Buildings

19 pages, 3126 KiB

Open AccessArticle

Heat Transfer Behavior of Green Roof Systems under Fire Condition: A Numerical Study

by Nataliia Gerzhova, Pierre Blanchet, Christian Dagenais, Jean Côté and Sylvain Ménard

Buildings 2019, 9(9), 206; https://doi.org/10.3390/buildings9090206 - 19 Sep 2019

Cited by 7 | Viewed by 3922

Currently, green roof fire risks are not clearly defined. This is because the problem is still not well understood, which raises concerns. The possibility of plants catching fire, especially during drought periods, is one of the reasons for necessary protection measures. The potential [...] Read more.

Currently, green roof fire risks are not clearly defined. This is because the problem is still not well understood, which raises concerns. The possibility of plants catching fire, especially during drought periods, is one of the reasons for necessary protection measures. The potential fire hazard for roof decks covered with vegetation has not yet been fully explored. The present study analyzes the performance of green roofs in extreme heat conditions by simulating a heat transfer process through the assembly. The main objective of this study was to determine the conditions and time required for the roof deck to reach a critical temperature. The effects of growing medium layer thickness (between 3 and 10 cm), porosity (0.5 to 0.7), and heating intensity (50, 100, 150, and 200 kW/m²) were examined. It was found that a green roof can protect a wooden roof deck from igniting with only 3 cm of soil coverage when exposed to severe heat fluxes for at least 25 minutes. The dependency of failure time on substrate thickness decreases with increasing heating load. It was also found that substrate porosity has a low impact on time to failure, and only at high heating loads. Full article

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26 pages, 4903 KiB

Open AccessArticle

Green Roofs and Greenpass

by Bernhard Scharf and Florian Kraus

Buildings 2019, 9(9), 205; https://doi.org/10.3390/buildings9090205 - 14 Sep 2019

Cited by 29 | Viewed by 7054

Abstract

The United Nations have identified climate change as the greatest threat to human life. As current research shows, urban areas are more vulnerable to climate change than rural areas. Numerous people are affected by climate change in their daily life, health and well-being. [...] Read more.

The United Nations have identified climate change as the greatest threat to human life. As current research shows, urban areas are more vulnerable to climate change than rural areas. Numerous people are affected by climate change in their daily life, health and well-being. The need to react is undisputed and has led to numerous guidelines and directives for urban climate adaptation. Plants are commonly mentioned and recommended as one key to urban climate adaptation. Due to shading of open space and building surfaces, as well as evapotranspiration, plants reduce the energy load on the urban fabric and increase thermal comfort and climate resilience amongst many other ecosystem services. Plants, therefore, are described as green infrastructure (GI), because of the beneficial effects they provide. Extensive green roofs are often discussed regarding their impact on thermal comfort for pedestrians and physical properties of buildings. By means of Stadslab2050 project Elief Playhouse in Antwerp, Belgium, a single-story building in the courtyard of a perimeter block, the effects of different extensive green roof designs (A and B) on the microclimate, human comfort at ground and roof level, as well as building physics are analyzed and compared to the actual roofing (bitumen membrane) as the Status Quo variant. For the analyses and evaluation of the different designs the innovative Green Performance Assessment System (GREENPASS^®) method has been chosen. The planning tool combines spatial and volumetric analyses with complex 3D microclimate simulations to calculate key performance indicators such as thermal comfort score, thermal storage score, thermal load score, run-off and carbon sequestration. Complementary maps and graphs are compiled. Overall, the chosen method allows to understand, compare and optimize project designs and performance. The results for the Elief Playhouse show that the implementation of green roofs serves a slight contribution to the urban energy balance but a huge impact on the building and humans. Variant B with entire greening performs better in all considered indicators, than the less greened design Variant A and the actual Status Quo. Variant B will probably bring a greater cost/benefit than Variant A and is thus recommended. Full article

(This article belongs to the Special Issue Quantification of Green Roof Benefits and the Implementation into Urban Politics)

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17 pages, 3615 KiB

Open AccessArticle

Building Energy Consumption Raw Data Forecasting Using Data Cleaning and Deep Recurrent Neural Networks

by Junjing Yang, Kok Keng Tan, Mat Santamouris and Siew Eang Lee

Buildings 2019, 9(9), 204; https://doi.org/10.3390/buildings9090204 - 11 Sep 2019

Cited by 24 | Viewed by 5476

Abstract

With the rising focus on building energy big data analysis, there lacks a framework for raw data preprocessing to answer the question of how to handle the missing data in the raw data set. This study presents a methodology and framework for building [...] Read more.

