Maged E. Georgy

A hybrid CAD-based construction site layout planning system using genetic algorithms

The efficient layout planning of a construction site is a fundamental task to any project undertaking. In an attempt to enhance the general practice of layout planning of construction sites, the paper introduces a novel approach for producing the sought layouts. This approach integrates the highly sophisticated graphical capabilities of computer-aided design (CAD) platforms with the robust search and optimization capabilities of genetic algorithms (GAs). In this context, GAs are utilized from within the CAD environment to optimize the location of temporary facilities on site. The functional interaction between GAs and CAD and the details of the GA-based layout optimization procedure are presented. A fully automated computer system is further developed to demonstrate the practicality of the chosen approach. In order to evaluate the systems performance, a local construction project with a 24,000m2 site is used. The automated system produced highly satisfactory results and showed notable flexibility through its CAD-based input/output media.

Sustainable construction management: introduction of the operational context space (OCS)

Sustainable construction is an emerging field of science that aims at incorporating the general sustainable development concepts into conventional construction practices. While the foundation of knowledge in this field is continuously expanding, sustainable construction is not yet standard industry practice. One major technical barrier that hinders enacting sustainable construction is the absence of an application framework that integrates both sustainability and construction practices at an operational level. This shortcoming is being addressed through a three‐dimensional operational context space (OCS) that achieves the sought integration aspect. The three dimensions of OCS are: (1) project life cycle phases; (2) project executing entities; and (3) sustainability performance parameters. Such OCS facilitates the association of responsibility, by assigning each sustainability requirement to a specific project entity (or entities) during specific project phase(s), and further provides a numerical assessment for construction projects using sustainability as a criterion. Steps of constructing the OCS and how it could be employed in the evaluation and benchmarking of a projects environmental performance are examined, along with sample illustrations in the area of construction waste management.

Using genetic algorithms in optimizing construction material delivery schedules

Purpose – To develop a systematic procedure and a computerized tool for optimizing the delivery and inventory of materials, as part of a comprehensive material management system in construction projects.Design/methodology/approach – A newly devised approach that employs genetic algorithms (GAs) for the optimization of material delivery schedules and their associated inventory control is presented. The approach is based on the project material requirement plans, and employs an objective function that minimizes the total costs associated with material deliveries. Furthermore, the computer system developed is used to examine and validate the adopted approach.Findings – GA proved to be a satisfactory approach for optimizing material delivery schedules and its associated inventory levels. The selected case study particularly showed the system to produce material delivery plans that have reduced costs compared with their actual counterparts. Also, the computer processing time for developing the optimized plans ...

LAYOUT PLANNING OF CONSTRUCTION SITES CONSIDERING MULTIPLE OBJECTIVES: A GOAL- PROGRAMMING APPROACH

The construction site layout planning problem has been studied by several researchers for the last 15 years; each presenting it from his/her own perspective. Yet, one fundamental aspect of site layout planning was not as well investigated and documented in the literature, that is, considering several planning objectives simultaneously. In principle, objectives nee d to be achieved by a site layout are many and could include transportation costs, labor movement, material handling, safety consideration, etc. These objectives are rather heterogeneous and in some cases conflicting. The paper attempts to handle this real ity by using the optimization capabilities of goal programming (GP). While traditional optimization tools aim at finding the optimum solution for an objective function, GP seeks a solution that satisfies as many goals as possible rather than optimizing a s ingle goal, which fully suits the case in hand. Formulation and specifics of the GP model are elaborated on in the paper, including use of the analytical hierarchy process (AHP) to identify the priorities among the various objectives. Following the computerization of the model, a case study of a university campus extension project in Toronto, Canada, was utilized to demonstrate the workings of this model.

A systems engineering approach for realizing sustainability in infrastructure projects

Abstract Sustainability is very quickly becoming a fundamental requirement of the construction industry as it delivers its projects; whether buildings or infrastructures. Throughout more than two decades, a plethora of modeling schemes, evaluation tools and rating systems have been introduced en route to realizing sustainable construction. Many of these, however, lack consensus on evaluation criteria, a robust scientific model that captures the logic behind their sustainability performance evaluation, and therefore experience discrepancies between rated results and actual performance. Moreover, very few of the evaluation tools available satisfactorily address infrastructure projects. This paper introduces a systems model that abstracts the environment, the construction product, and its production system as three interacting systems that basically exchange materials, energy and information. The model utilizes this setup to capture and quantify essential flows exchanged between such three systems, with the objective of evaluating sustainability. The paper walks through the development of a generic case of the model, and then demonstrates its utility in evaluating the sustainability performance of civil infrastructure projects using a typical water pipeline installation project that uses horizontal directional drilling (HDD) technology as a trenchless installation method. The developed model addresses an identified gap within the current body of knowledge by considering infrastructure projects. Through the ability to simulate different scenarios, the model enables identifying which activities, products, and processes impact the environment more, and hence potential areas for optimization and improvement.

