51 research outputs found
A Case Study Analysis of the Kentucky Transportation Cabinet’s Design/Build Pilot Projects
The current economic climate has forced transportation agencies to evaluate opportunities to save money. One possible opportunity lies in Design/Build (DB) delivery. In 2006, with the approval of the Kentucky General Assembly, The Kentucky Transportation Cabinet selected ten projects to be developed through the Design/Build method. DB delivery offers many attainable advantages, the most notable being expedited delivery. The research described herein presents a case study of these DB pilot projects in order to capture lessons learned on the use of the DB delivery method on future projects. In order to determine which projects are suitable for DB delivery, a scorecard was developed based upon factors observed over the course of the DB pilot projects. Another important aspect of the DB pilot projects was their cost, it was believed their costs were much higher than a comparable design/bid/build (DBB) projects. However, after a thorough cost analysis, it was determined that the DB projects cost the Cabinet only an estimated three percent more than comparable DBB projects. The DB pilot projects have had mixed results. Several recommendations are provided that will assist agencies with DB project selection and successful management of DB projects
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Modeling of work envelope requirements in the piping and steel trades and the influence of global anthropomorphic characteristics
Limited and unavailable workspace for crews on the jobsite results in losses of productivity. With the increased usage of Building Information Modeling (BIM) in the construction industry, four dimensional animation that brings together the three dimensional model of a building and its construction schedule to visualize construction process is emerging. To support space planning in the preconstruction management, this research provides a framework to integrate the knowledge of work envelope requirements among piping and steel trades. Typical work envelope requirements were defined through in-depth interviews with superintendents on U.S. industrial projects. Therefore, the rules and semantic information extracted from the interviews were summarized in seven decision trees, describing the geometric parameters relative to the body parts (e.g. chest and eye height). To compare the level of work envelope overlaps among global populations, anthropomorphic data was used to assess the absolute dimensions of the work envelopes. The results show that some work envelope requirements have a limited tolerance and are more sensitive to different body dimensions across global populations. It was found that in such situations the population anthropomorphic characteristics significantly impact the work envelope requirements. Therefore, this paper presents a decision supporting tool of work envelope requirements in compliment to space planning, which can improve the productivity, accuracy and efficiency of workspace management in the piping and steel trades
Updating the Kentucky Contract Time Determination System
The Federal Highway Administration requires State Transportation Agencies to have a formal method to estimate contract time for highway construction projects. To meet this requirement many states use an integrated scheduling system to estimate project durations based on assumed productivity rates and generic job logic. The current work investigated the accuracy of two of these systems found that both systems accuracy in predicting the duration of Kentucky Transportation Cabinet projects was greater than +200%. In response to this poor accuracy, a parametric project duration estimating tool was developed based on a multivariate regression analysis of bid item quantities and engineering and construction estimate. Five regression models were develop to estimate contract time for large projects (great than 1,000,000) as it appears that the duration of small projects is determined by factors outside of bid item quantities
Investigating Project Bundling Practices for Transportation Construction Projects
Project Bundling is an innovative contract procurement strategy that is being widely used in bridge and highway projects to save project delivery time and costs. The guidebook developed by FHWA on project bundling also provides a wealth of information on project bundling. However, the guidebook is primarily focused on the project bundling practices that STAs adopted for bridge projects. Thus, a knowledge gap in project bundling for roadway projects (such as added travel lanes, resurfacing, intersection improvement, interchange work, shoulder rehabilitation and repair, etc.), might exist
Construction Training for the Current and Next Generation of Technicians
Technicians are a vital component to the success of any roadway projects. Unfortunately, the Kentucky Transportation Cabinet (KYTC) is experiencing significant shortages of technicians among all aspects of construction and maintenance. Training and developing the adequate numbers of qualified technicians is a substantial endeavor that requires a comprehensive examination of the adequacy of current training program versus the anticipated skill needs of technicians on future projects. Two questionnaires were developed to identify this gap. One is to investigate the skills and trainings that the Cabinet’s technicians possesses and received, and the second is to investigate the skills and/or knowledge which section engineers believe are required among their technicians. Through the analysis of the two surveys, this research found current training programs in Kentucky could cover most of the necessary knowledge and skills for transportation technicians, although more wide cooperation and reciprocity with outside training agencies should be built. However, current training programs are not sufficient enough to satisfy the future technician training needs, especially in the area of grading, structure, soil and maintenance and environment. The research also found technician’s most favorite training methods are on-the-job and classroom hands-on, but on-the-job training has not become one of the major sources where the Cabinet’s technicians received their training. Inability to help promotion and increase salary, schedule conflict and certificate’s short validness are the major barriers which prevented technician’s training participation
Optimal Fall Protection System Selection Using a Fuzzy Multi-Criteria Decision-Making Approach for Construction Sites
Construction falls are a leading cause of fatalities in almost every construction industry around the globe, and fall protection systems are the key measures to ensure the safety of labor crews. This study develops a fuzzy multi-criteria decision-making model integrating analytical hierarchy process, fuzzy set theory and Technique for Order Preference by Similarity to Ideal Solution approach to analyze the overall performance of various fall protection plans for construction projects, which focuses on evaluation and selection of the appropriate protection plan considering the most influential safety, productivity, and economy factors. Results show that the optimal plan can be effectively identified and determined among all potential alternatives. Besides, the model overcomes the shortcoming of weight value uncertainty and ambiguous decision information through membership function calculations. As a result, it provides guidance for the improvement of construction performance, intending to minimize fall risks, improve labor productivity, and save economical cost on the jobsites
Integration of Building Information Modeling and Critical Path Method Schedules to Simulate the Impact of Temperature and Humidity at the Project Level
Steel construction activities are often undertaken in an environment with limited climate control. Both hot and cold temperatures can physically and psychologically affect construction workers, thus decreasing their productivity. Temperature and humidity are two factors that constantly exert forces on workers and influence their performance and efficiency. Previous studies have established a relationship between labor productivity and temperature and humidity. This research is built on the existing body of knowledge and develops a framework of integrating building information modeling (BIM) with a lower level critical path method (CPM) schedule to simulate the overall impact of temperature and humidity on a healthcare facility’s structural steel installation project in terms of total man hours required to build the project. This research effort utilized historical weather data of four cities across the U.S., with each city having workable seasons year-round and conducted a baseline assessment to test if various project starting dates and locations could significantly impact the project’s schedule performance. It was found that both varied project start dates and locations can significantly contribute to the difference in the man hours required to build the model project and that the project start date and location can have an interaction effect. This study contributes to the overall body of knowledge by providing a framework that can help practitioners better understand the overall impact of a productivity influencing factor at a project level, in order to facilitate better decision making
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