Assessment and Retrofitting of Building Structures: Experimental Testing and Modelling

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Civil Engineering".

Deadline for manuscript submissions: closed (15 June 2022) | Viewed by 24032

Special Issue Editor

CERIS, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
Interests: seismic engineering; structural engineering; experimental testing; numerical modelling; masonry infill walls; reinforced concrete structures; seismic vulnerability assessment; retrofitting; energy efficiency
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Special Issue Information

Dear Colleagues,

Collapse of, or severe damage to, existing buildings during strong earthquakes has resulted in significant economic losses, severe injuries, and casualties. Progress made over the last few decades has had a considerable impact on the seismic safety of modern buildings designed according to new standards. However, the majority of existing buildings in southern European countries do not meet the safety requirements set by the Eurocodes. Thus, the assessment of existing buildings not designed with modern codes and the development of effective retrofitting techniques are currently of paramount importance to society. The use of accurate modelling strategies and appropriate seismic assessment methodologies is crucial to understand the behaviour of existing buildings and to develop efficient and proper mitigation measures, thus preventing future damage, casualties, and economic losses. The effect of non-structural elements should not be neglected since they could play a vital role in buildings’ structural performance. Another major challenge is to ensure the sustainability of renovation schemes in terms of both the environmental burden (i.e., CO2) and economic investment in seismic regions. The sustainable renovation of existing buildings typically focuses on reducing operational energy consumption and using low-carbon materials in the refurbishment process, without accounting for structural deficiencies that could leave the building exceptionally unsafe and hamper the refurbishment investment, particularly in areas prone to seismic activity.

This Special Issue focuses on innovations in the context of “Assessment and retrofitting of building structures: experimental testing and modelling”.

Topics of interest for this Special Issue include, but are not limited to, the following:

  • Systematic reviews, literature reviews, and metanalyses;
  • Experimental work involving structural elements;
  • Material and mechanical characterization testing of non-structural elements;
  • Numerical simulations of RC building structure seismic responses;
  • Simplified and detailed modelling tools;
  • Detailed simulations of the structural performance of building components;
  • Advanced analysis to assess the structural safety of existing structures;
  • Assessment/design of analytical methods;
  • Comparison between seismic standards;
  • Seismic losses;
  • Effectiveness of retrofitting strategies;
  • Experimental characterization of multiple local or global retrofitting strategies;
  • Retrofitting with FRP, CFRP, TRM, ECC, steel, or RC jacketing;
  • Cost-effectiveness analysis;
  • Sustainable retrofitting approaches;
  • Seismic plus thermal retrofitting approaches.

Dr. André Furtado
Guest Editor

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Published Papers (11 papers)

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Editorial

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3 pages, 185 KiB  
Editorial
Assessment and Retrofitting of Building Structures: Experimental Testing and Modelling—Editorial
Appl. Sci. 2023, 13(1), 486; https://doi.org/10.3390/app13010486 - 30 Dec 2022
Cited by 1 | Viewed by 1307
Abstract
Collapse of, or severe damage to, existing buildings during strong earthquakes has resulted in significant economic losses, severe injuries, and casualties. Progress made over the last few decades has had a considerable impact on the seismic safety of modern buildings designed according to [...] Read more.
Collapse of, or severe damage to, existing buildings during strong earthquakes has resulted in significant economic losses, severe injuries, and casualties. Progress made over the last few decades has had a considerable impact on the seismic safety of modern buildings designed according to new standards. However, the majority of existing buildings in southern European countries do not meet the safety requirements set by the Eurocodes. Thus, the assessment of existing buildings not designed with modern codes and the development of effective retrofitting techniques are currently of paramount importance to society. The use of accurate modelling strategies and appropriate seismic assessment methodologies is crucial to understand the behaviour of existing buildings and to develop efficient and proper mitigation measures, thus, preventing future damage, casualties, and economic losses. The effect of non-structural elements should not be neglected, since they could play a vital role in buildings’ structural performance. Another major challenge is to ensure the sustainability of renovation schemes in terms of both the environmental burden (i.e., CO2) and economic investment in seismic regions. The sustainable renovation of existing buildings typically focuses on reducing operational energy consumption and using low-carbon materials in the refurbishment process, without accounting for structural deficiencies that could leave the building exceptionally unsafe and hamper the refurbishment investment, particularly in areas prone to seismic activity. This Special Issue focuses on innovations in the context of assessment and retrofitting of building structures: experimental testing and modelling. Full article

