Construction Phase Research Articles

Growing demand for housing and the productivity challenges in developing housing projects in Iraq

The housing sector in Iraq is facing growing demand. However, productivity challenges continue to hinder the timely and efficient delivery of residential projects. Recognising the urgent need to increase construction productivity (CP) in this sector, this study investigates critical factors that impact the performance of horizontal housing projects in Iraq. The novelty of this research lies in its focus on housing skeleton tasks, such as foundations, brickwork, and slabs, which are pivotal to project efficiency. A structured questionnaire was developed, encompassing 47 factors distributed across the planning, design, and construction phases. The survey was administered to a range of industry stakeholders, including project managers, consultants, engineers, and supervisors, and it achieved a high response rate of 79.6%. The results were analysed via a modified weighted relative importance index (RII), which incorporates respondents’ experience levels to yield a nuanced understanding of each factor’s impact. The key findings reveal that planning (RII = 0.874), team size (RII = 0.856), quantity of brickwork (RII = 0.838), supervision (RII = 0.815), and unit area (RII = 0.793) are among the most influential factors on CP. These insights provide valuable guidance for researchers and practitioners in identifying areas for strategic improvement, ultimately supporting the capacity of Iraq’s housing sector to meet escalating demands.

Solar Distillation as a Sustainable STEM Tool: Bridging Theory and Practice

This study addresses a gap in STEM education by integrating solar distillation as a sustainable, hands-on learning tool to enhance students’ comprehension of heat transfer concepts and increase their awareness of environmental challenges. Guided by Bruner’s constructivist theory, this project-inspired approach aims to bridge theoretical knowledge with real-world applications, particularly sustainability. Students participated actively in the solar still’s design, construction, and analysis phases, allowing them to apply scientific principles in practical contexts. The findings demonstrated that students understood heat and mass transfer concepts more profoundly and developed an appreciation for renewable energy technologies and sustainable practices. Additionally, the project highlighted the impact of external climatic conditions on system performance, promoting an awareness of environmental factors affecting sustainable solutions. This research illustrates the potential of combining constructivist learning with sustainable technology education, preparing students to address pressing global issues such as water scarcity and energy conservation.

Dating of mortars from Kastelli Hill, Chania, Crete, Greece, based on their compositional analyses

Abstract The study of mortars plays a crucial role in determining the chronology of construction phases. According to the database of mortars analysed from historical monuments in Crete and other areas of Greece, significant differences in mortar composition are observed across historical periods. In the present study, 14 mortars from Kastelli Hill and Katre Street in Chania, originating from the fortified wall and neighboring buildings, are analysed. The physico-chemical and mineralogical analysis aims at clarifying the nature of mortars, their manufacturing technology, and, in particular, to compare different construction phases. In addition, comparing historically identified mortars with those under study reveals similarities and differences across construction phases. The indicators considered include the trace elements of aggregates and binder, the characteristics of aggregate grain size, the type of binder (hydraulic or aerial), and the presence of pozzolanic additives. The comparisons indicated that the mortars from the wall were manufactured during the Roman period, since they are successfully compared with the mortars of buildings dating back to that time. Graphical abstract

Recycled used cooking oil (UCO) as a rejuvenator in high content reclaimed asphalt pavement (RAP) mixes: A life cycle assessment (LCA).

This study investigates the primary data collected at a used cooking oil (UCO) recycling facility to quantify its environmental impact when used as a rejuvenator in high content reclaimed asphalt pavement (RAP) mixes. Annual energy consumption data sets on transportation, storage, filtration, machinery, and purification are assessed using the life cycle assessment (LCA) methodology with the LCA software Simapro 9.4 to evaluate the influential parameters and processes in reducing emissions. Pearson correlations of the production process show a higher association of carbon footprint with two dominant recycling factors: (1) electricity consumption (r=0.89) and (2) fuel consumption for transportation (r=0.37). A comprehensive LCA conducted on asphalt pavements with various RAP contents shows that a 28.81% reduction of carbon emissions can be achieved during the construction phase by adding 60% rejuvenated RAP. However, the relative uncertainty around RAP moisture content at the time of usage and faster pavement deterioration over the service life when high RAP content is incorporated into asphalt mixes might hinder the environmental advantage of adding RAP during the maintenance phase. Non-properly treated, blended, and rejuvenated RAP can be susceptible to early cracking, thus resulting in increased periodic maintenance. Moreover, the break-even point of economic appraisal suggest over 50% RAP content is beneficiary even at the higher discount rates (12%). Conducted LCA and sensitivity analyses emphasise the importance of collecting primary data from recycling facilities and considering both the construction and maintenance phases for implementing effective sustainable strategies.

