相邻RC框架结构地震碰撞过程模拟与初步分析

相邻建筑物碰撞是指地震作用下其间距无法满足相对位移要求时造成的侧向撞击,常常导致或加剧结构破坏。选取Hertz-damp接触单元模型,推导了考虑碰撞的结构动力方程,模拟了相邻钢筋混凝土（RC）框架结构地震碰撞过程。分析碰撞过程,并利用梁柱单元破坏指数的变化解释了相邻RC框架结构地震碰撞破坏机理,指出地震碰撞破坏作用不完全随防震缝宽度的增加而降低。     

Probabilistic assessment of earthquake insurance rates for important structures: Application to Gumusova–Gerede motorway

A probabilistic model is presented for the assessment of the earthquake insurance rates for important engineering structures, for which the seismic losses could be quite significant. The proposed model is used to estimate the earthquake insurance premiums for the structures taking place in the Bolu Mountain Crossing in the Gumusova–Gerede motorway Section, Turkey. The model requires two types of studies, namely: seismic hazard analysis and estimation of potential damage to structures based on damage probability matrices (DPM). The computations are carried out according to the proposed model by using the seismic hazard results and the best estimate DPM’s developed in the study and the annual pure risk premiums are obtained for the different components of the motorway system by making a distinction between sections completed and sections under construction.     

砌体结构地震破坏程度的估计研究

砌体结构房屋的设计表现为建筑布置决定结构墙体的数量及面积。在地震作用下,基底剪力由地震方向的墙体承担,墙体数量越多,墙体面积越大,房屋抗震能力就越强,墙体面积对砌体结构抗震研究有着至关重要的影响。研究这一问题的主要途径之一就是从地震震害中找出墙体面积与结构破坏之间的规律,通过对2008年汶川地震中大量震损房屋震害的分析,研究了墙体面积与结构破坏程度之间的关系,以及在现有砌体结构抗震性能评估理论的基础上,提出了一个基于墙体面积大小的指标来估计砌体结构的在地震下的破坏程度。将该指标应用于一幢多层砌体结构房屋的抗震性能评估中,并通过与现场震害的对比说明了该指标的合理性,结果表明,该评估指标可以用于估计砌体结构的破坏程度。     

一种新型的混凝土结构双参数地震损伤模型

在结构的抗震设计、未来震害预测、震后经济损失评估等过程中,一个重要的任务就是选择合理的反应量建立结构损伤评估模型,以定量计算出结构在地震过程中的损伤指标。在分析现有的损伤参数以及几种双参数地震破坏准则的基础上,结合损伤力学的基本原理,提出了一种新型的混凝土结构双参数地震损伤模型,并根据已有的实验结果确定了模型参数。     

Verification of performance criteria using shake table testing for the vulnerability assessment of reinforced concrete buildings

Shake table experiments are conducted to support the selection of performance criteria and to verify the inelastic modeling approach for developing the fragility functions of reinforced concrete buildings. Two frames representing the lateral force‐resisting system of a preseismic code building are tested under the effect of an earthquake record with increasing severity. Shear failure is detected in columns at a PGA of 1.28g before other failure modes, which was effectively predicted by the fiber‐based numerical model, performance criteria, and shear supply approaches adopted for vulnerability assessment. Five buildings, ranging from 2 to 40 stories, are then assessed under the effect of far‐field and near‐source earthquake records, considering the experimentally verified modeling approach and shear failure prediction models that account for flexural ductility and shear‐axial force interaction. The impact of considering shear response on the vulnerability assessment results is considerable, particularly for the lower‐height wall structures when subjected to the near‐source earthquake scenario. Higher modes dominate the behavior of wall structures, principally under the latter seismic scenario, and shift their response to shear‐controlled. Therefore, seismic scenario‐structure‐based performance criteria are adopted for developing a range of analytically derived, experimentally verified fragility functions for the earthquake loss estimation of buildings with different characteristics.     

A new damage index for RC buildings based on variations of nonlinear fundamental period

Many vital reinforced concrete (RC) buildings experience moderate or severe earthquakes in their lifetime because they are located in hazardous areas. However, their importance cause to be evaluated by different types of damage functions. In these procedures, structures are usually modelled. These models neither correctly display the effects of the cracks that emerge and plastic hinges nor precisely consider the effects of asymmetric configuration and infill panels. Furthermore, the actual nonlinear dynamic behaviour of existing buildings could be evaluated by assessing nonlinear dynamic characteristics such as the fundamental period. These dynamic characteristics, which are obtained by some field tests such as forced and/or ambient vibration methods, comprise the aforementioned effects. This paper offers a damage index (pattern) for seismic damage assessment of RC buildings based on the variation of the nonlinear fundamental period, which is obtained by field tests. Finally, the seismic situation of existing RC buildings that have experienced an earthquake is precisely and expeditiously assessed by this new damage index. Copyright © 2010 John Wiley & Sons, Ltd.     

