Civil Engineering Project Management (4th Edition)

176 Civil Engineering Project Management
Assessment of extensions of time may have to be made several times during
a long contract and their cumulative effect will have to be assessed at or
near completion. The assessment needs to take account of all known circumstances
at the time, independently of what may happen later. Also the estimate
is unlikely to be precise because of complicating factors, such as delay
periods overlapping. The engineer has to decide whether delays fairly entitle
the contractor to an extension, so it may be that reference only to the contractor’s
programme is insufficient, since other factors need to be taken into
account to produce a fair result. To make this judgment the engineer needs
experience of constructional processes and their limitations.
An early look at a delay with reference to the contractor’s initial programme,
should take into account that this is only a statement of intent and
that the contractor is at liberty to change his programme. Some operations will,
in the nature of events, take longer or shorter to complete than anticipated.
A more realistic approach is to examine the as-built record of construction to see
if – had the delay not occurred – the construction could have been completed
faster, taking into account any changes made by the employer which have
caused delay. The advantage of this approach is that it is based on actual performance
including any mitigating measures that were taken to reduce delay.
A further discussion of assessing delay and evaluating any payment due is
given in Sections 17.10 and 17.11.
14.9 Estimating probable final cost of works
When a construction project is moving towards completion the employer may
ask for an estimate of its probable final cost. To deal with this it is a help if the bill
of quantities for the project is divided into separate bills for separate structures.
This makes it easier to identify where extra costs have arisen and where further
extras can be expected. The following type of analysis may then be adopted:
• An analysis of amounts incurred under variation orders is made, dividing
them out over the separate bills. The analysis should include VOs pending.
If a VO covers many items spread over several bills, it can be allocated
to general contingency money, to save time on too much detailed analysis.
• The page totals in the original priced bill of quantities should be compared
with the latest page totals for interim payments certified to date. Additions
should be made where, by examination, it is thought payment for items on
that page will come to £500 or more than the original page total shown.
Deductions will be made where it is expected a page total will reduce by
£500 or more because of items omitted, or for which payment under a VO
has been substituted. Smaller differences are ignored. The total for each bill
for a separate structure is then derived by adding up the revised page totals.
• The probable final cost outcome of the main construction contract can then
be assessed as shown in Table 14.1.