Seismic fragility assessment of RC frame structure designed according to modern Chinese code for seismic design of buildings

Following several damaging earthquakes in China, research has been devoted to find the causes of the collapse of reinforced concrete （RC） building sand studying the vulnerability of existing buildings. The Chinese Code for Seismic Design of Buildings （CCSDB） has evolved over time, however, there is still reported earthquake induced damage of newly designed RC buildings. Thus, to investigate modern Chinese seismic design code, three low-, mid- and high-rise RC frames were designed according to the 2010 CCSDB and the corresponding vulnerability curves were derived by computing a probabilistic seismic demand model （PSDM）.The PSDM was computed by carrying out nonlinear time history analysis using thirty ground motions obtained from the Pacific Earthquake Engineering Research Center. Finally, the PSDM was used to generate fragility curves for immediate occupancy, significant damage, and collapse prevention damage levels. Results of the vulnerability assessment indicate that the seismic demands on the three different frames designed according to the 2010 CCSDB meet the seismic requirements and are almost in the same safety level.

Seismic performance evaluation of typical dampers designed by Chinese building code

Adding dampers is a commonly adopted seismic risk mitigation strategy for modern buildings, and the corresponding design procedure of dampers has been well established by the Chinese Building Code. Even though all types of dampers are designed by the same procedure, actual seismic performance of the building may differ from one to the others. In this study, a nine-story benchmark steel building is established, and three different and typical types of dampers are designed according to the Chinese Building Code to realize structural vibration control under strong earthquake excitation. The seismic response of the prototype building equipped with a viscoelastic damper, viscous damper and buckling-restrained brace(BRB) subjected to 10 earthquake records are calculated, and Incremental Dynamic Analysis(IDA) is performed to describe progressive damage of the structure under increasing earthquake intensity. In the perspective of fragility, it shows that the viscoelastic damper has the highest collapse margin ratio(CMR), and the viscous damper provides the best drift control. Both the BRB and viscoelastic dampers can effectively reduce the floor acceleration responses in the mid-rise building.

Effect of URM infills on seismic vulnerability of Indian code designed RC frame buildings

Unreinforced Masonry (URM) is the most common partitioning material in framed buildings in India and many other countries. Although it is well-known that under lateral loading the behavior and modes of failure of the frame buildings change significantly due to infill-frame interaction, the general design practice is to treat infills as nonstructural elements and their stiffness, strength and interaction with the frame is often ignored, primarily because of difficulties in simulation and lack of modeling guidelines in design codes. The Indian Standard, like many other national codes, does not provide explicit insight into the anticipated performance and associated vulnerability of infilled frames. This paper presents an analytical study on the seismic performance and fragility analysis of Indian code-designed RC frame buildings with and without URM infills. Infills are modeled as diagonal struts as per ASCE 41 guidelines and various modes of failure are considered. HAZUS methodology along with nonlinear static analysis is used to compare the seismic vulnerability of bare and infilled frames. The comparative study suggests that URM infills result in a significant increase in the seismic vulnerability of RC frames and their effect needs to be properly incorporated in design codes.

An evaluation of force-based design vs.direct displacement-based design of jointed precast post-tensioned wall systems

The unique features of jointed post-tensioned wall systems, which include minimum structural damage and re-centering capability when subjected to earthquake lateral loads, are the result of using unbonded post-tensioning to attach the walls to the foundation, along with employing energy dissipating shear connectors between the walls. Using acceptance criteria defined in terms of inter-story drift, residual drift, and floor acceleration, this study presents a multiplelevel performance-based seismic evaluation of two five-story unbonded post-tensioned jointed precast wall systems. The design and analysis of these two wall systems, established as the direct displacement-based and force-based solutions for a prototype building used in the PREcast Seismic Structural Systems （PRESSS） program, were performed at 60% scale so that the analysis model could be validated using the PRESSS test data. Both buildings satisfied the performance criteria at four levels of earthquake motions although the design base shear of the direct displacement-based jointed wall system was 50% of that demanded by the force-based design method. The study also investigated the feasibility of controlling the maximum transient inter-story drift in a jointed wall system by increasing the number of energy dissipating shear connectors between the walls but without significantly affecting its re-centering capability.

