Construction Phase Research Articles

Implementation of Site Quality Management System for a Building Construction Project

Construction industry plays an important role in the development of any country. The development of construction industry depends on the quality of construction projects. Quality is one of the critical factors in the success of construction projects. Improvement in the quality of construction projects is linked with quality management in the project life cycle. Although quality management at every stage of project life cycle is important but the quality management at the execution (construction) stage contributes significantly on final quality outcome of construction projects. This project mainly focuses the importance and factors that affects the quality management in the execution (construction) phase. The project also includes visiting of some construction companies and conducts the questionnaire survey, then analyse the difficulties (major factors) and the cost variance due to quality defect in quality management and suggests some proactive measures for the improvement of quality in the execution phase of construction projects.

Challenges of Implementing Integrated Project Delivery in the Construction Industry in Egypt

Abstract The construction industry, being one of the biggest sectors globally, has a crucial part to play in achieving global sustainability goals. However, it faces criticism for practices that impede sustainability in construction projects. This is often attributed to the continued reliance on traditional construction methods and contracts, which typically separate design and construction phases. This separation hampers communication among project stakeholders and hinders construction professionals from offering feedback to improve project performance. Despite various efforts to address the shortcomings of traditional procurement methods and contracts, this issue persists. Integrated Project Delivery (IPD) offers a fresh strategy that combines people, systems, business models, and practices to boost value for clients, reduce waste, encourage teamwork, and increase efficiency throughout the entire project. Nonetheless, integrating this approach into the construction sector in Egypt and the MENA region encounters several hurdles. This study aims to explore the challenges associated with implementing IPD in Egypt’s construction industry. This research employs a qualitative approach, grounding its findings in a thorough review of literature and detailed case studies. It explores the nature of the construction industry, sustainability efforts, construction contracts, and IPD. Furthermore, it includes an analysis of three case studies to shed light on the benefits of implementing IPD in construction projects.

A new hybrid gadolinium nanoparticles-loaded polymeric material for neutron detection in rare event searches

Experiments aimed at direct searches for WIMP dark matter require highly effective reduction of backgrounds and control of any residual radioactive contamination. In particular, neutrons interacting with atomic nuclei represent an important class of backgrounds due to the expected similarity of a WIMP-nucleon interaction, so that such experiments often feature a dedicated neutron detector surrounding the active target volume. In the context of the development of DarkSide-20k detector at INFN Gran Sasso National Laboratory (LNGS), several R&D projects were conceived and developed for the creation of a new hybrid material rich in both hydrogen and gadolinium nuclei to be employed as an essential element of the neutron detector. Thanks to its very high cross-section for neutron capture, gadolinium is one of the most widely used elements in neutron detectors, while the hydrogen-rich material is instrumental in efficiently moderating the neutrons. In this paper results from one of the R&Ds are presented. In this effort the new hybrid material was obtained as a poly(methyl methacrylate) (PMMA) matrix, loaded with gadolinium oxide in the form of nanoparticles. We describe its realization, including all phases of design, purification, construction, characterization, and determination of mechanical properties of the new material.

Solving the yard crane scheduling problem with dynamic assignment of input/output points

This paper introduces an automatic yard crane scheduling problem with additional assignments of input/output (I/O) points at the block. I/O points are the buffer between the block and the rest of the terminal and containers are relocated from the block to the I/O points or vice-versa. The crane schedule therefore not only considers movements, storage and retrieval of containers, but must also be coordinated with the release and due times of containers at the I/O points, which are also limited and need to be assigned during the scheduling process. This results in a complex, but at the same time, more realistic problem. Two GRASP (Greedy Randomized Adaptive Search Procedure) heuristic approaches are proposed along with improvements to the solution construction and local search phases that are specifically tailored for this problem. The proposed algorithms are statistically calibrated and comprehensive experiments are designed to assess the performance of the method, including validation across small, medium, and large size instances. The experimental results show that the proposed methods are effective and competitive when compared to existing approaches. The GRASP manages to obtain an optimality average rate of 71.25% for small instances and finds 461 new best solutions in the 480 medium and large instances, with up to 200 containers, when compared to existing approaches for this problem.

