•Bioinspired sandwich CFRP composite is 0.73–4.4 more cost effective compared to steel.•CFRP and recycled concrete is useful in lightweight prefabricated construction.•Barriers identified: ...behavioral, technical, infrastructural, market and legal barriers.•Advanced prefabricated construction recommended in future smart cities and new projects.•Welfare, safety training and collaboration required for Covid-19 resilient construction industry.
Modular prefabricated construction has attracted global attention to meet increasing housing demands and infrastructural deficits owing to its construction speed and efficiency. Unfortunately, the benefits of such modular prefabricated structures are undermined by heavy steel utilization, which is susceptible to corrosion, and contributes to their heavy weight leading to transportation and erection problems during construction. Bioinspired lightweight sandwich CFRP composite reinforcement is investigated as an alternative to steel along with recycled concrete for sustainable prefabricated construction using a performance-based hybrid Taguchi-Response surface methodology multi-objective optimization approach. The optimized result exhibited improved mechanical properties and favourable, ductile failure mode attributed to the Bauschinger strain-reversal effects and composite actions of the bio-inspired CFRP reinforcements. Comparatively, the bioinspired sandwich composite reinforcement was found to be 0.73–4.4 times more cost-effective than steel reinforced concrete structures in terms of fracture toughness and has potential applications in lightweight prefabricated (modular) concrete structures. This study also revealed prevalence of behavioral, technical, infrastructural, market and legal barriers which hinder adoption of prefabricated construction and can be overcomed through appropriate regulatory framework, standards, centers of excellence, demonstration projects and incentives for advanced prefabricated construction. Government authorities should promote advanced prefabricated composite construction in new construction projects and future smart cities to minimize construction wastes and carbon emission problems prevalent in most cities, provide employment support to construction companies, improving safety/welfare training and encourage collaboration among construction firms to improve resilience of construction industry to on-going Covid-19 and future pandemics and associated socio-economic impacts.
•Reviewed recent progress and directed future research for modular buildings.•Commonly used in UK, Sweden, Japan and USA with growing interest in Australia and China.•Prefabricated components have ...demonstrated satisfactory structural performance.•Uptake barriers are mainly related to the lack of logistical support.•Prefabricated modular buildings is the next generation of housing.
Modular construction offers faster and safer manufacturing, better predictability to completion time, superior quality, less workers on site, less resource wastage, and a more environmentally friendly solution than the conventional construction process. Despite having several advantages of modular construction, the private sector still relies heavily on the traditional on-site construction method. To understand the scientific reason behind this situation, this paper critically reviews the recent developments, performances, challenges and future opportunities of modular buildings. Modular constructions are extensively used for low-rise buildings and further attracts strong interest for multi-storey building structures. Prefabricated modules demonstrated satisfactory performance under static, dynamic impact, cyclic, seismic, blast, fire and long-term sustained loading, and offer environmental, economic and social benefits. The acceptance and application of modular construction will further spread with the development of design guidelines, more skilled workers, addressing handing and transportation difficulties, and the development of novel interlocking connections between modules. Recently, composite materials demonstrated high potential to manufacture prefabricated building modules. In Australia, it is expected that modular construction will increase from the current stage of 3% to 5–10% by year 2030.
AbstractPrefabricated building projects (PBPs) have contributed significantly to addressing Hong Kong’s serious housing shortage and accommodate almost half of the residents in this densely populated ...city. The supply chains of PBPs involve large numbers of stakeholders, including clients, designers, main contractors, transporters, and assembly subcontractors, all of which need to interact with each other by frequent information exchanges. However, cross-border supply chains are found to be quite complex, resulting in risks that significantly affect the performance of PBPs. Supply chain risks (SCRs) are closely associated with the stakeholders involved and have high interdependency with each other. This paper adopts social network analysis (SNA) to develop the risk network of the supply chain of a PBP in Hong Kong to prioritize the stakeholder-associated SCR. The research findings show that poor planning of resources and schedule, poor control of working flows, and poor information sharing between stakeholders are the major challenges to the supply chains of PBPs. This is the first study to consider the dynamic risk interdependency and associated stakeholders in SCRs. By providing a greater understanding of the risks embedded across the supply chains of PBPs in Hong Kong, this study could assist practitioners dealing with such risks more effectively and efficiently.
