CE 403 Construction Methodology
Construction Productivity
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Measures of Construction Performance
Construction performance involves all aspects of the construction process.
It is a broad inclusive term that includes four elements:– Safety– Timeliness– Quality– Productivity
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WORK INJURY AND ILLNESS RATES
Incidence rates expressed as number of cases per year or days per 100 full-time employees or 200,000 employee hours per year
Incidence Rate = (# of cases or days per year x 200,000)/Total employee hours per year
Can be computed for each category of cases or days.
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Construction Performance: Timeliness
Interpreted both as “on schedule” and “everything is on hand when needed”
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Construction Performance: Quality
Means that the facility and all its elements meet the specification requirements
Owner’s Perspective: Test performances Craft (Field) Perspective: Rework
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CORRECTION: Field Productivity
Actual productivity determines whether or not the project will be completed within the cost budget and time schedule
Labor Productivity = Production Output/WorkhoursFactor Productivity = Production Output/Total CostProductivity Factor = BCWP/ACWPDirect Work Rates (i.e. tool time or wrench time)
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Factors Affecting Labor Productivity
Tools andConsumables
Material EngineeringDrawing Mgmt.
ConstructionEquipment
SupervisorDirection
Safety
ProjectMgmt.
Communi-cation
Labor
Foremen
Superin-tendents
TangibleControllable
+ -
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Weather
Shift Work
Disruption
SiteCongestion
ContractorBehavior
ForemenBehavior
Crew Size
ManningLevel
Project/SiteConditions
Engineering/Design
Materials
ConstructionManagement
Labor
Equipment
Temperature
Humidity
Windchill
Wind
Precipitation(Moisture)
CommunityRequirements
OwnerRequirements
ConstructionPermits
Local Codes
WorkerDensity
DesignQuality -
Errors andOmissions
EngineeringSupport
Resources
Owner E&CIn-house
Capabilities
SupervisionSkills
LaborMarket
WorkExperience
CraftFlexibility
WorkforceCulture
WorkforceStrategy
Multiskilling
Tier I and IIWorkforceStrategy
Factors Affecting ConstructionProductivity
Note:Local Factors (factors that can be modified by construction craft workers and theirsupervisor) are not shaded. Global Factors (factors that construction craft workers andtheir supervisors have limited to no authority to adjust) are shaded.
Legend:
Machine/Equipment Method
Material People
ConstructionProductivity
WorkEnvironments
Dust
Noise
Lighting
Temp. SiteLayoutDesign
ConfinedSpace Entry
RegulatoryRequirement
Size ofProject
ExistingObstructions
UnknownUndergroundConditions
ProjectExecutionStrategy
work type
SafetyProgram
Site Rules
Motivation
WorkerSatisfaction
Union/Non-Union
Above/Below GradeConstruction
Above/Below GradeConstruction
Scaffolding
GovernmentInspections
Proximity ofLaydown &Operating
Area
QA/QCRequirements
Constructability
ProjectComplexity
constructionmethod
Repetition
ChangeOrder
ProjectScope
Definition
Design/DrawingAvailable
Quality ofDesign Work
Complexityof change
order
Timing ofChangeOrder
Size ofChangeOrder
Modularization
Prefabrication
Quality ofMaterials
Capacity ofTransport
Infrastructure
DeliveryMethod
Sequence ofDeliveries
MaterialControl of
Items on Site
Organizationof Storage
Areas
Housekeeping
Materialavailability
Vendor Supply
MaterialHandling
FabricationError
PlanningMaterialDelivery
Type ofEquipmentTechnology
EquipmentAutomation
Ergonomics
EquipmentPower
EquipmentCapacity
Functionality Equipmenttool
availabilityMaintenance
AcceleratedSchedule
ContractingStrategy
SubcontractorCoordination
OwnerOrganization
ContractorStaff
Organization
SupervisorSupport
WorkOperationPlanning
ManagementControl Construction
Technique
Overtime
Skill Level
WorkerCompensation
Absenteeismand turnover
LearningCurves
Rework
Incentives
WorkSchedule
TrainingAvailability
ResourcesAvailable to
SupportTraining
TrainingReceived
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Factors that have an adverse effect on productivity
Overtime and/or fatigue Errors and omissions in plans and specifications Multitude of change orders Design complexity Design completeness Stacking of trades Dilution of supervision Reassignment of manpower from task to task Material location
– Above ground level– Above floor level
Adverse temperature or weather Inadequate lighting
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CORRECTION: Field Productivity
Actual productivity determines whether or not the project will be completed within the cost budget and time schedule
Labor Productivity = Production Output/WorkhoursFactor Productivity = Production Output/Total CostProductivity Factor = BCWP/ACWPDirect Work Rates (i.e. tool time or wrench time)
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What causes change orders…at least in Highway Work.
