Amr A. Oloufa

Model for Quantifying the Impact of Change Orders on Project Cost for U.S. Roadwork Construction

Change orders are very common in almost every construction project nowadays, often resulting in increases of 5–10% in the contract price. Understanding the consequences of such trends, several studies have attempted to quantify the impact of change orders on the project cost. Most of the studies aimed at the quantification of the change orders were sponsored by contractors’ organizations, where statistical models used to quantify the impact of the change orders on the project cost were based on data supplied by the contractors; a situation that can lead to owner-contractor disagreements related to the quantification method used. In addition, most of the studies tackled commercial and electromechanical work, and very rare studies tackled the field of heavy construction; a field that suffers from change orders because of errors and omissions, scope of work changes, or changes because of unforeseen conditions. This study addresses the need for a statistical model to quantify the increase of the contract pric...

Using DSM for modeling information flow in construction design projects

Construction design projects are multi-disciplinary requiring input from several players including planners and design professionals. Project managers have developed techniques for planning, organizing, monitoring, and optimizing complex design projects. The critical path method (CPM) is traditionally the most commonly used to address these issues. Various techniques have been added to CPM like splitting the activities to optimize project duration. However, the CPM approach is based on workflow and is not effective in handling the iterative process characterizing design projects. Also, while CPM can effectively handle sequential and parallel activities, it cannot handle coupled activities. The design structure matrix (DSM) approach differs from CPM in that it represents information flows in addition to workflows in a project. The DSM method can handle sequential, parallel, in addition to coupled activities. In this article, an algorithm has been developed based on a combined DSM and CPM methodology. The main objective of algorithm is to optimize the planning of design projects. A new concept has been introduced in the paper termed the ‘Trigger Value Matrix.’ The objective of the trigger value matrix is monitoring changes made in a multi-disciplinary design process as these changes can potentially lead to increased costs and durations. The application of the combined DSM–CPM and the trigger value matrix has been incorporated in a software tool (DSMPM V1.0) that can be used by design companies. Using DSMPM, management focuses on the essential information transfer requirements in the project thereby minimizing rework, and improving throughput and design quality.

Resource-based simulation libraries for construction

Abstract Discrete event simulation modeling has been used successfully in a wide range of industrial and manufacturing applications. In construction applications, even though simulation has been applied, it still is extremely limited in terms of wide deployment in construction projects. Several reasons limit the effective implementation of this technology in construction. Chief among them is the time needed to develop the simulation model. While developing models for industrial applications is just as time consuming, the perpetual nature of manufacturing activities, may make this investment worthwhile. However, this is not the case in construction. In this research, the authors approach the problem through the development of a library of preprogrammed construction resources. The user need only select the required resources, and specify the project logic by linking these resources together. Benefits of this approach are the increased communication between the members of the construction team. Also the potential application of simulation tools in unforeseen construction situations where the time associated with hiring a simulation programmer may not available and a quick response is required.

A GIS-based system for tracking pavement compaction☆

Abstract Compaction is an important operation for improving construction material stability in construction operations such as soils and asphalt pavement. Through the process of compaction, soil strength and stability can be increased to the magnitude required by the design. Quality control is an extremely important concern of State Highway Agencies and contractors. For asphalt pavements, performance and quality are affected by three primary factors: a properly designed mix, drainage, and adequate compaction. These three factors must be performed together to assure quality. For this reason, compaction is considered to be very important in the performance of asphalt pavements. This paper reports on research to develop a system to map the moving compaction equipment, transform this result into a geometrical representation, and to investigate the use of Geographic Information System (GIS) technology to develop a graphical representation depicting the number of coverages. Results are stored in a permanent record that can serve as a historical document.

Modeling and simulation of construction operations

Abstract This paper starts with a brief introduction to simulation, and a historical review of its applications. The introduction is followed by a review of simulation applications in construction. The technology of object-oriented modeling and programming and its application to construction applications is discussed along with enhancements to simulation modeling and analysis such as animation and visual programming.

