Geology Reference
In-Depth Information
Contractor is paid the
cost of completing works
in full. Disadvantage is
that there is no incentive
for the contractor to
resolve problems cost-
effectively when they
arise
Client takes all risks
Some compromise
alternatives:
agreed reference ground
conditions at start
cult ground
conditions.
clause allowing additional
payment
partnering (open book)
allowing both gain or loss to
both parties if conditions are
better or worse than
anticipated
RISK OF
UNEXPECTED
GROUND
CONDITIONS
A disadvantage is that
the contractor is
unable (or unwilling)
to price the risks with
any certainty. Can go
badly wrong (see
Chapter7)
Contractor takes all risks
In some forms of contract, the owner accepts all the ground risks and
that makes some sense in that it is his site, with all its inherent geological
and environmental conditions. This kind of contract works quite well
for simple sites and structures, for example, the cutting of a slope with
the installation of soil nails, where the work done by the contractor is
rather routine and can be simply re-measured against the provisional
BOQ priced by the contractor when he tendered to do the work. If he
excavates 2,300 m
3
of soil and 52,050 m
3
of rock during the contract,
then that is what he will be paid for, at the prices he originally quoted for
each type of excavation, although there might be some disagreement
over the de
nition of soil and rock by the parties. Specialist engineers
called quantity surveyors (QS) assess and recommend approval of such
payments to the engineer and then on to the owner.
In an attempt to make it clear-cut where the responsibilities lie, some
owners try to use contracts that place all the risks for ground condi-
tions solely on the contractor, but this is in
exible and offers no way
out when things go wrong. In practice, depending on commercial
pressures, the contractor may take a serious gamble (sometimes with-
out fully weighing up the risks) and it is then, when things start
becoming dif
cult, such as when the ground conditions are worse
than expected, that claims begin to be made and disputes can follow.
Even where all the risk has been accepted by the contractor, when
things become very dif
cult, he and his lawyers may try to use clauses
in the contract, such as claiming that the works were physically or
commercially impossible, or just give up on the project. The arguments
can be long and extremely costly for all parties. Such contractual
arrangements are rarely used these days for major projects.
For more complex projects and especially for constructions under-
ground, usually some of
the ground risks are accepted by the