Reason Code Frequency Avg. CO Amt. ($)Avg. Percent Change in Original Contract Amt.
Asphalt Lot Pay Adjustment
188 $7,699.93 0.79%
Fuel & Asphalt Adjustment
218 $82,336.07 7.05%
Contract Omission 243 $57,410.90 4.53%Utility Issue 60 $35,428.11 3.16%
Contract Item Overrun
227 $104,857.53 6.73%
Geotechnical Issue 71 $90,777.41 3.02%Owner Induced Enhancement
186 $88,297.13 7.80%
Environmental Issue 20 $19,737.72 0.47%F-Value 4.025 13.024P-Value 0.000 0.000
KYSPR-09-384
Statistical Analysis of Change Order Data610 Projects
246 New Construction364 Maintenance Projects
Projects Completed between 2005 and 2008
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Factors that have an adverse effect on productivity
Overtime and/or fatigue Errors and omissions in plans and specifications Multitude of change orders Design complexity Design completeness Stacking of trades Dilution of supervision Reassignment of manpower from task to task Material location
– Above ground level– Above floor level
Adverse temperature or weather Inadequate lighting
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Factors that have an adverse effect on productivity
Regulations of various types High absenteeism High turnover Material shortages High accident rates Jurisdictional disputes Work rules and restrictive work practices Availability of skilled labor Attitude of the workforce Crew size and composition Timeliness of decisions
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Construction Inflation
Empire State Building
Costs: $40,498,900 (1931 Dollars)
$559,321,201 (2006 Dollars CPI Adjusted)
Freedom Tower
Proposed Costs: $1.6 to 2.1 Billion (2006 Dollars)
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Company A: Absenteeism and Turnover Data
The study found that workers receiving training had a lower turnover and absenteeism rates than workers without training.
Workers without Training
Company Certified Workers
Worker Receiving Training
Turnover Rate 6.51% 3.39% 0.63%
Absenteeism Rate 7.28% 0.27% 2.51%
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0.96
0.98
1.00
1.02
1.04
1.06
1.08
76 78 80 82 84 86 88 90 92
Percent of Certified Workers
Per
form
ance
Fac
tor
Company B: Productivity Data
Company B Productivity Performance Factor vs. Percentage of Certified PlusTM Craft Workers
R2=0.39F value =6.478P value = 0.029
A declining performance factor indicates productivity improvement
TM Certified Plus is trademarked by NCCER
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Factors that have an adverse effect on productivity
Regulations of various types High absenteeism High turnover Material shortages High accident rates Jurisdictional disputes Work rules and restrictive work practices Availability of skilled labor Attitude of the workforce Crew size and composition Timeliness of decisions
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Factors that have an adverse effect on productivity
Impractical QA/QC tolerances Uncontrolled breaks Time of day and day of week Inadequate temporary facilities: parking,
change rooms, restrooms, etc.
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Current Methods for Assessing Work-Face Productivity
Work-face activities often get little attention Most construction analyses involve examining project
cost and schedule performance. A project’s success can be made or ruined at the
workface. Two categories of workforce assessment methods
– Informal– Formal
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Current Methods for Assessing Work-Face Productivity
Informal: – All construction managers will tell you they can judge how well
a work-face task is going by merely watching for a short period of time.
– However, they may not be asking themselves such questions as:
“Are materials and tools available and suitable?” “Is the work procedure and its sequencing the most efficient?” “Have tasks been assigned among members of a crew that best
uses available skills and keep all hands busy?”