Contract, network or hierarchy? Selecting governance mechanisms in megaprojects from the perspective of contractor alliances

Understanding the evolving governance mechanisms in megaprojects is crucial for reducing transaction costs and ensuring project success. However, previous literature primarily discusses the results of selecting governance mechanisms at different phases, with little research exploring the reasons behind these choices. To fill this gap, this article addresses the question of how to select effective governance mechanisms at different phases from the perspective of contractor alliances, based on transaction cost economics (TCE). We employ a longitudinal exploratory case study method to analyse the governance mechanism selection process across three phases (i.e. contractor alliance formation phase, shield construction phase and crisis response phase) of a large infrastructure project in China. The results indicate that the likelihood of opportunistic behaviour, uncertainty and the duration of the phase jointly explain the reasons for selecting specific governance mechanisms. Additionally, we also find that contractual governance, network governance and hierarchical governance are typically complementary in multiple phases of megaprojects. This article provides valuable managerial insights for future governance practices in megaprojects.

Key influence factors of carbon emissions in Malaysian construction operations

The urgency to mitigate carbon emissions has gained significant societal attention as the consequences of climate change continue to unfold. There is a notable scarcity of studies conducted on carbon emissions for construction operations. Hence, the aim is to identify the key influence factor of carbon emissions to develop a carbon reduction framework for construction operations. A survey was conducted with 297 Malaysian construction stakeholders to analyze 18 factors. Descriptive and Rasch analysis were used. Results revealed the reliability and validity of the model, which could help to explore ways to reduce carbon emissions during the construction phase. The findings indicate that a gradual transformation process is necessary to expedite the transition towards a low-carbon construction. The research enhances the existing literature by emphasising the key factors for stakeholders who aim to efficiently manage carbon emissions during a construction project. There are different ideas on how to estimate and manage carbon emissions in construction projects, but there are no standardized ways. This study looks into the main factors that contribute to the generation of carbon emissions in construction, to identify ways to reduce them evaluating these factors from the perspective of different stakeholders.

Multi-objective optimization and life cycle assessment of mass-integrated combined heat and power system

As the effects of climate change become more widely recognized, technical innovation and green energy will promote the growth of combined heat and power systems. This study proposes a novel mass-integrated combined heat and power system and conducts energy analysis, exergy analysis, and techno-economic analysis for the system. The optimization strategy integrated polynomial regression and non-dominated sorting genetic algorithm III is established, with system thermal efficiency, exergy efficiency, and return on investment (ROI) as objective functions. The system's environmental consequences are then assessed throughout its life cycle using life cycle assessment (LCA) under ideal operating circumstances. The findings reveal that the waste heat recovery heat exchanger has the highest exergy destruction in the system, with a value of 674.61 kW. Furthermore, the intermediate heat exchanger 1 and intermediate heat exchanger 2 (IHX2) with lesser exergy efficiency have an exergy destruction of less than 32.00 kW. The IHX2 is the most expensive equipment in the system, costing $90,931.19, but it also provides the most potential for system improvement. The multi-objective optimization findings suggest that the thermal efficiency, exergy efficiency, and ROI for the system are 0.17, 0.97, and 0.30, respectively. The LCA demonstrates that the system has a negligible influence on global warming and ozone generation with corresponding LCA findings of less than 4.20. The construction and operation phases of the investigation system have the most significant environmental consequences. The correlation between the raw materials necessary for the construction of the equipment in the system and the reaction temperatures, conditions, and waste composition during the preparation of the working fluids is large, so it is necessary to take corresponding environmental protection measures during production and processing to reduce the system's environmental emissions from the source and promote ecologically sustainable development.

