DELAYS IN CONSTRUCTION TASKS
Ing. OMAR RUIZ
2
Leaning Pisa tower
Loss of original plans, drawings and photographs Funding of the project by donationsDesigns during the ongoing construction
Stops of the projectAlterations to the original designCost overrunsOpposition against nuclear power
Additional projectsComplexity of the ship lift
War and battles in the region, flawed design, sink problems
Sagrada Familia
Three Gorges Dam
Temelin Nuclear Power Station
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3
Civil engineering> Coastal engineering> Construction engineering> Earthquake engineering> Environmental engineering> Geotechnical engineering> Water resources engineering> Materials engineering> Structural engineering> Surveying> Transportation engineering> Municipal or urban engineering
Construction management
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4
International Project Management Association IPMA in his book ICB (IPMA Competence baseline)
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5
Project management Institute PMI and his book PMBOK (a guide to the project management body of knowledge)
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6
Construction activity efficiencyparameters
TIME (SCHEDULE)
COST (BUDGET)
QUALITY (SPECIFICATION, NORMS, STANDARS)
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7
Network Logic diagram drawn using the Precedence diagramming method
Network Logic diagram drawn using the Arrow diagramming method
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8
Time scale network diagram
Bar (Gantt) Chart
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9
PERT duration Calculation
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Ref: Delay and Cost Overruns in Vietnam Large Construction Projects:A Comparison with Other Selected Countries
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Ref: Delays in construction projects: The case of Jordan
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Ref: Delays in construction projects: The case of Jordan
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14
Insufficientresources
Succedingactivities are
delayed
Succedingactivities are not delayed
Extended activityduration
Delayedstart
Changes in scope of work
Management decisions
Changedsiteconditions
Adverse weatherconditions
Delayeddesigninformation
Delayeddeliveries
Delayedcompletion of precedingactivities
Unavailableresources
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Example 1 is the representation of one task with unimpacted duration (DU).Example 2 is the same task but with late start duration (DLS).Example 3 again the same task but with extended duration (DE)Example 4, the same task taking into account both effects late start and extended duration (DLS + E)
DU
DLS
DE
DLS + E
1
2
3
4
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ANALYSIS PROCESS
Materials
Labor
Transport
Equipment
RESOURCES
AMOUNT PRODUCTION GRAPH
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Deterministic model ofthe activity production
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Effect of the factorsaffecting the production
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PU = Unaffected ProductionPL = Lost Production
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Stochastic model of theactivity production
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20t1 t2
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21Input
[Excel]
Average Speedof production or
productivity Random Numbergeneration
P = RAND[75%-250%]x Aver.Prod
Creation of graphs[production,
production speedand acceleration]
Find the time toaccomplish the
ammount of taskrequiered
Generation of theproduction charts for all iterations
InterpretResults
All iterationscompleted?
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22DELAYS IN CONSTRUCTION TASKS
200 simulations given therandomness in theprocess
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Frequency time distribution
24
Beta distribution with 80%of probability
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Distributions of times andproductions
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Envelope line for the range of times and its distributions
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CONCLUSIONS
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• The model gives another managerial parameters such as speedand acceleration through the virtual management momentumsimulation to evaluate the execution of the activity and not onlythe production chart.
• A further step is to assess also the cost implications in theexecution of the activity.
• And still ambitious step is not just application of the classicalmechanical model to the economic model of production but alsolook for the efficient energy required to perform the activity andmaybe the concurrent use of dynamical systems theory, chaostheory and Recurrent plots Analysis for a better understanding ofthe model.
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QUESTIONS
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THANK YOU.