delays in construction tasks - cvut.cz

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


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


4

International Project Management Association IPMA in his book ICB (IPMA Competence baseline)


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Project management Institute PMI and his book PMBOK (a guide to the project management body of knowledge)


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Construction activity efficiencyparameters

TIME (SCHEDULE)

COST (BUDGET)

QUALITY (SPECIFICATION, NORMS, STANDARS)


7

Network Logic diagram drawn using the Precedence diagramming method

Network Logic diagram drawn using the Arrow diagramming method


8

Time scale network diagram

Bar (Gantt) Chart


9

PERT duration Calculation


Ref: Delay and Cost Overruns in Vietnam Large Construction Projects:A Comparison with Other Selected Countries


Ref: Delays in construction projects: The case of Jordan


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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


PU = Unaffected ProductionPL = Lost Production

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Stochastic model of theactivity production


20t1 t2


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?


22DELAYS IN CONSTRUCTION TASKS

200 simulations given therandomness in theprocess


Frequency time distribution

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Beta distribution with 80%of probability



Distributions of times andproductions


Envelope line for the range of times and its distributions

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CONCLUSIONS


• 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.


QUESTIONS


THANK YOU.

delays in construction tasks - cvut.cz

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