Cliff Schexnayder

Defining a beta distribution function for construction simulation

In most applications of simulation to construction, the underlying probability distribution function (PDF) is generally unknown. Consequently, an expert has to select a PDF hoping that the one that is chosen matches the shape of the underlying distribution. This research attempts to quantify, through a sensitivity analysis, the effect of subjective information in choosing parameters for a Beta distribution to be used in earthmoving simulation models.

Construction Engineering Education: History and Challenge

Engineering has been defined as the vocation of guiding nature to produce something needed or desired. A historical review of the evolution of engineering and engineering education leads to the conclusion that sustainability in design and construction requires the engineer to approach nature with imagination and humility. As part of its Engineer of 2020 initiative, the National Academy of Engineering in 2001 questioned how engineering education should evolve to prepare the profession for the future. From that work and efforts by ASCE, it is clear that an educational system that fails to provide engineers with a broad base of learning results in graduates ill-prepared to enter professional practice. The National Academy Engineer of 2020 work and ASCE Policy Statement 465, “Academic Prerequisites for Licensure and Professional Practice,” echo a call to adopt a new educational model. The new model seeks to strengthen the cognitive ability of engineers and leads them to practices that work in cooperation and ...

Guidebook on Risk Analysis Tools and Management Practices to Control Transportation Project Costs

This guidebook provides guidance to state departments of transportation for using specific, practical, and risk-related management practices and analysis tools for managing and controlling transportation project costs. Containing a toolbox for agencies to use in selecting the appropriate strategies, methods and tools to apply in meeting their cost-estimation and cost-control objectives, this guidebook should be of immediate use to practitioners that are accountable for the accuracy and reliability of cost estimates during planning, priority programming and preconstruction.

Synthesis of Performance Measures for Highway Cost Estimating

The use of performance measures for evaluating projects or agencies as a whole is not a new idea. Performance measures have been in use for many years in the private and public highway construction sectors for a variety of areas and tasks. The American Recovery and Reinvestment Act of 2009 (ARRA) and federal transportation funding are now requiring state highway agencies to develop and document performance measures throughout their agency operations. However, few highway agencies use performance measures for cost estimating. This study synthesizes, categorizes, and validates existing performance measures for cost estimating of highway projects to assist with improving estimating accuracy. It provides a foundation for the development and use of new performance measures that agencies can share and use to improve estimating procedures. Performance measures for estimating were developed through an extensive literature review and content analysis to synthesize measures specifically for cost estimating in addition to categorizing the cost-estimating performance measures. These categories and performance measures were then validated with a questionnaire and interviews of selected state highway agency estimating experts. The main categories for these performance measures are bidding accuracy, estimating accuracy, competition effects, estimating processes, and contingency amounts. The results then provide a comprehensive list of valid performance measures for cost estimating in use today by highway agencies and a foundation for developing future measures.

Engineering with the Elements

The engineers of the Inka Empire had a unique consciousness of nature—the elements that strike brute mischief on man’s structures—because the foundation of their engineering knowledge was agriculture. These engineers, with a tradition of observing nature, succeeded in building their Andean road network because they learned to work with nature instead of trying to control it by domination. Close examination and reverse engineering of the past accomplishments of these ancient engineers can lead to thoughtful solutions to current engineering challenges, particularly the effort to construct sustainable infrastructure.

Observations on Bridge Performance during the Chilean Earthquake of 2010

AbstractThe joint U.S. State Department–Chilean Fulbright Program sent senior specialists to Chile after the 2010 “Maule” earthquake to perform collaborative studies with faculty from Chile’s main universities. The study described here found that concrete-girder bridges built since 1995 without diaphragms and shear keys suffered extensive damage while older bridges designed and built with these features did not suffer as greatly from twisting or rotation about the vertical axis. Because of the steepness of embankment slopes, many bridge abutments exhibited slumping. Concrete retaining walls and mechanically stabilized embankment walls were not damaged. Liquefaction induced pier settlements and lateral spreading impacted bridge performance in coastal regions.