With the rising focus on building energy big data analysis, there lacks a framework for raw data preprocessing to answer the question of how to handle the missing data in the raw data set. This study presents a methodology and framework for building energy consumption raw data forecasting. A case building is used to forecast the energy consumption by using deep recurrent neural networks. Four different methodologies to impute missing data in the raw data set are compared and implemented. The question of sensitivity of gap size and available data percentage on the imputation accuracy was tested. The cleaned data were then used for building energy forecasting. While the existing studies explored only the use of small recurrent networks of 2 layers and less, the question of whether a deep network of more than 2 layers would be performing better for building energy consumption forecasting should be explored. In addition, the problem of overfitting has been cited as a significant problem in using deep networks. In this study, the deep recurrent neural network is then used to explore the use of deeper networks and their regularization in the context of an energy load forecasting task. The results show a mean absolute error of 2.1 can be achieved through the 2*32 gated neural network model. In applying regularization methods to overcome model overfitting, the study found that weights regularization did indeed delay the onset of overfitting. Full article

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23 pages, 7017 KiB

Open AccessEditor’s ChoiceReview

Evaluation of the Adhesion between Overlays and Substrates in Concrete Floors: Literature Survey, Recent Non-Destructive and Semi-Destructive Testing Methods, and Research Gaps

by Jacek Szymanowski

Buildings 2019, 9(9), 203; https://doi.org/10.3390/buildings9090203 - 11 Sep 2019

Cited by 29 | Viewed by 7074

Abstract

Non-destructive testing (NDT) and semi-destructive testing (SDT) have recently been more frequently used for the evaluation and condition assessment of concrete floors in various types of buildings. The subject of the article is to briefly introduce the reader to the problem of adhesion [...] Read more.

Non-destructive testing (NDT) and semi-destructive testing (SDT) have recently been more frequently used for the evaluation and condition assessment of concrete floors in various types of buildings. The subject of the article is to briefly introduce the reader to the problem of adhesion between overlays and substrates in concrete floors and to illustrate the current state of knowledge on the subject. The aim of this paper was to briefly describe the recently used non-destructive and semi-destructive testing methods and the parameters useful for characterizing the adhesion between overlays and substrates in concrete floors, as well as the methods useful to characterize the functional properties of the overlays. A recent literature survey, related to the adhesion between the overlays and substrates in concrete floors, is thus shown. Special emphasis was placed on the critical review of the current research results. Based on the analysis of the literature review, research gaps have been presented in order to highlight future research directions. Full article

(This article belongs to the Special Issue Non-destructive Testing for Building Evaluation)

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15 pages, 5096 KiB

Open AccessArticle

About the Possible Limitations in the Usage of the Non-Destructive Ultrasonic Pulse Velocity Method for Assessment of Cracks in Reinforced Concrete Structures, Subjected to Direct Environmental Exposure

by Ivan Ivanchev and Veselin Slavchev

Buildings 2019, 9(9), 202; https://doi.org/10.3390/buildings9090202 - 11 Sep 2019

Cited by 4 | Viewed by 4310

Abstract

Failures occur in the structures of reinforced concrete buildings and facilities during their continuous exploitation, without being overloaded or exposed to extreme impacts, the most common being cracks. Their detection and change in time are related to the assessment of the state of [...] Read more.

Failures occur in the structures of reinforced concrete buildings and facilities during their continuous exploitation, without being overloaded or exposed to extreme impacts, the most common being cracks. Their detection and change in time are related to the assessment of the state of the structures, their safety, and reliability during their construction and especially for their safety exploitation. This paper describes the results of the experimental studies conducted by authors aiming to verify the possibility of using the non-destructive ultrasonic pulse velocity method (NDUPVM) for detection and evaluation of cracks. Results of an experimental study of 12 reinforced concrete beams are presented. In previous experiments, some of them were subjected to bending until the maximum crack width of 0.3 mm was reached and others until yielding of the longitudinal reinforcement. The results obtained from the measurements of the depths of the normal cracks with different widths with NDUPVM were compared with the visually measured ones. In the present research cracks with the same width and with a similar depth were chosen. The influence of extreme external conditions to the accuracy of the measured crack depths by the NDUPVM was investigated. Non-destructive ultrasonic research was done by a portable device Proceq TICO. Full article

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26 pages, 13176 KiB

Open AccessArticle

Prediction of the Maximum Seismic Member Force in a Superstructure of a Base-Isolated Frame Building by Using Pushover Analysis

by Kenji Fujii

Buildings 2019, 9(9), 201; https://doi.org/10.3390/buildings9090201 - 05 Sep 2019

Cited by 4 | Viewed by 3984

Abstract

It is essential for the seismic design of a base-isolated building that the seismic response of the superstructure remains within the elastic range. The evaluation of the maximum seismic member force in a superstructure is thus an important issue. The present study predicts [...] Read more.

It is essential for the seismic design of a base-isolated building that the seismic response of the superstructure remains within the elastic range. The evaluation of the maximum seismic member force in a superstructure is thus an important issue. The present study predicts the maximum seismic member force of five- and fourteen-story reinforced concrete base-isolated frame buildings adopting pushover analysis. In the first stage of the study, the nonlinear dynamic (time-history) analysis of the base-isolated frame buildings is carried out, and the nonlinear modal responses of the first and second modes are calculated from pushover analysis results. In the second stage, a set of pushover analyses is proposed considering the combination of the first and second modal responses, and predicted maximum member forces are compared with the nonlinear time-history analysis results. Results show that the maximum member forces predicted in the proposed set of pushover analyses are satisfactorily accurate, while the results predicted considering only the first mode are inaccurate. Full article

(This article belongs to the Special Issue Smart Solutions and Structural Systems for Seismic-Resistant Buildings)

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17 pages, 1431 KiB

Open AccessArticle

BIM4Ren: Barriers to BIM Implementation in Renovation Processes in the Italian Market

by Mohamed Elagiry, Valentina Marino, Natalia Lasarte, Peru Elguezabal and Thomas Messervey

Buildings 2019, 9(9), 200; https://doi.org/10.3390/buildings9090200 - 30 Aug 2019

Cited by 23 | Viewed by 6515

Abstract

As a part of BIM4REN (Building Information Modelling based tools & technologies for fast and efficient RENovation of residential buildings) H2020 project, an analysis of the barriers of the renovation process, the potential of digitalization to overcome those barriers, and the requirements to [...] Read more.

As a part of BIM4REN (Building Information Modelling based tools & technologies for fast and efficient RENovation of residential buildings) H2020 project, an analysis of the barriers of the renovation process, the potential of digitalization to overcome those barriers, and the requirements to ensure a successful digital workflow. This paper focuses on the Italian market where surveys, interviews, and a workshop were conducted, and then a diagnosis was made on the results obtained. Results show that technological innovation on BIM tools cannot be a stand-alone action to reach a full digitalization of the renovation sector, but it shall be supported by a major awareness of the actors involved, improved skills, and competences, as well as an important change of approach in the current construction practice. Full article

(This article belongs to the Special Issue Sustainability and Energy Efficiency of the Built Environment: from the Single Building to the District Scale)

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16 pages, 1200 KiB

Open AccessArticle

Differences in Occupants’ Satisfaction and Perceived Productivity in High- and Low-Performance Offices

by Özgür Göçer, Christhina Candido, Leena Thomas and Kenan Göçer

Buildings 2019, 9(9), 199; https://doi.org/10.3390/buildings9090199 - 30 Aug 2019

Cited by 38 | Viewed by 6305

Abstract

This paper reports the results from a dataset comprising 9794 post-occupancy evaluation (POE) surveys from 77 Australian open-plan offices. This paper specifically focuses on a sub-set of 20 offices (n = 2133), identified from ranking 10 offices each, with the least ( [...] Read more.

This paper reports the results from a dataset comprising 9794 post-occupancy evaluation (POE) surveys from 77 Australian open-plan offices. This paper specifically focuses on a sub-set of 20 offices (n = 2133), identified from ranking 10 offices each, with the least (n = 1063) and highest (n = 1070) satisfaction scores, respectively. The satisfaction scores were evaluated on the basis of seven factors (i.e., building/office aesthetics and quality, thermal comfort and indoor air quality, noise distraction and privacy, personal control, connection to outdoor environment, maintenance and visual comfort, and individual space). Using the POE survey data from 20 offices, regression analyses and two-way ANOVA tests were carried out to understand the differences in occupants’ satisfaction and perceived productivity arising from open-plan offices. According to the statistically significant regression analyses results, it was identified that building/office aesthetics and quality (β = 0.55, p < 0.001) and noise distraction and privacy (β = 0.33, p < 0.001) were the two strongest predictors contributing perceived productivity in low-performance offices. Two-way ANOVA test results for the 10 high-performance offices indicate that the perceived productivity was strongly associated with the office’s physical configuration, the employees’ working experience, and the working hours at that office. Full article

(This article belongs to the Special Issue Post-Occupancy Evaluation Studies: For High Performance, Sustainable and Healthy Environments)

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14 pages, 3130 KiB

Open AccessArticle

Determination of the Optimal Order of Grey-Box Models for Short-Time Prediction of Buildings’ Thermal Behavior

by Nivine Attoue, Isam Shahrour, Hussein Mroueh and Rafic Younes

Buildings 2019, 9(9), 198; https://doi.org/10.3390/buildings9090198 - 29 Aug 2019

Cited by 4 | Viewed by 3625

Abstract

The use of grey-box models for short-time forecasting of buildings’ thermal behavior requires the determination of the models’ order since this order could influence the grey-box models’ performance. This paper presents an analysis of the optimal order of these models for different thermal [...] Read more.

The use of grey-box models for short-time forecasting of buildings’ thermal behavior requires the determination of the models’ order since this order could influence the grey-box models’ performance. This paper presents an analysis of the optimal order of these models for different thermal conditions. The novelty of this work consists of considering the influence of the heating conditions on the determination of the performances of grey-box models. The analysis is based on experimental tests that were conducted in a room with different thermal conditions, related to the variation of the heating power. Experimental results were used for the determination of the optimal grey-box models’ order that minimizes the gap between the experimental results and the grey-box forecasting. Results show that the optimal grey-box models’ order depends on the buildings’ thermal conditions, but generally lies between two and three with an error less than 0.2 °C and a fit percent greater than 90%. Full article

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13 pages, 1921 KiB

Open AccessArticle

CO₂ Concentration and Occupants’ Symptoms in Naturally Ventilated Schools in Mediterranean Climate

by Jesica Fernández-Agüera, Miguel Ángel Campano, Samuel Domínguez-Amarillo, Ignacio Acosta and Juan José Sendra

Buildings 2019, 9(9), 197; https://doi.org/10.3390/buildings9090197 - 29 Aug 2019

Cited by 24 | Viewed by 5496

Abstract

A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in [...] Read more.

A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in Andalusia and the evolution of CO₂ concentration during school hours through in situ monitoring. Pressurization and depressurization tests were performed in 42 classrooms and CO₂ concentration was measured in two different periods, winter and midseason, to study the impact of the different levels of aperture of windows. About 917 students (11–17 years of age) were surveyed on symptoms and effects on their health. The mean n₅₀ values are about 7 h⁻¹, whereas the average CO₂ concentration values are about 1878 ppm, with 42% of the case studies displaying concentrations above 2000 ppm with windows closed. Full article

(This article belongs to the Special Issue Airtightness and Controllable Natural Ventilation for Buildings: Challenges and Trends)

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15 pages, 4232 KiB

Open AccessArticle

Seismic Behaviour of EC8-Compliant Moment Resisting and Concentrically Braced Frames

by Silvia Costanzo, Roberto Tartaglia, Gianmaria Di Lorenzo and Attilio De Martino

Buildings 2019, 9(9), 196; https://doi.org/10.3390/buildings9090196 - 28 Aug 2019

Cited by 23 | Viewed by 4640

Abstract

The design procedure codified within current Eurocode 8 for dissipative moment resisting and concentrically braced frames have led to the design of massive systems characterized in the most of cases by poor energy dissipation capacity. The research activity presented in the current paper [...] Read more.

The design procedure codified within current Eurocode 8 for dissipative moment resisting and concentrically braced frames have led to the design of massive systems characterized in the most of cases by poor energy dissipation capacity. The research activity presented in the current paper addresses the identification of the main criticisms and fallacies in the current EN 1998-1 for those seismic-resistant typologies. In this regard, the design provisions and codified rules for both moment resisting frames (MRFs) and chevron concentrically braced frames (CCBFs) are critically discussed and numerically investigated. Static and incremental dynamic analyses were performed on a set of 3 and 6-story frames designed compliant to EN 1998-1. The results from the numerical analyses are reported and discussed. Full article

(This article belongs to the Special Issue Smart Solutions and Structural Systems for Seismic-Resistant Buildings)

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12 pages, 240 KiB

Open AccessArticle

Does Leadership Style Differ between a Post-Disaster and Non-Disaster Response Project? A Study of Three Major Projects in New Zealand

by Frederick Witton, Eziaku Onyeizu Rasheed and James Olabode Bamidele Rotimi

Buildings 2019, 9(9), 195; https://doi.org/10.3390/buildings9090195 - 28 Aug 2019

Cited by 3 | Viewed by 4392

Abstract

Purpose–The leadership styles of three major infrastructure projects within New Zealand were determined and comparatively analysed to ascertain whether the leadership style employed in a post-disaster recovery project would differ significantly from a normal infrastructure project. A multifactor leadership questionnaire was administered to [...] Read more.

Purpose–The leadership styles of three major infrastructure projects within New Zealand were determined and comparatively analysed to ascertain whether the leadership style employed in a post-disaster recovery project would differ significantly from a normal infrastructure project. A multifactor leadership questionnaire was administered to project leaders and personnel of the three infrastructure projects. The statistically significant differences (p < 0.05) in leadership styles were determined using one-way ANOVA analytical tool in STATISTICA 13. Results showed all three projects have strong transformational and transactional leadership traits. There were similarities in leadership style amongst the projects. None of the projects had a significant laissez-faire leadership style. Hence there is no significant difference in leadership style between a disaster recovery project and a normal project. Plausible reasons and implications are provided to support these findings. This study provides insight into leadership styles employed in projects in New Zealand, which could assist in the decision-making process for new and existing projects. Future studies could investigate the effect a combination of leadership styles will have on project success and staff retention. More studies are required across New Zealand to verify the generalizability of the current study findings. Full article

24 pages, 1988 KiB

Open AccessArticle

Circular and Flexible Indoor Partitioning—A Design Conceptualization of Innovative Materials and Value Chains

by Bob Geldermans, Martin Tenpierik and Peter Luscuere

Buildings 2019, 9(9), 194; https://doi.org/10.3390/buildings9090194 - 26 Aug 2019

Cited by 16 | Viewed by 7546

Abstract

This article sheds light on the materialization and operation of residential partitioning wall components in relation to circular and flexible performance. The hypothesis is twofold: (1) A stronger integration of materialization and operation aspects is indispensable in establishing sustainable value-models, and (2) recent [...] Read more.

This article sheds light on the materialization and operation of residential partitioning wall components in relation to circular and flexible performance. The hypothesis is twofold: (1) A stronger integration of materialization and operation aspects is indispensable in establishing sustainable value-models, and (2) recent innovations, concerning the reversibility of material connections, will help disrupting the status-quo in that respect. Attention is drawn to renewable natural fibre composites (NFC), reversible adhesives, and biodegradable insulation materials. After a background sketch regarding the notion of time, change, and material circularity in design and planning, the housing challenge in the Amsterdam metropolitan area (AMA, the Netherlands) is described. Next, a design conceptualization stage is introduced, informed by two methods and tools in particular: Circ-Flex assessment, and activity-based spatial material flow analysis. Results of the conceptualization stage are presented regarding materialization and operation, culminating in Circ-Flex partitioning components, more specifically: Side panels and insulation. It was found that NFC can tackle current issues relating, most prominently, to circularity performance. Associated modifications in the value-chain occur, above all, in raw material sourcing, manufacturing, reutilization logistics, and data-sharing. The outcomes are valid for multiple building components other than indoor partitioning, such as kitchens and furniture, but also insulation—and interior side-sheeting—of walls and roofs in energy-renovations. Full article

(This article belongs to the Special Issue Sustainable Development of Buildings: Design, Construction, Quality Inspection, Operation Management)

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32 pages, 12239 KiB

Open AccessArticle

Technological Advances and Trends in Modern High-Rise Buildings

by Jerzy Szolomicki and Hanna Golasz-Szolomicka

Buildings 2019, 9(9), 193; https://doi.org/10.3390/buildings9090193 - 26 Aug 2019

Cited by 29 | Viewed by 96332

Abstract

The purpose of this paper is to provide structural and architectural technological solutions applied in the construction of high-rise buildings, and present the possibilities of technological evolution in this field. Tall buildings always have relied on technological innovations in engineering and scientific progress. [...] Read more.

The purpose of this paper is to provide structural and architectural technological solutions applied in the construction of high-rise buildings, and present the possibilities of technological evolution in this field. Tall buildings always have relied on technological innovations in engineering and scientific progress. New technological developments have been continuously taking place in the world. It is closely linked to the search for efficient construction materials that enable buildings to be constructed higher, faster and safer. This paper presents a survey of the main technological advancements on the example of selected tall buildings erected in the last decade, with an emphasis on geometrical form, the structural system, sophisticated damping systems, sustainability, etc. The famous architectural studios (e.g., for Skidmore, Owings and Merill, Nikhen Sekkei, RMJM, Atkins and WOHA) that specialize, among others, in the designing of skyscrapers have played a major role in the development of technological ideas and architectural forms for such extraordinary engineering structures. Among their completed projects, there are examples of high-rise buildings that set a precedent for future development. Full article

(This article belongs to the Special Issue Architecture and Engineering: the Challenges - Trends - Achievements)

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17 pages, 6162 KiB

Open AccessArticle

The Impact of Basalt Components on the Structure of Bricks Formed as a Result of Hydrothermal Treatment

by Anna Stepien and Paulina Kostrzewa

Buildings 2019, 9(9), 192; https://doi.org/10.3390/buildings9090192 - 26 Aug 2019

Cited by 6 | Viewed by 4124

Abstract

The article focuses on brick products, the production of which is based on natural components, such as lime (CaO), quartz sand (SiO₂) and water (H₂O), and which are created during the process of the so-called hydrothermal treatment. In the [...] Read more.

The article focuses on brick products, the production of which is based on natural components, such as lime (CaO), quartz sand (SiO₂) and water (H₂O), and which are created during the process of the so-called hydrothermal treatment. In the production process of the modified brick, basalt components (basalt aggregate, with graining of 2–4 mm, basalt powder and basalt fibers) were used because of their natural origin, mineralogical composition, high volume density, and possibly minimal absorbability. In the article thermodynamic properties of minerals forming the construction of basalt components were determined, as well as the phases that arise during the autoclaving process. Compressive strength and density were investigated due to acoustic properties. The product modified with basalt aggregate shows decrease in water absorption as a result of capillary action and in absorbability up to 9% (in the reference sample up to 16%). The sample with basalt aggregate shows compressive resistance of 33 MPa on average, with the increase of volume density to 2.29 kg/dm³. Modification of sand-lime mixture presented satisfying results with 10% basalt powder additive. Application of basalt fibers slightly changed the volume density and absorbability compared with the norm sample. However, it affected the compressive resistance. Full article

(This article belongs to the Special Issue Advances in Sustainable Building Material Engineering)

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37 pages, 6506 KiB

Open AccessReview

Delay Causes and Emerging Digital Tools: A Novel Model of Delay Analysis, Including Integrated Project Delivery and PMBOK

by Samad M. E. Sepasgozar, Reyhaneh Karimi, Sara Shirowzhan, Mohammad Mojtahedi, Sabbar Ebrahimzadeh and David McCarthy

Buildings 2019, 9(9), 191; https://doi.org/10.3390/buildings9090191 - 26 Aug 2019

Cited by 47 | Viewed by 18200

Abstract

Delay is one of the main challenges of construction projects, and there is still much to overcome in order to reach near zero delay in all construction projects. This project aims to conduct a systematic critical review including a bibliography analysis on delay [...] Read more.

