Hydraulic Design of a Longitudinal Culvert for Lock Filling and Emptying Systems

The U.S. Army Corps of Engineers is planning navigation improvements for many projects to meet predicted increases in tow traffic. Some of these improvements include the addition or replacement of the navigation lock. Innovative design and construction techniques are being investigated to try and reduce construction costs as well as operation and maintenance costs. The Corps identified that a savings in lock construction could be achieved if the conventional concrete gravity lock walls with culverts inside them could be replaced with thin walls and longitudinal culverts located inside the chamber. This culvert design was designated the In-Chamber Longitudinal Culvert System (ILCS). An extensive research effort led to the development of the ILCS design. This paper provides a brief summary of the research results and the accompanying design guidance developed for low to medium lift ILCS locks. The guidance includes culvert location; port size, location, and spacing; port extensions; culvert-roof overhang; and wall baffles. Lock chamber performance characteristics, based on acceptable filling and emptying operations determined using a laboratory model, are also presented. The ILCS is a feasible design based on the hydraulic performance determined from the investigation.     

Predicting Performance of Design-Build and Design-Bid-Build Projects

Design-build (DB) and design-bid-build (DBB) are two principal project delivery systems used in many countries. This paper reports on models constructed to predict performance of DB and DBB projects on 11 areas, using project-specific data collected from 87 building projects. The study included collecting, checking, and validating industry data, and the statistical development of multivariate linear regression models for predicting project performance. Robust models are developed to predict construction and delivery speeds of DB and DBB projects. Gross floor area of the project is the most significant factor affecting speed. Besides this, for DBB projects, contractors’ design ability, and adequacy of plant and equipment would ensure speedy completion of the projects. For DB projects, if the contract period is allowed to vary during tender evaluation, this would slow down the project. Robust models to predict turnover and system quality of DB projects are also constructed. A DB contractor’s track record is an important variable. They must have completed past projects to acceptable quality and have ability in financial, health and safety management.     

Analysis of the Design-Build Delivery Method in Air Force Construction Projects

The design-build (DB) method for construction project delivery continues to grow in both the private and public sector; additionally, research has shown that the DB method outperforms the design-bid-build (DBB) method. The Air Force has applied the results of these previous research efforts to its military construction (MILCON) program without performing empirical studies to validate the approach. Therefore, the objective of this study was to compare the performance of the DB delivery method with the traditional DBB approach for the Air Force MILCON program. Data related to 835 (278 DB and 557 DBB) MILCON projects for fiscal years 1996–2006 were subsequently analyzed. The DB method had better performance in three of six metrics with the performance being significantly better for cost growth and the number of modifications per million dollars. The traditional DBB method performed significantly better in terms of total project time. Furthermore, the DB method was best suited for various facility types. This study provides empirical evidence of how the DB method provides an advantage over the traditional DBB method for Air Force MILCON projects.     

Success of Supplier Alliances for Capital Projects

Energy sector capital projects typically cost hundreds of millions and even billions of dollars. Managing the engineered equipment is important not only because of their high dollar value but also because the long manufacturing lead times often drive the overall project schedules. In recent years, several supplier alliances have been successfully implemented on such projects leading to initial price savings in the range from 6 to 10%. This paper presents the result of a study to assess the opportunities and barriers with such partnerships. Interviewed company executives perceived that time savings and quality improvements, mostly due to the suppliers’ specialized expertise, are of much greater value than a lower bid price. Most surprisingly, very few companies use metrics to measure performance, thus leaving them in the dark on the question of how well an alliance worked or why it failed. The relevance of the presented work is in the amount of actual field data that has been generated and processed.     

Partnering on Small Construction Projects

Application of partnering concepts on small construction projects by owners or government functionaries could result in substantial savings for private owners and public exchequers annually. This paper develops a concept for partnering for small construction projects based on recent management research and theories being developed in universities with the lessons learned from the U.S. Army Corps of Engineers experiences on partnering for large projects. The discussion addresses current attitudes toward partnering, particularly, in small (i.e., up to $3,000,000) private or government sponsored projects. An objective of this paper is to share the benefits of partnering on small construction projects, based on practices and experiences of the U.S. Army Corps of Engineers. A final objective is to develop a primer for construction practitioners.     

Cash Flow Projections for Selected TxDoT Highway Projects

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.     

Comparison of U.S. Project Delivery Systems

Construction management at risk, design∕build and design∕bid∕build are three principal project delivery systems used in the United States today. This paper empirically compares cost, schedule, and quality performance of these three project delivery systems, using project-specific data collected from 351 U.S. building projects. The study included collecting, checking, and validating industry data, significance testing of univariate comparisons and the statistical development of multivariate linear regression models for predicting average project performance. A nonresponse study verified statistically that collected data were appropriate for analysis and representative of the industry from which they were drawn. Significance testing and multivariate comparisons used nearly 100 explanatory and interacting variables to explain project cost, schedule, and quality performance. Specific comparisons between project delivery systems, performance metrics, and six facility classes are discussed. Results and the level of confidence that surrounds each finding are presented.     

