results indicate that pounding worsens the buildings＇ condition because their seismic responses are amplified after pounding. Moreover, the underlying soil negatively impacts the buildings＇ seismic responses during pounding because the ratio of their seismic response under SSSI conditions with pounding to those without pounding is greater than that of the FB condition.

Influence of soil——structure interaction on seismic collapse resistance of super-tall buildings

Numerous field tests indicate that the soilestructure interaction （SSI） has a significant impact on thedynamic characteristics of super-tall buildings, which may lead to unexpected structural seismic responsesand/or failure. Taking the Shanghai Tower with a total height of 632 m as the research object, thesubstructure approach is used to simulate the SSI effect on the seismic responses of Shanghai Tower. Therefined finite element （FE） model of the superstructure of Shanghai Tower and the simplified analyticalmodel of the foundation and adjacent soil are established. Subsequently, the collapse process of ShanghaiTower taking into account the SSI is predicted, as well as its final collapse mechanism. The influences ofthe SSI on the collapse resistance capacity and failure sequences are discussed. The results indicate that,when considering the SSI, the fundamental period of Shanghai Tower has been extended significantly,and the collapse margin ratio has been improved, with a corresponding decrease of the seismic demand.In addition, the SSI has some impact on the failure sequences of Shanghai Tower subjected to extremeearthquakes, but a negligible impact on the final failure modes. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

Describe the Process of Retrofitting Existing Buildings and Evaluate the Effectiveness of it in Improving the Seismic Performance of Structures in Earthquake-prone Regions

At present,earthquakes are a serious problem for building.Severe damages and collapses of buildings were caused by earthquakes in different degrees.It is reported that there are more than 68,858 deaths and hundreds of billions RMB losses in the May 12,2008 Great Wenchuan Earthquake[16].So,more attention should be paid to seismic technology.In order to face the challenges of earthquake on building,the seismic retrofitting was put forward,which“is the modification of existing structures to make them more resistant to seismic activity,ground motion,or soil failure due to earthquakes”[2].

Extended consecutive modal pushover procedure for estimating seismic responses of one-way asymmetric plan tall buildings considering soil-structure interaction

Performance based design becomes an effective method for estimating seismic demands of buildings. In asymmetric plan tall building the effects of higher modes and torsion are crucial. The consecutive modal pushover （CMP） procedure is one of the procedures that consider these effects. Also in previous studies the influence of soil-structure interaction （SSI） in pushover analysis is ignored. In this paper the CMP procedure is modified for one-way asymmetric plan mid and high-rise buildings considering $SI. The extended CMP （ECMP） procedure is proposed in order to overcome some limitations of the CMP procedure. In this regard, 10, 15 and 20 story buildings with asymmetric plan are studied considering SSI assuming three different soil conditions. Using nonlinear response history analysis under a set of bidirectional ground motion; the exact responses of these buildings are calculated. Then the ECMP procedure is evaluated by comparing the results of this procedure with nonlinear time history results as an exact solution as well as the modal pushover analysis procedure and FEMA 356 load patterns. The results demonstrate the accuracy of the ECMP procedure.

Construction of Teaching Case Base of Anti-Seismic Design of Building Structure

Anti-Seismic Design of Building Structures is an important course in civil engineering majors,and it is also a course that pays equal attention to theory and practice.Therefore,by establishing a case base for Anti-Seismic Design of Building Structures,the obscure theoretical knowledge can be taught to students in the form of examples,and the knowledge becomes intuitive.In this way,the students’understanding of anti-seismic design theory and the efficiency of teaching can be improved,and the students’interest in learning can be stimulated.

“3 Degrees and 8 Combinations” Teaching Mode of Anti-Seismic Design of Building Structures

Earthquakes pose a significant threat to people’s property and personal safety.Improving the teaching of civil engineering and building structure anti-seismic design courses can enable students to do a good job in anti-seismic design in the future and effectively reduce the damage on buildings caused by earthquakes.In this paper,we analyzed the basic characteristics of a course in civil engineering major,which is Anti-Seismic Design of Building Structures,and the shortcomings of traditional teaching.It is proposed that the 3-degrees and 8-combinations teaching mode of anti-seismic design of building structures can effectively improve students’autonomy and enthusiasm in learning,helps to cultivate professional ethics among students,and improve their ability to apply what they have learned.