Research

Jump to: Editorial, Review

22 pages, 11457 KiB  
Article
Influence of Masonry Infill Wall Position and Openings in the Seismic Response of Reinforced Concrete Frames
Appl. Sci. 2022, 12(19), 9477; https://doi.org/10.3390/app12199477 - 21 Sep 2022
Cited by 6 | Viewed by 2126
Abstract
It is now widely recognized that the masonry infill frame used in reinforced concrete structures (RC) greatly enhances both the rigidity and strength of the surrounding frame. The lateral loading behavior of this RC frame is different from the frame without infill, although [...] Read more.
It is now widely recognized that the masonry infill frame used in reinforced concrete structures (RC) greatly enhances both the rigidity and strength of the surrounding frame. The lateral loading behavior of this RC frame is different from the frame without infill, although the structural contribution of infill walls is discarded in many countries, including Algeria. This paper aims to focus on the effect of openings and the effect of changing the distribution of masonry panels on the global behavior of buildings. For this, a pushover analysis is carried out to evaluate the seismic performance and assess the behavior of infilled RC, and to study the results related to capacity curve, inter-story drift and energy. The results obtained show that the effect of the openings and changing of the distribution of masonry panels can drastically change the overall behavior of the structures regarding enhancing strength capacities and energy absorption. Noticeable remarks in terms of distributing masonry panels within a frame are observed and several recommendations concerning the present practice might be important to be considered. Full article
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14 pages, 4975 KiB  
Article
Research on the Tie Cable Replacement Method of Half-through Tied-Arch Bridge
Appl. Sci. 2022, 12(16), 8286; https://doi.org/10.3390/app12168286 - 19 Aug 2022
Cited by 1 | Viewed by 1877
Abstract
The tie cable of the half-through tied-arch bridge generally uses external prestressed cables, which need to be replaced regularly similarly to cables and suspenders, but there is very little research in this area at present. Aiming at a method to replace the tie [...] Read more.
The tie cable of the half-through tied-arch bridge generally uses external prestressed cables, which need to be replaced regularly similarly to cables and suspenders, but there is very little research in this area at present. Aiming at a method to replace the tie cable for this kind of bridge, this study takes the third Lingjiang bridge, which had damage to the tie cable, as an example. Based on whether there is a temporary cable force-replacement structure, eight replacement schemes are designed. Firstly, the replacement process of each scheme is simulated by the finite-element model, and the influence of each replacement scheme on the upper and lower structures is analyzed. Then, according to the analysis results, the replacement schemes were compared and selected, and the best scheme was determined. Finally, based on the best scheme, the design and construction method of the temporary cable force-replacement structure were given. The results show that the replacement of tie cables of the half-through tied-arch bridge significantly impacts the piles. The internal forces of the pile and arch rib change greatly with the non-substitution method. Adopting the temporary substitution method can not only ensure structural safety but also improve the replacement speed, and the temporary substitution method of replacing one by one symmetrically on both sides proved to be the best. This study can provide a reference for the tie cable replacement of a half-through tied-arch bridge. Full article
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14 pages, 3789 KiB  
Article
Seismic Sequence Vulnerability of Low-Rise Special Moment-Resisting Frame Buildings with Brick Infills
Appl. Sci. 2022, 12(16), 8231; https://doi.org/10.3390/app12168231 - 17 Aug 2022
Cited by 2 | Viewed by 1901
Abstract
When buildings are exposed to earthquake sequence, damage aggravation is expected to occur. Although several studies report seismic vulnerability of reinforced concrete (RC) buildings under the mainshock–aftershock sequence, indicating damage aggravation due to aftershock, none, to the best of our knowledge, quantifies seismic [...] Read more.
When buildings are exposed to earthquake sequence, damage aggravation is expected to occur. Although several studies report seismic vulnerability of reinforced concrete (RC) buildings under the mainshock–aftershock sequence, indicating damage aggravation due to aftershock, none, to the best of our knowledge, quantifies seismic vulnerability of buildings under foreshock–mainshock–aftershock sequences. Since foreshock–mainshock–aftershock sequences are also expected in many active seismic regions, we aim to quantify the level of vulnerability under seismic sequences considering the seismically highly active Himalayan region as the case study location. Fragility functions are derived considering foreshock, foreshock–mainshock sequence, and foreshock–mainshock–aftershock sequence for a low-rise special moment-resisting frame (SMRF) building that represents a typical low-rise owner-built construction system in Nepal, one of the most active seismic regions in the world. The results highlight that the foreshock significantly increases seismic vulnerability of the structures with respect to the often-considered case of a mainshock–aftershock sequence. Full article
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14 pages, 8204 KiB  
Article
Combined Shear-Tension Loading of Composite Dowels in Cracked Concrete—Experimental Investigations and Design
Appl. Sci. 2022, 12(3), 1449; https://doi.org/10.3390/app12031449 - 29 Jan 2022
