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 薛晶 学 号 407112010104 学 院 工程学院 专 业 土木工程 指导教师 谌会芹 2011 年 5 月 4 日 外文原文 Seismic retrofit schemes for RC structures and local-global consequences summary A re
2、view of repair schemes 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
3、 repair schemes on the 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
4、global assessment of 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； str
5、uctural intervention； 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.
6、The interest of the 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, retrof
7、itting is a rather critical 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 n
8、ew materials (e.g. fiber-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 t
9、he original characteristics 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 perf
10、ormance. Framework of 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 materia
11、l and socio-economic 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 o
12、f the rehabilitation 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 a
13、nd/or mass reduction.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
14、 buildings is quite 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 ea
15、rthquake of 19 September 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
16、that the building is 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 an
17、d aesthetical compatibility 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 inte
18、rvention have to be 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 irregulari
19、ties of stiffness, strength 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
20、 structural system, 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. Sou
21、rces for the above information 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
22、and input pairs). The 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.