Special Issue on Construction Engineering: Opportunity and Vision for Education, Practice, and Research

Engineering is an applied science. In no other engineering specialization is this more relevant than in construction engineering. A challenge among construction engineering academics (both faculty and students) and industry practitioners is to transfer a method, technology, or practice that can be supported in the theoretical sense, whether in a laboratory or classroom setting, and make it applicable to the rarely ideal industry jobsite. This bridge between engineering in the theoretical sense and practice requires intimate collaboration and continuous communication, which has not always occurred between the university and the jobsite. As described by Dr. Michael C. Vorster, professor emeritus at Virginia Tech and conference keynote speaker, the dilemma from the academic perspective is that “we teach too much and our students learn too little.” A primary focus of the Construction Engineering Conference held at Virginia Tech from September 30 to October 2, 2010, was to bring academics and industry leaders together to share experiences, practices, and ideas. This interaction was intended to strengthen the connection between theory and practice for mutual benefit. The Construction Engineering Conference was a unique opportunity in the sharing of knowledge across aisles. The purpose of this special issue is to archive and disseminate the knowledge for current and future generations of construction engineers. Each conference speaker submitted a manuscript that was peer-reviewed by academic and industry reviewers. In many cases, industry speakers coauthored the manuscript with a construction engineering academic. In all, this special issue includes 28 manuscripts that cover a broad range of construction engineering topics. A debt of gratitude is owed to the authors for their thoughts and efforts in this overall body of work, which makes a significant contribution to the overall body of construction engineering knowledge. Furthermore, the editors are especially grateful to the reviewers, who ensured that the manuscripts maintained the rigorous standards for publication in the ASCE Journal of Construction Engineering and Management. Finally, the editors are grateful for the support provided by the Construction Engineering Conference committee and the senior editorial boardmembers of the Journal, especially Dr. JesusM. de la Garza. Without their guidance and advice, this special issue would not have been possible.

Strategies for Planned Project Acceleration

Departments of transportation in the United States are under increasing pressure to accelerate projects to meet user-defined constraints and reduce the inconvenience to the traveling public. Although there is information about acceleration projects in other industries, there has been little specifically aimed at highway projects. A domestic scan sponsored by the National Cooperative Highway Research Program was tasked with providing information in this area. The objective of this paper is to synthesize the resulting information into fundamentals that support successful planned accelerated highway project delivery. Case studies of how departments of transportation successfully accelerated the construction of four very different projects in California, Florida, and Texas serve as the basis for identifying these fundamentals. The fundamentals include upfront and detailed planning, designs that facilitate accelerated construction, a collaborative environment for project stakeholders, and incentives and disinc...

Rammed Earth: Construction Lessons from Experience

AbstractIf modern engineers devote careful attention to the environment of a project and study historical building techniques they can create more sustainable structures. Rammed-earth construction creates a thermal mass structure that cools the interior space during hot, dry summers and absorbs heat during cold winters. It is a historic building method dating back over 2,000 years, and the techniques of native practitioners offer suggestions as to how modern engineers can successfully apply the method.

Emergency Accelerated Construction

There are a number of transportation agencies that have experience with accelerated construction strategies. California and Alabama have in the last several years completed major accelerated construction projects. These projects served as the proving ground for acceleration approaches and methods. When on two occasions a fuel truck collision damaged a bridge at the I-65/I-59 interchange in Birmingham, the Alabama Department of Transportation dedicated the necessary staff resources to accelerated project delivery under emergency conditions. Caltrans has had similar emergency projects both in rural and urban settings. This paper identifies, through a set of project case studies, construction operational and management practices that support accelerated project delivery. From this study it is evident that successful project acceleration is achieved through a partnering atmosphere and contracting methods such as design-build plus incentive/disincentive clauses that encourage a contractor to expend the planning effort and resources necessary to reduce construction time.