Earthquake Hydrodynamic Pressure on Dams

Hydrodynamic pressures on the vertical upstream face of straight dams during horizontal earthquakes were studied by Westergaad in 1933, and an analytical solution was obtained. Assuming that water is incompressible, an approximation can be made to reduce Westergaad’s mathematical formulation to the Laplace equation. The computer program SEEP2D, from the U.S. Army Corps of Engineers (COE), is available for the study of seepage flow in porous media; this flow can be expressed mathematically in a form of the Laplace equation. Therefore, we can use this computer program to study the hydrodynamic pressure on dams during a horizontal earthquake in the upstream/downstream direction. In practice, the proposed procedure is not limited to SEEP2D but can also be applied to any computer model capable of solving Laplace equations in bounded domains. Two examples are presented to show the application of the COE’s computer program, and the accuracy of the proposed method is discussed.     

Economic Value of Combined Best Practice Use

This paper measures the value of best practices based on data taken from the Construction Industry Institute Benchmarking and Metrics database. A three-step process provides the basis for measuring the potential benefits of increased best practice use. First, a practice use index is derived to model the way in which best practices are utilized on actual projects. The index combines data from eight best practices to create a single measure of practice utilization. Second, a project performance index, combining cost and schedule metrics, is derived as an indicator of overall project performance. Third, the practice use index is correlated with cost, schedule, and overall project performance metrics. Both owners and contractors benefit from increased practice use. Potential cost savings for owners range from $1.7 to $3.4 million, depending on industry group and project size. Potential cost savings for contractors are higher, averaging $7.2 million for the typical $88 million heavy industrial project. Benefits from schedule reductions are most apparent for owners. On large building projects, schedule reductions for owners average 27 weeks. Finally, improvements in overall project performance on the order of 30% are observed for both owners and contractors.     

Empirical Comparison of Design/Build and Design/Bid/Build Project Delivery Methods

This study compares the performance of design/bid/build and design/build to see if one project delivery method is superior in regards to time and cost. Similar military buildings were used to identify two samples of projects delivered with each of the two delivery methods. These projects provide a meaningful comparison because they include buildings of the same typology (i.e., U.S. Navy Bachelor Enlisted Quarters) delivered using similar design models. Project duration, project duration per bed, project time growth, cost growth and cost per bed were statistically compared. Upon completion of the analysis, the hypothesis that design/build projects are superior to design/bid/build projects in regards to time and cost was tested. Design/build projects were proven superior in performance in almost every measure. Other findings, including recommendations to practitioners and researchers, will be provided as well.     

Urinary interleukin-6 and interleukin-8 in females with urethral syndrome]

Basing on the example of the project "Quality assurance in gynaecological surgery", we show which effects due to participation in an externally supported quality assurance measure can be reached short-term. 44 gynaecological clinics documented 42,433 operative procedures within the project in 1994. In 1995, seven participants continued the documentation (9,430 operations). We measured the quality of care over time, using 20 quality indicators that were formulated in the project. Quality improvements were achieved in the two-year study period particularly for indicators which focused on less complex processes of care (i.e. thromboprophylaxis with heparin). However, more complex processes of care, such as the indication for an operation, have not yet changed. Nevertheless, according to the results of structured interviews, we expect long-term quality improvements: due to the participation in the project, 26 clinics reported increasing attention to the quality of care, 12 clinics changed their organisation of the quality assurance system and 11 clinics began internal quality improvement projects on the basis of the study benchmarks.     

Selection of Project Delivery Method in Transit: Drivers and Objectives

This paper describes the results of research on alternative project delivery methods in transit projects in the United States. The research, sponsored by the Transit Cooperative Research Program, aimed to identify those factors that drive the decision in the choice of project delivery method. A rigorous case study analysis based on on-site structured interviews with the directors of several transit projects was used to identify decision drivers and the rationale behind the delivery method selection decision in transit agencies. The nine case studies conducted in this research represent a cross section of delivery methods, including design-bid-build/multiprime, construction manager-at-risk, design/build, and design/build-operate-maintain. The interviewees agreed that the use of alternative delivery methods have resulted in savings in schedule and cost for transit agencies. The research also found that achieving aggressive schedule compression is the most influential factor when selecting alternative delivery methods. Also, implementation of a formal risk analysis as part of the project development process appears to improve the project’s chances of meeting budget and schedule objectives.     

Benchmarking, Benchaction, and Benchlearning: Rework Mitigation in Projects

The Australian government has issued several calls to improve the performance of the construction industry. A lack of available benchmark metrics has made it difficult, if not impossible, for organizations to identify areas to target for process improvement. A significant factor that has been found to contribute to poor organizational and project performance is rework. Using the results of a questionnaire survey, the paper presents and discusses a series of benchmark metrics for the causes and costs of rework for 161 construction projects. A generic framework for benchmarking rework at the interfaces of a project’s life cycle is proposed, and unstructured interviews are used to subject the proposed framework to validation by industry practitioners.     

