英文翻译
英文原文
Comparative Application of Capacity Models for Seismic Vulnerability Evaluation of Existing RC Structures
Abstract胸椎压缩性骨折>郑成功. Seismic vulnerability asssment of existing buildings is one of the most common tasks in which Structural Engineers are currently engaged. Since, its is often a preliminary step to approach the issue of how to retrofit non-ismic designed and detailed structures, it plays a key role in the successful choice of the most suitable strengthening technique. In this framework, the basic information for both ismic asssment and retrofitting is related to the formulation of capacity models for structural members. Plenty of proposals, often contradictory under the quantitative standpoint, are currently available within the technical and scientific literature for defining the structural capacity in terms of force and displacements, possibly with reference to different parameters reprenting the ismic respon. The prent paper shortly reviews some of the models for capacity of R
C members and compare them with reference to two ca studies assumed as reprentative of a wide class of existing buildings.
泉水声音怎么形容
Keywords数量的英文: Asssment, Vulnerability, Capacity, Existing Structures, Reinforced Concrete.
INTRODUCTION
Seismic asssment of existing RC structures is a cutting-edge issue for structural engineers. The incread levels of safety required to new structures by the last generation of codes of standards indirectly emphasizes the lack in ismic performance usually affecting the existing ones. Seismic vulnerability evaluation can be carried out according to various code provisions about capacity of members of existing structures under earthquake actions. Different damage measures can be adopted for quantifying ismic capacity even depending on the type of structure considered. Three different parameters, besides other less common quantities, have been propod for measuring ismic performance of reinforced concrete structures.Indeed, plastic rotations are consid
ered in the U.S. code [6] for quantifying ismic capacity of beams and columns, while the total chord rotation is assumed as capacity measures for RC members in both the European [2] [3] and Italian [4] [5] ismic codes. Other proposals can be found within the scientific literature and the technical practice. For instance, the interstorey-drift angle is a parameter commonly ud for quantifying ismic capacity and demand on structures [1]; furthermore, on the basis of particular assumptions about the mechanism most likely to occur, interstorey drift values can be somehow converted into global displacements [7]. According to the general Performance-Level framework of the current codes, various levels of damage can be tolerated for every relevant Performance Level of the structures. Conquently,they assume different threshold values, in terms of the various measures mentioned above, for stating whether a given structure attains or not the Limit States of interest in ismic design and asssment. The prent paper, after a critical review of the various proposals for all the relevant Limit States, compares the various definitions of structural capacity of members for two existing RC structures, designed for gravitational loads, assumed as ca-studies.
关于人生的感悟
李白诗歌OUTLINE OF CAPACITY MODELS FOR RC MEMBERS
Several parameters and indices can be considered for measuring structural performance under horizontal actions induced by earthquake shaking. As a matter of principle, tho parameters should look after the cyclic nature of the ismic respon. Park&Ang Damage Index, Low-Cycle Fatigue Index [8] and other similar measures follow the cyclic evolution of the structural respon defining suitable threshold values of the corresponding indices for defining the achievement of the relevant Limit States.Although tho parameters explicitly consider the actual evolution of the structural respon, they are not so easy to evaluate at both local and global level. Conquently, capacity is more often defined in terms of displacement parameters who maximum value attained during the ismic respon is considered. Figure 1 shows the three different displacement measures which are more commonly considered within the scientific and technical literature:
桃花简笔画- the interstorey drift angle , which can be evaluated as ratio between the intestorey relative displacement a the storey height h;
- the plastic rotation which is defined as the concentrated rotation which is equivalent to the plastic curvatures arising around the column end throughout a length which is the length of the so-called plastic hinge;
淑妃传- the total chord rotation which is defined as the ratio between the relative displacement of the point of zero curvature and the distance between that point and the column end, namely the shear length .
FIGURE 1. Displacement parameters for quantifying ismic capacity of beams-columns.
Alternative definitions can be derived for the relevant ismic performance levels (PL) or Limit States (LS) utilizing the three measures listed and briefly defined above. Indeed, three possible PLs are usually considered within the structural codes:
