Concrete Residential Buildings Research Articles

An analysis to understand how the shape of a concrete residential building influences its embodied energy and embodied carbon

The built environment is recognized as a major hotspot of resource use and environmental impacts. Life Cycle Assessment (LCA) has been increasingly used to assess the environmental impacts of construction products and buildings and a new trend is characterized by the application of LCA to larger systems such as neighborhoods during early design phases. Assessing urban development projects at the master-planning stage raises the issue of inventory data collection, especially for building materials which are reported to account for about 20% of primary energy consumption in buildings, and up to 45% of associated greenhouse gas emissions. Urban planners focus on the urban morphology and little information is known about the buildings characteristics apart from their general shape. This paper proposes a simplified model for the assessment of buildings embodied energy and embodied carbon in relation with urban planners’ design levers. The model relies on the decomposition of buildings into functional elements in order to be sensitive to the shape of the buildings. A detailed sensitivity analysis and contribution analysis of the model is conducted on two types of generic building forms, in order to investigate the influence of parameters relating to shape on the embodied energy and embodied carbon of a building. The sensitivity analysis shows that the parameters relating to shape (such as the dimension of the buildings) are more influential on the embodied energy and embodied carbon per square meter of building than the ones relating to the elements themselves (such as the wall thickness). The contribution analysis also brings evidence of the relation between the compactness factor and the embodied energy and embodied carbon of a building.

Shear stress indicator to predict seismic performance of residential RC buildings

A large number of residential buildings in regions subjected to severe earthquakes do not have enough load carrying capacity. The most of them have been constructed without receiving any structural engineering attention. It is practically almost impossible to perform detailed experimental evaluation and analytical analysis for each building to determine their seismic vulnerability, because of time and cost constraints. This fact points to a need for a simple evaluation method that focuses on selection of buildings which do not have the life safety performance level by adopting the main requirements given in the seismic codes. This paper deals with seismic assessment of existing reinforced concrete residential buildings and contains an alternative simplified procedure for seismic evaluation of buildings. Accuracy of the proposed procedure is examined by taking into account existing 250 buildings. When the results of the proposed procedure are compared with those of the detailed analyses, it can be seen that the results are quite compatible. It is seen that the accuracy of the proposed procedure is about 80% according to the detailed analysis results of existing buildings. This accuracy percentage indicates that the proposed procedure in this paper can be easily applied to existing buildings to predict their seismic performance level as a first approach before implementing the detailed and complex analyses.

A Reliability Analysis of In-service Reinforced Concrete Residential Structures

Floor load and resistance of residential buildings, two important parameters for reliability analysis, pose direct influences upon the structural reliability. Based on the survey of floor live load of typical reinforced concrete residential buildings, strength of member materials, geometric parameters of reinforced concrete members and other resistance parameters, the reliability level of residential buildings is systematically studied, the standard value for floor live load and influences of the construction quality upon the reliability of residential buildings are analyzed, and primary causes of reduced reliability of reinforced concrete flexural members of residential buildings are obtained.

Evaluation of Building Retrofitting Alternatives from Sustainability Perspective

Buildings primarily provide shelter and acceptable comfort for its intended occupiers and they should also provide adequate protection in case of hazards. Unfortunately, in case of seismic events it is observed that in many cases earthquakes caused considerable damage to residential and commercial buildings, public facilities and infrastructures with substantial casualties due to inadequate engineering and faulty in construction practices. In this study, a reinforced concrete residential building that collapsed in 1999 Kocaeli Turkey Earthquake (MW 7.4) is focused and investigated using current seismic code. Afterwards, building is virtually retrofitted considering architectural plan and using common retrofitting methods for satisfying current seismic code requirements. These retrofit alternatives are then evaluated from structural, cost and environmental aspects and outcomes are discussed. Since structural components that are used in retrofitting the building consumes natural resources and responsible for energy consumption, sustainability criteria should be directly included in the retrofitting requirements. Consequently, structural engineers are able to use natural resources efficiently and reduce the environmental impacts in retrofitting.

