• Title, Summary, Keyword: self-centering wall

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Experimental study on component performance in steel plate shear wall with self-centering braces

  • Liu, Jia-Lin;Xu, Long-He;Li, Zhong-Xian
    • Steel and Composite Structures
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    • v.37 no.3
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    • pp.341-351
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    • 2020
  • Steel plate shear wall with self-centering energy dissipation braces (SPSW-SCEDB) is a lateral force-resisting system that exhibits flag-shaped hysteretic responses, which consists of two pre-pressed spring self-centering energy dissipation (PS-SCED) braces and a wall plate connected to horizontal boundary elements only. The present study conducted a series of cyclic tests to study the hysteretic performances of braces in SPSW-SCEDB and the effects of braces on the overall hysteretic characteristics of this system. The SPSW-SCEDB with PS-SCED braces only exhibits excellent self-centering capability and the energy loss caused by the large inclination angle of PS-SCED braces can be compensated by appropriately increasing the friction force. Under the combined effect of the two components, the SPSW-SCEDB exhibits a flag-shaped hysteretic response with large lateral resistance, good energy dissipation and self-centering capabilities. In addition, the wall plate is the primary energy dissipation component and the PS-SCED braces provide supplementary energy dissipation for system. The PS-SCED braces can provide up to 90% self-centering capability for the SPSW-SCEDB system. The compressive bearing capacity of the wall plate should be smaller than the horizontal remaining restoring force of the braces to achieve better self-centering effect of the system.

Residual drift analyses of realistic self-centering concrete wall systems

  • Henry, Richard S.;Sritharan, Sri;Ingham, Jason M.
    • Earthquakes and Structures
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    • v.10 no.2
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    • pp.409-428
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    • 2016
  • To realise the full benefits of a self-centering seismic resilient system, the designer must ensure that the entire structure does indeed re-center following an earthquake. The idealised flag-shaped hysteresis response that is often used to define the cyclic behaviour of self-centering concrete systems seldom exists and the residual drift of a building subjected to an earthquake is dependent on the realistic cyclic hysteresis response as well as the dynamic loading history. Current methods that are used to ensure that re-centering is achieved during the design of self-centering concrete systems are presented, and a series of cyclic analyses are used to demonstrate the flaws in these current procedures, even when idealised hysteresis models were used. Furthermore, results are presented for 350 time-history analyses that were performed to investigate the expected residual drift of an example self-centering concrete wall system during an earthquake. Based upon the results of these time-history analyses it was concluded that due to dynamic shake-down the residual drifts at the conclusion of the ground motion were significantly less than the maximum possible residual drifts that were observed from the cyclic hysteresis response, and were below acceptable residual drift performance limits established for seismic resilient structures. To estimate the effect of the dynamic shakedown, a residual drift ratio was defined that can be implemented during the design process to ensure that residual drift performance targets are achieved for self-centering concrete wall systems.

Application of self-centering wall panel with replaceable energy dissipation devices in steel frames

  • Chao, Sisi;Wu, Hanheng;Zhou, Tianhua;Guo, Tao;Wang, Chenglong
    • Steel and Composite Structures
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    • v.32 no.2
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    • pp.265-279
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    • 2019
  • The self-centering capacity and energy dissipation performance have been recognized critically for increasing the seismic performance of structures. This paper presents an innovative steel moment frame with self-centering steel reinforced concrete (SRC) wall panel incorporating replaceable energy dissipation devices (SF-SCWD). The self-centering mechanism and energy dissipation mechanism of the structure were validated by cyclic tests. The earthquake resilience of wall panel has the ability to limit structural damage and residual drift, while the energy dissipation devices located at wall toes are used to dissipate energy and reduce the seismic response. The oriented post-tensioned strands provide additional overturning force resistance and help to reduce residual drift. The main parameters were studied by numerical analysis to understand the complex structural behavior of this new system, such as initial stress of post-tensioning strands, yield strength of damper plates and height-width ratio of the wall panel. The static push-over analysis was conducted to investigate the failure process of the SF-SCWD. Moreover, nonlinear time history analysis of the 6-story frame was carried out, which confirmed the availability of the proposed structures in permanent drift mitigation.

