场地土类别与埋置土深度对排架结构自振周期的影响

本文结合我国现行《建筑抗震设计规范》,分析了场地土类别与埋置土深度对单层工业厂房排架结构自振周期的影响,给出了相应的结构自振周期修正系数。计算讨论了排架结构在考虑场地土类别与埋置土深度时的自振周期修正系数。     

基于位移的钢筋混凝土结构单层厂房易损性分析

通过按建筑结构抗震规范的规定构造加速度反应谱作为随机激励,构筑了我国四川地区典型钢筋混凝土结构单层厂房有限元模型,采用拟动力时程方法对结构的抗震性能进行了分析计算,得到了钢筋混凝土结构厂房的易损性曲线;同时,针对原型结构在地震作用下柱基础容易发生屈服破坏的情况,对原型结构基础采取了铅芯阻尼橡胶支座隔震加固措施,并对加固后的厂房结构进行了计算分析并得到了修正易损性曲线,通过对比得到结构在地基不失稳的前提下,在小震时发生中度以上损伤的概率非常小,在大震时随着承重结构进入塑性屈服发生中度以上的损伤概率开始逐渐变大,而且厂房结构纵横两个方向的易损性概率在大震时有差异,采取隔震加固措施后结构损伤概率明显减小。     

单层工业厂房地震时的非线性动力计算

本文将有高低跨的单层工业厂房及带天窗单层工业厂房各种结构简化为质点杆件，根据框图编写了计算程序，采用天津实测地震记录，进行了非线性地震反应动力数值分析。在验证程序正确性后分别针对多跨单层工业厂房及带天窗单层工业厂房计算了在不同时间、刚度、阻尼比、步长、杆件弹性力与塑性力比等条件下的单层工业厂房非线性地震支动力反应，为其震害预测提供了一定的依据。     

预应力CFRP加固钢筋混凝土受弯构件的抗力概率模型研究

预应力CFRP 加固混凝土结构技术因其在材料性能利用方面的优越性能已成为CFRP 加固的热点方向,其中预应力CFRP 加固结构的可靠性是这一方向研究的重要内容。该文分析了影响预应力CFRP 板加固钢筋混凝土受弯构件承载力的主要变量的概率特征,考虑CFRP 板尺寸效应和应力分布的影响,采用Weibull 分布推导了CFRP 板的极限强度概率分布函数,根据预应力CFRP 张拉工艺,分析了预应力损失随机变量,建立了在不同失效模式(破坏形态)下的受弯构件抗力概率模型,并开展了参数敏感性分析,获得各个失效模式下抗力概率模型的主要影响因素。研究结果表明:抗力概率模型是预应力CFRP 加固结构的失效概率计算与可靠度校准的重要内容之一,各参数的影响规律与各失效模式的破坏形式密切相关。     

基于设备的全寿命周期成本模型分析及其应用

本文全面介绍了全寿命周期成本的含义,分析了电网全寿命周期成本的分解结构,建立了全寿命周期成本最优的计算模型,结合江门电网规划应用为例,验证了本研究的成果。     

碳纤维增强环氧树脂复合材料层合板结构及间隙尺寸对铆接性能的影响

通过对不同纺织结构的碳纤维增强树脂基复合材料（CFRP）层合板与铝合金（AlMg3）异质材料连接结构进行单剪切拉伸研究,分析间隙尺寸对不同纺织结构CFRP层合板与AlMg3连接结构性能的影响。试验结果表明,当CFRP层合板铺层数目相同时,对于纺织结构不同、间隙配合尺寸相同的CFRP-AlMg3单铆钉单剪切连接结构,编织结构碳纤维增强树脂基复合材料（WO-CFRP）层合板所受挤压应力比非编织结构碳纤维增强复合材料（UD-CFRP）层合板所受挤压应力大25%左右;对于纺织结构相同、间隙配合尺寸不同的CFRP-AlMg3单铆钉单剪切连接结构,其各自铆钉所受剪切应力和连接CFRP层合板所受挤压应力相差不大。同时对相同间隙尺寸、不同纺织结构的CFRP-AlMg3单铆钉单剪切连接结构各个阶段挤压应力分析得知：其他条件一定,各个阶段中WO-CFRP的挤压应力比UD-CFRP的挤压应力高20%左右。最后研究间隙尺寸对CFRP-AlMg3单铆钉单剪切连接结构性能的影响,发现铆钉与孔壁间隙尺寸对位移为铆钉直径大小的4%时的CFRP层合板受到的挤压应力影响较大,铆钉与孔壁间隙大小增加0.1 mm,位移为铆钉直径大小的4%时的CFRP层合板受到的挤压应力降低约17%,而对CFRP层合板的初始损伤应力和破坏应力几乎没有影响,对铆钉所受剪切作用力和AlMg3板材所受挤压应力也几乎没有影响。     