Owner’s Risks versus Control in Transit Projects

This paper studies the characteristics of different project delivery methods in public transit projects with respect to the owner’s project control and its share in project risks. The most appropriate project delivery method is selected early in the project life cycle based on a number of objectives and criteria set forth by the owner. The ability to manage risk effectively and owner’s control over the project are among the most important factors for selecting the delivery method. These two factors are highly interrelated. This paper discusses the interaction of risk and control in the context of the project delivery method. Results of several interviews with transit authorities are used to ensure the validity of findings. This paper shows that higher control over the project is achieved only if the owner is willing to accept more risks. In other words, there is no delivery method that allows the owner to enjoy high levels of control and minimum risk simultaneously.     

Benchmarking Productivity Indicators for Electrical/Mechanical Projects

Labor-intensive industries such as the electrical and mechanical trades are considered high risk due to the high percentage of labor costs. Because of this high risk, it is important for contractors in these industries to closely track labor costs on projects and compare these costs to industry benchmarks. In this paper, benchmark indicators for these industries are established on the basis of actual project data. These benchmarks include the relationship between the percent complete or percent time and cumulative work hours or cost, project size and duration, project size and average man power, project size and peak man power, and average versus peak man power. These relationships were developed using regression analysis. Man power loading charts and the related S-curves were developed from actual project data. The man power loading charts and the related S-curves are useful for resource planning and for tracking progress on a construction project. They can be used to show the cause-and-effect relationship between projects impacted by outside factors and normal labor productivity.     

Benefits of Small Projects Team Initiative

Ordinarily, minimum design costs are associated with all construction projects regardless of their size or complexity. Consequently, the design costs are a higher percentage of the overall costs for small projects. This paper presents an analysis of the effectiveness of the Small Projects Team Initiative (SPTI) developed and implemented by the Seattle district of the U.S. Army Corps of Engineers. SPTI is intended to lower the design costs on construction projects where the design scope is simple and∕or the administrative and construction processes are somewhat routine. The Small Projects team consists of representatives from contracting, construction, engineering, and project management. This team produces specifications for selected projects with simplified design, design by shop drawing, and innovative contracting arrangements. Data from 77 projects completed within the Seattle district are compared with the data from 146 pre-SPTI jobs. Statistically confirmed benefits include reduced design costs and reduced schedule growth (when user requested changes are excluded). Lower median change-order rates are not confirmed, but further analysis of the nature of changes is recommended.     

Assessing the Accuracy of Cash Flow Models: The Significance of Payment Conditions

Cash flow forecasting methods have evolved to allow detailed predictions for individual projects. These methods, principally the cost-schedule integration (CSI) technique, make extensive use of project estimate and schedule data. An implicit assumption of these methods has been that accuracy is largely a function of the quality of data available to the model. To the writers’ knowledge, there has been no assessment of the ability of project specific cash-flow models to accurately predict cash flows given accurate input data. This paper makes two contributions. First, two complementary methods are presented—pattern matching logic and factorial analysis—that provide an ability to assess the accuracy of cash flow models. Second, through demonstration of these methods using data from two projects, a critique is made of the ability of existing CSI models to accurately predict cash flows. The paper concludes by recommending extensions of CSI models to include more detailed payment conditions, including differential payment lags, components for materials and labor, and payment frequency. A further conclusion is the call for more research to better understand the balance between managers’ need for information and the ability of predictive models to provide that information.     

Comparing Procurement Methods for Design-Build Projects

The design-build delivery method is increasingly used in the United States due to numerous advantages it can offer a project. An important issue associated with design-build delivery is the procurement method used to select the design-build team. It is a critical decision that involves several key project team members, including the owner, designer, and contractor organizations, and requires the owner to carefully choose the design-build procurement method that will be used to select the team that will deliver the project. This research quantitatively analyzed the correlation between the design-build procurement method and the performance of the design-build project with regard to cost, time, and quality metrics. The procurement methods studied were sole source, qualifications-based, best value, and low bid selection. Data were collected through surveys from 76 design-build projects in the United States. Based on the patterns and relationships identified from these data, a better understanding of the procurement process and how it influences project performance is achieved. The impact of project-specific factors and guidelines are presented to assist owners in selecting the design-build team procurement method that responds to their project goals.     

Project Delivery Systems and Project Change: Quantitative Analysis

Design/build has become one of the favored project delivery methods in the engineering construction industry. Numerous studies have advocated the use of design/build over the traditional design/bid/build delivery approach. A comprehensive analysis of 67 global projects from the Construction Industry Institute's database shows that design/build projects may not provide all the benefits to project performance. The study found timesaving was a definitive advantage of design/build project delivery, but, the positive effects of cost and productivity changes were not convincing. Based on the results of the study, the project management expertise and experience of the contractor may have a greater impact on project performance outcomes than focusing on project delivery strategy only.