Revision of seismic design codes corresponding to building damagesin the “5.12” Wenchuan earthquake

A large number of buildings were seriously damaged or collapsed in the "5.12" Wenchuan earthquake. Based on field surveys and studies of damage to different types of buildings, seismic design codes have been updated. This paper briefly summarizes some of the major revisions that have been incorporated into the "Standard for classification of seismic protection of building constructions GB50223-2008" and "Code for Seismic Design of Buildings GB50011-2001." The definition of seismic fortification class for buildings has been revisited, and as a result, the seismic classifications for schools, hospitals and other buildings that hold large populations such as evacuation shelters and information centers have been upgraded in the GB50223-2008 Code. The main aspects of the revised GB50011-2001 code include: (a) modification of the seismic intensity specified for the Provinces of Sichuan, Shanxi and Gansu; (b) basic conceptual design for retaining walls and building foundations in mountainous areas; (c) regularity of building configuration; (d) integration of masonry structures and precast RC floors; (e) requirements for calculating and detailing stair shafts; and (f) limiting the use of single-bay RC frame structures. Some significant examples of damage in the epicenter areas are provided as a reference in the discussion on the consequences of collapse, the importance of duplicate structural systems, and the integration of RC and masonry structures.

A comparison of IBC with 1997 UBC for modal response spectrum analysis in standard-occupancy buildings

This paper presents a comparison of the seismic forces generated from a Modal Response Spectrum Analysis （MRSA） by applying the provisions of two building codes, the 1997 Uniform Building Code （UBC） and the 2000-2009 International Building Code （IBC）, to the most common ordinary residential buildings of standard occupancy. Considering IBC as the state of the art benchmark code, the primary concern is the safety of buildings designed using the UBC as compared to those designed using the IBC. A sample of four buildings with different layouts and heights was used for this comparison. Each of these buildings was assumed to be located at four different geographical sample locations arbitrarily selected to represent various earthquake zones on a seismic map of the USA, and was subjected to code-compliant response spectrum analyses for all sample locations and for five different soil types at each location. Response spectrum analysis was performed using the ETABS software package. For all the cases investigated, the UBC was found to be significantly more conservative than the IBC. The UBC design response spectra have higher spectral accelerations, and as a result, the response spectrum analysis provided a much higher base shear and moment in the structural members as compared to the IBC. The conclusion is that ordinary office and residential buildings designed using UBC 1997 are considered to be overdesigned, and therefore they are quite safe even according to the IBC provisions.

A Comparison of Saudi Building Code with 1997 UBC for Provisions of Modal Response Spectrum Analysis Using a Real Building

The study uses an actual building to compare the modal response spectrum analysis results of Saudi Building Code (SBC) and the 1997 Uniform Building Code (UBC) used in Saudi Arabia before the introduction of SBC. A sample of four buildings with reported analysis of comparison between IBC and UBC is taken for confirming the comparison. Eight sample places from SBC map for Saudi Arabia together with two sample places of high seismic activity in USA were taken for the comparisons. The study used software package ETABS in this study for modeling and analysis. The results are dissimilar from the comparisons reported for test places of USA. It is concluded that at most places SBC base shear is higher for both ELFP and MRSA. However, the results cannot be generalized and considered always right. The same is factual for overturning moments. Consequently, we cannot report that SBC is more conservative than UBC for all scenarios.

Discussion on the application of the concept of environmental protection and energy saving in the design of building water supply and drainage

With the current,our country social economy rapid development,people's living standard and quality of life and therefore have got improved,at the same time,it is the concept of environmental protection and energy saving is also enhanced value,many fields in our country environmental protection and energysaving concept can be seen in the application,especially the application in building water supply and drainage design more widely,to protect the environment,to maximize the use of limited resources,how to reasonable use of water resources in building water supply and drainage construction,above is current the paper mainly discusses the problems in the construction field,this paper based on environmental protection and energy-saving concept,discusses its application in the building water supply and drainage design,for your reference.

Development of seismic force requirements for buildings in Taiwan

This paper describes static and dynamic procedures to calculate seismic demand specified by the current seismic design code for buildings in Taiwan, which was issued in 2005. For design levels with a return period of 475 years, the design spectral response acceleration can be developed for general sites, near-fault sites and Taipei Basin. In addition, in order to prevent building collapse during extremely large earthquakes and yielding of structural components and elements during frequent small earthquakes, the required seismic demands at the maximum considered earthquake level （MCE, 2%/50 years） and operational level are also included in the new seismic design code.For dynamic analysis procedures, both the response spectrum method and time history method are specified in the new seismic design code. Finally, procedures to generate spectrum compatible ground motions for time history analysis are illustrated in this paper.