DSM Versus CPM: Issues for Planning Design & Construction Activities

Construction design projects are multi-disciplinary requiring input from several players including planners and design professionals. Project managers have developed techniques for planning, organizing, monitoring, and optimizing complex design projects. The Critical Path Method (CPM) is traditionally the most commonly used to address these issues. Various techniques have been added to CPM like splitting the activities to optimize projects duration. However, the CPM approach is based on workflow and is not effective in handling iterations, which is a characteristic of design projects. Also, while CPM can effectively handle sequential and parallel activities, it cannot handle coupled activities. The Design Structure Matrix (DSM) approach represents information flows in addition to workflows in a project. The DSM method can handle sequential, parallel, in addition to coupled activities. The study reported here involves the application of DSM for design projects, and describes an algorithm to optimize planning of design processes. Using DSM and through finding critical activities, management focuses on the essential information transfer requirements in the project, thereby minimizing rework, and improving throughput and design quality.

An Object-Oriented Environment for the Construction Planning of High-Rise Buildings

New buildings are experiencing a continuous increase in the sophistication of their building systems and methods of construction. This situation creates a need for a planning tool that is capable of serving one or more of the complex set of activities during the project life phases. Several researchers have devised methods for the modeling of buildings in an attempt to develop a representation that is capable of supporting a collaborative environment for engineering and construction. Some of these modeling approaches attempt to enable the user to use the same model for conceptual and detailed design, while others target primarily the construction activities. Other models have also attempted to cover the design and construction interface. This paper will describe a modeling environment for the construction planning of high rise buildings. Issues covered include the development of an object-oriented CAD environment that enables the construction planner to evaluate potential construction sequences using both graphical, attribute, and knowledge-based inputs. The manuscript will conclude with other approaches described in the literature, problems that have limited their implementation, then extensions to this research.

An automated environment for soils- and terrain-dependent applications

This paper explains the development of an integrated information environment that is designed specifically for applications dependent on information related to soil types and terrain of the project site. This covers a wide variety of applications such as shallow and deep foundations, trenching, earthmoving and tunneling. The design of this environment takes into consideration the typical requirements of the project team with an emphasis on integrating requirements for both design and construction. The environment reported here is comprised of three main modules, a relational database for the storage and display of soil borelog information, a geographic information system that displays the geographical locations of soil studies, and a module that is used to develop a three-dimensional profile of the soil layers between any number of borelogs. The user may also develop cross sections of soil layers in any direction. This paper reports on the hardware and software used and concludes with a discussion of future extensions to the system.

Infrared Thermography for Asphalt Crack Imaging and Automated Detection

A research project evaluated the application of infrared thermography for the detection of asphalt cracking. Such detection has generally relied on image processing of pictures and videos of asphalt produced by analog and digital cameras that operate in the visual range of light. The presence of shadows, poor light conditions, white cracks, and a variety of other problems have presented serious challenges to automated crack identification and detection in this frequency region. The research reported here is primarily aimed at testing the hypothesis that asphalt cracks cause changes to surface conditions and emissivity, leading to perceived temperature differentials that can be exploited by infrared detectors in cameras. The research involved the production of tens of images from both conventional and infrared cameras. Several parameters were evaluated for both flexible and rigid pavements, including choice of infrared detection range, various lenses, and exposure during day and night hours. Under the right conditions, infrared thermography can yield superior results and allow the identification of tiny cracks about 1 mm in width, which are virtually impossible to detect with conventional cameras.

Relating structural failures to subsurface conditions using GIS

Abstract This paper discusses the use of GIS to disclose patterns of building structural failures, structural systems and the underlying soil types on a regional basis. The approach proposes the integration of a topologically specified logical data model of regional subsurface conditions in three dimensions with a model that describes the relevant attributes of the foundation/structural systems of buildings using the same geographical referencing systems as a layer of a GIS system. Attributes of structural failures associated with individual buildings are included in the database. With subsurface conditions on one hand and foundation/structural systems data on the other, it becomes possible to compare soil/structure combinations associated with specific types of failure and to give insights into the proper choice of structural systems in the region.