Experimental qualification of seismic strengthening of URM buildings in Nepal
Experimental qualification of seismic strengthening of URM buildings in Nepal
Nepalese buildings are typically constructed using unreinforced masonry (URM) as the lateral load-bearing system. In the 2015 Nepal Gorkha earthquake several URM buildings suffered heavy damage. The limited economic resources available in the country and the challenge of strengthening a large portfolio of buildings highlight the need for low-cost retrofitting techniques. This paper presents a large-scale experimental campaign aimed at quantifying the seismic performance of a typical URM wall when strengthened with splints and bandages. This represents one of the retrofit techniques that are most widely-used in Nepal. A 5 × 3 m URM wall was constructed using 1:6 cement–sand mortar as per the mechanical properties identified by material testing in Nepal. The URM wall was tested under a two-way ramp cyclic loading. Typical crack patterns associated with URM were observed. The wall was subsequently retrofitted with 8 mm rebars as splints and bandages and tested to failure. The results show that the strength of the retrofitted wall is almost twice that of the URM wall. The observed crack damage improved from EMS-98 Grade 2, with horizontal and diagonal shear cracks in the mortar bed, to Grade 1, with hairline cracks on the rendered splints and bandages. Overall, the experiment demonstrated the efficiency of this practical, low-cost retrofitting technique that is tailored to traditional Nepalese URM buildings. This work can be used to advise local stakeholders in the construction industry as well as to act as a benchmark to improve the reliability of fragility functions for URM buildings in Nepal.
Seismic performance, Seismic retrofit, Splints and bandages, URM buildings
Aminulai, Hammed Olanrewaju
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Baiguera, Marco
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Crump, Duncan A.
5fa2d636-89bc-4005-a948-32554ef3d951
Sextos, Anastasios
b97ee386-00d0-4aa5-b0e3-6f2a9a7a730d
Kashani, Mohammad
d1074b3a-5853-4eb5-a4ef-7d741b1c025d
October 2023
Aminulai, Hammed Olanrewaju
b2512804-1ab8-41c4-8e6b-f1f0bfb8d7bc
Baiguera, Marco
8d832edf-e16f-426a-be38-6bcdc7b83545
Crump, Duncan A.
5fa2d636-89bc-4005-a948-32554ef3d951
Sextos, Anastasios
b97ee386-00d0-4aa5-b0e3-6f2a9a7a730d
Kashani, Mohammad
d1074b3a-5853-4eb5-a4ef-7d741b1c025d
Aminulai, Hammed Olanrewaju, Baiguera, Marco, Crump, Duncan A., Sextos, Anastasios and Kashani, Mohammad
(2023)
Experimental qualification of seismic strengthening of URM buildings in Nepal.
Soil Dynamics and Earthquake Engineering, 173, [108130].
(doi:10.1016/j.soildyn.2023.108130).
Abstract
Nepalese buildings are typically constructed using unreinforced masonry (URM) as the lateral load-bearing system. In the 2015 Nepal Gorkha earthquake several URM buildings suffered heavy damage. The limited economic resources available in the country and the challenge of strengthening a large portfolio of buildings highlight the need for low-cost retrofitting techniques. This paper presents a large-scale experimental campaign aimed at quantifying the seismic performance of a typical URM wall when strengthened with splints and bandages. This represents one of the retrofit techniques that are most widely-used in Nepal. A 5 × 3 m URM wall was constructed using 1:6 cement–sand mortar as per the mechanical properties identified by material testing in Nepal. The URM wall was tested under a two-way ramp cyclic loading. Typical crack patterns associated with URM were observed. The wall was subsequently retrofitted with 8 mm rebars as splints and bandages and tested to failure. The results show that the strength of the retrofitted wall is almost twice that of the URM wall. The observed crack damage improved from EMS-98 Grade 2, with horizontal and diagonal shear cracks in the mortar bed, to Grade 1, with hairline cracks on the rendered splints and bandages. Overall, the experiment demonstrated the efficiency of this practical, low-cost retrofitting technique that is tailored to traditional Nepalese URM buildings. This work can be used to advise local stakeholders in the construction industry as well as to act as a benchmark to improve the reliability of fragility functions for URM buildings in Nepal.
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More information
Accepted/In Press date: 11 July 2023
Published date: October 2023
Additional Information:
Funding Information:
This work was funded by the UK Engineering and Physical Science Research Council (EPSRC) under the project “Seismic Safety and Resilience of Schools in Nepal” SAFER (EP/P028926/1). The authors acknowledged the support of the National Society for Earthquake Technology-Nepal (NSET) for the provision of models for experimental testing. We are also grateful to the technical staff at LSTL and TSRL at the University of Southampton for their assistance on the experimental test while thanking LST Projects for helping build the wall.
Funding Information:
This work was funded by the UK Engineering and Physical Science Research Council ( EPSRC ) under the project “Seismic Safety and Resilience of Schools in Nepal” SAFER ( EP /P028926/1). The authors acknowledged the support of the National Society for Earthquake Technology-Nepal (NSET) for the provision of models for experimental testing. We are also grateful to the technical staff at LSTL and TSRL at the University of Southampton for their assistance on the experimental test while thanking LST Projects for helping build the wall.
Publisher Copyright:
© 2023 The Author(s)
Keywords:
Seismic performance, Seismic retrofit, Splints and bandages, URM buildings
Identifiers
Local EPrints ID: 479968
URI: http://eprints.soton.ac.uk/id/eprint/479968
ISSN: 0267-7261
PURE UUID: 43645e8a-448d-4358-89ec-c000d192da1e
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Date deposited: 31 Jul 2023 16:50
Last modified: 17 Mar 2024 04:06
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Contributors
Author:
Hammed Olanrewaju Aminulai
Author:
Duncan A. Crump
Author:
Anastasios Sextos
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