Design between Architecture and Structure: Case Studies of Pilot Interventions on Italian Monumental Buildings

Two case studies,referring to historic Italian buildings housing city halls,provide an opportunity to investigate the design of non-standard elements aimed at protecting masonry vaults,with particular reference to the preliminary works prior to the actual structural restoration work.There is in fact a phase in which it is a priority to secure the vault to avert possible risks to the users of that portion of the building.This phase is temporarily intermediate between the detection and aggravation of injuries and the renovation and consolidation project.Although these are provisional works,they are intended for buildings that are often public and therefore intended for a wide range of users,such as schools,offices or monumental buildings.In analyzing traditional techniques and systems used in similar cases,the possibility of developing evolutionary aspects with respect to,above all,simple shoring techniques emerged.In these areas,hybrids between a structural and architectural project,it is possible to reconcile static requirements with architectural techniques of space management,attentive to the quality of the interior and the integration of the provisional work with the reference context.

Finite element modeling assumptions impact on seismic response demands of MRF-buildings

Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame ＂RC-MRF＂ buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element（FE） models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable FE models with various levels of refinement. The effects of the FE modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a FE model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model.

Development of a “Space-Saving Model” for a One-Family Dwelling Case Study of Japanese Architecture with Space Limitations

The rapid globalization of building standards and codes in regards of contemporary housing and the growth of populations during this century demands an immediate response from designers in terms of space rationalizing to fulfill the forthcoming lack of architectural habitat on earth. The differences in culture imply a difference in the way of living, and the way of living indicates a contrast in the way of designing houses. A western house does not need an extra room covered with tatami mats for relaxation as a modern Japanese home would most likely do, as a separate living-like space. Organizations, among others, like CABO (Council of American Building Officials) and, in our specific case study, BCJ (Building Center of Japan) together with BRI (Building Research Institute) try to overcome these differences to provide better housing conditions to the world through the formulation of global designing and building standards. International publications like UBC (Uniform Building Code), IBC (International Building Code), OTFDC (One and Two Family Dwelling Code) and BSLJ (Building Standard Law of Japan) have also played an important role to globalize safety and design codes to better understand global housing under normal conditions. However, space limitations and concentration of human masses in mega cities result in a crucial new consideration: the urgent need of investigating the possibilities of rationally living within less space. Minimums provided by most codes do not take into account the space issue and overpopulation of large cities. Providing with some design recommendations for one-family dwellings has been the departure point and main motivation to carry out this case study based on actual buildings with the lack of space conditioning in a country where these conditions turn into reality.

Eurocode8、CECS 160:2004与GB50011—2010中考虑土-结构相互作用效应的比较

我国新版《建筑抗震设计规范》(GB 50011—2010)于2010年12月1日起正式实施;从考虑土-结构相互作用效应方面,我国抗震规范与欧洲抗震设计规范(Eurocode8)2004版和我国建筑工程抗震性态设计通则(CECS 160:2004)进行了比较,旨在为从事工程抗震的设计和研究人员提供一定参考和借鉴。

秦岭保护视角下的工业建筑遗存更新实践——以翠华山游客服务中心改造为例

秦岭自然保护区的生态问题备受重视,其保护区内废弃厂房的改造更新更是保护发展的重点问题之一。文章以翠华山游客服务中心改造项目为例,首先对其项目区位、现状及改造问题进行分析,继而从功能空间、建筑立面、细部构造及绿色建筑四个方面对旧厂房建筑进行梳理重塑,为自然保护区内的工业建筑改造更新提供参考与借鉴。

A prototype online database-enabled design framework for wind analysis/design of low-rise buildings

This study presents a development of an advanced cyberbased database-enabled design module for low- rise buildings （DEDM-LR） which provides estimation of the wind-induced responses for main wind force resisting frames by making direct use of pressure time histories measured at a large number of pressure taps over a suite of building models. These responses may be considered in lieu of code-specified load effects in which the overall accuracy may be influenced by the inherent simplifications in codes. In addition, this new automated approach is particularly attractive and advantageous as it allows a web-based online analysis/design via intuitive user-friendly interfaces for both the input and output in terms of familiar web-style forms that are nowadays very common in most of web-based services. Presently, the DEDM-LR hosts an aerodynamic database developed by the Tokyo Polytechnic University （TPU）, Japan for a variety of building configurations like flat, gable, and hip roofs under suburban terrain flow condition with immediate application to other databases. The paper shows the efficacy and validity of the DEDM-LR by walking through its details and examples on selected gable-roofed buildings. The architecture of DEDM-LR platform offers the ability to pool resources by hosting other databases that may become available in the near future.

