Concrete Residential Buildings Research Articles

Assessing seismic performance of mid-rise reinforced concrete buildings using fragility curves

This paper focuses on the seismic fragility assessment of mid-rise reinforced concrete (RC) residential buildings in Cairo, Egypt. Structural safety is assessed by utilizing the damage that could occur to main components, such as columns and shear walls, and consequently, their failure that may lead to progressive (or partial) collapse of structures under extreme dynamic loads. Behaviors of mid-rise reinforced concrete (RC) buildings, which are designed in accordance with the Egyptian standards, are assessed analytically under the action of seismic loads. As such, non-linear time-history analyses (NLTHA), in addition to pushover analyses, were carried out on three (RC) frames with different number of stories varying from six to ten floors. In addition, fragility curves were developed in order to illustrate the probability of exceeding structural damage due to earthquakes as a function of ground motion indices. The lateral response of previously mentioned (RC) frames are evaluated by utilizing more than eighteen hundred NLTHA considering ten different earthquake records with fourteen peak ground acceleration in addition to the Egyptian response spectrum analysis. The output of this research includes roof drift and base shear histories, which are converted to damage in beams and columns in accordance with FEMA-356 guidelines. Based on statistics and probability distribution functions for the obtained results, fragility curves were then developed, which can be used as an effective tool for planning and implementing retrofit schemes, modifications to codified seismic provisions, seismic mitigation strategies, and for insurance-related applications.

Development of an SDOF Model for Seismic Performance Evaluation of Low to Mid-Rise Reinforced Concrete Residential Buildings

Development of an SDOF Model for Seismic Performance Evaluation of Low to Mid-Rise Reinforced Concrete Residential Buildings

Analysis of carbon emission characteristics and establishment of prediction models for residential and office buildings in China

Intensifying environmental issues make carbon reduction crucial, especially in the construction industry. Embodied carbon emissions (ECE) in buildings characteristically involve concentrated, intensive emissions over a short period. Implementing energy-saving and carbon-reducing technologies has raised ECE rates. Therefore, analyzing carbon emission (CE) characteristics during the production and construction phases is necessary. Currently, essential data on ECE is lacking, the calculation methods are complex, and ECE's characteristics and influential factors in residential and office buildings remain unclear. Moreover, there is a lack of prediction models for ECE in the construction phase that apply to current construction methods and CE factors. The research on prediction models for ECE has primarily focused on the production phase but has paid little attention to the contribution of non-structural materials to embodied carbon (EC). In this study, reinforced concrete residential and office buildings in hot summer and cold winter regions (located in the southeast part of mainland China, with a subtropical monsoon climate) were considered typical types, and the CE characteristics of two main phases, the production and construction phases, were analyzed. Based on critical features, such as the number of floors and the basement, prediction models for ECE in residential and office buildings were established at the design stage. The models were validated with mean absolute percentage error (MAPE) values below 4 %, and coefficient of variation (root mean square error) (CV [RMSE]) values less than 0.02. The prediction models enabled a rapid estimation of ECE, encouraging designers to consider EC in the early design stages.

Effects of impact and microphone positions on heavy-weight floor impact sound pressure levels in concrete buildings

This study aims to analyze the spatial distribution of heavy-weight impact sound transmitted to a receiving room in 59 households within a concrete residential building. The performance of buildings is generally regulated by single number quantities such as L′iA,Fmax. To enhance performance, it is important to understand the effect of the impact sound pressure level at designated impact positions and microphones. Therefore, this study proposes a method to quantify the impac sound pressure level for determining L′iA,Fmax according to the impact and microphone positions. Analysis of the data revealed that significant similarities in frequency spectra were observed when generating impacts at two positions near the window, in addition to two at the area near the corridor, both of which have similar boundary conditions. The central impact position exhibited the highest contribution at 24.6%, while other positions had contributions of 18.2–19.5%. For the microphone positions, those located at the corners on either side of the window showed contributions of 22.8–23.7%, whereas the remaining positions demonstrated lower contributions of 17.3–18.5%. These results can serve as basic data for developing construction methods to reduce floor impact sound.

Analyzing Contingency Estimation for Residential Turnkey Projects in Saudi Arabia: A Neural Network Approach

Utilizing a turnkey approach to deliver a construction project entails significant risks from the contractor’s perspective. Essentially, the owner awaits project completion without commitments regarding additional expenditures incurred by the contractor during the project’s duration. This paper specifically focuses on estimating and analyzing the contingency value for residential turnkey projects in Saudi Arabia. The contingency value across the project’s life cycle is estimated using six Artificial Neural Network (ANN) models, which are compared to identify the best-trained network according to project complexity, contingency factor, and contingency impact during the project phases. The output layer provides the contingency factor percentages for each project phase. A 13-story reinforced concrete (RC) residential building established in one of Saudi Arabia’s cities was selected to implement the developed methodology. The contingency estimation, performed using @Risk 7.5 and NeuralTools 7.5, was determined to be 11.34% and was distributed across the five phases of the project’s life cycle: 0.30% for predesign, 0.99% for design, 2.61% for preconstruction, 6.33% for construction, and 1.12% for postconstruction. Furthermore, it was found that the estimated contingency varies based on project complexity, which is 7.20% for low complexity, 8.16% for medium complexity, 9.41% for complicated, and 11.34% for very complicated projects. Historical data and peer review approaches are employed to validate the results, both of which are endorsed by professionals in this field. This paper highlights two main contributions: Firstly, it significantly enhances risk management by facilitating a comprehensive understanding and systematic analysis of risks, thus improving the contractors’ ability to mitigate potential negative impacts on projects. Secondly, it supports more informed decision-making through the use of advanced techniques to estimate and analyze contingency values. These contributions are critical for contractors engaged in Saudi construction projects, particularly those involving residential buildings.

Use of Microwave Tomography Technology for Water Seepage Investigation in Buildings

In metropolitan cities like Hong Kong, it is densely populated and most people live in privately owned premises of reinforced concrete residential buildings. Owing to material deterioration under (a) environmental exposure, (b) poor construction workmanship, (c) lack of proper maintenance and (d) alteration of premises into sub-divided flats with bathrooms, water may seep through the floor slabs of the premises and infiltrate into the subject premises below, and this create nuisance to the subject premises. In this paper, the causes of deterioration of concrete material are elaborated.

An mass ratio of permanent loads to variable loads of reinforced concrete buildings

ABSTRACT Environmental and resource crises necessitate sustainable development, yet construction lags in material conservation and carbon mitigation. Extensive use of reinforced concrete results in excessive permanent loads and larger building self-weight, elevating material use and energy consumption. A concept of mass ratio of permanent loads and variable loads ( R m ) is established for reinforced concrete buildings, and its reduction measures are outlined. Through statistical and regression analysis of 60 residential and 45 public buildings, R m have been validated as an indicator of structural value and design rationality, and its importance for material conservation and cost-effectiveness is underscored. Results shows that most reinforced concrete residential buildings have R m above 10, public buildings exceeding 7, indicating excessive structural self-weight. It requires lowering R m in structural and material innovations and optimized engineering design, to enhance material conservation. The innovation of this paper lies in three aspects: firstly, the concept modeling of R m addresses the quantitative assessment criteria in areas such as architectural materials and engineering design; secondly, the calculation of R m directly utilizes raw data from engineering design, providing a scientific and feasible approach for statistical analysis; thirdly, the inherent deficiencies in reinforced concrete buildings are intuitively indicated from the perspective of R m .

Assessment of Non-Linear Analyses of RC Buildings Retrofitted with Hysteretic Dampers According to the Italian Building Code

While the use of steel hysteretic dampers has spread in the last decade for both new and retrofitted constructions, the Italian Building Code (IBC), as well as the Eurocode 8, does not provide specific recommendations for the design and verification of structures equipped with this technology. Due to their strong non-linear behavior, the effectiveness of the design with these systems must be verified through non-linear analyses. Non-Linear Time-History analyses (NLTHAs) are the most reliable method, but they are computationally expensive. The aim of the study is to investigate the reliability of non-linear static procedures, allowed by the IBC as an alternative to NLTHAs, for the analysis of buildings equipped with hysteretic devices provided with high damping capability. A parametric study is conducted on two reinforced concrete residential buildings, typical of the Italian residential heritage, retrofitted with hysteretic braces characterized by different stiffness and ductility values. The retrofit design is verified using non-linear analyses, both static and dynamic, considering either natural or artificial accelerograms, as the IBC deems them as equivalent. Within this work, reference is made only to the IBC; however, given the significant similarity between the IBC and the European code, the outcomes are expected to have a broader impact and to be not limited to the Italian context. Therefore, although this work is a preliminary study, it is believed to offer some initial insights on the topic and serve as the foundation for a more in-depth study that could lead to a regulatory revision on the subject.

Mevcut Konut Yapılarında Enerji Etkin ve Depreme Dayanıklı İyileştirme Yöntemlerinin İncelenmesi

Many studies are carried out in the rehabilitation of existing residential buildings, addressing the energy released during the pre-construction, construction, use and demolition stages of the building and circularity. Furthermore, in Türkiye, earthquakes are one of the primary influencers impacting the lifespan of buildings. However, a limited number of studies take a holistic approach, integrating both energy efficiency and earthquake resistance in existing residential buildings. To promote awareness on the subject, it is aimed to systematically examine the rehabilitation methods in reinforced concrete residential buildings. Seven studies were reviewed through literature analysis to investigate structural strengthening methods, energy efficient improvement techniques and their costs. The studies concluded that rehabilitation and strengthening were carried out in the structure and different building elements, and energy costs were reduced. Based on the data obtained, the steps to be followed in rehabilitating the residential buildings in this context were determined.

Modular concrete structures for the restoration of destroyed residential buildings in Ukraine

AbstractSince the beginning of the military invasion by Russia on February 24, 2022 and subsequent hostilities in Ukraine, approximately 140,000 residential buildings (of which around 18,000 are apartment buildings) have been destroyed or damaged. Destructions require a systematic approach to the restoration or construction of new buildings. This article analyzes the types of destruction of multi‐story prefabricated reinforced concrete residential buildings and proposed methods for restoration of damaged and partially destroyed high‐rise buildings. Improved modular concrete structures developed from high‐performance concrete and different variations of rebar can significantly speed up the recovery of affected regions.

Tech Note. Analysis of practices of layer-by-layer use of expanded polystyrene in the operation of residential buildings

The purpose of this paper is to consider three aspects of the use of polystyrene as an effective heat-insulating material in three-layer load-bearing and enclosing structures of reinforced concrete residential buildings. The first aspect is related to the dependence of the enclosure heat transfer resistance degree on the method of combining expanded polystyrene with stone structural materials. For example, prefabricated expanded polystyrene concrete blocks for the construction of walls of low and medium-rise buildings and cast-in-situ expanded polystyrene concrete poured into the voids of the well brickwork in high-rise buildings. It is shown that the layer-by-layer application of pure expanded polystyrene and the concrete layers protecting it multiplies the degree of thermal insulation of the enclosing structure while retaining its strength and equal consumption of raw materials. The second aspect is associated with the fire resistance of reinforced concrete load-bearing and enclosing structures of residential buildings. A sufficient degree of fire resistance when protecting expanded polystyrene with cast-in-situ reinforced concrete layers is shown using examples. The third aspect shows the feasibility of using outer three-layer reinforced concrete walls with polystyrene insulation for panel heating of the buildings.

Comparison of Seismic Response of Multi-Storey Building Having Shear Walls Without Opening on STAAD-PRO and ETAB

In India’s main cities, high-rise reinforced concrete residential buildings with more than 15, 16, or 17 stories are widespread these days, which are aligned parallel to the Indian government’s “Pradhan Mantri Awas Yojna”. The development of an economical and eco-friendly R-C building by providing a limited area of shear walls at the diagonal corners of the structure is evaluated in STAAD-PRO and ETAB in this paper. This work also focuses on the location and minimal area of shear walls along with maximum strength, and its 3-D analysis gives conclusions. The paper concludes that the design of 20-story buildings in STAAD and ETAB with minimum shear walls gives safe results, and Horizontal forces increase the structure’s strength and stiffness requirements.

Cost Estimation of Structural Work for Residential Building with Seismic Design Consideration

The Sumatra-Andaman earthquakes had triggered local earthquakes in Malaysia by reactivation of ancient inactive faults. Previously on 5thJune 2015, Ranau, a region located in Sabah, Malaysia, had experienced a moderate earthquake of Mw6.1. The structural failures occurred because all existing buildings only designed for gravity load without any seismic provision. Recent research work exhibits the seismic designs’ impact on the cost of material and its parameters thatimpact the cost. There are two types reinforced concrete residential buildings called Type 1 and Type 2 for two storey and four storeywhich had been used as models. This research applied four seismicity levels to the reference peak ground acceleration value, αgR= 0.07g, 0.10g, 0.13g & 0.16g, and two soil types: Soil Types B and D. The result shows that for twostorey reinforced concreteresidential buildings on soil types B and D, seismic design increases structural work costs, which is around 0.62% to 1.31% and 0.61% to 2.16%, respectively,for Type 1 modelcompared to non-seismic design. Besides,model Type 2, the increment is around 0.24% to 1.22% and 0.20% to 1.71%, respectively.Otherwise, for reinforced concreteresidential building with four storeyon soil types B and D,the result shows that seismic design tends to have a higher structural work’s costaround 0.41% to 2.48% and 0.98% to 11.23%, respectively, for Type 1 model. Besides, for model Type 2 the increment is around 1.80% to 2.05% and 2.34% to 8.53%, respectively, compared to non-seismicdesign.

Behavior of Flood Resistant Building and Ductile Detailing of G +7 RC Building Using IS 13920-2016

Floods are one of the most widespread and destructive natural disasters occurring in the world and with the increase in constructions along river courses and concentration of population around floodplain areas, flood-induced damages have been continuously increasing. The annual disaster record reveals that flood occurrence increased about ten folds over the past five decades. Thus, floods are posing a great threat and challenge to planers, design engineers, insurance industries, policymakers, and to the governments. Structural and non-structural measures can be used to deal with floods. Structural measures include a set of works aiming to reduce one or more hydraulic parameters like runoff volume, peak discharge, rise in water level, duration of flood, flow velocity, etc. Non-structural measures involve a wide range of measures to reduce flood risk through flood forecasting and early warning systems, emergency plans, and posing land use regulations and policies. The futuristic reinforced concrete buildings can be considered as a symbol of modern civilization. These buildings are usually constructed based on the guide lines given by the standard code books(like IS: 456:2000 and IS 13920:2016).Unfortunately, the code provisions consider the seismic loads and wind effects alone, while accounting the dead and live design loads, and exclude the flood loads. This implies the necessity to bring out corrective measures that can be adopted to reduce vulnerability before harm occurrences. In this project focuses on both the incorporation of flood loads during the analysis and design in CSI-ETABS software and the assessment of flood vulnerability of reinforced concrete residential buildings. Vulnerability is expressed as a fraction of ground floor height and maximum flood level at most immerse the building up to ground floor and first floor level. The importance of the outcome arises from the need of a strengthening solution to avoid failure of new or existing structures during floods.

Generalised Storey Loss Functions for Seismic Loss Assessment of Italian Residential Buildings

ABSTRACT With a view to providing general Storey Loss Functions (SLFs) for existing reinforced concrete (RC) residential buildings in Italy, this paper layouts the procedure and the development of SLFs for different residential building typologies, using post-earthquake observational damage data of the 2009 L’Aquila earthquake. To do so, the addressed building typologies and the cost ratios, with respect to the total construction cost, for structural and non-structural elements were defined according to the Italian price bulletin of building typologies, using the current average construction cost per square meter. Fragility models available in the literature, which had been specifically calibrated for structural and non-structural elements commonly found in Italian and Mediterranean RC buildings, were employed and the assumed repair costs were the ones incurred for repairing the buildings damaged during the 2009 L’Aquila earthquake. The proposed SLFs were then employed to perform loss assessment on a representative portfolio of Italian existing masonry-infilled RC residential buildings, showing the consistency of the results with respect to available research studies. The outcomes therefore denote how the proposed SLFs can be a useful tool as an alternative to the simplified conservative loss assessment guidelines currently employed in Italy, with a view to planning risk mitigation measurements both at a regional and single-building level.

Monitoring the dynamic properties of a reinforced concrete building through its seismic strengthening

Ambient vibration surveys have been applied on a five-story reinforced concrete residential building during its seismic retrofit. Inadequate seismic performance of the building has been upgraded by the conversion of its single footing to a mat foundation, the addition of shear walls as two separate cores, jacketing of columns and beams, and the addition of a layer over the existing slabs. Five columns of the building have also been removed due to added cores. Starting from the original phase of the building, eleven sets of acceleration measurements have been recorded and analyzed until the completion of all construction works. Frequency domain methods have been used for system identification. The findings clearly showed the frequency decreases as the result of structural operations decreasing the stiffness of the building, such as partition wall demolition and column removal, while the seismic strengthening works, such as column jacketing and core addition increased the dominant frequencies of the building. The comparisons between the extracted modal frequencies revealed the effects of the performed construction works on the dynamic behavior of the building. Finite element models were also constructed for the original and retrofitted phases of the building. Thereby, the main aim of the study was accomplished by quantified experimental and numerical findings.