Quantitative and Qualitative Benefits of Using BIM in Design and Construction Stages for Railway Development

As railway infrastructure projects become increasingly complex, the potential of Building Information Modeling (BIM) technology to enhance project efficiency and management has garnered significant attention. This paper analyzes the quantitative and qualitative benefits of BIM in the design and construction stages of railway development projects through case studies and compares its effectiveness in these two phases. The results indicate that BIM primarily benefits the design stage by reducing design errors and optimizing processes to save costs and time, averaging cost savings of USD 41,000 and a reduction of 49 days in project duration. In the construction stage, the impact of BIM is even more pronounced, reflected in reduced rework, dynamic resource management, and shortened project timelines, leading to savings of USD 710,795 and a reduction of 89 to 104.5 days in project duration. The 3D modeling and real-time information-sharing capabilities of BIM significantly enhance cross-departmental collaboration efficiency and information transparency, minimizing rework caused by communication issues and greatly optimizing project management and execution. This study shows that BIM can lay the groundwork for construction during the design phase and further improve project management efficiency during the construction phase.

Prototype for thermal conductivity measurement of materials made in forest agroresidue

This research focuses on the development of a prototype machine to determine the thermal conductivity of insulating materials made from agroforestry residues and PET, following the ASTM C177 standard for the protected hot plate method. The study raises awareness of the importance of sustainable insulating materials as alternatives to conventional petroleum-based options. The prototype design incorporates a hot plate with heating elements, cold plates with peltier cells for cooling, and temperature sensors for data collection. The research provides a detailed description of the design process, material selection criteria based on their thermal properties, and construction phases. The results show the potential of the prototype in measuring the thermal conductivity of agroforestry residues and PET as sustainable insulating materials.

Digital delivery in architecture from design to execution

Digital delivery in architecture, as an innovative approach, enables the integration of design and construction processes through digital tools and technologies. This paper examines the role of these technologies in improving efficiency, reducing errors, and enhancing the quality of architectural projects. The primary aim of this research is to analyze the impact of digital technologies on the coordination between design and construction phases and to provide solutions for optimizing these processes. The study employs qualitative analysis and case studies to investigate the application of tools such as Building Information Modeling (BIM) and digital simulations in various projects. The findings indicate that the use of digital technologies can improve project timelines, reduce costs, and increase accuracy during execution phases. This study highlights the importance of digital delivery as an essential tool for architects and engineers in future projects and provides practical recommendations for utilizing these technologies effectively.

The Impact of Multi-Dimensional Incentives on the Performance of Rail Transit PPP Projects

This study investigates how different types of incentives impact the performance of rail transit PPPs, focusing on their construction and operational phases. By surveying 121 practitioners working in the Chinese rail transit industry, we propose a new classification of incentives (i.e., control-oriented, neutrality-oriented, and recognition-oriented incentives) based on psychological theories to broaden the categorization of “positive” (rewards) and “negative” (punishment) incentives. We further explore how these multi-dimensional incentives influence project performance by surveying another 256 industry professionals. Our findings reveal that (1) in addition to punishments, performance-based payment/bonus, credit ratings, and reputation mechanisms are newly recognized as control-oriented incentives, which can restrain the autonomy of the private sector; (2) control-oriented incentives positively influence project performance in the construction phase where clear, measurable goals are available, but their impact diminishes in the operational phase; (3) recognition-oriented incentives enhance project performance in both construction and operational phases (especially the latter), fostering long-term sustainability; and (4) neutrality-oriented incentives focus on risk allocation and collaboration between public and private sectors, showing a modestly positive effect in the operational phase. As such, the study provides decision-makers in the rail transit industry with valuable insights to enhance project performance effectively when implementing incentive policies.

