ESTIMATION OF EFFECTIVE STIFFNESS OF INFILL PANELS AT DAMAGE LIMITATION LIMIT STATE FOR LOW- AND MID-RISE INFILLED RC FRAMES

Several studies investigated the influence of infills on the response of reinforced concrete (RC) frames. However, possible shear brittle failures are generally neglected. The interaction between the infill panels and the surrounding frames can lead to anticipated brittle-type failures that should be considered in code-based assessment of lateral seismic capacity. This paper investigates, by means of simplified pushover analyses, on the effect of infills on the lateral seismic capacity explicitly considering possible brittle failures in unconfined beam-column joints or in columns. Archetype buildings representative of existing gravity load designed (GLD) RC frames of three different height ranges are obtained with a simulated design process and a sensitivity analysis is performed to investigate on the effect of infill consistency on the capacity. Moreover, possible alternative local retrofit interventions devoted to avoiding brittle failures are considered, evaluating their relative efficacy in case of different infill typologies. It is seen that for the considered existing GLD buildings, the attainment of life safety limit state is premature and happens before the damage limitation limit state. The capacity can be increased with application of local retrofit interventions. However, the retrofit efficacy varies depending on the infills consistency if the horizontal action transferred from the infills to the surrounding frame is not absorbed by the retrofit solution.

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Seismic and Energy Retrofit of Apartment Buildings through Autoclaved Aerated Concrete (AAC) Blocks Infill Walls

Sustainability ◽

10.3390/su11143939 ◽

2019 ◽

Vol 11 (14) ◽

pp. 3939 ◽

Cited By ~ 7

Author(s):

Antonio Artino ◽

Gianpiero Evola ◽

Giuseppe Margani ◽

Edoardo Marino

Keyword(s):

Energy Efficiency ◽

Energy Demand ◽

Residential Buildings ◽

Limit State ◽

Infill Walls ◽

High Performing ◽

Heating And Cooling ◽

Infill Panels ◽

Damage Limitation ◽

Structural Contribution

All around the world, a huge amount of buildings have been built before the enforcement of specific codes for seismic resistance and energy efficiency. Particularly in Italy, over 74% of residential buildings were constructed before 1980, when only 25% of the territory was classified as seismic, and nearly 86% were built before 1991, when the first restrictive regulation on energy efficiency was issued. This means that most buildings need both seismic and energy renovation actions to improve their sustainability level. The proposed combined retrofit strategy for reinforced concrete framed buildings is based on the replacement of the external layer of double-leaf infill walls, made of hollow bricks, with high-performing AAC blocks: this solution can be implemented by operating mainly from the outside of the building, thus reducing occupants’ disruption during retrofitting. The generally neglected structural contribution of masonry infill panels is here considered using a recently developed macro-element modeling approach. The results suggest that, from a structural viewpoint, the proposed intervention involves the highest improvement at the damage limitation limit state, while lower upgrades are recorded at life safety limit state and near-collapse limit state. In regards to the energy issues, the energy demand can be reduced by 10% and 4% for heating and cooling, respectively, just by replacing the outer layer of blocks; further savings can be achieved through the application of a supplementary insulation layer.

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Numerical Assessment of URM Infilled RC Frames Retrofitted With Near-Surface Mounted Reinforcing Steel Bars

Frontiers in Built Environment ◽

10.3389/fbuil.2020.590302 ◽

2020 ◽

Vol 6 ◽

Author(s):

Rajendra Soti ◽

Andre R. Barbosa ◽

Andreas Stavridis

Keyword(s):

Finite Element ◽

Nonlinear Finite Element ◽

Cohesive Crack ◽

Reinforcing Steel ◽

Near Surface ◽

Rc Frames ◽

Infill Panels ◽

Steel Bars ◽

Near Surface Mounted ◽

Infilled Rc Frames

This paper presents a study on a retrofit technique for masonry infilled reinforced concrete (RC) frames. The proposed retrofit technique involves the addition of reinforcing steel bars into epoxy-filled pre-cut grooves on the surface of infill walls. The feasibility of the developed technique is initially investigated experimentally through pull-out tests conducted on near-surface mounted (NSM) reinforcing steel bars. The experimental results are used to augment an existing nonlinear finite element modeling approach used to simulate the response of RC frames with the retrofitted infill panels and to calibrate the numerical models developed. The nonlinear finite element models employ smeared-crack and zero-thickness cohesive-crack interface elements to model the RC members and masonry infills, while nonlinear truss elements are used to model the reinforcing steel bars. The modeling scheme is used to numerically simulate the performance of one- and two-bay infilled RC frames with a variety of reinforcing steel retrofit configurations under lateral loads. The results indicate that the retrofit solution can improve the deformation capacity of existing infilled frames, and its effectiveness depends on the orientation and the distribution of the NSM reinforcement steel bars that are added to the infill panels.