CFRP-钢界面粘结性能试验与数值模拟

碳纤维增强聚合物基复合材料（CFRP）与钢板的界面粘结性能为CFRP加固钢结构的关键问题之一。开展了17个CFRP板-钢板单搭接试件的拉伸剪切试验,研究了不同环氧粘结剂与CFRP材料的CFRP-钢界面力学行为和破坏模式;分析了粘结剂类型和CFRP材料对界面粘结滑移本构和界面剪切性能的影响,讨论了其承载力计算方法。结果表明：采用不同的粘结剂或CFRP材料,界面破坏形式和抗剪承载力均差异较大。采用Sika 330、Lica粘结剂的试件为CFRP板或钢板与胶层的界面破坏,采用Araldite粘结剂的试件为CFRP板浅表层离,采用Sika 30粘结剂的试件为胶层内聚破坏,采用SF（Sika S512/80）碳板的试件为CFRP板深层层离;Araldite试件的抗剪承载力为其他试件的1.7~2.9倍。Sika 330、Araldite及Lica试件粘结滑移曲线无明显下降段,属脆性破坏,而Sika 30与SF试件存在缓坡下降段,失效前有一定征兆;SF试件的粘结滑移本构可简化为三折线模型,其余试件则可简化为双线性模型。SF试件抗剪承载力需用Xia-a模型表征,其余试件则可用Xia-b模型表征。基于粘聚力模型对界面力学行为进行了数值模拟,结果表明,粘聚力模型可以较好地模拟界面的非线性力学行为,剥离应力对本单搭接试件的界面粘结强度影响很小。     

船舶设备全寿命周期修理成本分析

运用全寿命周期成本理论,对船舶设备全寿命周期修理成本组成进行分析,引入资金时间价值,对运行设备未来成本费用进行折算,采用全寿命周期成本年均值方法构建计算模型,较好地解决了设备修理的决策问题。     

CFRP加固紧凑拉伸钢试件的疲劳试验研究

以紧凑拉伸试件(Compact-tension specimen,CT试件)为研究对象,针对未补强及不同碳纤维增强树脂复合材料(Carbon fiber reinforced polymer,CFRP)粘贴补强工况的CT试件开展疲劳试验。以CFRP材料类别、单/双面粘贴与CFRP材料用量作为变量,运用沙滩纹加载制度与非接触式全场应变测量(Digital image correlation,DIC)技术记录测量疲劳裂纹扩展长度与试件CFRP表面应变场,分析CFRP粘贴延长疲劳寿命的作用,从疲劳寿命与疲劳裂纹扩展速率入手,比较疲劳试验结果用以指导CFRP粘贴加固疲劳损伤钢构件。结果表明粘贴CFRP发挥其抗拉和抗压作用可以减小乃至抑制疲劳裂纹扩展速率的增长,从而有效推迟试件疲劳破坏,在特定工况下可最多延长试件疲劳寿命至未补强状态下的3.14倍。其中,双面粘贴的加固效果明显优于单面粘贴;增加碳纤维布的铺贴层数对疲劳寿命的增长具有一定的贡献;碳纤维复材板与试件粘接边缘的脱胶导致其补强效果不及刚度相似的碳纤维布;粘接界面是补强体系破坏过程中的薄弱环节,碳纤维复材板加固试件的破坏模式主要为胶层破坏与...     

基于全寿命周期成本分析的装配式结构加固方法

为了提高装配式建筑结构的抗震性能和经济效益,本文在全寿命周期成本分析基础上,提出了多种装配置结构加固方法,通过加固效果的比选,最终认为两边跨每层对称布置阻尼器的方式为最佳的加固方法。     

Experimental study on seismic behavior of RC frames strengthened with CFRP sheets

The purpose of this study was to investigate experimentally the seismic performance and hysteretic energy capacity of strengthened reinforced concrete (RC) frames using carbon fiber reinforced polymer (CFRP) sheets under low-cyclic lateral loading. Two test specimens were constructed and tested under low-cyclic lateral loading. Two 1/3 scaled one-bay and one-storey RC frames specimens were constructed to simulate a two-storey industrial workshop. One specimen was reinforced by CFRP at the ends of beams, columns and at the joints; the other specimen was not reinforced and was used for comparison. This experimental study mainly investigated the effects of CFRP sheets on specimen seismic behavior. The information about the crack development, the damage characteristics, the hysteretic curves of the steel bar and CFRP sheets and the skeleton curves of frame were presented. In addition, the maximum crack width and the ultimate bearing capacity were measured. Test results indicate that the CFRP sheets reinforced frame shows a good hysteretic energy capacity and a higher ductility, which indicates that the CFRP sheets reinforced frame has a better seismic behavior. The results provide an important insight of the role of CFRP sheets in improving the earthquake resistance of frame buildings.     