既存壁式プレキャスト鉄筋コンクリート構造集合住宅建物の基礎と地盤を考慮した地震応答解析

Existing wall-type precast reinforced concrete residential buildings maintain high structural quality, although they were constructed widely in Japan more than 40 years ago. A large number of the residential units in these existing buildings are standardized and typically small. Consequently, they do not suit for modern living uses. In order to utilize these buildings, seismic behavior was evaluated by static pushover analyses in past research. It was concluded that the failure mechanisms are rocking of the walls in the transverse direction and beam yielding in the longitudinal direction. In this research behavior of the foundations was not studied. Past large earthquakes such as Hyogoken-Nambu earthquake in 1995 showed that the WPC buildings maintained high structural seismic resisting performance and the foundations including piles were relatively weak. This fact implies need of analytical study of the seismic behavior of the buildings considering their foundation and soil. It is more true on the evaluation of their performance in the transverse direction, where the behavior of the foundation is more influential to the overall structural behavior than the longitudinal direction. In this research, time-history seismic response analyses of the WPC buildings under large earthquakes with 500 year of the recurrence period are conducted. Two cases of combinations of the soil condition and foundation system are studied. One is continuous footing on hard soil and the other is pile in soft soil. 2-D sway-rocking models were created for the two cases with corresponding sway and rocking soil springs. The superstructure is the model which is identical in the cases and composed of inelastic joint springs and elastic precast concrete panels. Pile stresses are evaluated by applying the seismic deformation method. Findings in this research are shown below: (1) In the study case for the building with the continuous foundation, uplift of the building by the overturning moment (OTM) is observed. It is referred that the failure mechanism is rocking of shear walls associated with failure of the vertical joints in past study of pushover analyses with the fixed-base model. In the time-history analyses, the maximum base shear coefficient (CQ1MAX), which is defined as the ratio of lateral force to the building weight, is 0.73. (2) In the study case with the pile foundation, the piles can fail in shear before the collapse of the superstructure. While CQ1MAX reaches 0.81 with the elastic pile model, it would be lower in studies considering inelastic shear failure of piles. (3) In the study case for the building with the continuous foundation, shear stress of shear walls is no more than 1.8N/mm2, which is lower than probable ultimate shear stress (2.0-2.7N/mm2). Although, in the study case with pile foundation, the shear stress is at most 2.1N/mm2, this is the lower limit of ultimate shear stress and would decrease considering shear failure of piles. Therefore, shear walls would not fail under the large earthquakes, while foundation may be damaged. This analytical finding agrees with the past seismic damage of this type of buildings.

Development of an automated estimator of life-cycle carbon emissions for residential buildings: A case study in Nanjing, China

Residential buildings consume a significant portion of energy and resources during the whole life-cycle phase and meanwhile discharge an enormous amount of carbon dioxide emissions, which has directly led to the aggravation of the greenhouse effect and become a great threat to the environment and human beings. To reduce the life-cycle carbon emissions from residential buildings, researchers have made many efforts to estimate the emissions accurately. Although several building-level carbon emission databases and related calculation systems have been set up in developed countries, there unluckily remains a vacancy in China. To fill in this gap, this study develops an automated estimator of life-cycle carbon emission for residential buildings entitled “Carbon Emission Estimator for Residential Buildings (CEERB)” in China. The development process was based on the life-cycle assessment (LCA) theory, standardized carbon emission calculation method, and collection and compilation of numerous carbon emission coefficients available in China. The database for storing carbon emission coefficients is based on the SQLite 3.0, and the user interface is designed with Qt 4.7. Followed by the establishment of the CEERB system, it has been exemplified in a masonry concrete residential building in Nanjing (China), demonstrating its applicability and capability in estimating the life-cycle carbon emissions of residential buildings. The results indicate that: (1) the life-cycle carbon emissions of this project were 1.7 million kg and the annual emissions per square meters were 19 kg/m2/year; (2) the O&M phase contributed the most (63%) to carbon emissions, followed by the material production (32%); (3) regarding to material embodied emissions, concrete reached roughly 44% of total material emissions, followed by the steel (20%); (4) during the construction phase, the superstructure project accounted for the most emissions (78%), primarily by tower cranes and hoist; (5) during the operation phase, electricity contributes 88.3% of emissions, followed by natural gas of 8%. Discussion and implicated policies, such as annual emission profile and impact of using recycled materials, have also been elaborated at the end of the study. Based on the proposed estimator CEERB, contractors can be more efficient and convenient to evaluate carbon emissions at the early stage of a project and make appropriate carbon management plans to reduce emissions when facing stricter environment policies in the future.

Life-span prediction of abandoned reinforced concrete residential buildings

The paper presents research findings on the deteriorating conditions of abandoned residential projects due to environmental factors of degradations. Sampling was made from two hundred and sixty-one abandoned housing projects. Structural degradations associated with the uncompleted buildings were studied. In a similar manner, a small-scale reinforced concrete structure was erected in an open and critically monitored for defects caused by environmental factors of degradations. The selected uncompleted buildings were assessed for surface salt deposits, crack formations and reinforcement corrosion. However, the small-scale structure was evaluated for performance degradations through destructive and non-destructive strength tests, steel tensile strength test and corrosion test. Results show that there is an alarming decrease in structural integrity and durability functions in abandoned reinforced concrete buildings with time. Eventually, performance-depreciation versus age graph was developed for assessing life-span limit beyond which unacceptable mechanical properties are eminent. Based on the surrounding exposure conditions, an abandoned reinforced concrete building could fail to perform acceptable designed strength functions within a period of twelve (12) years.

共用廊下増築を伴う既存壁式プレキャスト鉄筋コンクリート構造集合住宅建物の耐震性能評価

Significant number of wall-type precast reinforced concrete (WPC) residential buildings exist in Japan, constructed during the 1960-70s.They are assembled using prefabricated concrete panels for the slabs and walls and of high quality in terms of the structural conditions. In order to utilize them, seismic behavior of the existing buildings extended with new corridor and elevator structures were analytically evaluated. Static pushover analyses were conducted considering inelastic behavior of members and connections between the existing precast concrete wall panels. The ultimate lateral strength of the extended buildings were nearly equivalent to that of the existing buildings.

AN APPROACH FOR SAFETY COST ESTIMATION OF BUILDING CONSTRUCTION

Small or middle scaled residential projects have a big share in the industry and majority of the fatal accidents usually occur on such work sites. In this study, drawings, technical specifications, bill of quantities of 25 small or middle scaled concrete residential buildings with total areas that vary between 252 and 221.979 m2 in Istanbul were examined. The study aims to give an approach for safety cost estimation for the early stages of construction bidding phase using risk assessment activities and construction project scheduling by focusing on construction activities. Additionally, a cost analysis was performed and the results were compared and Primavera P6 was utilized for scheduling, and risk assessment was conducted using the techniques applicable for construction projects (i.e., L matrix and Fine-Kinney). Finally, activity-based techniques were used for cost estimation. The results of this study reveal that the percentage of occupational health and safety (OHS) cost to the total construction cost is 2.6%. Also, to comply with the current legislation and minimize risks; 0.95 USD per man-hour should be spent according to 2013 rates and OHS cost per unit area was found as approximately 9.37 USD.

Performance-based Seismic Design of an Irregular Tall Building — A Case Study

The structural design of a 50-story tall reinforced concrete residential building, which was planned to be constructed in Istanbul and given up afterwards by the investor, has been completed in accordance with the draft version of Seismic Design Code for Tall Buildings in Istanbul that adopts performance-based seismic design as the basic approach as Tall Buildings Initiative Guidelines do. The seismic design of the building has formed the main part of the structural design process due to high seismicity of the proposed location and the extremely irregular floor plan not conforming to usual tall building structures. The building consists of two individual buildings linked through stronger link slabs at top 13 stories whereas relatively weak slabs at lower stories. The building has been designed for design basis earthquake by elastic response spectrum analysis and its seismic performance has been checked for maximum considered earthquake by nonlinear time history analyses carried out using PERFORM-3D.

Activity based risk assessment and safety cost estimation for residential building construction projects

Fatal construction accidents are major problem in Turkish construction industry. Although new comprehensive legislation has been inured recently; level of consciousness in the industry is unsatisfactory and safety is perceived as an extra cost. Small or middle scaled residential projects have a big share in the industry and majority of the fatal accidents usually occur on such work sites. Focus of this study is small and middle-scaled residential construction sites. Drawings, technical specifications, bill of quantities of 25 concrete residential buildings with total areas that vary between 230 and 118,200m2 in Istanbul were examined. Site visits and information gathering were performed from site engineers. This study aims to give an approach for safety cost estimation for the early stages of construction bidding phase using risk assessment activities and construction project scheduling by focusing on construction activities. Additionally, a cost analysis was performed and the results were compared and analyzed with a former project that focused on 30 concrete residential projects in Istanbul. Primavera P6 was utilized for scheduling, and risk assessment was conducted using the techniques applicable for construction projects (i.e., L matrix and Fine-Kinney). Finally, activity-based techniques were used for cost estimation. The results of this study reveal that the percentage of safety cost to the total construction cost is 1.92%. Also, to comply with the current legislation and minimize risks; 0.85 USD per man-hour should be spent according to 2013 rates and safety cost per unit area was found as approximately 5.68 USD.

Seismic Fragility Curves for 1 and 2 Stories R/C Buildings

In this study, the fragility curves were formed for 1 and 2 stories reinforced concrete (RC) residential buildings. The information regarding the structures was taken from projects of the buildings. Nonlinear pushover (NP) analyze was performed to 84 RC buildings which were divided to 2 groups. The buildings built 1998 and later were called Group-A. The building built before 1998 was called Group B. As for nonlinear analysis, a 3D computer model was drawn for each building and nonlinear analyses were applied to these models. Each building was analyzed for 2 dimensions (X and Y). Totally 168 NP analysis were performed for each building. 4 damage limits (slight, moderate, heavy and complete) and 5 damage zones (undamaged, slight, medium, extensive and collapse) were determined according to maximum interstory drift ratio. Fragility curve parameters were obtained at the result of the NP analysis. Probability density functions were calculated with the help of lognormal mean and lognormal standard deviation values of limit states. The fragility curves were generalized for the buildings in Group A and Group B. At the conclusion of this work; 8 fragility curves obtained for 1 and 2 stories reinforced concrete buildings in. Using these 8 curves; damage possibility can be estimated for RC buildings which have same features.

Earthquake performance investigation of R/C residential buildings in Turkey

The aim of this study is to determine the earthquake performances of reinforced concrete (R/C) residential buildings in Turkey and to analyze the parameters that affect the performance. The performance of Turkish residential buildings, determined by their levels of damage, directly relates to their structural systems. Damage parameters observed from previous earthquakes define structural parameters selected to be used in the present study. Five different types of frame R/C buildings were modeled. For the analysis, the model buildings vary according to the number of stories, column sizes, and reinforcement and concrete strength parameters. The analyses consider gravity forces and earthquake loads through 1975 and 2007 Turkish design codes. In a total of 720 different R/C buildings were investigated for the analysis to obtain capacity curves. A performance evaluation was employed by considering the Turkish design code (TDC-2007). The current study ignores irregularities such as soft stories or short columns. The study`s analysis considers a comparison of the parameters` influence on the structural performance of the model buildings.

