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The purpose of this paper is to investigate the process optimization of a precast concrete component production line by using value stream mapping.

This paper is an empirical focused on of lean production theory and value stream mapping. The data in the case study were collected in real time on-site for each process during the production process of a prefabricated exterior wall.

The results of the current value stream map indicate that the main problems of the current production process are related to equipment, technology and organization. The equipment problems include simple demolding and cleaning tools and the lack of professional transfer channels. The technology problems include the lack of a marking mechanism and pipeline exit mechanism. There is a lack of standard operating procedures and incomplete process convergence. A comparison and analysis of the current value stream and the future value flow indicate that optimizations of the process flow, the production line layout, and the standard operating procedures have shortened the delivery cycle, reduced the number of workers, improved the operator’s operating level and balanced the production line.

The results of this study provide practitioners with a clear understanding of the optimization of the precast concrete component production and represent a method and basis for the process optimization of a factory production line; the approach is suitable for process optimization in other areas.

This research represents an innovative application of lean production theory and value stream mapping in a complex production line of precast concrete components and thereby fills the gap between the theory and practice of the optimization of a precast concrete component production line.

The Just‐In‐Time (JIT) philosophy holds tremendous potentials for improving the movement of precast concrete components from the prefabrication yard to, and within, the construction site. The space constraints for storage and the traffic congestion at the worksite can then be alleviated. Savings from the efficient management of precast concrete components can be used to offset the higher costs of procurement. By means of a survey, this paper examines if main contractors are ready to adopt the JIT philosophy to receiving and installing precast concrete components on site. Observations from the survey, however, suggest that JIT/lean operations need to work hand in hand with agile operations in the supply chain to cope with schedule fluctuations.

As part of the productivity movement, the Singapore government is this year (2001) legislating for “buildability”. Consequently, all building projects will need to fulfill a minimum buildable score before their development and building plans can be approved. Achievement of higher buildable scores can be attained by greater use of prefabrication technology. The Building and Construction Authority is attempting to promote the just‐in‐time (JIT) philosophy for managing precast concrete components. Components are expected to be manufactured and delivered just in time for installation and erection on site. By means of a survey, this paper examines the readiness of precasters in Singapore to adopt the JIT philosophy in producing and delivering precast concrete components to contractor‐clients.

This study evaluates the enablers and barriers for modular concrete construction in Lebanon. The purpose of this paper is to investigate various factors (time, cost, technical know-how, organizational, sustainability, etc.) and their influence on the choice of the construction method. The paper examines the different assessments of designers, manufacturers, and contractors regarding precast construction in comparison to traditional in-situ methods, and highlights the major differences in their views.

Structured face-to-face surveys were conducted with top management personnel of precast manufacturers, architectural and engineering firms, and contracting companies in Lebanon. In addition, a case study from the largest precast project in Lebanon was used to provide a deeper understanding of factors encouraging the use of precast concrete, and to highlight major onsite issues associated with its implementation.

On the one hand, the findings highlight technical, logistical, organizational, and cultural factors that inhibit the use of precast concrete as a construction method. On the other hand, results reveal that cost, time, sustainability, and flexibility factors are the main enablers for increasing the uptake of modular concrete construction.

The main contribution to knowledge is that this study presents different stakeholders’ perspectives on precast concrete construction. Moreover, this is the first research addressing precast concrete construction in the Middle East and Lebanon. The results of the study provide valuable global insights and recommendations that may help increase the uptake of precast concrete construction. They can also guide project stakeholders to properly match project characteristics and precast concrete as a construction method.

Production and transportation of precast components, as two continuous service stages of a precast plant, play an important role in meeting customer needs and controlling costs. However, there is still a lack of production and transportation scheduling methods that comprehensively consider delivery timeliness and transportation economy. This article aims to study the integrated scheduling optimization problem of in-plant flowshop production and off-plant transportation under the consideration of practical constraints of customer order delivery time window, and seek an optimal scheduling method that balances delivery timeliness and transportation economy.

In this study, an integrated scheduling optimization model of flowshop production and transportation for precast components with delivery time windows is established, which describes the relationship between production and transportation and handles transportation constraints under the premise of balancing delivery timeliness and transportation economy. Then a genetic algorithm is designed to solve this model. It realizes the integrated scheduling of production and transportation through double-layer chromosome coding. A program is designed to realize the solution process. Finally, the validity of the model is proved by the calculation of actual enterprise data.

The optimized scheduling scheme can not only meet the on-time delivery, but also improve the truck loading rate and reduce the total cost, composed of early cost in plant, delivery penalty cost and transportation cost. In the model validation, the optimal scheduling scheme uses one less truck than the traditional EDD scheme (saving 20% of the transportation cost), and the total cost can be saved by 17.22%.

This study clarifies the relationship between the production and transportation of precast components and establishes the integrated scheduling optimization model and its solution algorithm. Different from previous studies, the proposed optimization model can balance the timeliness and economy of production and transportation for precast components.

Monitoring of the quality of precast concrete (PC) components is crucial for the success of prefabricated construction projects. Currently, quality monitoring of PC components during the construction phase is predominantly done manually, resulting in low efficiency and hindering the progress of intelligent construction. This paper presents an intelligent inspection method for assessing the appearance quality of PC components, utilizing an enhanced you look only once (YOLO) model and multi-source data. The aim of this research is to achieve automated management of the appearance quality of precast components in the prefabricated construction process through digital means.