Rocking response of self-centring wall with viscous dampers under pulse-type excitations

  • Zhang, Lingxin;Huang, Xiaogang;Zhou, Zhen
    • Earthquakes and Structures
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    • v.19 no.3
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    • pp.215-226
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    • 2020
  • A self-centering wall (SCW) is a lateral resistant rocking system that incorporates posttensioned (PT) tendons to provide a self-centering capacity along with dampers to dissipate energy. This paper investigates the rocking responses of a SCW with base viscous dampers under a sinusoidal-type pulse considering yielding and fracture behaviour of the PT tendon. The differences in the overturning acceleration caused by different initial forces in the PT tendon are computed by the theoretical method. The exact analytical solution to the linear approximate equation of motion is also provided for slender SCWs. Finally, the effects of the ductile behaviour of PT tendons on the rocking response of a SCW are analysed. The results demonstrate that SCWs exhibit two overturning modes under pulse excitation. The overturning region with Mode 1 in the PT force cases separates the safe region of the wall into two parts: region S1 with an elastic tendon and region S2 with a fractured tendon. The minimum overturning acceleration of a SCW with an elastic-brittle tendon becomes insensitive to excitation frequency as the PT force increases. After the plastic behaviour of the PT tendon is considered, the minimum overturning acceleration of a SCW is increased significantly in the whole range of the studied wg/p.

Analytical investigation on lateral load responses of self-centering walls with distributed vertical dampers

  • Huang, Xiaogang;Zhou, Zhen;Zhu, Dongping
    • Structural Engineering and Mechanics
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    • v.72 no.3
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    • pp.355-366
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    • 2019
  • Self-centering wall (SCW) is a resilient and sustainable structural system which incorporates unbonded posttensioning (PT) tendons to provide self-centering (SC) capacity along with supplementary dissipators to dissipate seismic energy. Hysteretic energy dissipators are usually placed at two sides of SCWs to facilitate ease of postearthquake examination and convenient replacement. To achieve a good prediction for the skeleton curve of the wall, this paper firstly developed an analytical investigation on lateral load responses of self-centering walls with distributed vertical dampers (VD-SCWs) using the concept of elastic theory. A simplified method for the calculation of limit state points is developed and validated by experimental results and can be used in the design of the system. Based on the analytical results, parametric analysis is conducted to investigate the influence of damper and tendon parameters on the performance of VD-SCWs. The results show that the proposed approach has a better prediction accuracy with less computational effects than the Perez method. As compared with previous experimental results, the proposed method achieves up to 60.1% additional accuracy at the effective linear limit (DLL) of SCWs. The base shear at point DLL is increased by 62.5% when the damper force is increased from 0kN to 80kN. The wall stiffness after point ELL is reduced by 69.5% when the tendon stiffness is reduced by 75.0%. The roof deformation at point LLP is reduced by 74.1% when the initial tendon stress is increased from $0.45f_{pu}$ to $0.65f_{pu}$.

Snap back testing of unbonded post-tensioned concrete wall systems

  • Twigden, Kimberley M.;Henry, Richard S.
    • Earthquakes and Structures
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    • v.16 no.2
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    • pp.209-219
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    • 2019
  • Unbonded Post-Tensioned (UPT) precast concrete systems have been shown to provide excellent seismic resistance. In order to improve understanding of the dynamic response of UPT systems, a series of snap back tests on four UPT systems was undertaken consisting of one Single Rocking Wall (SRW) and three Precast Wall with End Columns (PreWEC) systems. The snap back tests provided both a static pushover and a nonlinear free vibration response of a system. As expected the SRW exhibited an approximate bi-linear inertia force-drift response during the free vibration decay and the PreWEC walls showed an inertia force-drift response with increased strength and energy dissipation due to the addition of steel O-connectors. All walls exhibited negligible residual drifts regardless of the number of O-connectors or the post-tensioning force. When PreWEC systems of the same strength were compared the inclusion of further energy dissipating O-connectors was found to decrease the measured peak wall acceleration. Both the local and global wall parameters measured at pseudo-static and dynamic loading rates showed similar behaviour, which demonstrates that the dynamic behaviour of UPT walls is well represented by pseudo-static tests. The SRW was found to have Equivalent Viscous Damping (EVD) between 0.9-3.8% and the three PreWEC walls were found to have maximum EVD of between 14.7-25.8%.

