• Title, Summary, Keyword: confined masonry

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Computational material modeling of masonry walls strengthened with fiber reinforced polymers

  • Koksal, H. Orhun;Jafarov, Oktay;Doran, Bilge;Aktan, Selen;Karakoc, Cengiz
    • Structural Engineering and Mechanics
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    • v.48 no.5
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    • pp.737-755
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    • 2013
  • This paper aims to develop a practical approach to modeling of fiber reinforced polymers (FRP) strengthened masonry panels. The main objective is to provide suitable relations for the material characterization of the masonry constituents so that the finite element applications of elasto-plastic theory achieves a close fit to the experimental load-displacement diagrams of the walls subjected to in-plane shear and compression. Two relations proposed for masonry columns confined with FRP are adjusted for the cohesion and the internal friction angle of both units and mortar. Relating the mechanical parameters to the uniaxial compression strength and the hydrostatic pressure acting over the wall surface, the effects of major and intermediate principal stresses ${\sigma}_1$ and ${\sigma}_2$ on the yielding and the shape of the deviatoric section are then reflected into the analyses. Performing nonlinear finite element analyses (NLFEA) for the three walls tested in two different studies, their stress-strain response and failure modes are eventually evaluated through the comparisons with the experimental behavior.

Evaluation of local and global ductility relationships for seismic assessment of regular masonry-infilled reinforced concrete frames using a coefficient-based method

  • Su, R.K.L.;Tang, T.O.;Lee, C.L.
    • Earthquakes and Structures
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    • v.5 no.1
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    • pp.1-22
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    • 2013
  • Soft storey failure mechanism is a common collapse mode for masonry-infilled (MI) reinforced concrete (RC) buildings subjected to severe earthquakes. Simple analytical equations correlating global with local ductility demands are derived from pushover (PO) analyses for seismic assessments of regular MI RC frames, considering the critical interstorey drift ratio, number of storeys and lateral loading configurations. The reliability of the equations is investigated using incremental dynamic analyses for MI RC frames of up to 7 storeys. Using the analytical ductility relationship and a coefficient-based method (CBM), the response spectral accelerations and period shift factors of low-rise MI RC frames are computed. The results are verified through published shake table test results. In general applications, the analytical ductility relationships thus derived can be used to bypass the onerous PO analysis while accurately predicting the local ductility demands for seismic assessment of regular MI RC frames.

Development of an integrated approach for Algerian building seismic damage assessment

  • Boukri, Mehdi;Farsi, Mohammed Naboussi;Mebarki, Ahmed;Belazougui, Mohamed
    • Structural Engineering and Mechanics
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    • v.47 no.4
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    • pp.471-493
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    • 2013
  • This paper presents a framework for seismic damage evaluation for Algerian buildings adapted from HAZUS approach (Hazard-United States). Capacity and fragility curves were adapted to fit the Algerian building typologies (Reinforced Concrete structures, Confined or Non-Confined Masonry, etc). For prediction purposes, it aims to estimate the damages and potential losses that may be generated by a given earthquake in a prone area or country. Its efficiency is validated by comparing the estimated and observed damages in Boumerd$\grave{e}$s city, in the aftermath of Boumerd$\grave{e}$s earthquake (Algeria: May $21^{st}$ 2003; $M_w$ = 6.8). For this purpose, observed damages reported for almost 3,700 buildings are compared to the theoretical predictions obtained under two distinct modelling of the seismic hazard. In one hand, the site response spectrum is built according to real accelerometric records obtained during the main shock. In the other hand, the effective Algerian seismic code response spectrum (RPA 99) in use by the time of the earthquake is considered; it required the prior fitting of Boumerd$\grave{e}$s site PGA (Peak Ground Acceleration) provided by Ambraseys' attenuation relationship.

Seismic vulnerability of old confined masonry buildings in Osijek, Croatia

  • Hadzima-Nyarko, Marijana;Pavica, Gordana;Lesic, Marija
    • Earthquakes and Structures
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    • v.11 no.4
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    • pp.629-648
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    • 2016
  • This paper deals with 111 buildings built between 1962 and 1987, from various parts of the city of Osijek, for which, through the collection of documentation, a database is created. The aim of this paper is to provide the first steps in assessing seismic risk in Osijek applying method based on vulnerability index. This index uses collected information of parameters of the building: the structural system, the construction year, plan, the height, i.e., the number of stories, the type of foundation, the structural and non-structural elements, the type and the quality of main construction material, the position in the block and built-up area. According to this method defining five damage states, the action is expressed in terms of the macroseismic intensity and the seismic quality of the buildings by means of a vulnerability index. The value of the vulnerability index can be changed depending on the structural systems, quality of construction, etc., by introducing behavior and regional modifiers based on expert judgments. Since there is no available data of damaged buildings under earthquake loading in our country, we will propose behavior modifiers based on values suggested by earlier works and on judgment based on available project documentation of the considered buildings. Depending on the proposed modifiers, the seismic vulnerability of existing buildings in the city of Osijek will be assessed. The resulting vulnerability of the considered residential buildings provides necessary insight for emergency planning and for identification of critical objects vulnerable to seismic loading.