Wind-induced vibration response of supertall sightseeing tower evaluation during construction through wind tunnel test of aeroelastic models

Four construction phases of an ultra-high sightseeing tower with a cable-barrel composite structure and their wind-induced vibration response were studied. The first-order natural vibration characteristic of the structure in four different construction phases was calculated through finite element models, and associated aeroelastic models were also designed. Meanwhile, rough strips are applied uniformly on the surface of the model to compensate the Reynolds number of the wind tunnel test. The performance of this method was investigated utilizing the pressure test of rigid segment models. The wind-induced vibration response under four construction conditions, and the effects of wind direction angle, wind speed and structural damping ratio were investigated through the wind tunnel test of aeroelastic models. The results show that sticking rough strips on the surface can effectively improve the Reynolds number of wind tunnel tests. As the wind speed during construction increases, the structural wind-induced vibration response intensifies. A large vortex-induced resonance occurs in the construction phase of a cable-barrel composite structure with the Strouhal number around 0.12 under turbulent conditions in this study. Furthermore, the crosswind-induced vibration response of the structure at a wind deflection angle of 0° is greater than 45° and 90°. Specifically, the mean value of downwind displacement and the maximum value of standard deviation (STD) of downwind and crosswind displacements on the prototype tower top at 0° during construction phases are 1.21 m, 0.35 m, and 0.25 m respectively. Thus, the risk of large wind-induced vibration should be fully considered during construction. Implementing corresponding damping measures to improve the damping ratio of the structure proves effective in restraining its vibration.

ProcSAGE: an efficient host threat detection method based on graph representation learning

Advanced Persistent Threats (APTs) achieves internal networks penetration through multiple methods, making it difficult to detect attack clues solely through boundary defense measures. To address this challenge, some research has proposed threat detection methods based on provenance graphs, which leverage entity relationships such as processes, files, and sockets found in host audit logs. However, these methods are generally inefficient, especially when faced with massive audit logs and the computational resource-intensive nature of graph algorithms. Effectively and economically extracting APT attack clues from massive system audit logs remains a significant challenge. To tackle this problem, this paper introduces the ProcSAGE method, which detects threats based on abnormal behavior patterns, offering high accuracy, low cost, and independence from expert knowledge. ProcSAGE focuses on processes or threads in host audit logs during the graph construction phase to effectively control the scale of provenance graphs and reduce performance overhead. Additionally, in the feature extraction phase, ProcSAGE considers information about the processes or threads themselves and their neighboring nodes to accurately characterize them and enhance model accuracy. In order to verify the effectiveness of the ProcSAGE method, this study conducted a comprehensive evaluation on the StreamSpot dataset. The experimental results show that the ProcSAGE method can significantly reduce the time and memory consumption in the threat detection process while improving the accuracy, and the optimization effect becomes more significant as the data size expands.

Carbon Accounting for Permeable Pavement Based on the Full Life Cycle Approach and Its Application

Conventional pavement in aging communities requires renovation in alignment with global carbon reduction initiatives. This study, centered on upgrading facilities in Guangdong, Hong Kong, and the Macao Greater Bay Area (GBA), utilized the Energy Expert platform to assess the carbon footprint of permeable pavement using life cycle assessment (LCA). The results revealed that the total carbon emission of the 64,065 m2 permeable pavement was 7066.21 tCO2eq. The carbon emission contribution, from highest to lowest, was the production phase, maintenance phase, end-of-life phase, and construction phase. Notably, transportation alone constituted a substantial portion, amounting to 30.15% of total carbon emissions. Compared to traditional pavements, permeable pavement showcased substantial potential for carbon reduction, primarily during the use phase, by enhancing groundwater recharge and mitigating the urban heat island effect, which is critical in reducing the carbon footprint. The estimated total carbon reduction was 853.10 tCO2eq. Sensitivity analysis highlighted diesel energy use in the maintenance phase (51.20%), transportation of cement raw materials in the production phase (45.80%), and transportation of graded gravel for disposal in the end-of-life phase (3.00%) as key factors. Our findings suggest that adopting specific carbon reduction measures, such as substituting gangue for cement binder, transitioning to manual sweeping, and recycling all discarded materials can achieve notable reductions in the respective phases. These findings contribute to a deeper understanding of the role of permeable pavement in reducing carbon emissions, providing insights for the renovation of aging communities.