Delay is one of the main challenges of construction projects, and there is still much to overcome in order to reach near zero delay in all construction projects. This project aims to conduct a systematic critical review including a bibliography analysis on delay literature in construction. The main questions consider what has been learnt from a decade investigating delay causes and effects in the construction literature and what factors have been missed in the literature. This paper also presents a new and challenging question regarding how digital tools and associated technologies may prevent any delay in construction projects, which can change the research direction from delay investigations to identifying prevention factors. The paper identifies the delay dataset, including 493 papers investigating delay in construction, and establishes a specific dataset of papers focusing on delay effects and causes (DEC), including 94 selected papers covering different factors examined in over 29 countries such as Iran, India, Turkey, Bangladesh, Saudi Arabia, the United Arab Emirates (UAE), Cambodia, Oman, Malaysia, Taiwan, China, Vietnam, the US, the UK, and Egypt. In addition, the paper identifies 30 critical factors with the frequency of occurrences over three times in the DEC dataset and computes their medians of ranking. This paper also discusses digital tools and methods that can be used for delay analysis and preventions, including MS Project, Oracle Primavera P6, and Open Plan by Deltek. The paper discusses the project schedule delay analysis from project management methodology perspectives. It also discusses the current method’s limitations and future directions, which are based on the identification of the deficiency areas. In total, four overlooked factors are identified and suggested, including faulty data analysis, unmatched structure of the research questionnaires with new knowledge and standards [e.g., Project Management Body of Knowledge (PMBOK)], overlooked effects of digital technologies [e.g., Digital twin, Navisworks, Building Information Model (BIM), Geographic Information System (GIS), and Integrated Project Delivery (IPD)], and ignored job-site technologies. In addition, the paper presents the DEC model for future studies, including four main key factors. These factors are resources (e.g., project budgets, labour, material, equipment, and digital tool), project context, stakeholders performance (e.g., owner/client, consultant/designer, contractor, vendor/supplier), and external factors (e.g., ground condition, site location, regulation, natural disaster), which may significantly affect delay prevention and should be concurrently considered in the future delay investigations, since they may be required for designing an effective mitigation strategy when these proof points are identified. This would significantly help to utilise digital systems to prevent time overruns in different construction contexts. Full article

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24 pages, 63696 KiB

Open AccessArticle

The Effect of Balcony Thermal Breaks on Building Thermal and Energy Performance: Field Experiments and Energy Simulations in Chicago, IL

by Irina Susorova, Brent Stephens and Benjamin Skelton

Buildings 2019, 9(9), 190; https://doi.org/10.3390/buildings9090190 - 22 Aug 2019

Cited by 5 | Viewed by 9229

Abstract

A common envelope performance problem in buildings is thermal bridging through balcony slab connections, which can be improved with the use of commercially available thermal break products. Several prior studies have used simulation-based and/or hot box test apparatus approaches to quantify the likely [...] Read more.

A common envelope performance problem in buildings is thermal bridging through balcony slab connections, which can be improved with the use of commercially available thermal break products. Several prior studies have used simulation-based and/or hot box test apparatus approaches to quantify the likely effect of balcony thermal breaks on effective thermal resistance of building enclosures. However, in-situ measurements of thermal performance in real buildings remain limited to date. This study uses a combination of field measurements and models to investigate the effects of installing balcony thermal breaks on the interior surface temperatures, effective thermal resistance, and annual building energy consumption. For the field experiment, yearlong measurements were conducted on the 13th floor of a 14-story multi-family building in Chicago, IL, in which thermocouple sensors were embedded into eight balconies and their adjacent interior floor slabs just before concrete was poured to complete the construction. The eight balconies included four control balconies without thermal breaks and four thermally-broken balconies with a commercially available thermal break product installed. The experimental data were then combined with 2-D heat transfer modeling and whole building energy simulations to investigate the impacts of the thermal break product installation on the envelope thermal resistance and overall energy use in the case study building as well as in several more generic building designs with simpler geometries. The results demonstrate that although the balcony thermal breaks helped regulate interior slab temperatures and improved the effective thermal resistance of the curtain wall enclosure assembly by an estimated ~14% in the case study building, the predicted effect on annual energy consumption in all modeled building types was small (i.e., less than 2%). The results also highlight the importance of paying careful attention to envelope design details when using thermal break products and considering the use of thermal break products in combination with other energy efficiency strategies to achieve high performance enclosures. Full article

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