古建筑保护中色彩采集方法及流程设计的应用研究——以岳麓书院为例

建筑色彩数据库的建立,是古建筑保护工作深化的重要技术节点,其技术流程可包括色彩体系的选择、取色仪器的匹配及色彩样本的误差处理。当前古建筑保护存在着色彩原真意识淡薄、数据资料缺乏以及采集规范不全等问题,古建筑色彩保护严谨性与科学性亟待提高。通过梳理色彩数据采集流程以及方法,初步建立了一个系统、明确、可执行的工作模式,为古建筑色彩采集工作提供参考;并规范色彩数据采集工作的流程设计以及数据定量纠偏方法,为古建筑色彩定量研究提供支持。实践结合岳麓书院古建筑群色谱研究,致力于解决建筑古迹色彩采集所涉及的样本选择、高度障碍、材质不均、光强条件、湿度差异、色温影响等重难点问题,为岳麓书院古建筑群后续色彩研究奠定数据基础,是古建筑色彩保护中色彩采集技术路线的有效支撑。

湖北工人文化宫超限结构设计

湖北工人文化宫的主要功能为职工培训和展览等,主体结构采用框架-剪力墙结构,存在扭转不规则、偏心布置、楼板不连续、局部跃层柱等不规则项,属于复杂超限高层建筑。采用抗震性能化设计对主要构件进行复核,采用YJK和MIDAS Building软件对结构进行多遇地震弹性计算和弹性时程分析以及罕遇地震下的动力弹塑性时程分析和楼板应力分析等。分析结果表明,整体结构可以满足规范的要求,达到预定的性能目标。并根据分析结果采取抗震加强措施。在容易产生共振的大跨度预应力楼盖区域,以高阻尼橡胶减振垫作为减振材料,对楼盖在人行激励下和有节奏运动激励下的楼板舒适度进行分析。分析结果表明,楼板舒适度满足规范要求。

基于建筑设计防火规范的高校课程设计实践研究

将建筑设计防火规范纳入课程设计教学过程中,是培养学生综合设计能力的重要教学任务,是工程认证体系(CDIO)的基本要求。文章结合燕山大学建筑学专业商业综合体课程设计,通过将建筑设计防火规范在不同设计阶段有针对性地引入课程设计过程中,让规范成为课程设计的重要内容,不仅对课程设计具有重要的指导作用,对学生树立消防安全和社会责任意识、保持对防火规范的敬畏感也具有重要现实意义,而且对于今后从事建筑设计工作都有深远的影响。

基于BIM的消防安全-经济耦合研究

针对建筑消防措施消防性能-消防投入经济性错配问题,提出了一个基于BIM的消防安全-经济耦合分析框架.利用BIM智能审图功能优化消防措施模型形成消防措施方案集,模拟设定火灾场景下消防措施方案集的烟气、温度、能见度等烟气参数确定消防性能,并关联各方案的消防投入开展消防安全-经济耦合分析,最后以某高校宿舍楼为案例进行验证分析.结果表明:基于BIM的消防安全-经济耦合分析框架可以用于优化消防措施设计,并实现消防安全-经济性的良好匹配.该框架有助于设计人员和业主在消防性能模拟的基础上进行透明合理的消防投入决策.

基于空间归属关系下的木构古建筑构件信息分类编码研究

古建筑构件的信息编码是实现信息共享和实施信息系统的基础,可为古建筑数字化保护工作提供支撑。目前古建筑构件分类方式多参考现代建筑构件的分类方法,不能契合古建筑构件构造特点。通过对我国木构古建筑相关文献的分析与现状的调研,进行了木构古建筑构件信息分类编码体系的研究。研究表明,我国传统木构建筑具有“三段式”的整体特点,以“间”为单位、强调轴线对称的平面布局特点以及造型、空间布局、构件构造相统一的体系特点,进一步从木构古建筑特点中发掘出构件与空间归属关系。基于此提出了“三分”构件分类原则并设计了构件位置码制订规则。结合实例对提出的传统木构建筑构件分类方法进行了说明和运用。该构件信息分类编码体系具有较高的适应性、可扩延性以及兼容性,可为实现各地区传统木构建筑构件信息标准化以及古建筑数字化保护工作奠定基础。