Innovative seismic and energy retrofitting of wall envelopes using prefabricated textile-reinforced concrete panels with an embedded capillary tube system

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This paper presents a series of shaking table tests conducted on a 60%‐scaled two‐storey infilled reinforced concrete building. The main parameters include the presence of openings in the masonry infills and the effect of bi‐directional dynamic shaking to the latter. The building was subjected to four different levels of shaking intensity, ranging up to the Maximum Considered Earthquake (MCE), equivalent to 150% of the design earthquake. The study focuses on and evaluates the damage caused by combined in‐ and out‐of‐plane shaking. Under the design level earthquake, the second‐storey infill walls with openings were severely damaged, with near‐collapse of a masonry pier. For the fully infilled direction without openings instead, diagonal cracking as well as out‐of‐plane inclination of the infill wall in the second storey were observed. Due to the interaction between the two loading directions and the direct adverse effect of the in‐plane damage on the out‐of‐plane resistance of the infills, the out‐of‐plane collapse of 3/4 of the second storey masonry infill occurred during the MCE. The reported damage observations on the masonry‐infills with or without openings provide further insights on the vulnerability of non‐seismically designed reinforced concrete buildings. Additionally, the seismic performance of the structure is assessed using further structural response quantities recorded during testing, including floor accelerations, inter‐storey drifts, base shear forces and reductions in natural frequency. Future testing will focus on investigating the effectiveness of retrofitting measures in improving the connection between the infill and frame, reducing in‐plane damage, and preventing out‐of‐plane failure of the infills.

Section: Introductionmentioning

confidence: 99%

Seismic assessment of the in‐plane/out‐of‐plane interaction of masonry infills in a two‐storey RC building subjected to bi‐directional shaking table tests

Baek,

Pohoryles,

Bournas

2024

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“…Therefore, the interest of authorities and stakeholders in integrated retrofit solutions is expected to increase dramatically within the following decades. At the same time, researchers worldwide have already been carrying out experimental and analytical research investigating the combined retrofit approach 5–12 …”

Section: Introductionmentioning

confidence: 99%

“…At the same time, researchers worldwide have already been carrying out experimental and analytical research investigating the combined retrofit approach. [5][6][7][8][9][10][11][12] The first step towards adopting appropriate integrated retrofit techniques is assessing the current energy efficiency and seismic resistance of the existing building stock. To that end, this paper presents the results from tests that are part of a broader experimental study aimed at evaluating the energy and seismic performance of typical residential reinforced concrete (RC) buildings, which constitute the most widespread building typology worldwide.…”

Section: Introductionmentioning

confidence: 99%

Seismic performance of a full‐scale five‐story masonry‐infilled RC building subjected to substructured pseudodynamic tests

Kallioras

Pohoryles

Bournas

et al. 2023

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This paper discusses the results of a series of hybrid earthquake tests on a full‐scale reinforced concrete (RC) building with masonry infills. The prototype was a five‐story structure representing the vulnerable part of a typical RC building in Southern Europe, with beams stronger than the columns and masonry infill walls weaker than the surrounding frame elements. The specimen was subjected to a sequence of unidirectional earthquake simulations of increasing intensity up to conditions of significant damage to the infills, using the pseudodynamic (PsD) testing method with substructuring. The input ground motion was a real earthquake recording, slightly modified in amplitude and frequency to match the elastic design code spectrum. The physical substructure of the hybrid model consisted of the first story of a two‐story mock‐up structure built in the European Laboratory for Structural Assessment (ELSA); the second story ensured realistic boundary conditions at the top of the first one. The characteristics of stories two to five were simulated by a numerical finite‐element model developed in OpenSEES and updated throughout the test sequence using data obtained from preceding tests. The experiments were terminated with the onset of a soft‐story mechanism at the first story of the physical substructure for an earthquake with a peak ground acceleration of 0.3 g. The paper summarizes the key characteristics of the specimen and the major observations from the hybrid tests, illustrating the evolution of structural/nonstructural damage and the cyclic hysteretic building response. The attainment of significant damage limit states is correlated with experimentally defined engineering demand parameters and ground‐motion intensity measures for the performance‐based seismic assessment of buildings. Data and observations from these experiments add substantially to our understanding of the effects of masonry infills on the seismic behavior of RC‐framed structures.