Collapse of an RC Building Under Construction with a Flat Slab System: Reasons, Calculations, and FE Simulations

The using of flat slab systems is a common structural solution for residential and commercial buildings as they are a cost-effective structural solution that simplifies and speeds up the construction phase. However, the flat slab systems have complex behavior, particularly in the slab–column connection zones, because of punching shear. Therefore, to prevent brittle flat slab collapse because of punching shear, there are some conditions which must be met in regulations such as Eurocode 2, American Concrete Institute’s Code, and Türkiye Building Earthquake Code—2018. Flat slab collapses because of punching shear can be caused by deficiencies in the design phase as well as deficiencies in the construction phase. The purpose of this study is to investigate the causes of flat slab collapses due to punching shear, focusing on whether these failures arise from design or construction deficiencies. The study highlights the importance of adhering to regulations to prevent brittle flat slab collapses. A case study of an actual building collapse due to punching shear was conducted. Theoretical punching shear strength was calculated based on the Türkiye Building Earthquake Code—2018. A finite element model of the collapsed part of the building was created, and collapse mechanism simulations were performed. It was examined whether the punching collapse mechanism was caused by deficiencies in the design or the construction phase. The findings revealed the critical role of proper design phases and construction practices in ensuring structural integrity.

From Junk to Genius: Robotic Arms and AI Crafting Creative Designs from Scraps

As sustainable architecture is increasingly emphasizing material reuse, this study proposes a novel, interactive workflow that integrates robotic arms and artificial intelligence to transform waste materials from architectural models into creative design components. Unlike existing recycling efforts, which focus on the construction phase, this research uniquely targeted discarded architectural model materials, particularly polystyrene foam, that are often overlooked, despite their environmental impact. The workflow combined computer vision and machine learning, utilizing the YOLOv5 model, which achieved a classification accuracy exceeding 83% for the polygon, rectangle, and circle categories, demonstrating a superior recognition performance. Robotic sorting demonstrated the ability to process up to six foam blocks per minute under controlled conditions. By integrating Stable Diffusion, we further generated speculative architectural renderings, enhancing creativity and design exploration. Participant testing revealed that human interaction reduced stacking errors by 57% and significantly improved user satisfaction. Moreover, human–robot collaboration not only corrected robotic errors, but also fostered innovative and collaborative solutions, demonstrating the system’s potential as a versatile tool for education and industry while promoting sustainability in design. Thus, this workflow offers a scalable approach to creative material reuse, promoting sustainable practices from the model-making stage of architectural design. While these initial results are promising, further research is needed to adapt this technique for larger-scale construction materials, addressing real-world constraints and broadening its applicability.

InSAR-based investigation of ground subsidence due to excavation: a case study of Incheon City, South Korea

Ground subsidence is one of geohazards, particularly in urban environment due to its negative impact to nearby buildings and civil infrastructures. This study investigates the amount and spatial distribution of ground subsidence in Incheon City, South Korea, where ground excavation was made. Interferometric Synthetic Aperture Radar (InSAR) was used to monitor surface deformation around the excavation site. The study analyzed subsidence during an excavation project using Sentinel-1b satellite data, and the InSAR results were compared with traditional leveling methods and field measurements. Notable subsidence during the early construction phase was identified, which demonstrates the effectiveness of InSAR in urban environment. The research contributes to understanding of the excavation-inducing ground subsidence due to the reclamation layer.

Causal mechanisms of 100 accidents in sewage system facilities

ABSTRACT The safety of urban sewage system facilities, including wastewater treatment plants and pipeline facilities, has become increasingly critical due to accidents. Numerous accidents frequently occur during the construction and operation phases, posing a significant threat to human health and jeopardizing lives. This paper investigates safety incidents and analyzes their causes to identify common patterns. The results indicate that human factors are the primary contributors to accidents, with those involving chemical and toxic gas poisoning standing out as particularly severe incidents. This paper proposes several measures to reduce accident risks, emphasizing the need for stronger supervision, the establishment of a regular management system, and the resolution of key technical challenges.

