William Ibbs

Construction Change: Likelihood, Severity, and Impact on Productivity

AbstractChange on construction projects is a regular occurrence and impedes project success for both the owner and the contractor. Many papers have been written about change, but few document its prevalence, severity, and impact on labor productivity in a reliable, quantitative way. The purpose of this paper is to help project owners, contractors, and other parties understand and benchmark their projects against a large set of construction projects. Data from two independent research studies are analyzed to quantify the impact of change on project cost, schedule, and productivity. The result is a set of curves and reference points that contrast the amount and likelihood of change with the amount and nature of its impact. One major finding of this study is that the ratio of final project costs to estimated project costs is substantially higher than conventionally thought. Previous reports hold that two-thirds of all projects should have fewer than 15% change. The equivalent number found in this study was 1...

Design and construction coordination problems and planning for design–build project new users

Design–build (DB) is adopted as a project delivery method in hopes to improve performance. Previous studies focus on upstream issues such as conditions for adoption and contractor selection, but few address the design and construction coordination issues that are very likely to be encountered in execution by new users. This paper investigates coordination problems arising from design and construction concurrence and solutions by studying five ongoing DB projects and interviewing nine major contract parties. Inconsistent application of the design and construction process and infrequent feedback are two major problems found to have high influence on DB execution. A work unit planning process with five steps is presented in this paper to help better manage the design and construction coordination of a DB project.

Analysis of Adverse Weather for Excusable Delays

Severe weather conditions can be disruptive to construction. Contractors typically obtain time extensions for weather days beyond normal conditions. However, contracting parties often dispute the extent of weather-related time extensions. Typical industry contracts may overlook many important points that can provide an acceptable resolution. This paper classifies seven factors causing discrepancies in analysis of adverse weather for time extensions; namely, the definition of normal weather, weather thresholds, type of work, lingering days, criteria for lost days, lost days equivalent due to lost productivity, and work days lost versus calendar days lost. An analysis of an actual weather-caused delay claim illustrates the impacts of those factors on the outcomes of the analysis. A contract should define anticipated weather delay days and their lingering days and provide threshold values for weather parameters to differentiate between predictable and unpredictable severe weather. The contract should clearly define how a time extension is granted in calendar days as a result of work days lost, and also address how a time extension is granted due to inefficiency caused by unusually severe weather. Future research may provide an appropriate mechanism for analyzing equivalent lost days to account for lost productivity.

Concurrent Delays and Apportionment of Damages

This paper focuses on the subject of concurrent delay from a general contractor (GC)-subcontractor perspective. When there is a concurrent delay by multiple subcontractors, or between the GC and other subcontractor(s), there has not been a uniform approach as to how the liquidated damages are apportioned. Previous research seems to ignore this issue. This paper first reviews some relevant court cases. Using a warehouse project as a case study, it then examines different practices that the GC could take in apportioning damages of concurrent delays to both himself/herself as well as to the responsible subcontractors. Results are very inconsistent between and within the apportionment practices. This supports an alternative hypothesis that apportionment is an important issue. Practitioners should specify which apportionment practice will be used and under what circumstances it will be applied in their subcontracts. Researchers may develop a more consistent and reliable approach for this type of apportionment.

Thinking about Delay, Disruption, and the Cumulative Impact of Multiple Changes

Change is any addition, deletion, or revision to a contract (Ibbs and Allen 1995). This may be a design or construction contract, and it may affect the scope or administration of that contract. Such change often causes an adjustment to the price of the contract, its duration, or both, and regularly occurs on projects. These cost and time dislocations may stem from the impact change has on labor productivity, which, when lowered, will require more labor hours to perform a task. With that increase in labor hours comes an increase in the costs and time required to complete the work. In turn, this may reduce or eliminate the contractor’s profitability and impair the owner’s return on investment and the utility of the project. This may lead to friction, acrimony, and even litigation between the owner and contractor. The problem gets even worse if many changes occur on a project because a special condition called cumulative impact may result. Cumulative impact may result from changes that delay the critical path or disrupt the work to such an extent that their sequences or means and methods are changed. Disruption may not impact the critical path of a project, but may still damage productivity. Delays and disruption may occur in any phase of a project (e.g., an owner’s acquisition of property, permitting, design, or procurement) and ripple through to hurt the productivity of a later stage of the project (e.g., construction). Cumulative impact has gained popularity (or, in the minds of some people, notoriety) in recent years, but it is often poorly understood, poorly explained, poorly demonstrated, and poorly quantified. The subject has become so important that the American Association of Cost Engineers (AACE) has even seen fit to address it in one of their recommended practice guides. There is a clear need to better understand cumulative impact.

Measured-Mile Principles

AbstractChange is any addition, deletion, or revision to the general scope of a contract. It may cause an adjustment to the contract price or contract time of a design or construction project. Many disputes arise out of change, and successful resolution of those disputes requires that three elements be evaluated: liability, causation, and resultant injury (damages). One specific type of damage that is frequently alleged on changed projects is loss of labor productivity. One way to evaluate and quantify loss of labor productivity damages is through use of the measured-mile technique. Problems exist with the measured-mile approach, however, because the guidelines for developing and applying it are unclear. Based on a review and synthesis of project management literature and court and appeal board decisions, this paper presents guidelines for development and application of the measured-mile methodology. The intent is to help contractors, owners, consultants, and other parties step through a logical process f...

Practical Ways to Identify Measured Miles

AbstractChange is any addition, deletion, or revision to the general scope of a contract and may require an adjustment to the contract price or contract duration of a design or construction project. Many disputes arise out of changes, and successful resolution of those disputes requires that three elements be evaluated: liability, causation, and resultant injury (damages). A particular type of damage frequently alleged on changed projects is loss of labor productivity. One way to evaluate and quantify loss of labor productivity damages is through use of the measured mile technique. Problems exist with the measured mile approach, however, because there are no generally accepted guidelines for developing and applying the technique. Based on review and synthesis of project management literature and court and appeal board decisions, this paper presents practical considerations in the identification and application of measured miles. The intent is to help contractors, owners, consultants, and other parties ste...

Weather’s Effect on Construction Labor Productivity

AbstractWeather impacts construction worker productivity, both physiologically and psychologically. Weather’s effect on productivity is therefore an important topic and has been the subject of a co...

Visualizing Skipped and Out-of-Sequence Work

AbstractSkipped and out-of-sequence work on construction projects is disruptive to work flow and damaging to labor productivity. It is a condition in which the originally planned, and probably most...

Process Model for Identifying and Computing Allowable Home Office Overhead Cost Claims

AbstractConstruction change often leads to both direct and indirect cost damages. Direct costs are the bricks and mortar costs, which arise from extra craft labor and extra material. Indirect costs include the overhead costs associated with supporting a project. Those indirect costs include the contractor’s home office overhead costs. When a project is delayed, those overhead costs may be extended and the contractor may seek to recover some portion of these costs. Claims for such home office overhead damages are frequently controversial and hard to compute. A widely used method to calculate these costs is the Eichleay formula. However, its application is not always successful, partly due to misunderstanding and partly due to misapplication. Based on a review of the project management literature and legal decisions, this paper presents a process model and guidelines for identifying circumstances eligible for home office overhead damage claims and for applying the Eichleay formula. These guidelines and the ...