The paper begins by establishing an improved YOLO model and an image dataset for evaluating appearance quality. Through object detection in the images, a preliminary and efficient assessment of the precast components' appearance quality is achieved. Moreover, the detection results are mapped onto the point cloud for high-precision quality inspection. In the case of precast components with quality defects, precise quality inspection is conducted by combining the three-dimensional model data obtained from forward design conversion with the captured point cloud data through registration. Additionally, the paper proposes a framework for an automated inspection platform dedicated to assessing appearance quality in prefabricated buildings, encompassing the platform's hardware network.

The improved YOLO model achieved a best mean average precision of 85.02% on the VOC2007 dataset, surpassing the performance of most similar models. After targeted training, the model exhibits excellent recognition capabilities for the four common appearance quality defects. When mapped onto the point cloud, the accuracy of quality inspection based on point cloud data and forward design is within 0.1 mm. The appearance quality inspection platform enables feedback and optimization of quality issues.

The proposed method in this study enables high-precision, visualized and automated detection of the appearance quality of PC components. It effectively meets the demand for quality inspection of precast components on construction sites of prefabricated buildings, providing technological support for the development of intelligent construction. The design of the appearance quality inspection platform's logic and framework facilitates the integration of the method, laying the foundation for efficient quality management in the future.

This study applied the lean approach to the reinforcement work process in the component production of industrialised building system precast concrete construction (IBSPCC). The purpose of this paper is to identify and eliminate non-value added (NVA) activities to enhance the efficiency of the production process.

Data were collected via a case study of six-storey precast concrete building. A mapping of the reinforcement work process was conducted based on observations using time study technique and time-lapsed video, complemented by semi-structured interviews.

Through this application, several NVA activities, such as unnecessary inventory, excessive movement and coordination issues, were identified. Production performance could be enhanced by implementing Just-in-Time, Kanban, and layout improvements, which would address NVA activities.

Due to the complexity of the construction process, only specific process elements were observed. To map the complete process, comprehensive observation must be conducted from beginning to end, which, though worthwhile, would be very time and resource intensive.

This paper focusses on strategies for improving the efficiency of the IBSPCC production process in Malaysian construction by developing a conceptual framework of the lean approach for the reinforcement work process. Certain aspects in the process such as layout and inventory need to be redesigned and simplified by minimising NVA activities.

The purpose of this paper is to show that the growing global trend of quality assurance indicates the potential of precast concrete (PC) to improve construction quality and productivity, reduce wasteful construction, and achieve design standardization and to accelerate construction time. However, its current approach for dynamic characteristics, such as stiffness and displacement on beam-column connection system design, is not effective in achieving the required quality and operational requirements.

A design tool based on the literature and data analysis in product planning and safety is proposed for the practice of PC building construction.

The results reveal the need for improvement of PC building performance in the construction industry, especially for the beam-column connection system. The issues include improper design, improper specification and defective concrete and steel components compared to other manufacturing methods.

A novel and sophisticated technique based on physical internet-enabled building information modeling (PI-BIM) is proposed to improve the planning process and safety for PC buildings in Malaysia.

Construction materials take up a significant proportion of the total construction cost. Without careful planning and controlling on the flow of construction materials, it is possible that the cost of materials may increase unnecessarily. In view of that, this paper aims to examine whether the development of logistics cost analysis can help determine suitable logistics strategies for a project which involves the use of bulky components like precast concrete units.

The cost elements incurred during the logistics process of precast components from the supplier's yard to the construction site are first identified through the activity‐based costing (ABC) approach. Under each element, the resources necessary to fulfil the specific element are analysed. By representing those cost components through the cost functions, simulations can be carried out to determine the logistics cost under different logistic scenarios.

Through the ABC approach, the resources consumed can be traced back to the consuming activity and subsequently to a particular cost element. More importantly, the results indicate that the simulation model can identify a logistics option which would result in the lowest logistics cost without affecting the construction schedule.

This paper should help increase understanding of managers and planners on construction logistics activities and their related costs so as to increase their bid competitiveness and/or improve the chance of success at the construction stage by minimising the construction logistics cost.

The purpose of this study is to investigate the factors affecting the cost of concrete component prefabrication using the moderating role of organizational readiness, compatibility and competitive pressure.

The information collected in this study was obtained from 188 questionnaires filled out online by civil engineers active in the Iranian construction industry. Data analysis was performed by partial least squares structural equation modeling.

The results reveal that perceived risk has the greatest impact on cost of using precast concrete components (PCC). Furthermore, the organizational readiness, competitive pressure and compatibility variables have moderating role in the relationship between perceived risk and perceived usefulness. The results can help policymakers and managers to apply the appropriate perspective and strategy to promote this method by illustrating the factors affecting the cost of using PCC in the building construction.

Using the variables of perceived risk, perceived usefulness, and perceived ease of use to predict factors affecting the cost of using PCC is considered as an innovation in this research. In addition to identifying the most important factors affecting the cost of PCC prefabrication in the construction industry, this research tries to identify the impact of environmental factors on the model by examining the moderating role of organizational readiness, competitive pressure and compatibility.