Time cost-control

Updating Construction Schedules
• Procedure:
– Change the duration of all completed activities
to zeros.
– Identify all activities on which work is currently
proceeding as live activities.
– Put early start time of live activities equals the
update time and their durations equal the
remaining duration given by the update report.
– Change durations of future activities as given in
the update report.
– Carry out network analysis in the normal way
and prepare a new activity schedule.
Spring 2008, Time and Cost Control 1
King Saud University Dr. Khalid Al-Gahtani

Example

Spring Time and Cost Control 2
2008, Dr. Khalid Al-Gahtani

Example
• The position of the activities at the end of the fifth
week is as follows:
– Activities B, C, D and E have been completed.
– Activity F is ready to start at beginning of week 6.
– Remaining duration of activity H is 4 weeks.
– Remaining duration of activity I is 3 weeks.
– Activity G will not start until end of week 7.
– Volume of work in activity L has been increased by 33%
approximately.
– Activity J has been omitted.
– It is decided to shorten activity K by 2 weeks.

• Construct the updated schedule indicating the critical
path and showing new activities times.

Work Breakdown Structure
• WBS divides the project into recognizable systems (work
packages, WP’s or Bid Packages) that responsible
assignable work units, and for which accountability can
be expected/assigned.

P ro ject

W o rk P ackages

A ct ivit ies S equenc ing


Traditional A/E PDS

O w ner

A /E GC

Su b1 Su b2 Su b3 Su b4


Professional Construction Management

O w ne r

A /E CM

W P1 W P2 W P3 W P4 W P4


Developing WPs
• Develop WBS
– Identify WPs
• Draw a WPs Network

W P3
W P1

W P4 W P6
W P2

W P5


Developing WPs
• Each WP must have
– One Performing Agency (PA) such as
Subcontractor
– One Responsible Agency (RA) such owner’s
Project Engineers
• Interconnection between Packages should
be district and clear to facilitate
coordination
W P1 W P2

W P3

Developing WPs
• Bid a WP at the most short time so as to
stimulate competition (Keep away
uncertainty)

W P1 W P2 W P3 W P4


Cost Coding System
• Cost Central level = Lowest level at which
functional responsibility for individual WBS
element exit.
– XXX XXX XXX XXX
• An example:
– 0534.02220.21.A.00.cf34


MASTERFORMAT system
T A B L E 1 M a jo r D ivisio ns in the U nifo rm C o nstructio n Inde x

0 C o nd itio ns o f the co ntract 9 F inishes
1 G enera l requ ire m e nts 10 S pec ia lt ies
2 S ite w o rk 11 E quip m e nt
3 C o ncrete 12 Furnishing s
4 M aso nry 13 S pec ia l co nstructio n
5 M etals 14 C o nve ying syste m
6 W o o d and p last ic s 15 M echa nica l
7 T herm a l a nd m o isture prevent io n 16 E lectrica l
8 D oors and w indo w s


Cost Coding System
• Advantages of coding systems are:
– Provide a numbering system to replace verbal
descriptions of items.
– These codes reduce the length or complexity of the
information to be recorded.
– aids consistency in definitions and categories
between projects and among the various parties
involved in a project.
– aid in the retrieval of historical records of cost,
productivity and duration on particular activities.
– electronic data storage and retrieval operations are
much more efficient with standard coding systems.

Project Cost Control
• Budgeted Cost of Work Scheduled (BCWS) is the
budgeted amount of cost of the work scheduled to be
accomplished in a given time period (including support
and allocated overhead).

• Budgeted Cost of Work Performed (BCWP) is the
budgeted amount of cost for the work completed in a
given time period, including support effort and allocated
overhead. (This is sometimes referred to as “earned
value of work accomplished”.)

• Actual Cost of Work Performed (ACWP) is the amount
reported as actually expended in completing the
particular work accomplished within a given time period.