Optimal design base shear forces for reinforced concrete buildings considering seismic reliability and life-cycle costs

The objective of this study is to propose a novel estimation procedure for optimal design base shear forces for reinforced concrete (RC) buildings while considering the seismic reliability and life-cycle costs (LCCs) incurred by life-cycle earthquake events. By simulating life-cycle earthquake events within a specified period and using nonlinear dynamic analysis, including earthquake occurrences and their peak ground accelerations (PGAs), this study also derives the damage states of an RC building considering the effect of the cumulative damage. Additionally, besides life-cycle earthquake events, a simplified model is developed to modify the structural properties of a structure without seismic repair after earthquakes. Given the uncertainty of the occurrence time and PGAs of earthquake events, the seismic reliability, and expected current values of LCCs are calculated using Monte Carlo simulation. Although the case study addresses only an RC building with five stories in Taipei, optimal design base shear forces for low-rise RC buildings calculated via the same procedure can be derived and utilized when making decisions on the seismic level of a building based on safety and economic considerations. Therefore, the proposed method can help both owners and investors to identify LCCs of RC buildings due to seismic structural damage within a specified service life.     

OPTIMAL ASEISMIC STRUCTURAL STANDARDS FOR THE REPLACEMENT OF EXISTING BUILDINGS

The problem of defining optimal structural standards for the resistance of buildings to lateral earthquake-induced loads is examined. Reference is made to a minimum global cost criterion, taking into account both building cost of the new buildings and expected future damage to the entire settlement. The variables of the optimum problem are: the seismic coefficient to be assumed for the design of new or strengthened buildings (that will replace the old ones) and the time in which the replacement process is completed. The minimum cost criterion permits the derivation of an optimality relationship between the duration of the replacement process and the standards of seismic resistance for new or strengthened buildings.     

预应力碳纤维条带加固混凝土圆柱的地震损伤模型

为了研究预应力碳纤维条带加固混凝土圆柱的地震损伤性能,利用包括对比柱在内的13根混凝土圆柱试验数据,对修正的Park-Ang损伤模型进行改进,建立了预应力碳纤维条带加固混凝土圆柱的地震损伤模型;根据试件的轴压比、纵向配筋率、考虑了预应力碳纤维条带及箍筋的双重横向约束作用对组合参数进行非线性回归分析,得到了该文推荐模型中组合参数的经验表达式;基于所提出的地震损伤模型,计算出了不同损伤状态的特征点所对应的地震损伤指标,据此给出了预应力CFRP加固混凝土圆柱的抗震分级标准;有限元分析得到的CFRP加固混凝土圆柱的损伤指标与试验结果基本符合,证明了该损伤模型以及加固柱的抗震等级划分标准的合理性。     

地震灾害农居易损性新方法研究

如何从定性到定量评价研究建筑结构抗震能力,尤其是量大面广的农村民居的抗震能力是一个重要而又棘手的问题。该文对12组墙片进行拟静力试验,得到了墙片的滞回曲线、骨架曲线和破坏状态,墙片的骨架曲线和破坏状态进行对比,按照对应的剪应力和位移角进行破坏等级划分,得到了农居主要承重构件墙片的破坏等级双参数定量划分方法。对五大类农居进行了6度~10度的震害矩阵完善,在农居震害矩阵的基础上提出了易损性指数计算新方法,解决了震害矩阵之间的评价问题。     

Cost optimal design of R/C buildings

A systematic approach is proposed for evaluating the cost-effectiveness of existing or proposed design criteria from the standpoint of life-cycle cost consideration. A series of alternative designs of a model structure representing a class of R/C buildings would be developed following an existing code procedure, except that the code requirements or parameters will be varied for the alternative designs so that a suite of different structures will be obtained each with a different level of safety or reliability. For each of the designed structures, the probability of exceeding the various damage levels under a given earthquake intensity may be calculated. Aggregating and integrating all the cost components with the damage probability density functions for each of the designed structures, as well as with the probabilities of all possible earthquake intensities over a given life will yield the expected life-cycle costs for the respective structures as a function of structural reliability. From these results, the design with the minimum expected life-cycle cost may then be identified; its underlying safety or reliability can also be determined. The approach is illustrated for a class of reinforced concrete buildings under earthquake loading.     

