土建专业外文翻译---预应力混凝土结构的抗震加固方案与局部影响

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1、 本科生毕业设计 外文翻译 题 目 Seismic retrofit schemes for RC structures and local-global consequences 外文来源 Progress in Structural Engineering and Maerials 姓 名 学 号 学 院 工程学院 专 业 土木工程 指导教师 2011 年 5 月 4 日 外文原文 Seismic retrofit schemes for RC structures and local-global consequences summary A review of repair schem

2、es for reinforced concrete frame buildings is presented in this paper, within the context of global objectives of the intervention process. Local as well as global intervention measures are discussed and their technological application details outlined. The effect of the reviewed repair schemes on t

3、he member, sub-assemblage and system performance are qualitatively assessed. The important role of the foundation system in the rehabilitation process is outlined and measures that are consistent with the super-structure intervention methods are given. The paper concludes with a global assessment of

4、 the effect of repair methods on stiffness, strength and ductility, the three most important seismic response parameters, to assist researchers and practitioners in decision-making to satisfy their respective intervention objectives. Keywords: retrofit； repair； strengthening； structural intervention

5、； seismic upgrading Introduction In recent years, devastating earthquakes worldwide confirmed the deficiencies of building structures. The experience gained from field observations and back-analysis led to improvement of the level of knowledge and the evolution of seismic codes. The interest of the

6、research community is focused on buildings that do not comply with current seismic codes and exhibit deficiencies such as poor detailing, discontinuous load paths and lack of capacity design provisions. Since such buildings comprise the majority of existing building stock, retrofitting is a rather c

7、ritical issue. Rehabilitation schemes that will provide cost-effective and structurally effective solutions are necessary. Many intervention methods used in the past have been revised and developed in the light of the new seismic code requirements and new methods often based on new materials (e.g. f

8、iber-reinforced polymers FRPs) have been proposed. In this paper, the term rehabilitation is used as a comprehensive term to include all types of repair, retrofitting and strengthening that lead to reduced earthquake vulnerability. The term repair is defined as reinstatement of the original characte

9、ristics of a damaged section or element and is confined to dealing with the as-built system. The term strengthening is defined as intervention that lead to enhancement of one or more seismic response parameters (stiffness, strength, ductility, etc.), depending on the desired performance. Framework o

10、f seismic rehabilitation Performance objectives are set depending on the structural type, the importance of the building, its role in post-earthquake emergencies, the economic consequences of business interruption, its historical or cultural significance, the construction material and socio-economic

11、 factors. They can be specified as limits on one or more response parameter such as stresses, strains, displacements, accelerations, etc. Clearly, different limit states have to be correlated to the level of the seismic action, i.e. to the earthquake demand level. The selection of the rehabilitation

12、 scheme and the level of intervention is a rather complex procedure, because many factors of different nature come into play. A decision has to be taken on the level of intervention. Some common strategies are the restriction or change of use of the building, partial demolition and/or mass reduction

13、.In addition, methods such as base isolation, provision of supplemental damping and incorporation of passive and active vibration control devices may apply. The alternatives of no intervention or demolition are more likely the outcomes of the evaluation if the seismic retrofit of buildings is quite

14、expensive and disruptive. Socio-economic issues have to be considered in the decision of the level and type of intervention. Surprisingly, there are documented cases where aesthetic and psychological issues dictate the rehabilitation strategies. For example, in the Mexico City earthquake of 19 Septe

15、mber 1985, where external bracing was popular, because it instilled a feeling of confidence in the occupants that significant and visible changes have been made to the structure to make it safer. Cost vs importance of the structure is a significant factor, especially in the case that the building is

16、 of cultural and/or historical interest. The available workmanship and the level of quality control define the feasibility of the proposed intervention approach. The duration of work/disruption of use and the disruption to occupants should also be considered. The functionality and aesthetical compat

17、ibility of the intervention scheme with the existing building is an additional engagement. Even the reversibility of the scheme in case it is not accepted on a long-term basis should be taken into account. From a technical point of view the selection of the type and level of intervention have to be

18、based on compatibility with the existing structural system and the repair materials and technology available. Controlled damage to non-structural components and sufficient capacity of the foundation system are essential factors that are often overlooked. Issues such as irregularities of stiffness, s

19、trength and ductility have to be considered in detail. A convenient way to discuss the engineering issues of evaluation and retrofit is to break down the process into steps. The first step involves the collection of information for the as-built structure. The configuration of the structural system,

20、reinforcement detailing, material strengths, foundation system and the level of damage are recorded. In addition, data relevant to the non-structural elements (e.g. infill walls) which play a significant role and influence the seismic response of structures are also compiled. Sources for the above i

21、nformation can become visits to the site, construction drawings, engineering analyses and interviews with the original contractor. The rehabilitation objective is selected from various pairs of performance targets and earthquake hazard levels (i.e. supply and demand, or response and input pairs). Th

22、e performance target is set according to an acceptable damage level (performance target). Building performance can be described qualitatively in terms of the safety of occupants during and after the event, the cost and feasibility of restoring the building to pre-earthquake condition, the length of time the building is removed from service to effect repairs, and the economic, architectural or historic impacts on the larger community.