The Comparative Study of Costume and Ornaments between Shilla and Uighur (신라복식과 위구르복식의 관계 연구)

  • 한윤숙
    • Journal of the Korean Society of Costume
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    • v.24
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    • pp.15-28
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    • 1995
  • This thesis focuses on the study of costume and ornaments of Shilla which had been severely affected by Uighur, and those of Uighur in Uighur self-governing district located in Shin Kang. East Turkestan, in Centrals Asia. This study aims to identifty the way of intergration of Uighur's costume and ornaments into Shilla, and orgins of Shill's costume and ornaments which had amix of internationl elelemnts thoursh cross exchanges, by comparing the differences between the two, and at the same time to clarify the pedigree of Korean costume and ornaments which are said to be udner a severe Chinese influence, by highlingting its uniqueness and originality . The result of the study demonstrates and originality of SHilla by melting foreign cultures into its own style in the process of accepting them. This means that the Shilla has recreated them in t도 form of simplification, and added naturalistic abstratness which is an element of Norther culture. The costume and ornaments are divided into coronets men's costuem, women's costume, and accessories 1. Coroncts A horse-riding man, and the costume type of 유고제 착유지체형 tell the Northern culture's influence on 백화수피기마인물채화담립 and patterns of a lotus flowr and arabesque show the 백화수피기마인물채색답립 has an influence of Buddhism with cluture of bordering countries of Western China , The origin of 뱍회수피제안형건(원정형, 방정형) lies in Northern cultures which can be found in ancient tombs of the Huns in noin-Ila , and stone caves of Jizil in Kochang. The wall paintings in Alexandropol, Murutuk and 돈황 No. 409 cave show that 초화형입식계금관 is under the influence of Northern culture, and Bezerkrick No, 25 cave and 회 번 in Kocho also show 수목녹각형입식관 is under the influence of Northern culture, with its origin in Novecherkaask. In this regard, the transformed coroncts of Shilla has shows a blended culture of Shilla with Nothern, Chinese, and Western cultures. 2. Men's Costume 반령포 derives from cultures of bordering countries of Western China centering around Uighur and Turkey. 연주문 in Uighur prince's costume and in Uighur paintings of Central Asia were reflected into the arts of Shilla in a direct way, and the motive of Uighur was deviatelly expressed at Shilla's arts in the form of simplicity , and naturalistic abstract paintings as in shown at 입수쌍조문 in tiles and brick. Along with this , 고착지체형 costume originates from Eurasia's Northern horseriding costumes as was shown in a golden man in B.C.4-5C which is now possessed by Kazakstan Republic Academy Archelogy Center Museum, and a golden figure from Skitai ancient caves, an the origin is carried away into wall paintings of Kizil No.14. cave in 8c and Astana's early period ancient tomb. No.6. 3. Women's Costume The hair styles of Shilla people are either 변발 or up -style with a lot of hair around it whose origin can be seen in Astana No.216 and No.187 caves of Kochang and Uighur's wall paintings of royal princess's hair style. Astana's middle period No. 206 and No.230 tombs reveal the its origin of 고착장군 while Astana early period No. 6 tomb shows that of 광유풍만형. 4. Accessories The earrings with small golden beads is seen at earring of figure holding a sword in wall painting of figure holding a sword in wall painting of Kizil in about 5 C. and those of a offering people in Sorchuk wall paintings. The earrings with small golden beads originates from a golden pendant of Shivargan, Afganistan, and golden pendants and other golden and metal accessories from Chrioba ancient tombs in Skiti Critia peninsula. Shilla's costume derives from the costume style of horse-ridding man, which proves the fact that Shilla people are horse-ridding peoplewith excellent horse-ridding techniques, and traditions. The people of Shilla are from horse-ridding people of local mounted momads in Northern part of Siberia steppe and this origin of Northern culture had been carried into Uighur in East Turkestan. At the same time , Shilla has a wealth and power since it was rich in gold and iron , thus producing lots of materials made of them. The results of this study emphasizes Shilla's identity and self-control by creating an independent an innovative heterogeneous culture since Shill's active exchanges with East Asia allowed it to accept the most civilized Uighur culture in East Turkestan among Altai languate which had frequent cross contacts with India and Europe.

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