Khaled Hesham Hyari

Conceptual Cost Estimation Model for Engineering Services in Public Construction Projects

AbstractCost estimation for public projects includes, but is not limited to, construction costs and engineering services costs. The available cost estimation models for these projects focus on the construction phase, with little or no consideration given to engineering services. This paper presents an artificial neural network model for the conceptual cost estimation of engineering services for public construction projects that considers both design costs and construction supervision costs. In developing the model, the authors first identify the factors that influence the cost of engineering services, and then apply a suitable artificial neural network for a cost estimation model. The model predicts the cost of engineering services as a percentage of construction cost based on project type, engineering services category, project location, and project scope. The model is trained on a data set obtained from the Governmental Tenders Department in Jordan, and then tested on some core data samples that had not...

Handling Unbalanced Bidding in Construction Projects: Prevention Rather Than Detection

AbstractUnbalanced bidding is a common practice associated with both unit price and lump sum contracts. This practice is not usually in the owner’s best interests and is used in different forms by contractors for various reasons. Bid evaluation practices try to identify unbalanced bids and may reject the lowest bid if it is perceived to be unbalanced. Previous research on this topic focused on either helping contractors unbalance their bids or detecting imbalance in bids in order to reject them. This paper proposes a model based on a prevention, rather than detection, approach to handling unbalanced bidding. The proposed model balances all the bids submitted for a project and thereby neutralizes the impact of manipulating bid prices to obtain undeserved payments from owners. This approach protects the interests of the owners while maintaining the essence of competitive bidding by awarding the project to the bidder who submitted the lowest bid in a fair competitive process. Two examples, representing the b...

A Multi-Attribute Decision-Making Model for Construction Enterprise Resource Planning System Selection

ABSTRACT Enterprise resource planning (ERP) systems are increasingly becoming essential business technologies. Selection of the optimal ERP system among numerous alternatives is regarded as a major challenge for the decision-maker. This choice is complicated by multiple attributes that the decision-maker needs to consider when evaluating different ERP options. The purpose of this article is to propose a multi-attribute decision-making model for ERP system selection based on data envelopment analysis (DEA). The strengths of the proposed DEA model include the input-output framework, which allows decision-makers to incorporate multiple attributes when evaluating different ERP options. These attributes are not required to be congruent. They can be measured by such criteria as monetary sums, time, or subjective score. Additionally, DEA can accommodate a large number of options (i.e., ERP systems) and variables (i.e., attributes). The proposed approach was utilized by a construction contractor to select the optimal ERP option out of eleven alternatives. During the evaluation process, the decision-maker incorporated six attributes to make the decision. These considered attributes are total cost, implementation schedule, functionality, user friendliness, customization capability, and service and support quality. Sensitivity analysis proved that the proposed model is stable and robust.

Owner’s Countermeasures to Skewed Bidding in Construction Projects: Review of Current Practices and Proposal for New Countermeasures

AbstractSkewed bidding is advocated as a contractor bidding strategy to obtain higher profit at the expense of the owner or gain competitive advantage over other bidders. Many scholars presented bi...

Handling Risks of Quantity Variations in Unit-Price Contracts

AbstractUnit-price contracts are awarded based on estimated quantities while payment to the contractor is based on actual quantities of work. In many cases, estimated and actual quantities never pe...

Damage detection in steel structures with semi-rigid connections using unscented Kalman filter

Purpose The purpose of this paper is to detect damages in steel structures with actual connections, i.e. semi-rigid connections. The method will detect the damages by tracking the changes in the stiffness of structural members using only a limited number of dynamic responses and without knowing the type or time history of the dynamic force applied on the structure. Design/methodology/approach The paper proposes a technique that combines the iterative least-square and unscented Kalman filter (UKF) methods to identify the stiffness of beams and columns in typical two-dimensional steel-framed structures with semi-rigid connections. The detection of damages is by using nonlinear time-domain structural health monitoring method. Findings The technique is verified by using numerical examples using noise-free and noise-included dynamic responses from two different types of dynamic forces: harmonic and blast loads. The results showed that the UKF method with iterative least-square is a powerful approach to identify and detect damages in structures that have nonlinear behavior and the method was able to detect the damages in beams with a very high accuracy for noise-free and noise-included dynamic responses. In addition, the optimum number and locations of dynamic responses (accelerometer sensors) required for damage detection were determined. Originality/value This paper fulfills an identified need to detect damages in steel structures using only a limited number of accelerometer sensors.

Two-stage system identification approach for three-dimensional structural systems

A two-stage finite element system identification (SI) technique is proposed in this paper to identify stiffness of elements and detect damages in three-dimensional framed structures. The technique combines in stage 1 the iterative least-square and in stage 2 the unscented Kalman filter (UKF) to identify the stiffness of elements using only limited measured response time histories from only four to six accelerometers instead of dozens of accelerometers of the whole structure and assuming the time history of dynamic load applied on structure is unknown. The method will identify the stiffness and detect the damages in the elements by tracking the changes in the recordable dynamic output responses between damaged and undamaged states. The optimum number and locations of accelerometers were studied in this paper. The algorithm is verified using numerical examples. The results showed clearly that the technique can identify damaged and undamaged three-dimensional steel framed structures and the minimum number of sensors required for such frames.