EEC’s Michael Brockman publishes a paper titled “Accuracy analysis of selected tools for estimating contract time on highway construction projects”.  Mr. Brockman published this paper with Purdue University’s Construction Research Congress.

The Abstract and list of Author’s for the paper are below:

In many highway construction projects, the time available to complete construction is set by the contract documents. Most transportation agencies have developed tools to assist project planners in estimating the amount of time required to complete the project but how accurate are these systems in estimating project duration? The current work examines the accuracy of integrated scheduling systems from two state transportation agencies in estimating contract time for previously completed Kentucky highway construction projects. The accuracy of the systems where tested against project data from 66 completed Kentucky Transportation Cabinet Projects. The analysis revealed that the average accuracy of both systems in predicting project duration was greater than +200% across a variety of projects. A pilot study of the use of multivariate regression analysis of the data from 66 completed Kentucky Transportation Cabinet projects was performed to identify specific combinations of work item quantities with the engineer’s cost estimate that produce the most accurate estimate of project duration. The accuracy of the developed regression equation in predicting highway construction project duration was +25%. The current work contributes improved understanding of the accuracy of integrate scheduling systems in predicting highway construction duration.

Authors
Timothy R.B. TAYLOR - Assistant Professor, Department of Civil Engineering, University of Kentucky, 151A Raymond Building, Lexington, KY 40506; PH: (859) 323-3680
Michael BROCKMAN - Engineer, Eta Engineering, 5802 Brown Lane, Catlettsburg, KY 41129; PH (606) 739-6805
Dong ZHAI - Post-Doc, Department of Civil Engineering, University of Kentucky, 151D Raymond Building, Lexington, KY 40506; PH: (859) 323-3680
Paul M. GOODRUM - Professor, Department of Civil Engineering, University of Kentucky, 151A Raymond Building, Lexington, KY 40506; PH: (859) 257-5416
Roy STURGILL - Engineer, Central Office, Division of Design, Quality Assurance Branch, Kentucky Transportation Cabinet, 200 Metro Street, Frankfort, KY 40622; PH: (502) 564-3280

If you would like to request a copy of the full article feel free to contact EEC and reference the paper title of “Accuracy analysis of selected tools for estimating contract time on highway construction projects”

Read More

EEC attended the 2012 AIChE and submitted a paper on “Using a process simulator to improve relief system analysis”. The Author is Donald P. Malone, P.E. of EEC. Below is the abstract from the paper and the post Mr. Malone presented at the 2012 AIChE:

Incorporating a process simulator in the design and/or analysis of pressure relief systems can improve the quality of the effort in a cost effective manner.
Often some variation of a fire case is the basis for a relief system design. These cases usually involve vessels or piping exposed to large heat fluxes caused by flame impingement from an uncontrolled fire. Before process simulators were incorporated in relief systems design and analysis, designers focused on selecting the appropriate size relief device and the adequacy of the inlet and outlet piping from the relief device. Typically a worst case vapor flow was calculated based on empirical relationships developed by ASME, API and others. The main criterion was avoiding exceeding the maximum allowable working pressure of the vessel. This approach could be described as a single point design. Designers often had no awareness of events occurring at other times even though these events potentially could compromise the safety of the system in question.
Initially process simulators were developed to model steady state processes because everything else was much more difficult. As process simulators became more sophisticated and computational processing power exploded many non-steady state features were incorporated into these simulators. Today several quality process simulators are commercially available. Each one may have various capabilities to model different aspects of pressure relief systems. This paper describes how EEC used WinSim Design II in a pressure relief system analysis and design of vessels and piping in a gasoline/diesel terminal.
The simulator allowed EEC to model thermal expansion in liquid full vessels with respect to how PSV’s are affected, the relief discharge into piping with and without liquid flowing in the downstream piping, the frequency of PSV reseating, the change in temperature of vessel walls with time and to characterize the consequences of the time required to extinguish the fire. The availability of this information allows for a much more meaningful relief system design or analysis, often in less time. This approach allows identification and prioritization of potential safety issues that would otherwise be unknown and facilitates a cost effective mitigation strategy for these threats.

 

 

 

 

 

 

 

 

If you would like to request a copy of the full article feel free to contact EEC and reference the paper title of “Using a process simulator to improve relief system analysis”.

Read More