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Current Methods for Assessing Work-Face Productivity
Formal: – Most common assessment methods: slippages in
schedule and cost overruns. – Problems:
Can be based on after-the-fact information May be inaccurate (not recorded accurately)
– Errors in coding – Falsified to hide slippage
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Current Methods for Assessing Work-Face Productivity
Other formal methods:– Time studies using photographic or video methods– Questionnaires and Interviews
Eg. Foreman Delay Surveys
– Work Sampling
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Work Sampling
Consists of observing and classifying a small percentage of a project’s labor activity
Involves making and analyzing the results of field observations to determine what individual workers are doing at specific instants in time.
Most of the data is recorded in the following Categories:– Productive Work
Direct Work Tools Materials Information
– Non-Productive Personal Travel Waiting
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Work Sampling
Direct Work (25-65%):– Activities directly involved in the actual process of putting
together or adding to a unit being constructed– Includes necessary disassembly of a unit that must be
modified and movements essential to the process where the work is being done
– E.g. painting a wall, placing bricks, nailing boards to a wall, hauling material from an excavation, threading pipe, mixing mortar, cutting boards before nailing.
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Work Sampling
Support Work:– Preparatory Work or Instructions
Receiving instructions Receiving drawings Using telephones or radios for work related reasons Discussing material, tool, or equipment needs
– Tools and Equipment Locating a tool in a gangbox and transporting it to the task areas Obtaining and transporting slides, shackles or similar tools equipment Putting on and adjusting personal protection equipment (PPE)
– Material Handling Supporting crafts transporting bulk materials (Operators and Teamsters
are Direct Work)
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Work Sampling
Delays:– Doing something that is in no way necessary to
complete the job. – Waiting– Travel (empty handed (toolbelts), walking to and
from work areas)– Personal (rest periods outside break times,
adjusting personal clothing, rest room or water breaks outside break time).
Activity Categories
Activity Categories
Activity Categories
Activity Categories
Activity Categories
Activity Categories
Activity Categories
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Work Sampling
The rating should be taken at the first instant of observation. Don’t anticipate a person’s action
Counts should not begin until at least ½ hour after start time and ½ hour before quitting or lunch time.
Must be an equal likelihood of observing every worker. Sample shall contain no less than 384 observations Basic characteristics of the work situation must remain
the same.
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Direct Work
Support
Delay
Want to maximize
Total Construction Time
0%
25%
50%
100%
Work Sampling
Break down into subcategories for class project.
Case Study Idaho Falls Nuclear
Decommissioning Project. Treating nuclear, sodium-
bearing waste from a liquid to a solid state using a steam reforming process
Primary Trades: Piping, Concrete, and Instrumentation
Initial Budget: $84M Final Budget: $176M
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Project
Activity Category
Wood
RiverProject A Project B Project C Project D Project E Average
Idaho Falls
Direct Work 31% 28% 42% 30% 28% 27% 31% 20%
Prep Work 13% 16% 13% 8% 11% 11% 12% 18%
Tools/Equip 8% 12% 12% 7% 11% 19% 12% 9%
Mat'l Hand 4% 4% 2% 5% 8% 9% 5% 3%
Waiting 15% 16% 11% 20% 14% 12% 15% 19%
Travel 16% 13% 13% 24% 23% 17% 18% 22%
Personal 13% 11% 7% 6% 5% 5% 8% 9%
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Work Sampling Example: Edmonton Project
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Work Sampling Limitations
Work Sampling provides a measure of worker efficiency
Worker efficiency can only be considered an indirect measure of productivity.
Reviewed with great suspicion by craftsmen and foremen
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75
Percent Direct Work by Crafts*
Pipefitters/Welders 28% Boilermakers 27% Electrical Workers 28% Laborers 41% Carpenters 42% Insulators 26% Operating Engineers 39% Ironworkers 31% Millwrights 32%
* “Productivity in Power Plant Construction,” Marjatta Strandell, 1976 AACE Transactions, pp. 334-337
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Source: Oglesby, C., Parker, H., and Howell, P. (1989) Productivity Improvement in Construction. McGraw-Hill, New York, New York.