Building Information Modelling (BIM) serves as a useful tool in facilitating the on-site assembly services (OAS) of prefabricated construction for its benefits of powerful management of physical and ...functional digital presentations. However, the benefits of using BIM in the OAS of prefabricated construction cannot be cultivated with an incomplete, inaccurate, and untimely data exchange and lack of real-time visibility and traceability. To deal with these challenges, an Internet of Things (IoT)-enabled platform is designed by integrating IoT and BIM for prefabricated public housing projects in Hong Kong. The demands of the stakeholders were analysed; then smart construction objects (SCOs) and smart gateway are defined and designed to collect real-time data throughout the working processes of on-site assembly of prefabricated construction using the radio frequency identification (RFID) technology. The captured data is uploaded to cloud in real-time to process and analyse for decision support purposes for the involved site managers and workers. Visibility and traceability functions are developed with BIM and virtual reality (VR) technologies, through which managers can supervise the construction progress and approximate cost information in a real-time manner. The IoT-enabled platform can provide various decision support tools and services to different stakeholders, for improving the efficiency and effectiveness of daily operations, decision making, collaboration, and supervision throughout on-site assembly processes of prefabricated construction.
•Current BIM system has drawbacks.•A platform is developed by integrating internet of things and BIM technologies.•Intelligent decisions could be made to inform managers and workers.•Managers can supervise the construction progresses and cost information in real time manner.
Prefabricated construction has become increasingly popular over the recent years, given its benefits including higher construction speed, lower cost, and improved quality. To facilitate the ...operations of prefabricated construction, various technologies have in parallel been introduced. However, due to its project-based feature and the involvement of numerous Small and Medium Enterprises (SMEs), the adoption of information technologies is insufficient and varies between SMEs, thereby hindering the improvement of the efficiency of prefabricated construction. Considering these issues and aiming at realizing lean prefabricated construction, this paper proposes an integrated cloud-based Internet of Things (IoT) platform through exploiting the concept of cloud asset. Its operation model has also been worked out to enable SMEs to adopt IoT technologies economically and flexibly. Besides, to make the platform compatible and scalable on managing diverse physical assets in different companies and scenarios, a unified cloud asset data model is proposed. Furthermore, an IoT service-sharing module is developed to support different levels of service-sharing on the platform. Finally, a real-life prefabricated construction project in Hong Kong and several lab-based LEGO construction models are adopted to verify the feasibility and effectiveness of the proposed platform.
•The operation model for SMEs to economically and flexibly use IoT technologies is proposed.•A cloud-based IoT platform is established that could fulfill the diverse requirements among different prefabricated construction projects.•The compatible and scalable cloud asset data model is proposed to represent diverse physical assets.•The IoT service sharing module is developed to share diverse services among users flexibly.•A real-life case study is conducted, which shows the platform is effective on improving the leanness of prefabricated construction.
•Snow loads may cause catastrophic damages at prefabricated industrial buildings.•Brittle damages may occur at the thinned ends of the purlin.•Different prefabricated RC purlin tests have been ...conducted.•The proposed Z type reinforcement enhanced shear capacity of the purlin.•The results were compared with TS-9967 standards and field tests.•The numerical analysis was performed using ABAQUS to determine optimum Z type reinforcement.
In prefabricated industrial buildings, damages and collapses may occur under snow loads. If the necessary precautions are not taken, the damage can spread to the whole structure which leads to total collapse. Therefore, it is very crucial for manufacturers to comprehend the nature of the damage and to take necessary precautions to prevent this damage. In this present study, the damages occurred at dapped-end region of prefabricated purlins due to snow load accumulated at the roof and the reasons for these damages were investigated in detail. Pursuant to this goal, comprehensive experimental and numerical studies have been undertaken. 10 specimens with 5 different configurations were tested under four point loading. A novel reinforcement detail and the usage of practical methods used by the manufacturers are selected as main parameters. In all purlins, damages occurred at the dapped-end in shear formation. The experimentally obtained results were compared with field tests and TS9967 design code. It was observed that the specimen with “Z” type of the proposed novel reinforcement exhibited approximately 30% higher load capacity than that of other specimens. Moreover, the numerical analyses were performed in order to determine optimum “Z” type reinforcement for dapped-end purlin beams using finite element methods.