建筑结构"中震可修"性能指标的确定方法

本文以结构顶点位移作为结构的性能参数,综合考虑结构物理状态以及经济效益双重标准,确定结构“中震可修”的性能指标。目的是把我国现行建筑抗震设计规范中“中震可修”由定性描述转化为定量描述,方便在实际设计中应用。同时也为实现基于性能抗震设计提供基础研究。     

Seismic performance assessment of masonry infill reinforced concrete buildings in Eastern Canada

In Eastern Canada, most of moment resisting reinforced concrete frames with unreinforced masonry infill (MI-MRF) buildings were constructed between 1915 and 1960. These pre-code structures, in terms of seismic requirements, are considered vulnerable to earthquake due to insufficient ductility and resistance. The goal of this study is to provide a quantitative assessment of their seismic performance using fragility functions. Fragility functions represent the probability of damage that corresponds to a specific seismic intensity measure (e.g. peak ground acceleration at the site). Based on a structural characterisation study on existing buildings in Québec region, a case study three storey–three bay MI-MRF was selected as representative for mid-rise buildings. Pushover analyses were conducted on a nonlinear model of the infill frame to obtain the corresponding lateral load-deformation capacity curve. The nonlinear behaviour of the reinforced concrete beams and columns was modelled with concentrated plastic hinges at members’ ends and a modified strut-and-tie model was used for the infill to account for multiple failure modes. A simplified probabilistic nonlinear static procedure was applied to obtain the seismic demand model at increasing levels of seismic intensity. Fragility functions were then developed using an experiment-based damage model that correlate the extent of damage to the displacement demand. Damage assessment using the developed functions was conducted for an earthquake scenario compatible with the design-level seismic hazard in Quebec City with a 2% and 10% probability of exceedance in 50 years. The developed functions and methodology are particularly useful in probability-based seismic loss assessment and in planning mitigation solutions.     

Post-earthquake loss assessment based on structural component damage inspection for residential RC buildings

There is substantial evidence showing that the seismic performance of many existing buildings may be inadequate to resist another strong earthquake. The losses from a devastating earthquake are always huge. In order to prevent damage extension and to restore the damaged community as quickly as possible, immediate post-earthquake damage assessment is always conducted through site inspection on structural components within a restricted short period of time to screen buildings that are damaged to certain levels or in danger of collapse. Without detail financial loss estimation, engineers have to face the challenge to decide whether a badly damaged building is worth retrofitting for sustainability, or needs to be demolished because existing loss estimation models are not based on the post-earthquake damage rating system. Based on some post-earthquake damage data of RC residential buildings, this paper aims to link inspected component damage level, building damage state and direct financial loss in terms of repair to replacement cost ratio. Damage of structural components are quantified by a set of damage factors and finally integrated as a building damage indicator. Building repair to replacement cost ratio and storey repair to replacement cost ratio corresponding to various damage levels of RC residential buildings have been estimated. With these statistical data, relationships of building damage indicator to repair to replacement cost ratio has been built from regression analysis.     

砖砌体房屋三水准抗震能力判别方法

震前对现有砖砌体房屋抗震能力的判别是对该类房屋采取有效抗震减灾措施的重要依据,对减少该类房屋在地震中的破坏有着重要的实用价值。在我国现有《建筑抗震鉴定标准》(GB 50023—2009)给出的砖砌体房屋抗震能力指数法的框架下,引入抗震能力系数法,实现与抗震设计规范相对应的砖砌体房屋基于烈度的三水准抗震能力判别方法;将其与地震动参数联系起来,给出地震动参数-破坏状态的对应关系,实现砖砌体房屋基于地震动参数的三水准抗震能力判别方法;对汶川地震中发生震害的一栋砖砌体房屋进行抗震能力判别,与实际震害相比较,吻合得很好,并对其进行了三水准抗震能力的判别,表明该房屋满足抗震设防烈度为VII度时小震不坏、中震可修、大震不倒的抗震设防要求,验证了方法是可行和有效的,对同时进行不同设防水准下房屋抗震能力的判别是实用的。     

