The Impact of Change Orders on Mechanical Construction Labor Efficiency

The Impact of Change Orders on Mechanical Construction Labor Efficiency

Author: Paul Joseph Vandenberg

Publisher:

Published: 1996

Total Pages: 236

ISBN-13:

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Change orders impact many areas of construction projects. However, the impacts that change orders have on labor efficiency are much harder to quantify and are, therefore, a significant risk to contractors. Little research has been completed in the past quantifying these impacts so that disputes are common between owners and contractors regarding the actual cost of change. This study uses data from 43 projects, 27 impacted by changes and 16 not impacted by changes, to develop a linear regression model that predicts the impact on labor efficiency. The input factors needed for the model are: (1) Total Actual Project Hours, (2) Total Estimated Change Hours, (3) Impact Classification, and (4) Timing of Change. Timing of Change is calculated by breaking the project schedule down into six periods (i.e., changes before construction start, 0 - 20%, 20 - 40%, 40 - 60%A, 60 - 80%, and 80 - 100%), listing the percentage of change that occurred in each period, and calculating a weighted timing factor. The model calculates the labor loss or gain in efficiency for a particular project so that owners and contractors will better understand the true change impact on labor efficiency. Significant results have been found in hypothesis testing. The results show that impacted projects have larger amounts of change, have a larger decrease in labor efficiency, and are more impacted by change that occurs later in the project schedule. These results appear to be consistent with the intuitive judgement of industry professionals. The research is limited to the mechanical trade, but does include specific work in plumbing, HVAC, process piping, and fire protection.


Handbook of Cumulative Impact Assessment

Handbook of Cumulative Impact Assessment

Author: Jill A.E. Blakley

Publisher: Edward Elgar Publishing

Published: 2021-05-28

Total Pages: 416

ISBN-13: 1783474025

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This important Handbook is an essential guide to the state-of-the-art concepts, debates and innovative practices in the field of cumulative impact assessment. It helps to strengthen the foundations of this challenging field, identify key issues demanding solutions and summarize recent trends in forward progress, particularly through the use of illustrative case examples.


Construction Project Management

Construction Project Management

Author: Eddy M. Rojas

Publisher: J. Ross Publishing

Published: 2009-06-15

Total Pages: 433

ISBN-13: 1604270020

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Construction Project Management offers some of the best project management studies commissioned by ELECTRI International: The Foundation for Electrical Construction that were selected, coordinated, and monitored by some of the most progressive contractors and performed by outstanding scholars from top U.S. universities. Topics include pre-construction planning, early warning signs of project distress, impact of change orders, project sequencing, ideal jobsite inventory levels, tool and material control systems, recommended safety practices, partnering, total quality management, quality assurance, performance evaluations, and contract risk management. All specialty and general contractors will find value in this practical book. The concepts presented will improve your understanding of the main issues affecting construction project management and will provide you with tools and strategies to enhance your company's productivity and profitability.


Applying Earned Value Management to Design-Bid-Build Projects to Assess Productivity Disruption

Applying Earned Value Management to Design-Bid-Build Projects to Assess Productivity Disruption