Cited by 1 | Viewed by 1583
Abstract
The importance of slim decks has led engineers to the exploration of high-strength materials and also of innovative shallow shear connectors, such as composite dowels in the case of composite constructions. Minimizing the overall slab depth often leads to composite girders being weakened [...] Read more.
The importance of slim decks has led engineers to the exploration of high-strength materials and also of innovative shallow shear connectors, such as composite dowels in the case of composite constructions. Minimizing the overall slab depth often leads to composite girders being weakened by means of web openings that are necessary for installations such as ventilation ducts. Depending on the geometrical and loading conditions, some of the shear connectors are subjected to a combination of tensile and shear forces. However, the load-bearing behaviour of these connectors has only been rudimentarily investigated in the case of shear-tensile interaction. In addition, the load-bearing capacity of composite dowels under combined tensile and shear forces has not been investigated in cracked concrete. Earlier investigations under pure shear and pure tensile loading indicate a dependence of the connectors’ load-bearing behaviour on the crack width, so that under combined loading, a similar influence is expected. In this paper, experimental investigations on composite dowels in transversely cracked concrete under systematically varied shear-tension loading combinations are presented. Hereby, predefined crack widths and patterns were considered using a special test rig. Finally, a design approach for concrete failure of composite dowels under shear-tension loading is proposed based on the test results. Full article
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16 pages, 25224 KiB  
Article
Modeling Flexural and Compressive Strengths Behaviour of Cement-Grouted Sands Modified with Water Reducer Polymer
Appl. Sci. 2022, 12(3), 1016; https://doi.org/10.3390/app12031016 - 19 Jan 2022
Cited by 31 | Viewed by 1858
Abstract
By using the American Society for Testing and Materials and British Standards standards, the impact of various grading of sand (Five types of sand) on the compressive strength (CS) of the cement grout (CG) treated with water reducer polymer is investigated. The properties [...] Read more.
By using the American Society for Testing and Materials and British Standards standards, the impact of various grading of sand (Five types of sand) on the compressive strength (CS) of the cement grout (CG) treated with water reducer polymer is investigated. The properties of CG treated with polymer up to 0.16 % of cement weight were investigated and quantified in both fresh and hardened states. The water to cement ratio (w/c) was reduced by 21.9% to 54.1%, and the CG flow time was retained between 18 and 23 s. The highest compression strength was achieved at seven and 28 days for the cement-grouted sand using the coarser-graded sand than finer-graded sand at low w/c ranged between 0.50 and 0.53. The highest compression strength was obtained at high w/c for the cement grout mixed with the fine-grained sands compared to coarse-grained sands. Adding water reducer polymer enhances the compressive strength (σpc) and cylindrical compressive strength (σcc) by 113% to 577% and 53% to 459%, depending on mix proportion and curing period. An amorphous gel fills the porous places between the cement particles were formed when the CG was treated with water reducer polymer, which reduces voids, increases porosity, and increases the cement’s dry density; as a result, the CS of the CG increases significantly. To evaluate the CS of CG with different grain sizes, w/c, percentage of polymer, and curing age, linear and nonlinear techniques were used. according to the bs standard, the CS of the CG produced was 71% higher than that of the identical mix produced according to the ASTM standard. Compared to the other sands, the cement grout produced with finer sand grading had the maximum flexural strength at all testing ages. Full article
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12 pages, 2806 KiB  
Article
Prediction of Deflection of Shear-Critical RC Beams Using Compatibility-Aided Truss Model
Appl. Sci. 2021, 11(23), 11478; https://doi.org/10.3390/app112311478 - 03 Dec 2021
Cited by 2 | Viewed by 1356
Abstract
This study proposes a method for predicting the deflection of shear-critical reinforced concrete (RC) beams. Shear deterioration of shear-critical RC beams occurs before flexural yielding. After shear deterioration occurs in the shear-critical RC beams, the deflection caused by shear is greater than the [...] Read more.
This study proposes a method for predicting the deflection of shear-critical reinforced concrete (RC) beams. Shear deterioration of shear-critical RC beams occurs before flexural yielding. After shear deterioration occurs in the shear-critical RC beams, the deflection caused by shear is greater than the flexural deflection obtained from the elastic bending theory. To reasonably predict the deflection of shear-critical RC beams, it is necessary to evaluate deflections due to shear as well as flexure. In this study, the deflections produced by flexure and shear were calculated and superposed to evaluate the deflection of shear-critical RC beams. The method recommended by ACI 318-19 was employed to calculate the flexural deflection, and a compatibility-aided truss model able to calculate the shear stress and shear deformation at each load stage was used to consider the shear deflection. A comparison of the experimental and analytical results showed that the proposed analytical method can effectively predict the deflection of shear-critical RC beams. Full article
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24 pages, 28959 KiB  
Article