A Balanced Risk Treatment For Construction Projects

Risk management is an integral part of a successful project planning and control mechanism. Standards, e.g., AS/NZS ISO 31000:2009, establish frameworks on how to perform comprehensive risk management process. However, there remain gaps in enacting such standards in reality, one of which is balancing risk treatment with the associated costs to risk-bearing project stakeholders. Although many studies were carried out to identify the range of factors representing project risk events and the recommended responses, very little has addressed the means of making such decisions. In this context, the guided search capabilities of evolutionary algorithms can play a role. After discussing and modeling the costs and benefits of alternative risk treatment strategies, the paper introduces ant colony as a capable algorithm for the balanced selection of such strategies. The research is being applied in the pipeline construction sector and made use of professional knowledge and project records from a mega construction company in the Middle East.

System Dynamics Approach for Forecasting Performance of Construction Projects

Accurate and reliable prediction of project performance is critical to the success of construction projects and companies alike. Such prediction assists in obtaining early warnings against potential problems. Existing project performance forecasting models are fragmented, especially regarding the consideration of interdependency between multidimensional performance indicators. To address these limitations, a system dynamics (SD) model was developed to simulate the complexities that exist among interdependent variables and forecast their dynamics over time. The proposed model integrates eight construction project performance indices, which have been identified through literature review and interviews with domain experts. Performance dimensions include cost, schedule, quality, profitability, safety, environment, team satisfaction, and client satisfaction. This model focuses on the construction phase of projects under unit price contracts and is intended for use by contractors. The model was tested on a road construction project to assess its practicality and accuracy. Results demonstrate general agreement between actual and forecasted performance indices. The model was also used to simulate four possible intervention scenarios by the project manager. Results of various scenarios show overall agreement with expected impacts of the interventions. The research advances the state of practice and knowledge of project performance forecasting through the creation of a more holistic and interdependent model of project performance metrics.

Ontology-based investigation of construction delay analysis methodologies in Egypt

Delays in construction projects are more commonplace than most of us wish. The intensified market competition is driving all to accept tighter schedules, shrinking budgets and slimmer contingency allowances. Such pressures give rise to claims, disputes, and litigation in courts. Understanding how to utilize Critical Path Method (CPM) Delay Analysis Methodologies (DAMs) is inevitable to resolving these problematic project situations. This study was initiated to investigate the level of awareness, frequency of usage, information needs, complexity of application, and success rate of each CPM DAM used in the Egyptian construction market where authors work or had previously worked. Research was conducted through a triangulation approach for data collection that employed a Quantitative Questionnaire and a Qualitative Interview. Distribution of questionnaire followed a thorough analysis of the market structure, size of organizations in the Egyptian construction market, and the required sample size to sufficiently reflect the differences between the targeted groups. Collected data was subsequently analyzed with the aid of SPSS software. An unbiased hypothetical determination of the level of awareness, usage and success rate of each DAM among different groups within the Egyptian construction market shall develop an understanding of the DAMs that should be adopted for a more successful settlement and resolution of disputes.

Employing Ant Colony for the Optimal Reduction of Project Risk Severity

Efforts undertaken in identifying, analyzing and assessing project risks are only made good use of when proper risk treatment strategies are decided upon and pursued. Based on the criteria established by senior management, the risk management plan goes about defining how each risk is to be handled. There are options to that end, including acceptance, avoidance, transfer and mitigation. Whilst these strategies are known to all in the industry, the decision-making process is far from easy. A research was undertaken to optimize risk treatment in construction projects, where both costs and benefits are balanced out at the project level. The paper particularly introduces Ant Colony Optimization (ACO) as a capable algorithm for the balanced selection of risk treatment strategies; that is to reduce the overall risk severity in a project at the minimum cost possible. ACO resembles the real life behavior of ants in their intelligent and guided search for food. The research is being applied in the pipeline construction sector and made use of professional knowledge and project records from a big construction company in the Middle East. The paper further presents an example project to demonstrate how ACO explores the risk treatment alternatives in a project and chooses the optimal set of strategies in such context.

Towards improving the planning and scheduling of construction projects in the UAE: a review of the human factor

The agenda of effectiveness, efficiency and economics has dominated business organisations operating in an agile environment where teamwork, accountability, transparency and responsiveness to client are paramount ingredients for business survival. Construction organisations also have to shift their focus to preplanning stages of a project to eliminate or reduce the risks during the construction phases of the project. This paper proposes an integrated conceptual model to enhance planning and scheduling stages. The model, discussed within the context of the United Arab Emirates (UAE), consists of six main parameters with associated elements include: the project (size, scope and complexity), the organisation (structure, lines of responsibilities, span of control and culture), the human aspects (education, experience and support), the construction methodologies (methods, preferred techniques, resources, out-sourcing, supply chain, health and safety) and the technology (software, tools and support); the contractual framework (obligations, risks legal); and the environment (internal and external).