中国宜宾、日本山形、美国加州Ridgecrest地震破坏力分析与对比

该文对近期发生的我国宜宾长宁6.0级地震、日本山形6.7级地震、美国加州7.1级地震进行了破坏力分析和对比,包括典型强震记录的峰值和反应谱对比;典型地震动对典型单体结构与区域的破坏力对比;真实地震灾情的对比。主要对比结果包括：对于自振周期较短的砌体结构,宜宾地震破坏力最强;对于自振周期较大的多层框架结构,加州地震破坏力最强加州地震与山形地震的区域震害均轻于宜宾地震。上述结果表明地震震级、地面运动加速度、建筑物震损情况关系复杂,仅通过震级或最大地震动峰值加速度来判断地震破坏力是不合适的,应结合国家台网建设,发展城市抗震弹塑性分析。     

On the effect of plastic hinge relocation in RC buildings using CFRP

Relocation of nonlinear inelastic hinges away from the column faces towards the beams using externally bonded carbon fibre reinforced polymer (CFRP) is suggested as a promising method for retrofitting of reinforced concrete (RC) joints. This approach would also prevent the formation of undesirable brittle joint failure. In order to investigate the effects of this type of retrofit in the seismic performance of RC buildings, a numerical investigation pertaining to strengthening of an 8-storey intermediate RC frame using CFRP was conducted. The retrofit strategy focused on the relocation of the plastic-prone region away from the column faces and out into the beams. To pursue this objective, composite sheets were applied at the top and bottom sides of the plastic hinge regions of beams increasing the bending moment resistance. The additional flexural stiffness generated by the composite materials at the beam to column connections is calculated by a comparison of the moment-rotation of CFRP retrofitted and original joints obtained from the finite element analysis. A rigorous seismic assessment of the retrofitted frame was implemented using the nonlinear pushover procedure and the capacity spectrum approach. The analysis results indicate that a rehabilitation design as described combined with the strong-column weak-beam design philosophy would improve the seismic performance of structures significantly.     

Flexural retrofitting of RC buildings using GFRP/CFRP – A comparative study

The effectiveness of fibre reinforced polymers (FRPs) in retrofitting/repairing of the reinforced concrete (RC) components has been studied in the past to great detail. However, the seismic performance of RC structures retrofitted using FRP composites is yet to be scrutinised in terms of lateral resistance, ductility, and failure mechanism. This is of high importance if the retrofitted structures are to withstand higher seismic ground motions than they were designed for and/or pulse-type ground motions. In a comparative study, this paper reports on the results of an investigation into the flexural strengthening of RC buildings using glass/carbon fibre reinforced polymers (GFRP/CFRP). An 8-storey code-compliant RC building was considered as the case study to represent the medium-rise structures. With a slight intervention in the lateral displacement ductility and provision of the weak-beam strong-column design philosophy, the strengthening design strategy is aimed at increasing the lateral resistance. For this purpose, composite sheets are designed to be applied at the two end regions of all beams and columns on a practical flange-bonded scheme. The nonlinear pushover analysis with lumped plasticity approach was implemented in order to compare the seismic response of the original structure with the GFRP/CFRP retrofitted structures. Following validation of the adopted models, the force–deformation curves of the nonlinear plastic hinges are determined in a rigorous approach considering the material inelastic behaviour, reinforcement details, and dimensions of the members. While the nonlinear results confirm a significant increase in the lateral load carrying capacity using both composite materials, the CFRP improvement was as much as twice of the GFRP. However, the latter provides higher ductility.     

Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Strong aftershocks generally occur following a significant earthquake. Aftershocks further damage buildings weakened by mainshocks. Thus, the accurate and efficient prediction of aftershock-induced damage to buildings on a regional scale is crucial for decision making for post-earthquake rescue and emergency response. A framework to predict regional seismic damage of buildings under a mainshock–aftershock (MS–AS) sequence is proposed in this study based on city-scale nonlinear time-history analysis (THA). Specifically, an MS–AS sequence-generation method is proposed to generate a potential MS–AS sequence that can account for the amplification, spectrum, duration, magnitude, and site condition of a target area. Moreover, city-scale nonlinear THA is adopted to predict building seismic damage subjected to MS–AS sequences. The accuracy and reliability of city-scale nonlinear THA for an MS–AS sequence are validated by as-recorded seismic responses of buildings and simulation results in published literature. The town of Longtoushan, which was damaged during the Ludian earthquake, is used as a case study to illustrate the detailed procedure and advantages of the proposed framework. The primary conclusions are as follows. (1) Regional seismic damage of buildings under an MS–AS sequence can be predicted reasonably and accurately by city-scale nonlinear THA. (2) An MS–AS sequence can be generated reasonably by the proposed MS–AS sequence-generation method. (3) Regional seismic damage of buildings under different MS–AS scenarios can be provided efficiently by the proposed framework, which in turn can provide a useful reference for earthquake emergency response and scientific decision making for earthquake disaster relief.