Journal of Construction Engineering and Management

Choosing validation methods in construction research is challenging. This study explores trends in the use of validation methods and their impacts based on a statistical analysis of a sample set of 365 research articles on construction productivity. This sample set provides a balance of the breadth and cohesion required for significant comparisons and the temporal depth required for longitudinal analysis. The contributions of this research include (1) a critical review of the validation methodologies that can be used for research projects in construction engineering and management, (2) an investigation of the statistical relationship between validation methods and the impact in terms of citations of research over time in different source categories, and (3) statistically significant observations over the preceding thirty years of the increased use of functional demonstration as a validation methodology and the decreased existence of unclear validation. These results may be used in the future to influence the choice of validation methods to increase the impact of construction productivity research.

It is important for project owners to select only those construction contractors who are uniquely qualified to perform the work because this leads to the greatest chance for achieving project success. Owners typically screen contractors by using the following key criteria: financial stability, technical ability, management capability, health and safety, and reputation. This study focuses primarily on the construction contractor’s financial stability during the prequalification phase and employs a dynamic threshold cash flow based structural model (DCFM) to assess the credit quality score for each construction contractor. This model differs from the existing credit model because it only requires accounting statement information; thus, it is applicable to both publicly listed and private construction contractors. Moreover, only a small portion of companies are rated in the construction industry; this model is especially useful for owners to assess the credit quality of unrated construction companies. The Standard & Poor’s issuer credit rating is used as the benchmark to evaluate the model’s discrimination ability to differentiate financially qualified contractors from unqualified contractors. Additionally, the validation indicator area under curve (AUC) is utilized to demonstrate whether the DCFM can identify different credit grade firms according to the model’s credit quality scores. The AUC results of the first three years of this model are 0.861, 0.833, and 0.819, indicating that this model achieves excellent discriminatory ability and is useful for assessing the credit risk of construction contractors.

The radio frequency identification (RFID) technology has proven its potential in locating and tracking construction resources, a critical task in construction project control. However, the main challenge is how to achieve desired levels of locating accuracy. This paper presents an enhanced boundary condition method that incorporates the tag-reader angle and the reader geometric configuration factors to control the accuracy of a locating system that integrates RFID and real time kinematic (RTK) global positioning system (GPS). Controlled laboratory experiments were conducted to assess their effects and create quality control filters. This study demonstrated the relationship between the detecting range and the tag-reader angle and used it to separate valid/invalid boundary points. Spatial dilution of precision (SDOP) was formulated to measure the geometric configuration of readers forming the boundary constraint. Correlating SDOP to the locating error through a polynomial regression model, a mechanism was created to use SDOP to predict and control the locating accuracy. Open field experiments validated that appropriate SDOP, and tag-reader angle filters could be created to achieve varying levels of accuracy.

In tall-building construction, the equipment-driven table formwork method is a useful alternative for improving productivity of horizontal formwork with less skilled labor. The lifting system significantly affects the productivity and costs of table formwork operation. This study proposes a new system integrated with the construction hoists for automating the lifting process of table formwork. The system targets crane-independent transportation for productivity improvements while overcoming the limitations of the existing independent lifting system, which include high initial cost and extra work for assembly and operation. In a case study, the proposed system showed 49.4% improved productivity over a tower crane, and equipment costs were 73.8% lower than those of the existing independent system. The simplified structure of the system through integration with the hoist could minimize the additional time and cost inputs for its assembly and operation. The proposed system could provide more flexible and stable scheduling at a lower cost in tall-building construction with short cycle times and excessive lifting loads.

The major aspects of highway planning are cut and fill calculations, cost estimation, and schedule duration planning. These items of highway planning are often complex and time consuming. Designing and comparing different alignment alternatives is even more time consuming and tends to be very costly. When planning for a new highway alignment, the general practice is to identify multiple alignment options and determine the best option based on multiple factors. This research proposes to automatically generate multiple alignment alternatives and the cut and fill quantities, costs, and schedules associated with each alternative in comparing different highway alignment alternatives. Building information modeling (BIM) technology has been increasingly used in resolving the complexity of a project in the building industry. However, the development of highway data schema and model using an object-oriented three-dimensional (3D) visualization is still underway and has not been fully implemented yet. This research proposes an object-oriented data model in compliance with ISO 10303 for highway design and construction. With the newly proposed data structure in highway design and construction, the automation of cost estimating and duration scheduling was achieved in identifying and comparing an optimum solution for alternative modeling and data output whose values provided aid in the selection process of design comparison. In summary, the explicit contribution to the body of knowledge that this paper claims is to propose a research procedure to improve current highway design and construction practices by applying a 3D object-oriented modeling approach to solve the problem of time-consuming highway planning related to alignment comparison.