ce 403 construction methodology construction productivity

CE 403 Construction Methodology

Construction Productivity

Construction Methodology2

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

04/10/233

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.


Construction Performance: Timeliness

Interpreted both as “on schedule” and “everything is on hand when needed”


Construction Performance: Quality

Means that the facility and all its elements meet the specification requirements

Owner’s Perspective: Test performances Craft (Field) Perspective: Rework


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)


Factors Affecting Labor Productivity

Tools andConsumables

Material EngineeringDrawing Mgmt.

ConstructionEquipment

SupervisorDirection

Safety

ProjectMgmt.

Communi-cation

Labor

Foremen

Superin-tendents

TangibleControllable

+ -


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


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


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)

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



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



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


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)


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%


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



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



Impractical QA/QC tolerances Uncontrolled breaks Time of day and day of week Inadequate temporary facilities: parking,

change rooms, restrooms, etc.


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



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?”



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



Other formal methods:– Time studies using photographic or video methods– Questionnaires and Interviews

Eg. Foreman Delay Surveys

– Work Sampling


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


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.


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)


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


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.


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


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%



Work Sampling Example: Edmonton Project


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

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


Source: Oglesby, C., Parker, H., and Howell, P. (1989) Productivity Improvement in Construction. McGraw-Hill, New York, New York.

ce 403 construction methodology construction productivity

Documents

labor productivity slide

new construction

construction process

rework slide

nccer slide

wrench time slide

absenteeism rates

turnover data