土木工程畢業(yè)設(shè)計外文翻譯--一個預(yù)測鋼筋混凝土剪力墻非彈性地震響應(yīng)的分析模型 （英文）

1、Engineering Structures 24 (2002) 85–98www.elsevier.com/locate/engstructAn analytical model to predict the inelastic seismic behavior of shear-wall, reinforced concrete structuresP.A. Hidalgo *, R.M. Jordan, M.P. Martinez

2、Department of Structural and Geotechnical Engineering, Catholic University of Chile, Av. Vicuna Mackenna 4860, Casilla 306, Santiago, ChileReceived 10 July 2000; received in revised form 5 June 2001; accepted 11 June 200

3、1AbstractThe development of an analytical model to predict the inelastic seismic response of reinforced concrete shear-wall buildings, including both the flexural and shear failure modes is presented. The use of shear-wa

4、ll buildings is quite common in a number of seismic countries as a result of their successful seismic behavior during past severe earthquakes. The objective of this study has been to develop a computer model capable of p

5、redicting the seismic behavior of shear-wall buildings. Such model would allow better estimations to be obtained of both the ultimate lateral strength of these buildings as well as their inelastic deformation demand unde

6、r severe ground motions. Such information may be used in the implementation of performance-based design procedures, and to improve present code design procedures. To fulfill this objective, a shear failure mode model bas

7、ed on experimental results has been added to the computer program larz. This paper discusses the most relevant problems and solutions devised during the development of this model. Validation of the model proposed to pred

8、ict the inelastic seismic response of shear-wall structures was carried out by comparing its results with the actual response of two real buildings during the March 3, 1985 Chilean earthquake. In spite of the fact that t

9、he model is two-dimensional and, hence, it ignores the torsional response, the results obtained are satisfactory. ? 2001 Elsevier Science Ltd. All rights reserved.Keywords: Shear-wall buildings; Reinforced concrete build

10、ings; Inelastic behavior; Shear failure model1. IntroductionProperly designed multistory R/C shear-wall buildings should behave in a ductile flexural manner when sub- jected to severe earthquake ground motions. Conse- qu

11、ently, design forces are usually much smaller than those required to design a structural system without the characteristics of ductility and toughness typical of buildings with predominant flexural failure mode. Neverthe

12、less, there are cases where this ductile failure mode may not be achieved due to the large flexural strength as compared with the shear strength of the walls. In such cases, an undesired shear failure mode is likely to d

13、evelop. This may be the case of structural sys- tems that have a large wall area relative to the floor plan area. This situation may also happen in shear walls* Corresponding author. Tel.: +56-2-686-4207; fax: +56-2-686-

14、 4243. E-mail address: phidalgo@ing.puc.cl (P.A. Hidalgo).0141-0296/02/$ - see front matter ? 2001 Elsevier Science Ltd. All rights reserved. PII: S0141-0296(01)00061-Xcoupled by stiff lintels that may induce bending mom

15、ent to shear force ratios in the wall too small relative to the length of the wall. On the other hand, even in the case that ultimate strength is controlled by a ductile flexural behavior of the shear walls, structural d

16、amage in the form of mild or extensive shear cracking may affect the objectives of performance-based design. Several examples of these situations have been found in the response of R/C shear-wall buildings after severe e

17、arth- quakes like the March 3, 1985 Chilean earthquake. The use of shear-wall buildings is quite common in some earthquake-prone countries such as Chile; their seismic behavior has been successful during past severe eart

18、hquakes, both, from a serviceability as well as a safety standpoint [1]. Therefore, their use has been rec- ommended in earthquake-resistant design [2] as long as its true behavior is included in building modeling. Conse

19、quently, the objective of this study has been to develop a computer model capable of predicting the seis- mic behavior of such buildings. The model proposed allows better estimations to be obtained of both the ulti-87 P.

