Hisham Said

Optimizing Material Procurement and Storage on Construction Sites

Efficient planning of materials procurement and storage on construction sites can lead to significant improvements in construction productivity and project profitability. Existing research studies focus on material procurement and storage layout as two separate planning tasks without considering their critical and mutual interdependencies. This paper presents the development of a new optimization model for construction logistics planning that is capable of simultaneously integrating and optimizing the critical planning decisions of material procurement and material storage on construction sites. The model utilizes genetic algorithms to minimize construction logistics costs that cover material ordering, financing, stock-out, and layout costs. The model incorporates newly developed algorithms to estimate the impact of potential material shortages on-site because of late delivery on project delays and stock-out costs. An application example is analyzed to demonstrate the capabilities of the construction logistics planning model in simultaneously optimizing material procurement decisions and storage layout plans.

Prefabrication Best Practices and Improvement Opportunities for Electrical Construction

AbstractPrefabrication is a construction operations approach that moves project work to a controlled offsite facility to be accomplished in a standardized and efficient manner. Prefabrication is increasingly becoming attractive to electrical contractors to improve their competitiveness due to reported safety, time, and cost benefits. This paper presents the findings of an industry-sponsored research study to identify current best practices of electrical construction prefabrication and future improvement opportunities that consider prefabrication dependency on supply chain collaboration and labor union relations. The study tasks are performed in three main phases. First, current state of electrical construction prefabrication is identified through a comprehensive data collection plan that included semistructured interview, site visits, case studies, and questionnaires. The second phase included suggesting a set of best practices of electrical contracting industrialization, related to prefabrication operati...

Modeling and Likelihood Prediction of Prefabrication Feasibility for Electrical Construction Firms

AbstractElectrical contracting firms have consistently pursued industrializing their business through the implementation of prefabrication, lean production, and supply chain integration. Despite the pioneering prefabrication efforts of electrical contractors, there is still no clear understanding of the determinants of electrical prefabrication feasibility in terms of supply chain collaboration and surrounding industry requirements. Accordingly, this paper presents the development of prediction models of prefabrication feasibility for electrical contractors. The research tasks of this study were performed in three main phases. The first phase included various data collection tasks, including conducting semistructured interviews, providing an online questionnaire, and obtaining relevant local economic data of the respondents’ metropolitan areas. The second phase involved the utilization of the collected questionnaire responses and economic data to develop logistic regression models that relate the prefabri...

Financial Evaluation for Toll Road Projects Considering Traffic Volume and Serviceability Interactions

The rapid increase in both financial demands and the need for large and comprehensive highway infrastructure systems necessitates public authorities to muster support from the private sector. Public-private partnerships (PPP) have been increasingly adopted and cited as one of the most effective project delivery systems, which bring balance to risks and rewards between involved project participants. However, a number of PPP infrastructure projects around the world have been reported to have operating deficits and difficulties in debt-servicing. One of the major reasons for these difficulties is the unrealistic and inaccurate prediction of project investment performance during the initial stages of project viability and profitability analysis. Therefore, the research reported in this paper presents a formulation of a comprehensive framework that evaluates financial viability of PPP toll road projects. The framework utilizes a modified user-equilibrium traffic-assignment algorithm to estimate toll road traffic volume considering critical demand-influencing factors, which include travel time, pavement serviceability, and out-of-pocket user trip expenses. The proposed framework also considers the effects of the rehabilitation maintenance activities on the equilibrium flow pattern and project financial viability. This makes possible an estimation of the maintenance costs and frequency as well as an evaluation of the effects of rehabilitation programs on the traffic volume. The research reported in this paper also demonstrates the difference in traffic-flow patterns with and without interactive changes in pavement performance and traffic volume to demonstrate the need for incorporation of pavement performance and network levels of service into PPP highway project evaluation.

Optimizing Material Logistics Planning in Construction Projects

Construction logistics can be used by contractors to plan and control the efficient and effective flow of materials from the suppliers to their incorporation into the finished structure. This paper presents the development of a construction logistics planning model that simultaneously optimizes the decisions of material supply and site layout in order to minimize logistics costs that include ordering, carrying, shortage, and layout costs. New methodologies are incorporated in the developed model to represent the interdependencies between material supply and layout decisions as well as to measure the impact of these decisions on project delays. An application example is analyzed to highlight the capabilities and performance of the proposed model.