Probabilistic pre-estimation of life-cycle costs of road bridges using dynamic Bayesian networks

Proper life-cycle cost (LCC) estimation of vital transportation network assets, such as road bridges, is crucial for cost-efficient projects. This study presents a probabilistic framework for the LCC estimation of concrete bridges based on Dynamic Bayesian Network (DBN) modelling that stakeholders can consult in projects’ preliminary stages for suitable decision-making. The proposed model consists of two separate modules. The first accounts for the probabilistic estimation of material quantities and their relative costs during the construction phase, specifically for the bridge’s superstructure and foundation. The second one refers to the operational phase of the bridge’s components. For illustrative purposes, the maintenance costs of deck expansion joints are presented, as they are regarded as vulnerable bridge components with regular repairs. The suggested DBN includes time-dependent and continuous variables thoroughly documented over multiple time stages. The DBN is formulated using actual records of 78 concrete bridges’ construction, deterioration, inspections and maintenance from the Egnatia Odos motorway in Greece. The presented approach is an effective tool for bridge management enhancement owing to stochastic dynamic interdependencies among parameters and continuous information updating.

ARCHAEOLOGICAL RESEARCH IN 2023 ON THE TERRITORY OF THE DOMINICAN MONASTERY IN VINNYTSIA

Archaeological researches of 2023 on the territory of the site of architecture and urban planning «Dominican Monastery» in Vinnytsia was carried out by the Archaeological Expedition of the Vinnytsia Regional Museum of Local Lore as part of the «Program of Archaeological Research on the Territory of Sites which are part of the Vinnytsia City Territorial Community for 2022—2024» approved by the Vinnytsia City Council. The main task for 2023 was to open a preserved excavation area (excavation area 1) and to complete it. This excavation area was established and explored in 2013—2018 by the Archaeological Expedition of the Institute of Archaeology of the National Academy of Sciences of Ukraine, headed by Dr. Larysa Vynogrodska. In the Excavation area 1 several objects in 2023 were discovered: building 1 — the remains of the foundations of a cult (?) building from the late 17th — the first half of the 18th century and constructive ditches of the building (the name and number according to the numbering of Dr. L. Vynogrodskaya); building 2 — the remains of the foundations of the building, constructed in the late 19th — the first half of the 20th century; building 3 is a deepened structure, explored in 2013—2014 (the name and number according to the numbering made by Dr. L. Vynogrodska); building 4 — a brick crypt (?) of the late 17th — early 18th centuries; object 1 — deepened with a step (partially explored) — late 16th — 17th centuries; object 2 is a burial contained the remains of five persons (burials 3—7), burials 5 and 6 are dated ca. late 17th — early 18th century; pits 1, 3 — objects of the 20th century (pit 2 is the object explored in 2013—2014); burial 1 — an animal skeleton in anatomical order which was discovered in the 17th—19th century layer (sector B6—B7 in the excavation area); burial 2 — a human burial approximately dated to the 18th century. Photofixation, processing and drawing of the material have been done, orthophoto plans and 3D modeling of objects in excavation area 1 were made based on the results of the archaeological expedition of the Vinnytsia Regional Museum of Local Lore in 2023. In addition to archaeological research, all known written sources of the 17th century about the territory of the Dominican monastery, its founders and clergy were widely involved. These sources were processed by researcher of Vinnytsia Museum Victoria Kolesnyk. Due to her sophisticated research in 2023 it was possible to attribute the architectural remains in excavation area-1 as the stone foundations of the Dominican monastery during its first phase of its existence. Probably, the discovered remains are traces of the renovation of the monastery building from the late 17th — the first half of the 18th century and existed until the time of the second phase of construction, which began in the second half of the 18th century. The result of the second phase of construction is the raising of a complex of buildings which are in use for now and as a complex with a status of National Importance, named the «Dominican Monastery».

