Journal of Construction Engineering and Management

This paper presents the concept used to construct a complex residential tilt-up-panel structure utilizing three-dimensional (3D) modeling and animations. The residence comprises of 108 precast concrete panels of varying rectangular shapes with “dog legs” and window and door “cutouts” that look like an assembled jigsaw puzzle. The erection and installation procedure called for a maximum panel-to-panel joint tolerance of $1.27\mathrm{cm}$ $\left(0.5\mathrm{in.}\right)$ , often in $90°$ joints between panels. 3D animations were used to experiment with the construction process on the computer screen prior to construction in order to avoid potential costly on-site errors. In addition, the 3D animations were also used as a training tool for the contractors. This paper focuses on describing the methodology used to integrate a crane selection algorithm and optimization model with 3D modeling and animation for the selection, utilization, and location of cranes on construction sites. Analytical optimization processes were used to decrease the traveling time and distance of the selected crane, to improve the crane lifting sequence and to minimize the use of panel casting slabs.

This paper focuses on the procedure utilized in the construction of tilt-up irregular concrete panels that are constructed on-site using concrete slabs and wooden formwork. The case study required high-quality concrete finishing. The erection and installation procedure called for a maximum panel-to-panel joint tolerance of $1.27\mathrm{cm}$ $\left(0.5\mathrm{in.}\right)$ , often $90°$ joints between panels. To meet precision requirements, the casting slabs were leveled and flattened with laser screed technology and smoothed with chemical solutions. To ensure that the final result met expectations, a mock-up model was built using different types of materials and to simulate site constraints. The architectural design is a composition of precast concrete panels like “Lego” pieces assembled similarly to a jigsaw puzzle. The unique construction process required a state-of-the-art analysis to produce the set quality. Quality conditions as set by the owner included creating a smooth concrete surface on all panels while avoiding damages and reducing equipment and material costs. The proposed methodology is described through its implementation on the case study, which is also described in this paper.

Warranty contracts are expected to enhance product quality and service life at lower life-cycle cost. Recognizing that such benefits could be offset by the generally higher costs of warranties, an assessment of the relative cost-effectiveness of warranty contracts compared to their traditional counterparts is currently of great interest. Using pavement data from Indiana, this paper evaluates the costs, effectiveness, and cost-effectiveness of warranty and traditional contracts. Effectiveness was measured in terms of pavement condition and treatment service life. The paper determined that the warranty contracts generally had higher agency costs but produced pavements with superior condition and service life, and lower construction periods and work-zone user costs, compared to their traditional counterparts. Over a $5\text{-}\text{year}$ period, the warranty contracts were found to be 27–30% less cost-effective than their traditional counterparts. Over the long term, the warranty contracts were found to be 70–90% more cost-effective on the basis of service life and 58–65% more cost-effective on the basis of both service life and pavement condition. The study results suggest that the higher long-term cost-effectiveness of warranty contracts is more perceptible when both cost and effectiveness are viewed over the entire life of the pavement treatment and when both agency and user cost are used in the cost analysis. The paper discusses certain aspects of such comparative evaluation studies that could lead to biased inferences and calls for careful screening of warranty and traditional contracts for such studies.

Partnering as a concept has matured in its application and many empirical studies provide evidence of its impact on project performance beyond the rather prescriptive and anecdotal claims of earlier cookbooks on the subject. What has remained elusive, however, is a guiding theory on partnering. Drawing on the literature, partnering is explained within the framework of intergroup contact theory and teamwork in organizations. More specifically, partnering has the potential to create the essential conditions for optimal intergroup contact and hence, to reduce bias and increase cooperation among construction project workgroups and, consequently, favorably impact on project performance. Demonstrating a close fit with the published literature on partnering provides useful support for the proposed model. The model can clearly help project managers to focus their attention on the necessary aspects of workgroup processes that lead to high cooperation and performance.

In planning for contractor payments, an owner with multiple projects needs to estimate the amount of money to be paid to contractors in coming months. For an owner as large as the Texas Department of Transportation (TxDoT), one is faced with the problem of organizing the budget to ensure that there are sufficient funds for all projects. This investigation was requested by TxDoT to provide a tool to forecast future project payments. Recent account summaries of TxDoT projects from 2001 to 2003 were analyzed for creating mathematical models representing monthly payments for various projects. The data were organized into categories of project types and subcategories of project contract amount. A fourth degree polynomial regression analysis was run on the data and the regression curve, when statistically significant, was taken to be the forecast payment curve. Finally, a computer program was developed to implement the results of the investigation for TxDoT’s needs. The methodology provided will help other highway agencies to create their own equations to better predict project cash flows and trends. This investigation might also benefit researchers in projecting cash flows and trends, while also allowing for improvements.

This paper presents the methods used and a case study of a project management system (PMS) to manage daily progress in the construction of multiple apartment buildings in South Korea. A dilemma encountered in previous research in the field of progress management is that efforts to enhance data accuracy cause the data handling workload to soar. A main feature of the method presented by the writers for calculating the budgeted cost work schedule is to allocate the project budget into control attributes, activities, and tasks that are defined in a work-packaging model, according to daily weight value. The method offers enhanced practicability by reducing data-handling workloads while not sacrificing the rationale of progress management. The work-packaging model is designed to enable project managers to acquire and process data for progress management at various levels of detail. The budgeted cost of work performed is measured daily at the tasks level using the earning percentage rate from daily work reports. The implementation of PMS focuses on functions to distribute the budget according to daily weight values and acquire the earning percentage from the daily work report. The PMS was applied to a construction project of 54 apartment buildings in South Korea. The case study of its use shows that company headquarters and managers in the field can acquire data for progress management without additional data-handling workloads, and can analyze the progress daily at various levels of detail.

The production equation called Little’s law has been applied to construction data recently. However, Little’s law was derived for steady-state conditions assuming constant input and output rates and long production runs. Production in construction is inherently temporary, and learning curves and environmental influences often render input and output rates unequal and nonlinear. Starting with a conservation of mass formulation, general equations for work-in-process and cycle time for unsteady-state conditions and limited run production are developed. The motivation behind these equations is to explain common trends in production variables seen on construction projects. Previous studies have shown that when output from a construction production system is drastically increased, a significant upward impact is also seen on cycle time and work-in-process, and this work provides underlying theory and equations to explain these trends. Cycle time and work-in-process equations are presented as functions of time and on average. Data from construction activities are used to show that unsteady-state conditions commonly occur. Reasonable simplifications of the general equations provide guidelines for buffer sizing and resource allocation decisions.

Trade coordination and claims documentation is a challenge on any project, particularly for specialty subcontractors. The writers introduce a schedule control method initiated by the subcontractor, which facilitates coordination and communication between a subcontractor and other project participants as well as documentation to the prime contractor. A case study illustrates the preparation of a trade-specific critical path method (CPM) schedule, which is updated on a regular basis. The writers also address the interrelationship between the CPM schedule, internal reporting, schedule of values, and labor tracking. It is difficult to ensure that all subcontractor-produced documentation is complementary, but it is well worth the effort when it comes to supporting a claim. Monthly schedule updates and narratives communicate the conflicts, issues, and schedule constraints the subcontractor experiences or anticipates on a project, thereby providing contractually required notice to the prime contractor during the project. This increases the likelihood of resolving issues during the project, while simultaneously protecting a subcontractor’s position if change order requests are denied or if back charges are levied prompting a subcontractor to enforce its rights, execute a claim, or proceed to litigation.