Agent-Based Simulation of Labour Emergency Evacuation in High-Rise Building Construction Sites

Construction sites are vulnerable to natural and manmade disasters that impose direct threat to contractor employers. High-rise building projects are more critical in such emergency situations because of the need to evacuate a large number of laborers who are working on the different floors of the building. Occupational safety regulations require general contractors to establish employee emergency action plans that specify emergency evacuation procedures and escape route assignments. These emergency plans are usually evaluated and practiced using real life drills, which face some critical challenges related to egress practicality and changing construction environment, especially in high-rise building construction sites. To overcome these challenges, this paper presents a conceptual agent-based simulation framework that would support general contractors in evaluating labour emergency evacuation plans in high-rise building construction projects. The framework is designed to facilitate: 1) modelling of construction activities workspaces that represent the number and locations of activities crews; 2) representing labour egress behaviour using software autonomous agents; 3) modelling of the physical space and evacuation routes of the building; and 4) evaluating the performance of emergency action plans. The proposed framework should prove useful to general contractors and public safety officials in effectively analyzing emergency action plans.

Analysis of the Growth Dynamics and Structure of Modular Building Construction Industry

The modular construction industry has made significant advances in the last two decades that qualifies it as a more efficient, greener and affordable alternative for delivering building projects. Modular construction depends on moving portion of the project work to off-site manufacturing locations where the building is manufactured in modules, transported to the site, and erected in the designed configuration. Currently, modular construction is a sizable industry that encompasses its own stakeholders, customers, vendors, and supply chains. However, there is no comprehensive understanding of the structure and growth dynamics of this industry that is necessary for predicting its future performance trends. Accordingly, this paper presents a comprehensive description of the modular construction industry structure and a preliminary analysis of previous growth trends and dynamics. Different aspects of the industry are described, in terms of its main stakeholders, supply chain interactions, logistical requirements, and economical attributes of manufactured modular buildings. The industry growth dynamics and trends are analyzed by examining available historical performance data of the modular construction industry that have been collected by the Modular Building Institute since 1994. The findings of this analysis should prove useful in developing future advanced models to help in designing efficient policies and measures to support the growth of the modular building industry.

Modeling of the sustainability goal and objective setting process in the predesign phase of green institutional building projects

AbstractThe process of constructing a sustainable green building presents a number of challenges compared with regular buildings. Additional work and documentation is needed in every stage of the project life cycle for the sustainable building to reach its goal of being certified according to one of the available sustainability rating systems. One of the most important steps toward achieving that goal is the eco-charrette process that takes place during the predesign phase of the project. The importance of this step stems from the fact that it sets the sustainability goals and objectives for the entire project. This necessitates the creation of an effective decision support methodology that will support project stakeholders in setting the sustainability goals and objectives of the project before committing valuable time and budget resources to the eco-charrette process. Therefore, this paper presents the development of an agent-based model for simulating the interactions between project stakeholders in th...

Optimization Application for Financial Viability Evaluation of PPP Toll Road Projects

The limited financial capabilities of public owners gave rise to the PublicPrivate Partnership (PPP) approach as an innovative project finance to attract private investment to highway projects. Nonetheless, many privately financed road projects have had difficulties in fulfilling construction debt obligations due to operating deficits. These difficulties are mainly attributed to incomprehensive evaluation of project financial viability and poor selection of key concession items. This research presents a comprehensive framework which provides an optimal set of key concession items for setting up financial viable PPP toll road projects. These key concession items include toll rates, a concession length, an equity level, and a rate of return. The proposed framework utilizes a modified User Equilibrium traffic assignment algorithm to help estimate revenue from toll road traffic volume considering its interaction with levels of service. The framework also takes into consideration the relationships between the deterioration of the pavement serviceability and required maintenance caused by the traffic volume, which facilitates the quantification of the toll road maintenance expenditures. From the estimated cash flow, a Genetic Algorithm (GA) will be applied to search for an optimal combination of the key concession items that would maximize profit from private investment in public highway projects.

GLOBAL OPTIMIZATION OF DYNAMIC SITE LAYOUT PLANNING IN CONSTRUCTION PROJECTS

Dynamic site layout planning in construction projects focuses on identifying the location and space of temporary construction facilities on sites while considering the dynamic changes in the needs and availability of site space over the project duration. Existing dynamic site layout planning models generate layout plans of construction stages chronologically without considering their future effects which may lead to non-optimal or infeasible solutions. This paper presents the development of an Approximate Dynamic Programming (ADP) model that is capable of globally optimizing dynamic site layout plans of construction projects in order to minimize overall site layout costs. The developed model is equipped with the look-ahead capabilities of ADP to consider the future effects of site layout decisions in early stages on layout quality and feasibility in future stages. An application example is analyzed to illustrate the use and capabilities of the developed model in generating global optimal solution for dynamic site layout planning of construction projects.