Environmental impacts of solar energy systems

The yearly growth in worldwide energy usage, coupled with the associated environmental problems and worries, are major factors driving the widespread adoption of sustainable and renewable energy on a global scale. Solar energy systems have garnered significant attention in the past decade, surpassing other forms of renewable energy systems. Nevertheless, renewable energies might still cause negative environmental impacts. Therefore, it is crucial to prioritise careful consideration and implement appropriate precautionary measures. This report delivers a detailed assessment of the environmental impacts of both established and innovative solar energy solutions, shedding light on their effects on the ecosystem, considering their impact on the environment at both small and large sizes. The study examines both the associated advancements and the crucial components in their systems. The strategy encompasses all steps, commencing with the designs, and progressing through the manufacture, materials, construction or installation phases, as well as the operation lifetime and decommissioning. This article explores targeted strategies for various systems, including waste reduction and recycling, as well as providing technically and ecologically beneficial suggestions for minimising their effects.

The Historical Building and Room Acoustics of the Stockholm Public Library (1925–28, 1931–32)

The Stockholm Public Library was realized in two distinct phases of construction in the 1920s and early 1930s, and remains a well-known work in twentieth-century architecture, with a heritage status today. While previous studies have focused on the library’s architectural design, particularly its lighting, acoustics were also an important aspect of the building’s design and construction. This study marks the first detailed investigation of the library’s architectural acoustics, with a suite of standard measurements performed to assess and characterize the library’s historical room and building acoustics. Reverberation time measurements in the library’s reading rooms yielded results of about 1.5–2 s for frequencies associated with speech. A significantly longer reverberation time of 5–6 s was measured in the library’s central rotunda, confirming a prominent acoustic issue in the library, where appropriate heritage discussions are needed in the future as the library undergoes a major renovation in the coming years. A comparison of the measured airborne and impact sound insulation of the 1920s and 1930s reading room ceilings also yielded interesting results. While the materials in library’s two construction periods are notably different, the airborne sound insulation performance of the 1920s and 1930s floors or ceilings was comparable and in line with contemporary standards. Impact sound insulation results from the 1920s and 1930s floors, however, differed significantly, with the latter displaying a relatively poor performance. Flanking transmission effects related to historical construction details and deviations from archival plans were investigated and discussed. This work emphasizes the practical and academic importance of conducting on-site measurements, and the close mutual development of modern architecture, construction, and architectural acoustics.

A morphology-Euclidean-linear recognition method for rebar point clouds of highway tunnel linings during the construction phase

PurposeLaser point clouds are a 3D reconstruction method with wide range, high accuracy and strong adaptability. Therefore, the purpose is to discover a construction point cloud extraction method that can obtain complete information about the construction of rebar, facilitating construction quality inspection and tunnel data archiving, to reduce the cost and complexity of construction management.Design/methodology/approachFirstly, this paper analyzes the point cloud data of the tunnel during the construction phase, extracts the main features of the rebar data and proposes an M-E-L recognition method. Secondly, based on the actual conditions of the tunnel and the specifications of Chinese tunnel engineering, a rebar model experiment is designed to obtain experimental data. Finally, the feasibility and accuracy of the M-E-L recognition method are analyzed and tested based on the experimental data from the model.FindingsBased on tunnel morphology characteristics, data preprocessing, Euclidean clustering and PCA shape extraction methods, a M-E-L identification algorithm is proposed for identifying secondary lining rebars in highway tunnel construction stages. The algorithm achieves 100% extraction of the first-layer rebars, allowing for the three-dimensional visualization of the on-site rebar situation. Subsequently, through data processing, rebar dimensions and spacings can be obtained. For the second-layer rebars, 55% extraction is achieved, providing information on the rebar skeleton and partial rebar details at the construction site. These extracted data can be further processed to verify compliance with construction requirements.Originality/valueThis paper introduces a laser point cloud method for double-layer rebar identification in tunnels. Current methods rely heavily on manual detection, lacking objectivity. Objective approaches for automatic rebar identification include image-based and LiDAR-based methods. Image-based methods are constrained by tunnel lighting conditions, while LiDAR focuses on straight rebar skeletons. Our research proposes a 3D point cloud recognition algorithm for tunnel lining rebar. This method can extract double-layer rebars and obtain construction rebar dimensions, enhancing management efficiency.