Unveiling Ancient Constructive Phases With Integrated Geophysical Prospection in the Group of the Columns, Mitla, Oaxaca

ABSTRACTThe archaeological zone of Mitla has an invaluable place within the Mexican cultural heritage. This pre‐Hispanic city concentrated the political and religious power of the central valleys of Oaxaca, south of Mexico, mainly during the Postclassic period. However, despite its great cultural importance and considering the risk to its monuments due to the high seismicity of the region, very few studies have focused on the systematic exploration of the subsoil of this area. The present research aimed to characterize the subsoil of one of the architectural compounds of the archaeological zone, the Group of the Columns, aiming to identify possible underground elements such as architectural structures, tunnels or tombs. For that purpose, three non‐invasive geophysical methods were applied, ground penetrating radar (GPR), electrical resistivity tomography (ERT) and ambient noise tomography (ANT). In the palace, all three methods showed the presence of a substructure below the Hall of the Columns. In the Plaza of the Columns, the GPR detected anthropogenic walls and platforms at different depths that suggest a different configuration of the square and a more prolonged occupation of this group. The results open the discussion about the temporality of the first construction of this architectural group.

A Component-Design-Based Carbon Emission Calculation Method in the Life Cycle of a Prefabricated Building Structural Member System

Carbon emissions from buildings account for a large proportion of total social carbon emissions. Prefabricated buildings can effectively reduce carbon emissions in the construction materialization phase. The existing building carbon emission calculation method for prefabricated buildings seems too complicated due to the large amounts of data that need to be consulted in the production, transportation, construction, and demolition phases of each building. Meanwhile, the traditional building carbon emission calculation method must be carried out after the completion of construction drawings, because the consumption of labor, materials, and machinery must be calculated according to these drawings. This paper proposes a building carbon emission calculation method for prefabricated buildings based on the component design method. A case study proved that our method can calculate carbon emissions in the materialization phase of construction more quickly than the traditional quota carbon emission calculation method, and the results of the two methods differ by less than 10%. This method significantly improves the prediction of carbon emissions in the building materialization phase.

Delays in Infrastructure Projects: Main Reasons in the Design, Procurement, and Construction Phases

Delays in Infrastructure Projects: Main Reasons in the Design, Procurement, and Construction Phases

The Synagogue at Ḥorbat Merot: Its Construction Phases and a New Interpretation of the Finds (Hebrew; English summary)

The Synagogue at Ḥorbat Merot: Its Construction Phases and a New Interpretation of the Finds (Hebrew; English summary)

Determination of scales and measures for assessing social sustainability practices in construction projects

PurposeThis paper addresses the scarcity of research on social sustainability (SS) in sustainable construction (SC) by establishing indicators and descriptors for SS throughout the construction project life cycle. The objective is to provide an objective assessment and improve SS practices.Design/methodology/approachThe study employs a comprehensive methodology involving literature review, semi-structured interviews, focus group discussions and structured interviews. A total of 42 indicators were identified from the literature and presented to 20 expert panels, resulting in the addition of seven indicators. A refined set of 49 indicators was then presented to 25 experts via focus group discussions, and structured interviews were conducted to determine suitable descriptors and scales for each indicator.FindingsThe study identified 19 indicators for the pre-construction phase, 25 for the construction phase and 4 for the post-construction phase. These findings offer an objective assessment of SS practices across the construction project life cycle. The indicators and descriptors serve as a valuable tool for industry practitioners to monitor and improve social aspects, fostering SC.Research limitations/implicationsThe study’s limitations include the context-specific nature of the findings and the potential subjectivity introduced through the selection of expert panels.Practical implicationsThe identified indicators and descriptors have practical implications for industry practitioners, providing guidelines to enhance social sustainability practices throughout the project life cycle.Originality/valueThis study fills a research gap by focussing on SS in construction. The comprehensive methodology contributes to theory development and provides practical tools for practitioners to advance social sustainability practices.

