既有建筑结构检测鉴定规范的现状和发展趋势

文章回顾总结既有建筑结构检测和鉴定规范制定的历史和现状,提出其中存在的问题,指出既有建筑结构可靠性鉴定工作今后发展的方向,分析了既有建筑结构检测和鉴定规范的发展趋势,提出既有建筑结构可靠性的评估应该与现今的设计规范相协调,结构的时变性能、损伤累积以及结构的耐久性等问题应该在既有建筑结构的可靠性分析中予以考虑,并在检测和鉴定规范中予以体现,     

可靠度理论在既有建筑鉴定中存在的问题

既有建筑结构的可靠性鉴定与新建结构之间既有共同点又有差异。本文分析了既有结构可靠度的随机因素与设计拟建建筑的异同点,并对已有的既有房屋可靠度鉴定标准做出讨论,提出了可靠度理论在既有房屋鉴定应用中目前存在的问题。     

谈既有房屋结构可靠性鉴定

从既有房屋结构可靠性定义、既有结构鉴定依据、方法,可靠性评定目的及内容,可靠性鉴定存在的缺陷及发展方向等方面进行论述,对既有建筑可靠性评定的研究有着非常广泛和深刻的社会意义。     

宜昌建管大楼绿色改造节能与经济性分析研究

该文分析了宜昌建管大楼现状,对项目进行节能诊断分析及结构可靠性鉴定。依据现行《既有建筑绿色改造评价标准》,拟定既有建筑绿色改造目标,结合以往既有建筑改造经验及绿色建筑技术,研究制定绿色改造技术方案。运用软件模拟分析改造前后大楼能耗情况及节能率,并进行经济性分析。     

在役轴心受压钢筋混凝土短柱后续使用年限探讨

根据现行的《工程结构可靠性设计统一标准》中的结构构件目标可靠指标,以既有结构的材料强度及恒载为实测值,给出了构件可靠度的计算方法,可以用来计算在役轴心受压混凝土短柱的后续使用年限,供工程鉴定参考。     

浅谈无资料既有建筑检测鉴定的方法和步骤

在既有建筑检测鉴定工作当中,经常会遇到由于各种原因,建筑物没有任何建筑结构图纸和技术资料,但又需要确定建筑物目前结构安全性现状,为结构加固维修提供依据。为此将既有建筑物的结构安全性检测鉴定分为两级,依据现行检测鉴定标准规范,采用二级鉴定程序能够明确检测鉴定项目,完整且全面地反映建筑物结构现状,防止漏判误判,规范检测鉴定程序。     

既有自立式钢结构通讯塔结构的安全性检测与鉴定方法初探

介绍了既有自立式钢结构通讯塔结构的安全性检测与鉴定方法,结合现场实测数据及塔体三维实体有限元建模分析结果,依据现行相关标准规范要求,按地基基础和上部塔体结构两个子单元综合评定钢结构通讯塔结构的安全性,根据安全性评定结果给出合理的鉴定结论及建议,指导结构的加固工作。并以攀枝花市某既有自立式钢结构通讯塔结构的安全性检测与鉴定工作为例,具体阐述了这一方法的操作过程。     

既有建筑结构安全性鉴定中现浇楼板最小配筋率的探讨

总结了既有建筑按照现行《民用建筑可靠性鉴定标准》(GB 50292-2015)进行安全性鉴定中会遇到既有建筑现浇板不符合现行《混凝土结构设计规范》(GB 50010-2010)最小配筋率规定的情况.分析了当现浇楼板承载力满足现行规范的要求且无明显外观缺陷损伤时,仅楼板最小配筋率不满足现行设计规范要求,把现浇楼板评定为c...     

既有建筑结构安全性鉴定中现浇楼板最小配筋率的探讨

总结了既有建筑按照现行《民用建筑可靠性鉴定标准》(GB 50292—2015)进行安全性鉴定中会遇到既有建筑现浇板不符合现行《混凝土结构设计规范》(GB 50010—2010)最小配筋率规定的情况。分析了当现浇楼板承载力满足现行规范的要求且无明显外观缺陷损伤时,仅楼板最小配筋率不满足现行设计规范要求,把现浇楼板评定为c;级或d;级的不合理性。探讨了双向和单向现浇楼板安全性鉴定应以是否出现脆性破坏为原则进行判别,在承载力满足要求且未出现结构损伤情况下,其楼板最小配筋率大于导致脆性破坏的配筋率时,应把所鉴定的现浇楼板构件安全性等级评定为a;级或b;级。     

钢-砌体结构混合的既有建筑结构检测与鉴定方案探讨

结合实际的钢-砌体混合砌体结构工程,在收集、查阅图纸等相关工程资料,勘查既有建筑现场的环境条件与受力情况,制定安全和适用的检测方案。在对现场的检测和结构体系进行分析后,进行既有建筑的可靠性鉴定与抗震性鉴定分析,可作为类似工程的参考。     

关于结构设计可靠性的探讨

按照规设计准则进行结构设计，只保证了结构构件极限状态的可靠度对目标可靠度的最小偏离，实际上无法得知构件的状态究竟是安全的还是不安全的；并且对于复杂的结构，规范难以保证分项系数的合理性。此时应该如何判断结构件设计的合理性：为此从结构设计中设计参数的确定方法出发，通过对设计过程进行几何描述，指出按照传统的设计方法得到的设计参数并不一定能保证结构构件的可靠性。问题解决的方法是对结构构件进行可靠度分析。通过对文末一个算例的分析，说明了以可靠度理论为基础的设计参数确定准则。     

Future directions and challenges in shell stability analysis

Recent advances in structural analysis and design technology for buckling-critical shell structures are discussed. These advances include a hierarchical analysis strategy that includes analyses that range from classical analysis methods to high-fidelity nonlinear finite element analysis methods, reliability based design methods, the development of imperfection data bases, and the identification of traditional and nontraditional initial imperfections for composite shell structures. When used judiciously, these advances provide the basis for a viable alternative to the traditional and conservative lower-bound design philosophy of the 1960s. These advances also help answer the question of why, after so many years of concentrated research effort to understand the behavior of buckling-critical thin-walled shells, one has not been able to improve on this conservative lower- bound design philosophy in the past.     

