• Title/Summary/Keyword: Civil & Environmental Engineering

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Rapid evaluation of in-plane seismic capacity of masonry arch bridges through limit analysis

  • Breccolotti, Marco;Severini, Laura;Cavalagli, Nicola;Bonfigli, Federico M.;Gusella, Vittorio
    • Earthquakes and Structures
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    • v.15 no.5
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    • pp.541-553
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    • 2018
  • In this paper a limit analysis based procedure for the rapid evaluation of the in-plane seismic capacity of masonry arch bridges is carried out. Attention has been paid to the effect of the backfill on the collapse load. A parametric investigation has been performed by varying the rise/span ratio and the results have been compared with those obtained by finite element modelling. The comparison highlights the conservative feature of the proposed model in terms of ultimate loads and a good agreement in terms of collapse mechanisms.

Absorption and Regeneration of [eeim] Ionic liquid ([eeim]이온성액체의 흡수 및 재생특성)

  • Baek, Geun-Ho;You, Seung-Han;Lee, Jung-Hyuk;Choi, Hee-Young;Cha, Wang-Seog
    • Proceedings of the KAIS Fall Conference
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    • 2010.05b
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    • pp.1119-1122
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    • 2010
  • 본 논문에서는 상용 이온성 액체를 대체하기 위해 손쉽게 구입할 수 있는 원료물질을 사용하여 이온성 액체를 실험실 규모로 제조한 후 고압 연소전 조건에서 이산화탄소의 용해도 및 재생력을 측정하기 위해 기-액 흡수평형장치를 이용하여 연구하였다. [eeim]ethyl sulfite를 제조하여 흡수실험을 실시한 결과 흡수평형압력이 25bar의 조건에서 0.72 mol $CO_2$ /mol IL의 흡수력을 보였으며, 재생성능은 탈착 전후의 흡수력 차이가 약 9%로 우수한 편이었다. 희석제를 첨가하였을 경우 흡수력은 약 38% 감소하였으나, 합성단계가 간단하며 원료물질이 저렴한 장점을 가지고 있다.

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Development and application of a vision-based displacement measurement system for structural health monitoring of civil structures

  • Lee, Jong Jae;Fukuda, Yoshio;Shinozuka, Masanobu;Cho, Soojin;Yun, Chung-Bang
    • Smart Structures and Systems
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    • v.3 no.3
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    • pp.373-384
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    • 2007
  • For structural health monitoring (SHM) of civil infrastructures, displacement is a good descriptor of the structural behavior under all the potential disturbances. However, it is not easy to measure displacement of civil infrastructures, since the conventional sensors need a reference point, and inaccessibility to the reference point is sometimes caused by the geographic conditions, such as a highway or river under a bridge, which makes installation of measuring devices time-consuming and costly, if not impossible. To resolve this issue, a visionbased real-time displacement measurement system using digital image processing techniques is developed. The effectiveness of the proposed system was verified by comparing the load carrying capacities of a steel-plate girder bridge obtained from the conventional sensor and the present system. Further, to simultaneously measure multiple points, a synchronized vision-based system is developed using master/slave system with wireless data communication. For the purpose of verification, the measured displacement by a synchronized vision-based system was compared with the data measured by conventional contact-type sensors, linear variable differential transformers (LVDT) from a laboratory test.

Real-time hybrid simulation of a multi-story wood shear wall with first-story experimental substructure incorporating a rate-dependent seismic energy dissipation device

  • Shao, Xiaoyun;van de Lindt, John;Bahmani, Pouria;Pang, Weichiang;Ziaei, Ershad;Symans, Michael;Tian, Jingjing;Dao, Thang
    • Smart Structures and Systems
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    • v.14 no.6
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    • pp.1031-1054
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    • 2014
  • Real-time hybrid simulation (RTHS) of a stacked wood shear wall retrofitted with a rate-dependent seismic energy dissipation device (viscous damper) was conducted at the newly constructed Structural Engineering Laboratory at the University of Alabama. This paper describes the implementation process of the RTHS focusing on the controller scheme development. An incremental approach was adopted starting from a controller for the conventional slow pseudodynamic hybrid simulation and evolving to the one applicable for RTHS. Both benchmark-scale and full-scale tests are discussed to provide a roadmap for future RTHS implementation at different laboratories and/or on different structural systems. The developed RTHS controller was applied to study the effect of a rate-dependent energy dissipation device on the seismic performance of a multi-story wood shear wall system. The test specimen, setup, program and results are presented with emphasis given to inter-story drift response. At 100% DBE the RTHS showed that the multi-story shear wall with the damper had 32% less inter-story drift and was noticeably less damaged than its un-damped specimen counterpart.