Exploring the possibility of assessing the damage degree of liquefaction based only on seismic records by artificial neural networks

This study presents a new approach to determine the damage degree of liquefaction caused by a large earthquake. We propose an artificial neural network (ANN) model based only on the seismic records of ground and define the degree of liquefaction “DDL” as a damage index. This ANN model predicts the degree of excess pore water pressure increase as the correct output label based on the seismic records obtained from the three-dimensional shaking table test. The proposed model achieved high accuracy, and the outcomes from training data indicated that the ANN model is suitable to function as a liquefaction assessment system. Further, to evaluate the applicability of the proposed ANN model in the real world, the datasets of waves from three actual seismic records were input to the ANN as validation data. The DDL judgment obtained was a good fit with the real phenomena observed.     

汶川地震建筑震害启示——三水准设防和抗震设计基本要求

汶川大地震造成大量房屋建筑破坏倒塌,通过对砌体结构和工业厂房、设备及设施的震害调查与分析,对我国《建筑抗震设计规范》(GB 50011-2001)的三水准设防和抗震设计基本要求进行探讨,分别对比了在遭遇"小震"、"中震"和"大震"情况下,按一定设防烈度设计的房屋建筑的破坏状态,判别是否达到了设防目标。结果表明,在1990年以后设计建造的房屋建筑,基本都能达到三水准抗震设防目标,严重破坏或倒塌的大多是建造年代较早、设计不满足规范要求或施工质量存在问题的建筑。针对抗震设计规范中有关结构整体性、传力路径、地基基础、抗震缝、疏散通道、设备和设施的抗震设计基本要求,对照实际震害情况,包括过去地震震害情况,总结经验教训,提出改进意见。对震前经过加固的建筑物在地震中的表现作了介绍,证明了结构抗震加固的效果和必要性。     

汶川地震建筑震害启示——抗震概念设计

汶川大地震造成大量房屋建筑破坏倒塌,通过在地震区对遭受中震、大震作用的砌体结构和钢筋混凝土结构以及非结构构件的震害调查与分析,以典型的结构破坏为例,针对多道抗震防线、强柱弱梁、剪力墙连梁、砌体结构整体性、楼梯间、非结构构件等抗震设计问题,对照《建筑抗震设计规范》(GB 50011-2001)所规定的抗震概念设计原则进行讨论,总结经验教训,提出改进建议。震害分析结果表明,只要严格按照规范设计,保证施工质量,房屋建筑就能达到"小震不坏,中震可修,大震不倒"的三水准设防目标。     

Probabilistic seismic risk assessment of hall buildings in Turkey

Steel space framed hall buildings are dedicated as shelters for people suffering from earthquakes. In general construction, steel space frames are built on reinforced concrete (R/C) frames or wall structures above the bottom side. For this reason, the bottom side has higher rigidity comparing with the upper side. In Turkey, where there is a very high earthquake risk, earthquake‐resistant steel space framed structures is an important issue. In this current research, hall buildings in Turkey, involving two different rigidity parts as R/C and steel, are taken into consideration regarding earthquake effect. In this study, three different hall structures were modeled with different elastic moduli for the analysis part. Nonlinear time history analyses were applied with 25 different earthquake data for performance estimation. After the time history analyses, probabilistic seismic assessment was carried out for the model buildings through fragility analyses. For each model, analysis results were evaluated and compared. As a result, the hall buildings were found to be vulnerable to damage during expected future earthquakes. Moreover, elastic moduli have significant effect on the structural response. Copyright © 2011 John Wiley & Sons, Ltd.     

Machine vision-based automated earthquake-induced drift ratio quantification for reinforced concrete columns

This paper presents a novel method for estimating the seismic peak interstory drift ratio (IDR) in reinforced concrete (RC) columns after an earthquake using surface crack image analysis. The quantitative representation of the complexity and irregularity of crack images in damaged RC columns is obtained through the consideration of the generalized fractal dimensions. The authors have compiled a comprehensive database consisting of 445 crack maps obtained from cyclic experiments conducted on 110 rectangular RC column specimens exhibiting double-curvature deformation mode. This database is utilized by the authors to develop and validate the proposed procedure. The research database contains a wide range of structural and geometric features. Five closed-form equations are developed with the objective of estimating the peak IDR experienced by the RC columns during a seismic event. The predictive equations are derived through the utilization of symbolic regression technique, with the input parameters varying according to the availability of columns characteristic parameters. Results reveal that generalized fractal dimensions, especially D₋₁, are strong vision-based indicator of damage in RC columns having correlation coefficients with IDR ranging from 0.82 to 0.92 across the considered plans. The seismic peak IDR obtained through the empirical equations can serve as the input engineering demand parameter (EDP) in the seismic loss estimation frameworks. This allows for the determination of the probability of exceeding damage states for structural and nonstructural components of concrete buildings. Finally, the practical implementation of the methodology is examined by its application to an actual case of a damaged column during the Kermanshah earthquake of magnitude 7.3 that occurred in 2017.     