Author: Stephen P. Warhoe

Publisher: Universal-Publishers

Published: 2013

Total Pages: 392

ISBN-13: 1612334164

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One of the most important jobs of a project manager is to manage a project's budget and schedule. These tasks can easily be very difficult to accomplish on projects that are complex, especially since successful project execution relies heavily on people who are expected to perform their roles individually and as a team. One of the most difficult aspects of managing projects is estimating how fast and effectively humans will perform a task; that is, determining how productive workers collectively will be each day, each week, or within any time period during the life of a project. Because projects are unique and are typically one-off endeavors, there is usually little previous empirical data to rely upon for the project manager to forecast productivity before or during the project's execution. The crux of the problem lies with adequately identifying not only the labor work flow process, but also the influences that affect the work flow process. When scope changes are introduced into the work flow of a project, the types and number of influences and their cause and effect relationships can significantly increase in numbers. This phenomenon often turns complicated projects into extremely complex ones and the final outcome can be greater than the sum of the individual inputs. For project managers who are unable to get their arms around this very real situation, forecasting the outcome of a project often becomes out of control, especially for projects that are large and heavily labor intensive. This study takes a post-positivist approach to design and builds a system dynamic model with which construction projects that are delivered using the design-bid-build methodology can be simulated to show generically how the influences that affect construction projects can affect worker productivity. No other studies are known to exist that design or build such a model for construction projects that use the design-bid-build delivery method. The model that was designed in the study is based on the works of several academics' works as well as the input of several experts in the construction field, including this study's author. As opposed to attempting to create a simulation model based on the uniqueness of a single project, a "mosaic" approach was used in creating the model in that elements of the model were identified and taken from studies found through the literature review as well as interviews with construction industry experts. The stock and flow structure of the study's model is intended to be a composite of many construction projects and can be used for any project delivered using the design-bid-build methodology. From the research, the model was created and tested using good modeling practice in that the model testing phase followed the process created by one of the pre-eminent system dynamic modelers in the world (refer to Sterman, 2000). The result is a model that simulates the work flow of labor hours in a design-bid-build construction project which can be affected by an immeasurable number of influences that can and do occur on construction projects.


Evaluating Contract Claims

Evaluating Contract Claims

Author: John Mullen

Publisher: John Wiley & Sons

Published: 2019-08-28

Total Pages: 711

ISBN-13: 1118918134

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An important guide to the quantification of contract claims in the construction industry, updated third edition The substantially expanded third edition of Evaluating Contract Claims puts the spotlight on the quantification of claims in the construction industry after liability has been established, including by reference to the terms of several standard forms of contract in common use. The authors clearly demonstrate the potential alternative approaches to quantification, the processes, principles and standard of analysis required to produce acceptable claims for additional payment. The third edition covers a number of heads claims not considered in previous editions and offers an important guide for those working with building or engineering contracts. Evaluating Contract Claims explains in detail how the base from which evaluation of additional payments may be established, the effect of changes on the programme of work and the sources of information for evaluation of additional payments. The book also contains information for evaluating the direct consequences of change in terms of the impact on unit rates, and evaluating of the time consequences of change in terms of prolongation, disruption, acceleration and more. This important book: Concentrates on the quantification of contract claims after liability has been established Offers a guide that is appropriate for any form of contract Considers the potential alternative approaches to quantification of different heads of claim Contains the principles and methods that should be reflected in the evaluation of claim quantum Includes the standard of substantiation which may be required Presents information that is equally applicable in both building and engineering disputes Is substantially expanded from its previous editions Written for construction and engineering contract administrators, project managers, quantity surveyors and contract consultants, Evaluating Contract Claims offers a revised third edition to the essential guide for quantifying claims in the construction industry once liability has been established.


The SAGE Handbook of Spatial Analysis

The SAGE Handbook of Spatial Analysis

Author: A Stewart Fotheringham

Publisher: SAGE

Published: 2008-12-22

Total Pages: 529

ISBN-13: 1446206505

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The widespread use of Geographical Information Systems (GIS) has significantly increased the demand for knowledge about spatial analytical techniques across a range of disciplines. As growing numbers of researchers realise they are dealing with spatial data, the demand for specialised statistical and mathematical methods designed to deal with spatial data is undergoing a rapid increase. Responding to this demand, The Handbook of Spatial Analysis is a comprehensive and authoritative discussion of issues and techniques in the field of Spatial Data Analysis. Its principal focus is on: • why the analysis of spatial data needs separate treatment • the main areas of spatial analysis • the key debates within spatial analysis • examples of the application of various spatial analytical techniques • problems in spatial analysis • areas for future research Aimed at an international audience of academics, The Handbook of Spatial Analysis will also prove essential to graduate level students and researchers in government agencies and the private sector.