Out-of-Plane Experimental Study of Strengthening Slender Non-Structural Masonry Walls
Appl. Sci. 2021, 11(19), 9098; https://doi.org/10.3390/app11199098 - 29 Sep 2021
Cited by 4 | Viewed by 2507
Abstract
Non-structural masonry partition walls, which are mainly designed to functionally separate spaces in the buildings and provide physical barriers between rooms, were traditionally built from either solid or hollow clay units or autoclaved aerated concrete blocks. Recent earthquakes have revealed the high vulnerability [...] Read more.
Non-structural masonry partition walls, which are mainly designed to functionally separate spaces in the buildings and provide physical barriers between rooms, were traditionally built from either solid or hollow clay units or autoclaved aerated concrete blocks. Recent earthquakes have revealed the high vulnerability of these elements, even in the case of low to moderate seismic events. Public buildings (e.g., hospitals and schools) are particularly vulnerable. Due to their greater floor-to-floor heights and the response spectra of floors, the dynamic response of primary structure may provoke significantly higher seismic loads on partition walls. The main goal of the presented experimental study was to investigate the behavior of slender partition walls loaded out-of-plane with a simple and cost-effective approach that may be applied through routine refurbishment works. Eleven full-scale slender non-structural masonry partition walls were built with brickwork and cement–lime mortar. Eight of them were additionally strengthened with different techniques, including glass fiber-reinforcing fabric and low-cost glass fiber-rendering mesh. To evaluate the efficiency of the applied strengthening solutions, out-of-plane quasi-static cyclic experiments were conducted. By applying meshes over the entire surfaces, the resistance was significantly improved with the low-cost approach reaching half of the resistance of the commercially available strengthening system preserving the same displacement capacity. Full article
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23 pages, 5240 KiB  
Article
Compressive and Diagonal Tension Strengths of Masonry Prisms Strengthened with Amorphous Steel Fiber-Reinforced Mortar Overlay
Appl. Sci. 2021, 11(13), 5974; https://doi.org/10.3390/app11135974 - 27 Jun 2021
Cited by 5 | Viewed by 2053
Abstract
A technique for strengthening masonry walls by plastering with amorphous steel fiber-reinforced mortar (ASFRM) is investigated through compressive and diagonal tension tests for masonry prisms. The vertical joint between masonry units was not completely filled with mortar to mimic poor workmanship, which is [...] Read more.
A technique for strengthening masonry walls by plastering with amorphous steel fiber-reinforced mortar (ASFRM) is investigated through compressive and diagonal tension tests for masonry prisms. The vertical joint between masonry units was not completely filled with mortar to mimic poor workmanship, which is typically reflected in low-cost buildings. The test variables include the number and thickness of mortar overlays, fiber volume fraction, and additional reinforcement using glass fiber mesh or shear connectors. In most strengthened specimens, the ASFRM is not damaged but separated from the masonry prisms after its maximum strength is reached. Additional tests for the bond strength between the ASFRM overlay and masonry surface are conducted to evaluate its contribution to the strengthening effects. Based on experimental observations, equations for predicting the compressive and diagonal tension strengths of masonry prisms strengthened with ASFRM are proposed. The compressive strength can be predicted more accurately by considering the asymmetrical distribution of compressive stress when strengthening is performed on only one side. The diagonal tension strength after strengthening can be predicted by incorporating the contribution of the bond strength between the ASFRM overlay and masonry prism to the initial strength. Full article
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14 pages, 16905 KiB  
Article
Experimental Study on Slender CFRP-Confined Circular RC Columns under Axial Compression
Appl. Sci. 2021, 11(9), 3968; https://doi.org/10.3390/app11093968 - 27 Apr 2021
Cited by 6 | Viewed by 3059
Abstract
The test results on the performance of carbon fiber-reinforced polymer (CFRP)-confined reinforced concrete (RC) columns under axial compression load are presented in this study. Twelve slender CFRP-confined circular RC columns with a diameter of 200 mm were divided into two groups. Six specimens [...] Read more.
The test results on the performance of carbon fiber-reinforced polymer (CFRP)-confined reinforced concrete (RC) columns under axial compression load are presented in this study. Twelve slender CFRP-confined circular RC columns with a diameter of 200 mm were divided into two groups. Six specimens with different slenderness ratios of 12, 20, 32, 40, 48, and 56 were contained in each group. The experimental results demonstrated the circumferential CFRP wrap was effective in enhancing the ultimate axial load of slender CFRP-confined circular RC columns compared with unwrapped RC columns. The experimental investigation also showed that the slenderness of the specimens had important influences on the axial compressive behavior, and the axial bearing capacity of slender CFRP-confined circular RC columns decreased as the slenderness ratio increased. In order to predict the load-carrying capacities of slender CFRP-confined circular RC columns, a formula was proposed and the prediction agreed with the experiments. The slenderness of slender CFRP-confined circular RC columns was recommended to be less than 26.5 in practical engineering. Full article
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Review