Due to the advantages of prefabricated structure, its applications in utility tunnels are increasing. However, more connection joints have raised concerns about the vulnerability of prefabricated ...utility tunnels in earthquake disasters. The main objectives of this research are to analyze the seismic response, vulnerable parts and failure modes of a prefabricated utility tunnel. A pair of twin models of prefabricated utility tunnels with two‐compartment layouts were designed, and then set up to load ground motions synchronously through a large‐scale shaking table of 6 m × 6 m under two different boundary conditions: one buried inside a soil box and its twin laid outside the soil as a comparison. The results show that: the damage of the split‐type prefabricated utility tunnel is mainly concentrated in the connection joints, and the connection joint at the top corner of the compartment with larger cross section is the vulnerable part that needs special attention; the SSI effect has a great influence on the seismic response of the prefabricated utility tunnel, and the model buried inside the soil box shows stronger seismic response than its twin laid outside the soil. The experimental results and analysis in this paper can provide a helpful reference for risk assessment and prevention, seismic design, and structural optimization of prefabricated utility tunnels.
Prefabricated concrete building (PCB) can save resources, reduce construction, improve quality, and reduce pollution. Understanding PCB environmental benefits versus traditional buildings could ...reinforce relevant policies and adoption. This study aimed to develop a holistic life-cycle accounting system based on BIM technology to calculate carbon emissions of PCB accurately and efficiently, and verify the effects of energy saving and emission reduction. Existing international and national databanks allowed the compilation of carbon emission factors. Five representative residential PCB projects were enlisted to calculate carbon footprints in six individual life-cycle construction stages. In most stages, carbon emissions were reduced with an increasing prefabrication rate. In the operation and maintenance stage, carbon emissions accounted for approximately 91% of the total, and the building materials production stage accounted for about 11%. The “negative carbon emission” in the demolition and recycling stage was about −4%. Carbon emissions of the remaining three stages were minimal at about < 2%. This study established the whole life-cycle carbon-emission indices of residential prefabricated buildings, with average annual carbon emission per unit area at around 105.88 kgCO2/(m2.a), and computed values for individual building stages. For comparison, a completely cast-in-place building was studied, with average annual carbon emission per unit area at around 130.79 kgCO2/(m2.a), significantly higher than the PCB. The study contributed to knowledge by furnishing the holistic carbon footprint calculation method and establishing the empirical patterns and trends of carbon emissions of PCB. The findings could inform construction projects' carbon-emission control and achieve the construction industry's green and low-carbon goals.
In order to understand the overall picture, the different technologies for the use of thin‐walled prefabricated elements in bridge construction as well as the first‐time application of them in a ...bridge project in Austria are described in this paper. Thereafter a newly developed construction method for the on‐site fabrication of lightweight box‐shaped segments from thin‐walled concrete elements, strengthened with steel girders, is explained with the focus lying on the construction of a prototype in a 1:1 scaling. The conceptional design, the manufacturing in a prefabrication plant in Austria and the transport to a construction site are illustrated. Finally, an application example of the new technology is shown based on a design using the incremental launching method. The research confirms the feasibility of the on‐site assembly of segments from thin‐walled prefabricated elements and that this construction method, once minor constructive details will be solved in the ongoing research project, has great potential for a broad application in bridge construction.
PurposeConstruction schedule delays and quality problems caused by construction errors are common in the field of prefabricated buildings. The effective monitoring of the construction project process ...is one of the key factors for the success of a project. How to effectively monitor the construction process of prefabricated building construction projects is an urgent problem to be solved. Aiming at the problems existing in the monitoring of the construction process of prefabricated buildings, this paper proposes a monitoring method based on the feature extraction of point cloud model.Design/methodology/approachThis paper uses Trimble X7 3D laser scanner to complete field data collection experiments. The point cloud data are preprocessed, and the prefabricated component segmentation and geometric feature measurement are completed based on the PCL platform. Aiming at the problem of noisy points and large amount of data in the original point cloud data, the preprocessing is completed through the steps of constructing topological relations, thinning, and denoising. According to the spatial position relationship and geometric characteristics of prefabricated frame structure, the segmentation algorithm flow is designed in this paper. By processing the point cloud data of single column and beam members, the quality of precast column and beam members is measured. The as-built model and as-designed model are compared to realize the visual monitoring of construction progress.FindingsThe experimental results show that the dimensional measurement accuracy of beam and column proposed in this paper is more than 95%. This method can effectively detect the quality of prefabricated components. In the aspect of progress monitoring, the visualization of real-time progress monitoring is realized.Originality/valueThis paper proposed a new monitoring method based on feature extraction of the point cloud model, combined with three-dimensional laser scanning technology. This method allows for accurate monitoring of the construction process, rapid detection of construction information, and timely detection of construction quality errors and progress delays. The treatment process based on point cloud data has strong applicability, and the real-time point cloud data transfer treatment can guarantee the timeliness of monitoring.
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