Seismic Fragility Curves for 1 and 2 Stories R/C Buildings

In this study, the fragility curves were formed for 1 and 2 stories reinforced concrete (RC) residential buildings. The information regarding the structures was taken from projects of the buildings. Nonlinear pushover (NP) analyze was performed to 84 RC buildings which were divided to 2 groups. The buildings built 1998 and later were called Group-A. The building built before 1998 was called Group B. As for nonlinear analysis, a 3D computer model was drawn for each building and nonlinear analyses were applied to these models. Each building was analyzed for 2 dimensions (X and Y). Totally 168 NP analysis were performed for each building. 4 damage limits (slight, moderate, heavy and complete) and 5 damage zones (undamaged, slight, medium, extensive and collapse) were determined according to maximum interstory drift ratio. Fragility curve parameters were obtained at the result of the NP analysis. Probability density functions were calculated with the help of lognormal mean and lognormal standard deviation values of limit states. The fragility curves were generalized for the buildings in Group A and Group B. At the conclusion of this work; 8 fragility curves obtained for 1 and 2 stories reinforced concrete buildings in. Using these 8 curves; damage possibility can be estimated for RC buildings which have same features.

Use of Cumulative Distribution Functions in order to Estimate Damage Probability

In this study, the cumulative distribution function was formed in order to estimate the probability of earthquake damage risk of the residential buildings. Nonlinear Pushover analysis was performed to 25 reinforced concrete residential buildings. The information regarding the buildings was taken from their projects. A 3D computer model was drawn for each building and analysis was applied to these models. 4 damage limits (slight, moderate, extensive and complete) and 5 damage zones (undamaged, slight, medium, extensive and collapse) were determined on the modal capacity curves of the buildings. Probability density functions were calculated with the help of lognormal mean and lognormal standard deviation values of limit states. The cumulative distribution functions were generalized and the probability of the damage was shown. With the results of this work; damage possibility can be estimated for any reinforced concrete residential building which has same features such as soil type, story height, irregularities, soft story etc.

Performance‐based seismic design of an irregular tall building in Istanbul

SummaryStructural design of a 50‐story tall reinforced concrete residential building, which was planned to be constructed in Istanbul and given up afterwards by the investor, has been completed in accordance with the draft version of Seismic Design Code for Tall Buildings in Istanbul that adopts performance‐based seismic design as the basic approach as Tall Buildings Initiative Guidelines do. Seismic design of the building has formed the main part of the structural design process due to high seismicity of the proposed location and extremely irregular floor plan not conforming to usual tall building structures. The building consists of two individual buildings linked through sky floors at the top 12 stories whose design was one of the most challenging works. The building has been designed for design basis earthquake by elastic response spectrum analysis, and its seismic performance has been checked for maximum considered earthquake by nonlinear time‐history analyses carried out using PERFORM‐3D. Copyright © 2015 John Wiley & Sons, Ltd.

Study of structural capacity and serviceability affecting the obstruction of residential door

The last Chilean earthquake, occurred on February 27, 2010, allowed establishing important patterns of structural failures in reinforced concrete residential buildings; however, limited progress has been made in the study of basic standards of serviceability, such as obstruction of doors. Thus, this study focused on measuring the influence of design specifications and construction criteria of lintels and columns, in terms of obstruction of doors, considering capacity thresholds for certain levels of displacement. The study consisted of the design and construction of a full-scale prototype of a reinforced concrete frame, designed in accordance with all the ACI-318-08 requirements, taking into account typical aspects of geometry and materiality widely used by the real estate industry, for location and size of doors. In order to quantify the structural capacity of the prototype and to study the serviceability of the door, a quasi-static cyclic test was conducted, according to load and displacement protocols specified in FEMA 356 and FEMA 461, which was adjusted by using virtual models based on a static nonlinear analysis called Pushover. This research verified that, for displacement levels even five times higher than those established by codes considered, the cracking degree was minimal and fully recoverable. It was also found the door evidenced malfunction when the displacements were greater than those specified by design only, validating a high degree of accomplishment of current codes, in terms of capacity and serviceability, when dealing with obstruction of residential doors.