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33 pages, 12290 KiB  
Review
A Review of the Performance of Infilled RC Structures in Recent Earthquakes
Appl. Sci. 2021, 11(13), 5889; https://doi.org/10.3390/app11135889 - 24 Jun 2021
Cited by 17 | Viewed by 2869
Abstract
The primary objective is to present the most representative types of damage observed in reinforced concrete (RC) structures due to earthquakes. Those damages are divided according to the ten most representative types. Examples and the main reasons that could trigger each failure mechanism [...] Read more.
The primary objective is to present the most representative types of damage observed in reinforced concrete (RC) structures due to earthquakes. Those damages are divided according to the ten most representative types. Examples and the main reasons that could trigger each failure mechanism are presented. The definition of these damage types is supported by post-earthquake damage reconnaissance missions in Sichuan (China) in 2008, L’Aquila (Italy) in 2009, Lorca (Spain) in 2011, Emilia-Romagna (Italy) in 2012, Gorkha (Nepal) in 2015, Muisne (Ecuador) in 2016 and Chiapas (Mexico) in 2017. An extensive discussion is presented concerning the infill walls’ seismic behaviour and their interaction with the RC structural elements. The presentation of the significant learnings and findings concerning the typical damage herein presented and discussed are compared with the common Southern European construction practice. The impact of the infill walls on the rehabilitation costs of damaged RC buildings is also studied. These costs are compared to those related to the structural damage and rehabilitation of the entire building structure to understand the impact of the infill walls. Finally, a case study is presented to study the effect of implementing simplified retrofitting strategies to prevent the soft-storey mechanism, one of the most common problems observed in past earthquake events. Full article
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