Type of performance
BC W P

BC W S

ACW P

Fast & L o w

King Saud University Dr. Khalid Al-Gahtani BCWS

Type of performance
ACW P

BC W P

BC W S

Fast & H ig h

Type of operformance
Fast & L w

BCWS

BCW P

AC W P

S low & Low

TypeFast & performance
of H ig h
BCWS

AC W P

BCWP

S low & H igh

Cost Index
C o st V ariance = B C W P A C W P
+ ve U nder B udget
C o st V ariance 0 W ithin B udget
- ve O ver B udget
C o st P erfo rm ance Index = B C W P /A C W P
> 1 U nder B udget
CPI = 1 W ithin B udget
< 1 O ver B udget
% co st o verrun/u nderrun

ACW P BCWP
= ,
BCWP

Schedule Index
S chedu le/P erfo rma nc e V aria nce =B C W P -B C W S .
+ve A head S chedule
S ch./per. V ariance 0 O n S chedule
-ve B ehind S chedule
S chedu le P erfo rma nce Inde x = B C W P / B C W S .
>1 A head S chedule
SPI =1 O n S chedule
<1 B ehind S chedule


B udgeted C o st A t C o m pletio n (B A C )

Estimatedo fCost/Timenit price
= T o tal Q uantities U At Completion

P udgeted C e A t t o o pletio n (T A C C
Blanned T imo st A CC mm pletio n (B A ) )

= T o tal o f Q uantities ÷ P lanned P ro ductivity
uantities U nit price
E lanned T imo st A CC mm pletio n (E A C )
P stim ated C e A t t o o pletio n (T A C )

= T oC Wo f oD ate
A tal PT Q uantities ÷ P lanned P ro ductivity
BAC
= BAC =
B C W PT oD ate C P I T oD ate
E stim ated C o st A t C o m pletio n (E A C )
M ore accurate estim ate can be reach ed by using these form ulas:
T o D ate VA C W P T im e
ariance BAC
T oD ate
E stim ated=C o st A t Co m p let B A C = C )
io n (E A
BB C W PoD ate
C W PT C P I T oD ate
T oD ate
= 1 T im e T oD D ate
(B A C - B C W PT o ate )
= V arianceate im
T o D ate A CB C W S T oD atee
W P T oD T
C P I T hisPeriod

ESpring ated T im eC W CooD ate letandn (EControl )
stim B A t PT m p io Cost T A C
Time 21
2008, = 1 T im e
Dr. Khalid Al-Gahtani T oD ate

Project Example


Project Example
E N G IN E E R IN G SU B T ASKS ST AT U S AT E N D O F M O N T H 3
(tho usands o f do llars)

T ask Status BCW S BCW P ACW P
System design C o mp leted $131.0 $131.0 $144.0
Subco ntract specs Started 132.0 82.0 84.0
M aterial tests C o mp leted 22.0 22.0 22.5
Specs review Started 22.0 15.0 15.5
D rafting Started 97.0 59.0 59.0
Fabricatio n/assembly suppo rt C o mp leted 29.0 29.0 36.0
Fabricatio n/assembly pro cess Started 100.0 63.0 67.0
T est suppo rt Started 21.0 21.0 21.0
E ngineering release and review N ot Started
T otal $554.0 $422.0 $449.0


Project Example
Figure 5 -9 S tatus sum m ary o f engineering subtasks in pro gress and estim ate to co m plete.

T ask BCWS BCWP ACW P S tatus
S ubco ntract specs $132 $82 $84 B e hind sc hedu le and o ver co st
S pecs review 22 15 15.5 B e hind sc hedu le and o ver co st
D ra fting 97 59 59 B e hind sc hedu le but w ithin co st
Fa bricat io n/asse m b ly pro cess 100 63 67 B e hind sc hedu le and o ver co st
T est suppo rt 21 21 21 O n sc hedu le a nd w it hin co st
449
E stim ated to co m p lete: 765 = $812 K
442
S u m m ary: E ng ine ering w o rk is be hind sc hedu le a nd a co st o verrun is o ccurring


Time cost-control

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