20、A. Hidalgo et al. / Engineering Structures 24 (2002) 85–98similar soil conditions as for the buildings were used as input for the computer model.2. Model for flexural failure modeThe SINA hysteresis model implemented in

21、the larz computer program (Fig. 2) was adopted in this study to model the non-linear flexural behavior and the moment- curvature hysteretic relations for wall elements. As shown in Fig. 2, pinching effects and stiffness

22、and strength reductions due to repeated cycles at the same deformation level were not implemented in the model for flexural behavior. The model operates on a primary M–f envelope curve consisting of four linear segments

23、for positive and nega- tive bending as shown in Fig. 2. The primary curves need not be symmetric about the origin, but a single straight line must be specified for moments below the cracking moment in both directions (li

24、ne C?C in Fig. 2). Points Y and U (and Y? and U?) correspond to moments asso- ciated with first yielding and a concrete compressive strain of ?cu=0.003, respectively. An horizontal line fol- lowing point U is assumed, an

25、d collapse is defined by a maximum curvature fmax, associated to a concrete compressive strain of ?cmax=0.01. For moments below the cracking level, loading and unloading follow the primary curve. For moments above the cr

26、acking moment, unloading follows a line con- necting the unloading point with the cracking point in the other direction (line PC? in Fig. 2). If the yield moment is exceeded and unloading takes place at point P1, the slo

27、pe of the unloading branch P1P2 is taken asKun?Ky?c? fy fm?a (1)where fm is the maximum curvature attained in the load- ing direction and Ky?c the slope of the line connecting the yield point in the loading direction wit

28、h the cracking point in the opposite direction. The exponent a controls the slope of the unloading branch after yielding, and was taken equal to 0.5 as suggested by Saiidi and Sozen [3]. A detailed description of all the

29、 hysteresis rules can be found elsewhere [3]. The bending moment and curvature values were defined using the standard theory for reinforced concrete elements; both the boundary reinforcement and the dis- tributed vertica

30、l reinforcement are taken into account in defining the primary M–f curve for wall elements. Further, the axial load force values due to gravity, assumed to remain constant throughout the seismic response, are considered

31、in the calculation of moment and curvature associated with points C, Y and U of the primary curve. This constitutes an approximation for shear walls coupled by spandrel beams, since thesebeams may develop significant sei

32、smic shear forces that induce variable axial loads on the walls, but the resulting error in the axial loads becomes smaller as the flexural strength of the coupling elements decreases. The evaluation of the bending momen

33、t for the collapse point defined by fmax , assumes the same compressive stress block in the concrete that was used for point U. This is obviously an approximation since it always yields to fmax=3.33fu in Fig. 2. This ass

34、umption is verified by computing the moment-curvature relationship for some of the walls using a realistic stress–strain curve for the concrete. In all cases a slightly larger value of fmax is obtained by using the more

35、‘exact’ method. Neverthe- less, when the model was used in this study to predict the inelastic seismic behavior of real buildings, the maximum curvature never exceeded the value of fu.3. Model for shear failure modeShear

36、 dominated behavior was also modeled using the SINA hysteresis model as shown in Fig. 3. Pinching effects and strength reduction due to repeated cycles at the same deformation level were now implemented in the hysteresis

37、 model. The model for the shear failure mode assumes independence of the shear strength of walls on both the bending moment and the axial force present in the wall. This is also an approximation, but to neglect interacti

38、on between shear and axial force is consistent with the current ACI design provisions for walls [6]. The model was initially developed for squat shear walls with an aspect ratio M/(VLw) of 1.0 or smaller, where M is the

39、bending moment at the base of the wall, V the shear force, and Lw the length of the wall. It was then extended to the case of slender shear walls with aspect ratio larger than 1.0, as explained later. In Fig. 3, point C

40、represents the point where a change in the slope of the envelope of the load–displacement relationship is experimentally observed; the new value of the stiffness of the specimens is about 60% of the initial stiffness. Po

41、int C was generally very close to the point at which the first diagonal crack from corner to corner of the walls was developed during the tests. Point Y corresponds to the largest value of shear load attained during the

42、test, while point U may be associated with the ultimate con- dition under which the element may still be considered as an effective part of the resisting mechanism of the structure. The definitions of points C, Y and U i

43、n the envelope curve (Fig. 3) are based on the experimental results obtained from the cyclic test of 26 full scale, shear wall specimens. All these specimens were designed to exhibit a shear mode of failure and had aspec