3E Comparative Analysis of Brayton–ORC Cycle Using Two Thermal Sources: Solar Energy and Coconut Shell Biomass

Solar energy and biomass offer sustainable alternatives to meet the energy demand and reduce the environmental impact of fossil fuels. In this study, through mass and energy balances, a comparative analysis of energy, exergy, and environmental impact (LCA) was conducted on two renewable thermal sources: solar energy and coconut shell biomass, both coupled to a supercritical CO2 Brayton cycle (sCO2) with an organic Rankine cycle (ORC) for waste heat recovery. The sCO2–ORC–biomass configuration showed higher exergy efficiency (41.1%) and lower exergy destruction (188.88 kW) compared to the sCO2–ORC–solar system (23.76% and 422.63 kW). Thermal efficiency (50.6%) and net power output (131.73 kW) were similar for both sources. However, the solar system (204,055.57 kg CO2-equi) had an 85.6% higher environmental impact than the biomass system (109,933.63 kg CO2-equi). Additionally, the construction phase contributed ~95% of emissions in both systems, followed by decommissioning (~4.5%) and operation (~0.1%). Finally, systems built with aluminum generate a higher carbon footprint than those with copper, with differences of 2% and 3.2% in sCO2–ORC–solar and sCO2–ORC–biomass, respectively. This study and an economic analysis make these systems viable thermo-sustainable options for clean energy generation.

Development of Delay and Disruption Cause Monitoring Framework for Megaprojects: A Claim Management Approach from the Contractor’s Perspective to Enhance Sustainability in the Built Environment

Delays and disruptions (D&D) are considered chronic peculiarities of the construction phase of the built environment, especially in megaprojects. Systematic monitoring of claimable D&D causes becomes crucial for the contractors to compensate for their losses caused by delays and disruptions, enabling sustainable use of resources. Thus, this study proposed a delay and disruption (D&D) cause monitoring framework that enables contractors to timely and accurately detect claimable delays and disruption causes/events in megaprojects. At the outset, a systematic literature review was conducted to design an initial version of the framework and extract claimable D&D. Then, focus group discussion (FGD) sessions were conducted to revise and refine the initial version of the framework and a list of claimable D&D causes. Next, a fuzzy Analytical Hierarchy Process (AHP) analysis was conducted to determine the relative importance of each claimable D&D cause in terms of its impact on the megaprojects. Finally, a consistency analysis was conducted to demonstrate the reliability of the dataset. Findings revealed that claimable D&D causes are indispensable parts of the claim management process. In this manner, the proposed framework recommends monitoring the claimable D&D causes regularly during the whole construction phase of the megaprojects. The fuzzy AHP analysis also revealed that causes such as “Suspension of project activities by the owner”, “Errors and clashes in the design”, “Shortage of construction materials in the market”, “Discovery of fossils and historical artifacts”, “Unavailability of the commissioning team on the due date”, and “Late delivery of testing materials and utilities by the owner” were particularly rated as highly critical causes, needing urgent and sophisticated monitoring plan for timely detection and data collection. By introducing a proactive approach to avoid lengthy and costly dispute resolution processes, this study enables decision-makers to enhance sustainability in the built environment.

Research on Deflection Risk Assessment for Steel Box Girder Bridges Based on GA-BP Neural Network

Steel box girder bridges constitute a pivotal structural component in modern bridge engineering, confronting intricate mechanical environments and dynamic conditions during construction, with a particularly notable risk of deflection. Risk assessments predominantly rely on traditional mechanical analyses and empirical judgments, which need help to fully capture the dynamic construction changes and latent risks. This study introduces an innovative risk assessment methodology grounded in finite element analysis (FEA) and optimized by a genetic algorithm-enhanced back propagation neural network (GA-BP) to address these limitations. This approach entails constructing an FEA model to precisely simulate and predict the mechanical behavior during the construction phase, with field data validation ensuring the model’s accuracy. The GA-BP assessment model is established by further incorporating the genetic algorithm to optimize the BP neural network, enabling comprehensive, systematic, and efficient risk assessment. Through practical application case studies, this methodology demonstrates the ability to accurately identify the critical risk factors influencing deflection during the construction phase of steel box girder bridges, providing a scientific basis for construction control. This research holds significant theoretical value and practical significance, and it offers a scientific foundation for risk management, construction optimization, and safety assurance in future bridge engineering projects, thereby enhancing the overall quality and safety of bridges.