Improvements of Energy Balance of Existing Residential Buildings

The paper is oriented on searching for possibilities, which would approach the existing residential buildings to zero energy buildings. Existing residential buildings must remain competitive in the real estate market. Therefore, this paper is focused on progressive solutions, which application will significantly contribute to the approach towards zero energy balance. I have done my research on a concrete residential building in Bratislava. Scientifically I analyze the individual phases of improvement of this residential building. Firstly, I calculate the annual energy balance for individual phases, then I evaluate them. The basic improvement phases of energy balance of concrete residential building: insulation, regulation of heating system, application of heat pumps, application of solar collectors and photovoltaic modules. The scientific outputs are presented by well arranged graphs. Each improvement phase is analyzed in detail with introduced risks and contribution for energy balance. I will point out the problem of incorrect architectural design from the energy point of view, which remains a serious obstacle for further possible improvements with modern technological systems. By this research, I want to point out new possibilities for existing residential buildings.

The Assessment of the Refurbished Reinforced Concrete Buildings in Point of the Climate Change

Changes in climate have various impacts on the built environment: e.g. the building design and the materials together with the operation and the maintenance. Therefore, it is extremely important to account for the future weather conditions during both the design of new buildings and the renovation of existing buildings. According to the Hungarian meteorological researches as a consequence of the global warming the climate of Hungary is going to become warmer and drier as well as the number and the intensity of the extreme weather events is expected to grow. One of the main directions of actions in the Climate Change Strategy is the adaptation to the changing circumstances, the improvement of the adaptive capacity of the built environment. In this study, the prefabricated reinforced concrete large-panel residential buildings are analysed: a bottom-up methodology was developed based on typological approach to assess the vulnerability of the ‘panel buildings’ to climate change by analysing the extreme weather events. After assessing the sensitivity and the adaptive capacity of the determined building types, their vulnerability to the increased number of windstorms and extreme rainfalls was estimated and the influence of their refurbishment was analysed.

Full Scale Field Blast Tests on Reinforced Concrete Residential Buildings – From Theory to Practice

The spread of terror threats aimed against built up urban areas has grown considerably during the years and attracts the attention and concern of many countries. The severity and potential danger of an extreme blast event in an urban area and especially in the proximity of buildings was demonstrated most severely in past events. Many countries, including Israel, are facing different threats of war and terror. Therefore, the Israeli Home Front Command (IHFC) is continuously engaged in theoretical and experimental research activities that are related to the response of civilian buildings to these threats. This paper focuses on blast pressure which is a major effect of these threats. The experience gained in recent years, in relation to the structural response of RC buildings, with emphasis on residential buildings that are subjected to blast loads, can be very helpful in the development of improved requirements and guidelines for design of such buildings, aimed mainly at reducing of the damage, and taking measures for damage localization in an attempt to reduce the occurrence probability of a progressive collapse of these buildings. The aforementioned experiences combine lessons learnt from different accidental events with the results of continuous research on major topics of blast response, including theoretical and experimental studies. Controlled experimental studies in general and full scale field tests in particular are most important and educative in these aspects. This paper describes the basic ideas behind full scale field blast tests aimed at studying the blast resistance and the response of reinforced concrete residential buildings and of various structural and nonstructural components that are incorporated in these buildings. Producing controlled blast loads of different intensities in the vicinity of the tested buildings enables identification of the structural elements' response at different damage levels, as well as at their ultimate state. It also enables to follow the overall response of multistory buildings to blast loading and assess their vulnerability to progressive collapse. This paper aims at addressing the full scale field tests of buildings subjected to blast, discussing some basic concepts and presenting some full scale field blast tests that had been performed in recent years. These tests have been performed by the IHFC, in cooperation with the National Building Research Institute (NBRI) at Technion-Israel Institute of Technology and partly with international research laboratories partners. This presentation aims at providing some insight into full scale field blast tests in general with some emphasis on a 5 story reinforced concrete residential building that was heavily instrumented with more than 200 gauges, including pressure, acceleration and strain gauges. The measured signals provide valuable information on the dynamic response of the tested structure that can be compared with predictions of its response made by different computational tools. The main objective of the present paper is to overview the potential benefits of field blast tests and to describe the ongoing studies. The detailed description and in depth analysis of any single test is beyond the scope of this paper, and is a subject matter for complementary specific papers in this field of blast response of reinforced concrete structures.