Determining the regional disaster risk analysis of buildings in Erzincan

Erzincan is located in a region sensitive to seismic activities, which can destroy buildings and lead to loss of life because of severe earthquakes. Furthermore, analysing and determining structural risks is important because it reduces possible disaster risks and provides mitigation strategies. This study aims to assess the seismic vulnerability of existing buildings in Erzincan using a rapid visual screening method and create a regional-scale inventory. Furthermore, 490 residential reinforced concrete buildings in five neighbourhoods were analysed using a street scanning method (first-level evaluation) developed by METU, and maps were created using the ArcGIS program. The results revealed that poor construction quality, soft ground, and heavy overhang are the main vulnerability parameters that change the risk priority range of reinforced concrete residential buildings. Conversely, poor construction quality affected most first-priority buildings. Therefore, there is a need for effective seismic mitigation planning for Erzincan, as 49 % of buildings in the surveyed neighbourhoods required a second-stage assessment. In addition, the method ranks the buildings according to their risk priorities, and the obtained data on the map provided useful information for effective strategies for implementing risk reduction policies in Erzincan.

Effect of seismic design on the cost of structural works for two-storey residential building

Malaysia's low to moderate seismic threat should not be disregarded, and seismic design in structures should be considered. The region has previously seen significant earthquakes, especially in Sabah, as evidenced by the current increase in the frequency of minor earthquakes every day, where a current moderate earthquake magnitude of Mw 6.0 struck on 5th June 2015 in Ranau. Although the Ranau earthquake was not high-level. Malaysia suffered fatalities and millions of dollars in infrastructure and building destruction. This is mainly caused by the fact that structural design in Malaysia only considers gravity loads and does not account for seismic practices. Recent research has demonstrated how seismic designs affect material prices and cost-influencing parameters. In this study, Type 1 and Type 2 two-storey reinforced concrete residential buildings were chosen as models. Four seismicity levels were employed, each corresponding to the reference peak ground acceleration value, αgR= 0.07g, 0.10g, 0.13g, and 0.16g, as well as two soil types, Soil Types B and D. According to observations, seismic design increases the cost of structural works, ranging from 0.62% to 2.16% higher than nonseismic design for Type 1 models. Furthermore, the increment for Type 2 models ranges from 0.24% to 1.71%.

NSE seismic demand characterization: the case of a Spanish RC residential building

In reinforced concrete buildings, non-structural elements (NSE), such as masonry infills and parapets, constitute the cause of a considerable number of fatalities and huge economic losses in developed countries, in the case of medium magnitude earthquakes (4-6 Mw). As an example, during the 5.2Mw 2011 Lorca (Spain) earthquake, falling debris from unreinforced masonry NSE gave rise to the nine fatalities incurred. The majority of these elements were located in 4 to 6-storey reinforced concrete residential buildings. Within this framework, this contribution addresses the characterization of the seismic demand of NSE through the study of the response of a building in Lorca pertaining to the described structural type, by means of the Floor Response Spectra (FRS) method. For this purpose, the infilled frame model was created in SAP2000 with masonry infills simulated by equivalent struts. The infilled frame model is calibrated so as to fit with the main elastic period of the building, identified by means of ambient vibration tests conducted with a Tromino device. The FRS results obtained with the numerical model by a Linear Time-History (THA) analysis simulating the Lorca earthquake, are compared with the results suggested by the Eurocode in force and by the Italian Building Code. Specifically, in the case of the Italian Building Code, both the simplified formulation for moment resisting frame buildings and the modal superposition spectrum-to-spectrum approaches are considered. Finally, the potential resonance of the dynamic behaviour between the obtained FRS and the natural periods of the masonry parapets located at the top of the building is discussed.

Numerical evaluation of period elongation for the assessment of seismic damage and usability of RC residential buildings

During an earthquake, the progressive damage of structural and nonstructural components of a structure yields to the degradation of their stiffness, thus resulting in a progressive increase of the vibration period of the structure as a whole.Also, the damage amount on structural and nonstructural elements, also known as Damage State (DS), can be determined by visual inspection or predicted, for a given earthquake scenario, by means of numerical analyses by relating the exceedance of a certain Engineering Demand Parameter (EDP) threshold to the attainment of a certain DS. Also, upon an earthquake, the observation of a certain DS in a building is the basis for the decision regarding its usability.In this work, numerical incremental time-history analyses are performed on case-study reinforced concrete residential buildings. The analyses results are used to establish the expected DS attained by structural and nonstructural components and, so, by the considered building: this is also related to a certain usability judgment, as already mentioned. In tune, the analyses results are also used to evaluate the period elongation of the building at increasing intensity of the seismic demand.The objective of the study is establishing a preliminary relationship between a) the DS attained by a certain building due to the occurrence of an earthquake with a certain intensity, and, so, the consequent usability judgment, with b) its period elongation. This is done in order to establish whether the vibration period elongation – which can be practically evaluated by means of ambient vibration tests – can be used for the assessment of structural usability after an earthquake as a tool for decision supporting in the aftermaths of a destructive event