Sustainable Performance of Industrialised Building Systems in the Construction Phase

The Industrialised Building System (IBS) is a construction method where components are manufactured in controlled environments, either on-site or offsite, before being assembled into construction works. Over the past several decades, it has garnered growing interest as a method to promote sustainable building. This study identified sustainable indicators through literature reviews, extracting sixteen indicators for a sustainability evaluation. A survey was conducted among developers, designers, civil and structure (C&S) consultants, mechanical and electrical (M&E) consultants, manufacturers, and contractors in North Malaysia, focusing on Kedah state, to identify their perceptions on the sustainable indicator performance of IBS construction. The participants had experience in both IBS and conventional construction. The data collected from the questionnaires were analysed for the mean and Relative Importance Index (RII). The results revealed significant changes in IBS construction compared with conventional construction across all indicators. The top three indicators were reducing the amount of formwork, labour availability, and reducing site disruption. Next, the analysis of the within-group comparison using Intra-class Correlation (ICC) of the indicators revealed that contractors, developers and manufacturers possessed moderate similarity within the same group of organisations. This research gives an overview of the present perspectives of performance of sustainable indicators across key stakeholders in the Kedah construction sector. This is especially beneficial because IBS has grown in popularity and popularity owing to its ability to enhance the building environment, quality, and productivity.

Circular Economy-Related Strategies to Minimise Construction- and Demolition- Waste Generation in Australian Construction Projects

The construction industry in Australia generates a significant amount of construction and demolition (C&D) waste, necessitating better waste management (WM) practices. This research addresses this issue by investigating CE strategies aimed at minimising C&D waste in Australian construction projects (CPs). Utilising a qualitative approach, the study is based on 20 interviews and four case studies of commercial CPs, analysed through NVivo content analysis. The findings emphasise the need to integrate CE strategies at every CP stage. In the pre-design phase, setting sustainable objectives and engaging stakeholders early is crucial for aligning goals to reduce C&D waste. The tendering process benefits from incorporating WM into contracts, demonstrating early commitment to sustainability. The design phase, through Building Information Modelling and designing for disassembly, offers substantial waste-reduction opportunities. Modular and prefabricated components during the construction phase enhance material reuse and recycling. Operational strategies like regular maintenance and retrofitting extend material lifespan, while selective demolition and digital cataloguing at the end-of-life phase enable efficient material recovery. This highlights the essential roles of policy, technology, and stakeholder collaboration in advancing CE practices, providing practical insights for construction professionals and policymakers to implement CE-related strategies in CPs. The research concludes that adopting CE strategies can lead to significant reductions in C&D waste and improved sustainability in the construction sector.

Highly graphitized carbon foam to construct phase change materials composites for multiple solar−thermal energy conversion