Specification of design criteria based on probabilistic measures of design performance

To date, reliability-based structural design standards have been developed using deterministic design procedures that are formulated to achieve target levels of structural reliability (target safety indices) without requiring explicit reliability calculations. Target safety indices have been selected to match typical safety levels in previous design standards. However, the current levels of structural safety are not necessarily the most appropriate, and it has been suggested that explicit risk-based measures of structural performance should be used to optimise the target levels of design performance. Explicit risk-based measures could be used to underpin deterministic design requirements or they could be used directly for explicit risk-based design. The paper discusses the use of risk-based measures in the development and application of design Standards. The paper also discusses broader issues related to the development of design Standards, including the influence of international standardisation.     

结构生命周期的可靠性管理

结构的抗力性能、使用条件、环境作用等都是随时间变化的过程。结构的运行规律复杂且具有大量的不确定性和不确知性,单纯依靠设计来保证结构的安全性是不够的,而应该综合考虑设计、检测、维护等策略对结构生命周期的可靠性进行管理。首先分析了目前的可靠度设计方法的优点和局限性,对可靠性管理的概念和必要性进行了阐述。继而引入时变可靠度和时点可靠度指标,建立一套考虑安全控制和风险优化的结构生命周期可靠性管理框架,并对其中的若干理论问题进行了讨论。该框架的特点在于,由静态思路转向动态思路,强调信息的更新和充分利用,与现有设计理论和工程实践保持协调。     

On the relationship between platform topology, topside weight and structural reliability under storm overload

The relationship between platform configuration and structural reliability is investigated by comparing the collapse behaviour of simple jacket, jack-up and monopod topologies under storm loading in moderately shallow North West Shelf (NWS) waters. Two different pushover analysis methods are used to find the ultimate strength, which give quite different reserve strength ratio (RSR) results for certain structures. The effect on the structural reliability of varying topside weight is also assessed. It is found that the reliability trends are strongly dependent on structural topology — an effect that is not included in current Codes of practice. It is also shown that a single set of partial load factors for dead and environmental loads cannot achieve uniform reliability across different platform configurations in the same environment. Furthermore, in some cases, a working stress design format gives more consistent reliability results than the load and resistance design factor approach.     

建筑结构抗倒塌分析方法

建筑结构的倒塌可分为两种模式:建筑物侧向增量倒塌与竖向连续倒塌。本文论述了建筑物结构失效模式的如何辨识以及侧向倒塌能力点确定准则的相关研究进展。介绍了现有的连续倒塌研究方法,尤其是基于备用荷载路径的竖向非线性动力分析方法。为建筑结构整体抗震可靠度研究以及结构抗震性能评定与设计提供参考。     

Reliability-based integrated design of steel portal frames with tapered members

Integrated structural designs, with consideration of system reliability for steel portal frames comprising tapered members, are studied in this paper. The reliability-based integrated design (RID) directly checks the structural system limit states and the corresponding system reliability, based on structural nonlinear analysis. The nonlinear integrated analysis model, the semi-analytical simulation method employed for system reliability assessment, the development processes of RID format and the design application of RID formula and curves are presented in this paper. Design examples and comparisons among three different design formats demonstrate that RID proposed in this paper is of certain and consistent system reliability levels, and provides a feasible way for structural engineers to improve the design quality and flexibility of steel frame structures.     

Damage assessment and reliability evaluation of existing structures

Problems involving damage assessment of existing structures have been studied by many engineers in recent years. However, a complete and rational solution is not available to date. Meanwhile, the theory of structural reliability has been well developed with many applications during these past three decades. Nevertheless, to estimate the reliability of an existing structure remains a very challenging problem. In this paper, the concept of structural identification is examined. Moreover, several possible approaches making use of full-scale dynamic test data are reviewed and discussed.     

工程结构设计可靠度理论综述

简单评述了工程结构设计理论的发展,概括性总结了结构可靠度理论的国内外研究现状;详细叙述并分析了可靠度理论的各种适用方法,指出了我国结构设计可靠度理论的不足及发展方向。     

基于整体承载极限状态的钢结构可靠度设计方法及其在门式钢刚架设计中的应用

本文提出了基于整体承载极限状态的钢结构可靠度设计思路。这种思路建立在钢结构整体非线性分析和验算的基础上,并确保结构整体而非构件的可靠度水平,使结构整体的实际可靠度水平尽可能地接近于设计的目标值。本文针对门式钢刚架结构建立了一套实现这种设计的方法,包括结构整体非线性分析、结构体系可靠度计算以及实用的设计表达式。通过三个门式钢刚架结构设计实例比较了传统的构件设计方法,不考虑体系可靠度的整体承载极限状态设计方法和本文考虑体系可靠度的整体承载极限状态设计方法的设计结果,说明本文所提出设计思想的先进性。