Construction Systems

 

Date of this Version

5-2015

Comments

A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Engineering (Construction Engineering and Management), Under the Supervision of Professors Terence Foster and Eddy M. Rojas. Lincoln, Nebraska: May, 2015

Copyright (c) 2015 Nirajan Mani

Abstract

The efficiency of construction operations is typically determined by comparing actual versus historical productivity. This practice is accurate if historical data reflects optimal values. Otherwise, this comparison is a gauge of relative rather than absolute efficiency. Therefore, in order to determine absolute efficiency, one must compare actual versus optimal productivity. Optimal productivity is the highest sustainable productivity level achievable under “good management” and “typical field conditions,” while the productivity frontier is the theoretical maximum achievable under “perfect conditions.”

The productivity frontier is an abstraction useful in the estimation of optimal productivity of construction operations. This research contributes to the body of knowledge by introducing a novel framework to estimate the labor productivity frontier and applying it in a pilot study and a detailed study on the installation of lighting fixtures and the fabrication of sheet metal ducts activities.

The pilot study analyzed data on the fluorescent bulb replacement task up to the action level, collected from a school in Omaha, Nebraska to estimate the labor productivity frontier. Following two approaches–observed durations and estimated durations–the productivity frontier computed from this pilot study was found to be 22.32 stations per hour. The detailed study analyzed both action and movement levels by collecting data from a workshop at a mechanical specialty constructor in Omaha, Nebraska. The pilot study only analyzed the sequential actions of a single worker. The detailed study analyzed the sequential and parallel actions and movements of crews of multiple workers involved in the fabrication activity. The productivity frontier for this activity computed from the detailed study, following both observed durations and estimated durations, was found to be 2.83 ducts per crew-hour.

Moreover, this research explores advanced automated frameworks using video cameras and a Kinect sensor in order to estimate the labor productivity frontier. One of the advantages of the proposed framework is that constructors, rather than being constrained by historical data, can also estimate the productivity frontier for activities they have never performed. Furthermore, scopes of this research–such as virtual environment development, recombinant synthetic workers development, and ergonomics and safety analysis–are also discussed.

Advisors: Terence Foster and Eddy M. Rojas

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