基于BIM技术与模拟退火算法的村镇轻钢框架结构智能设计方法

传统村镇住宅结构设计需要进行大量的人工试算与重复建模,而受制于建设成本,村镇住宅无法像城镇住宅一样通过设计师进行专业的结构设计与验算,其安全性与经济性均难以满足要求。为此,提出一种村镇轻钢框架结构智能设计方法,包括智能建模与智能优化两个环节。基于图层自动识别算法、光学字符识别技术、自适应分块算法提出村镇轻钢框架结构BIM智能建模方法,包括图层识别、轴文本数据提取、墙体轮廓提取等,智能建模结果基本满足实际工程要求。基于提出的两阶段模拟退火算法给出村镇轻钢框架结构的智能优化方法,优化速度较快,优化效果良好。通过实际工程案例对提出的智能设计方法进行验证,结果表明,提出的村镇轻钢框架结构智能设计方法具有可行性,与传统的人工设计方法相比,设计周期可缩短70%以上,材料用量、结构设计指标接近人工设计结果。

泸定6.8级地震城镇居住建筑典型震害及启示

为分析泸定68级地震中城镇居住建筑的破坏情况,对位于震中磨西镇及周边城镇居住建筑的典型震害进行调查,总结了城镇居住建筑中框架结构及砌体结构的震害特征,详细介绍了一栋采用框架结构的高层住宅及一栋采用砌体结构的多层员工宿舍的破坏情况,并分析破坏原因。调查与分析结果表明:本次地震中,框架结构和砌体结构破坏普遍在底层更严重;框架结构震害总体较轻,未合理设计的楼梯及填充墙依然是框架结构中震害集中区;砌体结构墙体出现常见的各种斜向裂缝;除设计因素外,造成少量砌体结构倒塌可能原因是传统砌体结构抵抗竖向地震作用能力不足以及特殊场地地震放大效应。根据两种结构类型的建筑震害特征,对灾区重建及既有房屋改造提出了重点加强老旧建筑合规性排查、合理计算不利地段建筑的地震作用、适当引入合适的减隔震装置等针对性的设计建议,以提高城镇居住建筑的抗震能力,同时体现韧性城镇的设计理念。

装配式建筑结构顶升逆作法原理与技术发展

顶升逆作法综合了顶升和逆作法两种技术的不同特性,是一种在邻近地面对建筑逐层建造并逐层顶升的新型建造工艺。通过对顶升各阶段的原理分析,结合强时变结构特点,对顶升点选择等关键技术进行研究,分析了竖向顶升位移不同步工况下的结构受力机理,厘清了装配式建筑结构顶升逆作法的受力特点,梳理了现有的相关配套技术,指出了目前装配式建筑结构顶升逆作法待解决的技术难题。针对新型建造工艺的强时变特征,提出了结合数字孪生和人工智能两种技术进行智能调控的发展趋势,构建了面向减碳优化的综合目标函数,并通过算例证明合理的顶升方案对减少建造阶段构件内力的作用。结果表明:依托装配式建筑结构顶升逆作法原理,采用机械化施工取代人工作业、大重量顶升替换高空吊运,减少设备的层间转运和材料的竖向运输,能够在提高施工建造效率的同时,将工艺流程控制在临近地面的有效高度范围内,有望降低环境影响、减少碳排放、提高建筑结构在未来服役末期的资源化可行性,助力建筑业绿色低碳发展。

甘肃积石山6.2级地震村镇建筑震害调查与分析

积石山地震对甘肃和青海部分地区房屋建筑造成了严重破坏。调查了地震烈度7度和8度地区的11个调查点的村镇建筑震害。震害调查表明:地震灾区主要为乡镇和农村地区,房屋结构类型主要为土木、砖木和未设防砖混结构;在烈度8度地区,土木结构房屋主要表现为严重破坏或倒塌破坏,砖木结构和未设防砖混结构房屋主要表现为中等破坏和严重破坏,设防砖混和钢筋混凝土框架结构房屋主要表现为轻微破坏和中等破坏;在烈度7度地区,土木结构房屋以中等破坏为主,砖木结构和未设防砖混结构房屋以轻微破坏和中等破坏为主,设防砖混和钢筋混凝土框架结构房屋以轻微破坏和基本完好为主。此次地震震害较同级别地震偏重,与震区复杂地形、地震动峰值放大效应、建筑砌筑质量差和结构受力不合理等因素相关。建议进一步开展复杂地形场地放大效应及频谱影响研究,重视建筑非结构构件抗震宣传与实用技术研发。

模块化建筑阵列多调谐质量阻尼系统的实现与减震研究

基于建筑模块化和悬挂楼板减震的原理提出了悬挂楼板模块体系(modularized suspended floors system,MSFS)。利用楼板作为质量块,组成分布阵列式多调谐质量阻尼器(distributed array multiple tuned mass dampers,d-array-MTMDs)系统。通过输入32条远场和近场地震动记录进行时程分析,对平均调谐频率比η、调谐频带宽度系数β、调谐阻尼比ζ_(T)、TMD数量n以及主结构层数N,共5个参数展开研究。结果表明:d-array-MTMDs的减震效果优于普通MTMDs系统;ζ_(T)对系统减震性能影响较小,当η为0.7~1.0、β为2.0时,系统具有更好的减震效果;当n大于某阈值时,系统的减震效果趋于稳定,阈值与η线性正相关,与ζ_(T)非线性负相关。随着模块建筑层数的增加,系统也能维持较好的减震效果。