Nowadays, converting and storing solar energy is crucial in contemporary society. Thermal energy storages (TESs) can be vital in harnessing solar energy effectively. Phase change materials (PCMs) are favorable candidates for TESs owing to the smoothing outcome and, thus, increasing reliability. However, these materials suffer from limited thermal conductivity, inadequate light absorption, and high leakage during phase transition. In the present study, a facile and scalable graphitized carbon foam/Ni nanoparticles composite with exciting properties such as excellent light adsorption and high thermal conductivity was prepared as a platform to overcome the PCMs challenges. To obtain this composite, the coated commercial melamine foams (CMF) with an ethanolic solution containing the phenolic resin and NiCl2.6H2O were pyrolyzed at 900 °C. The composite foam (CNiF) was utilized as a framework for paraffin (PA), which was soaked in melted PA at 75 °C under the vacuum drying oven for 50 min (CNiF/PA). The prepared black and magnetic composites exhibited high photo-to-thermal energy efficiency of 66, 80, and 92 % under light intensities of 900, 1000, and 1100 W/m2, respectively. In addition, the composite controls voltage fluctuations and prevents voltage drops in thermoelectric generators (TEGs) in solar thermal systems. The output voltages were 0.51, 0.63, and 0.81 V under light intensities of 1500, 1800, and 2100 W/m2, respectively. Moreover, the magnetically moving magnetic carbon foam solar absorber within the molten PA along the solar illumination path dramatically enhances the speed of solar-thermal energy storage. The set-up was subjected to light with an intensity of 1500 W/m2, which revealed a decrease in melting time, with the PA melting in 86 min. The PA melting time decreased by 37 % under solar irradiation.

Construction control of rigid frame-continuous girder bridge based on grey theory

To address the issue of excessive mid-span deflection in rigid frame-continuous girder bridges during the later stages of normal use and to provide a basis for setting the pre-camber of this bridge type. This study focused on a specific rigid frame-continuous girder bridge. Based on the outcomes of finite element analysis, a GM(1,1) model developed using grey theory was utilized to forecast the vertical deflection of the primary girder in the construction phase of a rigid frame-continuous girder bridge, resulting in notable outcomes. The results suggest that the GM(1,1) model grounded in grey theory offers precise estimations of the vertical deflection of the primary girder during the prestressing tendon tensioning stage, displaying a minimal deviation of merely 1.73 mm compared to actual measurements. Consequently, applying the GM(1,1) model based on grey theory for projecting the vertical deflection of the primary girder in the construction process of rigid frame-continuous girder bridges can advance the accuracy of construction management. Through comparative analysis of measured values estimated values and theoretical values at the construction site, it is evident that the predictive model effectively controls the displacement, thus serving as a reference for construction control in similar projects.

A macro-level life cycle environmental-economic impact and benefit assessment of sponge cities in China

Urban runoff source control facilities (URSCFs) are integral components of Sponge City (SC), playing a pivotal role in providing ecosystem services and managing water quality and quantity. To accurately assess the performance of URSCFs, it is crucial to quantify their environmental and economic impacts. However, previous studies have predominantly focused on location-specific case studies, lacking a macro-level perspective necessary for informing public policy development pertaining to SC initiatives. This study aims to bridge this gap by conducting a macro-level life cycle assessment across China's 16 initial pilot SCs, categorized into three zones based on their annual rainfall volume control rate α (i.e., Zone II (80 % to 85 % for α), Zone III (75 % to 85 % for α), and Zone IV (70 % to 85 % for α)). By simulating five rainfall drainage scenarios, we delve into the environmental benefits of SC construction. The results indicate that Zone III incurs the highest environmental and economic costs during the construction phase, followed by Zones II and IV. In Zone III, bioretention contribute significantly to the environmental impact and economic cost, while constructed wetland and detention cells are the key contributors for Zone II. During the operation phase, Zone III demonstrates the largest environmental and economic benefits, with Zone IV and II trailing behind. The investment payback period for SCs in all zones is less than eight years, with Zone IV recovering costs the fastest (3.9 years) and Zone II the slowest (7.5 years). Facilities like detention cells, green roofs, and permeable pavements tend to have longer payback periods. Based on our findings, we recommend that Zone II exercise caution in constructing detention cells, permeable pavements, and wetlands, while Zone III should carefully consider green roofs and bioretention to optimize SC investments. Due to the fewer URSCFs constructed in Zone IV, it exhibits the lowest environmental impact compared to Zones II and III. Our research provides valuable insights to support policymaking with regards to future SC planning and development.