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Procedures for calibration of linear models for damage limitation in design of masonry-infilled RC frames

Earthquake Engineering & Structural Dynamics ◽

10.1002/eqe.2709 ◽

2016 ◽

Vol 45 (8) ◽

pp. 1315-1335 ◽

Cited By ~ 12

Author(s):

Paolo Ricci ◽

Maria Teresa De Risi ◽

Gerardo Mario Verderame ◽

Gaetano Manfredi

Keyword(s):

Linear Models ◽

Rc Frames ◽

Damage Limitation ◽

Infilled Rc Frames ◽

Masonry Infilled Rc Frames

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Experimental Evaluation of Masonry-Infilled RC Frames

Journal of Structural Engineering ◽

10.1061/(asce)0733-9445(1996)122:3(228) ◽

1996 ◽

Vol 122 (3) ◽

pp. 228-237 ◽

Cited By ~ 234

Author(s):

Armin B. Mehrabi ◽

P. Benson Shing ◽

Michael P. Schuller ◽

James L. Noland

Keyword(s):

Experimental Evaluation ◽

Rc Frames ◽

Infilled Rc Frames ◽

Masonry Infilled Rc Frames

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Finite Element Modeling of Masonry-Infilled RC Frames

Journal of Structural Engineering ◽

10.1061/(asce)0733-9445(1997)123:5(604) ◽

1997 ◽

Vol 123 (5) ◽

pp. 604-613 ◽

Cited By ~ 101

Author(s):

Armin B. Mehrabi ◽

P. Benson Shing

Keyword(s):

Finite Element ◽

Finite Element Modeling ◽

Element Modeling ◽

Rc Frames ◽

Infilled Rc Frames ◽

Masonry Infilled Rc Frames

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Seismic retrofit of masonry wall infilled RC frames through external post-tensioning

Bulletin of Earthquake Engineering ◽

10.1007/s10518-017-0241-4 ◽

2017 ◽

Vol 16 (3) ◽

pp. 1487-1510 ◽

Cited By ~ 6

Author(s):

Gholamreza Soltanzadeh ◽

Hanim Bin Osman ◽

Mohammadreza Vafaei ◽

Yousef Karimi Vahed

Keyword(s):

Seismic Retrofit ◽

Masonry Wall ◽

Rc Frames ◽

Post Tensioning ◽

Infilled Rc Frames

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Cyclic behavior of GFRP strengthened infilled RC frames with low and normal strength concrete

Science and Engineering of Composite Materials ◽

10.1515/secm-2017-0060 ◽

2019 ◽

Vol 26 (1) ◽

pp. 30-42 ◽

Cited By ~ 3

Author(s):

Mehmet Emin Arslan ◽

Ahmet Durmuş ◽

Metin Hüsem

Keyword(s):

Lateral Loading ◽

Cyclic Behavior ◽

Test Results ◽

Normal Strength Concrete ◽

Strength Concrete ◽

Rc Frames ◽

Load Carrying ◽

Concrete Blocks ◽

Normal Strength ◽

Infilled Rc Frames

AbstractThis paper presents the experimental behavior of plane, non-strengthened and glass fiber reinforced polymer (GFRP) strengthened infilled reinforced concrete (RC) frames with low strength concrete (LSC) and normal strength concrete (NSC) under lateral reversed cyclic loading. For this purpose, eight full-scale, one-bay, one-storey plane and infilled (brick and aerated concrete blocks which are commonly used in RC construction) RC frames with LSC and NSC were produced and in-plane lateral loading tests were carried out. Test results indicate that infill walls considerably change the behavior of frames by increasing rigidity and load carrying capacity. By contrast, GFRP fabric used for strengthening of infilled RC frames improves ductility, load carrying and energy dissipation capacity of infilled frames with LSC and NSC as well. After all the test results were evaluated together, a GFRP strengthened brick infilled frame demonstrated the best performance under cyclic lateral loading.

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