“…29,30 Further research on prefabricated TRC panels involves the inclusion of capillary tubes (TCPs) for improving energy performance and the implementation of quasi-static cyclic loading tests on infilled RC frames and masonry walls. 31 Despite intensified research efforts, seismic-plus-energy upgrading through a single intervention is a relatively new concept presenting several challenges that have not been addressed yet. Relevant solutions need to reach higher technological readiness level to enable extensive practical applications in the construction industry.…”

Section: Introductionmentioning

confidence: 99%

“…Other researchers have investigated the use of prefabricated panels made of textile reinforced concrete (TRC) with embedded phase‐change materials (PCMs) as a quick onsite intervention for enhancing the structural and thermal performance of building envelopes 29,30 . Further research on prefabricated TRC panels involves the inclusion of capillary tubes (TCPs) for improving energy performance and the implementation of quasi‐static cyclic loading tests on infilled RC frames and masonry walls 31 . Despite intensified research efforts, seismic‐plus‐energy upgrading through a single intervention is a relatively new concept presenting several challenges that have not been addressed yet.…”

Section: Introductionmentioning

confidence: 99%

Seismic and energy upgrading of existing buildings—full‐scale testing of retrofitted masonry‐infilled RC frames

Christis Z,

Renos,

Nicholas

et al. 2023

Taking into consideration the seismic vulnerability and the poor energy performance of the European building stock, and the increasing socio‐economic and environmental need for integrating seismic upgrading with energy efficiency improvement, an experimental study involving the lateral load testing of full‐scale one‐story one‐bay masonry infilled RC frames and load‐bearing masonry walls was carried out in the framework of the SupERB research project aiming to investigate the efficiency of integrated seismic and energy upgrading systems. The integrated approach is based on the use of textile reinforced mortar (TRM) overlays combined either with traditional thermal insulation (extruded polystyrene, XPS) or with thermally efficient mortar incorporating phase change material (PCMs). The proposed integrated approach can be applied on the exterior face of the structure, so as to facilitate its application in real structures in the easiest possible way and with minimum disturbance to the inhabitants of the buildings. In this paper, only the structural performance of masonry‐infilled RC frames retrofitted with the proposed integrated approach is presented, while the energy benefits will be presented in a separate paper. Thus, in this paper, the structural performance of an integrated seismic and energy upgrading approach was assessed through five full‐scale one‐story one‐bay masonry infilled RC frames that were retrofitted with different schemes of TRM combined with thermal insulation materials subjected to in‐plane displacement‐controlled cyclic loading. The following parameters were investigated experimentally: the number of TRM overlays (one or two layers of TRM combined with thermal insulation), the use of thermally efficient PCM‐enhanced TRM layer in contrast to the use of conventional XPS insulation, and different retrofitting configurations (placement of the TRM in a sandwich form over and/or under the novel or the traditional insulation). From the results obtained in this study, it can be concluded that all energy and seismic upgrading systems examined have a positive impact on the response of the structural system to cyclic loading, with the ones with two layers of TRM having a better performance compared to the ones with one layer of TRM and all of them a better performance than the control specimen. The use of two layers of TRM cancels the drawback of infilled frames, which at very small drifts they reach their maximum capacity and after that they rapidly fall to the capacity of the bare frame, providing capacities above 80% of their peak capacity for drifts up to 2%. In all the tests the TRM whether it was combined with XPS or included PCMs contributed to a better distribution of the cracks in the infill and delayed premature brittle failures. The presence of the TRM had also the advantage that it remained intact throughout the tests preventing the fall of debris out of the plane of the infilled frame, both in the retrofitted and unretrofitted sides.