城市区域建筑群地震灾害场景仿真的高真实感可视化方法研究

地震灾害场景仿真是提高城市综合抗震防灾能力的重要手段,建筑震害高真实感的可视化是地震灾害场景仿真的重要内容。为提高城市区域建筑群震害模拟结果的可视化效果,研究采用易于获取的城市3D多边形模型,开发了建筑对象识别算法和楼面外形生成算法,实现了建筑外形数据自动获取;提出建筑位移插值和建筑外形网格重划分处理方法,实现了建筑群震害的高真实感可视化;并将该方法运用于北京CBD建筑群的震害结果高真实感可视化,该可视化的结果显著优于常规的2.5D可视化方法。文中的成果可为地震灾害场景仿真研究提供参考。     

混合结构房屋抗震设计探讨

结合工程实践经验，分析了混合结构房屋抗震设计中存在的主要问题，介绍了提高砖房抗震能力的措施，从而使得这类房屋的地震破坏降低到最低限度。     

RC框架基于典型相关分析的地震动多元破坏势评估

为了更加全面地评估地震动对结构的潜在破坏势,考虑多个地震动强度参数和多个结构损伤参数对地震动破坏势的影响,提出一种基于典型相关分析的地震动多元破坏势评估方法。为说明所提方法,以具有不同高度和不同抗震设防水平的16个钢筋混凝土框架结构为研究对象,采用100条真实地震动记录作为地震输入。将与地震动加速度、速度和位移相关的8个地震动强度参数进行对数线性组合,构造成地震动多元强度参数的典型变量。将结构最大层间位移角、整体损伤指数、最大楼层加速度进行对数线性组合,构造成结构多元损伤参数的典型变量。通过使地震动强度参数的典型变量和结构损伤参数的典型变量的相关系数达到最大,获得可以较好评估地震动破坏势的复合地震动参数。研究结果表明：相比于单一地震动参数,复合地震动参数可以更好地评估地震动的破坏势,其与结构损伤的相关性也更强。     

Combination model for conventional pushover analysis considering higher mode vibration effects

This paper aims to propose a combination model for conventional pushover analysis with invariant lateral load patterns to consider the effects of higher mode vibrations on the seismic responses of high‐rise buildings. Rectangular concrete‐filled steel tubular (RCFT) structures having two types of deformation, namely, shear type RCFT frame structures and shear‐flexural type RCFT frame‐shear wall structures, are selected and investigated. Finite element models are created using Perform‐3D. Both pushover analysis with three conventional lateral loading patterns, namely, uniformly distributed loading, first‐mode vibration loading, and concentrated loading at the vertex, and time‐history analysis with 15–21 earthquake records chosen for each RCFT structure are performed. Regression analysis is used to fit the interstory drift ratios obtained by the pushover analysis with those from the time‐history analysis. Further, the relations between the partial regression coefficients and the structural fundamental periods under certain lateral loading patterns are analyzed. On this basis, using these conventional lateral loading patterns, combination models for high‐rise buildings with two types of deformation are proposed and verified. The results demonstrate that the proposed method can estimate the seismic responses of high‐rise buildings with a high accuracy and has the advantages of ease of implementation and operation.     

半刚性楼盖房屋的抗震空间分析

建筑震害调查和结构实测数据表明,某些工业与民用建筑的屋盖和楼盖平面内的抗推刚度是有限的,地震时产生了显著的水平变形。对于此类半刚性楼盖房屋,用于计算水平地震作用的振动模型不能再沿用仅适用于刚性楼盖或柔性楼盖房屋的串联质点系。给出了半刚性楼盖房屋的抗震空间分析方法,为计入楼盖水平变形对质点水平地震作用数值和构件地震内力的影响,对于单向地震输入和双向地震输入,分别提出串并联质点系和双向串并联质点系振动模型,以计算结构的二维振型或三维振型以及相应的构件地震内力。可供《建筑抗震设计规范》修订时参考。