外文翻譯--智能材料改進(jìn)混凝土剪力墻結(jié)構(gòu)

1、附Ⅰ 附Ⅰ 外文翻譯原文 外文翻譯原文Improvement of Concrete Shear Wall Structures by Smart Materials Mehdi Ghassemieh1*, Mohammad Reza Bahaari1, Seyed Mohyeddin Ghodratian1, Seyed Ali Nojoumi2 1School of Civil Engineering, University of

2、Tehran, Tehran, Iran 2Civil revised June 10, 2012; accepted June 20, 2012 ABSTRACT Smart materials have found numerous applications in many areas in civil engineering recently. One class of these mate-rials is shape mem

3、ory alloy (SMA) which exhibits several unique characteristics such as superelasticity and shape memory effect. Due to these characteristics, research efforts have been extended to use SMA in controlling civil struc-ture

4、s. This paper investigates the effectiveness of SMA reinforcements in enhancing the behavior of shear walls, espe-cially when subjected to seismic excitations. Two ordinary and coupled shear walls were introduced as ref

5、erence struc-tures and were modeled by ABAQUS software. For improving the seismic response of the shear walls, vertical SMA reinforcing bars were proposed to be implemented like conventional steel reinforcements, throug

6、hout the height of the structures and in every connecting beam in the coupled shear wall system. The one dimensional superelastic model of SMA material was implemented in the computer software using FORTRAN code. The d

7、ynamic response of the shear walls subjected to seismic loading was investigated through time history analyses under El-centro and Koyna records. The results showed that using superelastic SMA material instead of steel

8、 bars caused remarkable reduction in residual displacement for both ordinary and coupled shear walls. In addition, SMA reinforcements could significantly decrease the maximum deflection of the coupled shear wall system.

9、 Keywords: Smart Material; Shape Memory Alloy; Shear Wall; Superelasticity; Seismic BehaviorIntroduction Many multi-storey buildings contain shear walls around the elevator shafts and stairwells as lateral resisting sy

10、s-tems. For the concrete shear wall systems, it is difficult to satisfy the very ductile behavior conditions. Therefore, such structures have often suffered damages caused by earthquake events. Shearing damage, bending

11、which has variable stiffness and strength. Saiidi and Wang presented the application of SMA bars instead of steel bars in plastic hinge zone of reinforced concrete bridge piers [13]. Motahari et al. also introduced a sp

12、e-cial SMA damper to have both re- centering and energy dissipating characteristics simultaneously [14]. Li et al. experimentally studied the behavior of smart concrete beams with embedded shape memory alloy bundles [15

13、]. They used SMA bundles as actuators to achieve recovery force. Andrawes and DesRoches compared the efficiency of SMA restrainers with three other retrofit devices including conventional steel restrainers, metallic dam

14、pers and viscoelastic dampers [16]. Johnson et al. conducted a large scale testing program to evaluate the effect of SMA restrainer cable on the seismic performance of in-span hinges of multiple-frame concrete box girde

15、r bridge sub-jected to strong ground motion [17]. Rahman et al. in-vestigated the effect of cross section geometry on the bending of a beam and also buckling of a column made of SMA through a numerical study [18]. Shara

16、bash and Andrawes studied the application of SMAs as seismic passive damper devices for vibration mitigation of cable stayed bridges [19]. The feasibility of superelasticity in increasing ductility capacity and decreasi

17、ng residual dis-placement of concrete bridge column was investigated by Saiidi et al. [20]. Ozbulut and Hurlebaus explored the effectiveness of SMA-rubber based isolation systems for seismic protection of bridges agains

18、t near-field earth-quakes. They also compare the performance of SMA- rubber based isolation systems with SMA-based sliding isolation system [21]. Kari et al. evaluated the effective-ness of a new dual bracing system for

19、improving the seismic behavior of steel structures [22]. In this study the behavior of concrete shear walls rein-forced with SMA bars is investigated. Finite element program, ABAQUS, was used in order to assess the re-sp

20、onse of the structures subjected to seismic loading. Two ordinary and coupled shear walls were introduced as reference structures and their seismic behavior with and without SMA reinforcement was evaluated through time

21、history analyses. 2. Shape Memory Alloy Shape Memory Alloys are new class of metallic alloys that display multiple incomparable characteristics, based on martensitic phase transformation. SMAs are able to undergo large

22、 strains (8% - 10%) without leaving per-manent deformations in the material. They can recover their initial shape at the end of the deformation process, instinctively (called superelasticity) or by heating (called shape