不同结构因子下带连廊高层建筑外墙火竖向蔓延数值模拟

目的 研究带连廊高层建筑发生火灾时火焰蔓延的变化规律,为该类建筑的防火设计提供参考。方法 应用火灾数值模拟软件FDS建立一个33层带连廊建筑模型,分别改变结构因子、窗口数量两种因素进行模拟,分析该模型在不同条件下的温度分布等温线和温度曲线。结果 结构因子为0.4、0.8、1.2,窗口数量为二、三、四时,达到危险温度540℃,火焰融合高度随结构因子和窗口数量增加而上升;随着结构因子的增加,火焰融合高度提高了0.25~12.5 m;随着窗口数量的增加,火焰融合高度上升了0.9~6.37 m;结论 带连廊高层建筑外墙火焰蔓延高度受结构因子和窗口数量影响;随着窗口数量增加,结构因子对火焰融合高度影响越大,结构因子越大,火焰融合高度越高;建议带连廊高层建筑连廊部分结构因子小于0.8,并选用结构因子为0.8时的火焰融合高度作为外部蔓延防火阻隔区高度。

北航主楼群结构鉴定与加固设计

通过北航主楼群项目的实际工程案例,论述了结构鉴定过程及结果、加固方案,阐述了结构鉴定和加固设计中应注意的问题,并分析通用规范的实施对既有建筑鉴定及加固的影响,提出了相应的意见及建议,对既有建筑结构鉴定及加固设计具有一定的借鉴意义。

地铁上盖建筑振动响应预测及舒适度分析——以南京地铁1号线停车维修库综合体上盖住宅项目为例

对南京市地铁1号线车库段上部待建住宅楼进行研究,探讨地铁上盖建筑受地铁出入库振动的影响。通过现场测试与数值模拟,预测不同工况下待建建筑的振动响应以及室内振动加速度限值范围。模拟结果表明,采用底部加速度法将所测轨道、混凝土柱的振动输入计算模型中,可以获得待建建筑三向位移变化,并进行结构易损部位及预警分析,判断建筑安全性。通过模拟8种工况,计算得到1~80 Hz频率范围内各建筑楼板1/3倍频程中心频率下的加速度响应有效值和加速度振级,获取了住宅舒适度影响较大区域的具体坐标。研究成果对结构减振及舒适度提升具有参考意义。

铰接方钢管组合异形柱框架抗震性能研究

为解决村镇住宅体系存在的装配式程度及标准化程度较低、现场焊接工作繁多、室内建筑面积浪费等问题,提出了一种铰接方钢管组合异形柱框架体系。该体系中异形柱采用3根空钢管通过钢板与加劲肋组合而成的L形柱,梁柱节点为腹板螺栓连接的铰接节点。通过拟静力试验对该体系的抗震性能进行研究。研究结果表明:相比于铰接钢管混凝土组合异形柱,铰接空钢管组合异形柱框架体系先于梁端出现转角,最后破坏模式为柱脚破坏,具有更优良的抗震耗能和更缓慢的强度与刚度退化,并通过对比刚接节点和铰接节点的骨架曲线,发现节点刚接程度对结构整体的抗侧刚度影响较大。

空间约束下电动汽车无线充电系统磁耦合结构优化

电动汽车无线充电系统在尺寸大小与位置偏移等因素的影响下,会导致系统传输能力下降。为了在空间约束条件下提升系统的输出功率、传输效率及抗偏移能力,针对位置偏移与底盘高度不同的实际情况,在经典D4线圈的基础上分别设计了收发端非对称D4和收发端非对称D4Q双层线圈磁耦合结构,以提高耦合系数和抗偏移能力。在不同方向的偏移和旋转的情况进行仿真测试,表明收发端非对称D4Q双层线圈在出现横向偏移300 mm、纵向偏移400 mm、传输距离230 mm和旋转偏移45°以内具备无线电能传输能力。通过搭建实验平台对偏移进行测试与验证,结果表明,所提出的收发端非对称D4Q磁耦合结构的最大输出功率相对于收发端对称D4磁耦合结构增加约60.34%,最大传输效率增大11%。

基于BIM的公路工程标准化EBS分解方法

工程结构分解(EBS)是公路工程全寿命周期信息化管理的基础。为了提高公路工程建设期信息化水平,基于BIM技术应用,提出了公路工程标准化EBS分解方法。标准化分解方法根据工程中不同路段,梳理专业划分以及空间位置划分原则,并依据行业标准,确定标准化EBS结构的叶子节点,提供公路工程EBS结构树模板示例。研究结果旨在提高高速公路数字化交付中的数据处理标准建设,为实施公路工程数字化提供基础支持。