Tunnel Business Magazine

FEB 2018

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TUNNELINGONLINE.COM 3 3 TBM: TUNNEL BUSINESS MAGAZINE // FEBRUARY 2018 ing those caissons, the builder promised he would'. The court upheld the principle of certainty of price and performance. In the cas eneral of Hong Kong under a remeasurement contract where actual quantities were in different proportions from those esti- mated in the B.o.Q, the judge quoted the definition of 'variation' from Hudson's Building and Engineering Contracts (10th edition) at p. 506 as follows: ' Works which are not ex- pressly or impliedly included in the original contract and, therefore, are not included in the contract price, are gener - ally termed variations, …' [em- phasis added] What is foreseen in the contract must be included in the price, but the obliga- tions under changed conditions depend on the contract stipulations and the law governing the contract. Therefore, the first question is what conditions are expressly or impliedly foreseen under the contract. When the parameters of ground conditions that ought to be foreseen cannot be reasonably obtained by the contractor through his site investiga- tions, the information provided by the employer at tender stage becomes es- sential to define what is foreseeable under the contract, as shown below. In the 'tufa' case Bacal Construction evelop- ment Corporation, where the employer prepared a report on ground conditions on which the tender price was to be based, an English Court held that 'there should be an implied term or warranty that the ground conditions would ac- cord with the hypothesis upon which the contractors had been contracted' and the risk, under differing circum- stances, should be borne by the employ- er. If a ground conditions report is not expressly incorporated in the contract, it is not considered a term of the con- tract on which rights and obligations are measurable by reference to it, but 'would require an unambiguous wording to give rise to such a result' and 'it does not contain any statement sufficiently definite and unqualified to amount to a representation upon which [the parties] (…) could reasonably have relied.' Under the circumstances, the stringent perfor- mance requirements of Thorn v London Corporation apply to the contractor. In conclusion, since 'it is legitimate, and commercially desirable, that both parties should be able to measure the risk, and agree the price on the basis of the warranties which have been giv- en and accepted', data and reports on ground conditions may be considered a term or a warranty when they are ex- pressly incorporated in the contract, as long as there is no uncertain language and there are no waivers or disclaimers. The Geotechnical Baseline Reports: General Concepts Geotechnical Baseline Conditions or Report (GBR) is a single 'contract docu- ment containing measurable contrac- tual descriptions of the geotechnical conditions to be anticipated (…) during construction', (D. Page, 2009). In fact GBR should be included as a represen- tation, and not be merely provided 'for information'. The Joint Code of Practice for Risk unnel Works (2003) defines Geotechnical Baseline Condi- tions as follows: Definitive statements about (…) the ground (…) and ground - water together with geotech- nical properties of the ground which serve as the basis for construction Contract ten - dering purposes and for sub- sequent application of the contract with respect to the conditions actually encoun - tered during Tunnel Works. A similar definition is included in A Code of Practice f Tunnel Works, prepared y 2012, which used the term of 'Ground Reference Conditions'. The above definitions provide the syn- thesis of the purposes of GBR, i.e. the site data to be considered and relied upon, a measure of the risks to be included in the contract price, the watershed for risk allocation under the contract, and the basic list of hazards to be considered for ground risk management. Then, the contractor does not need to be predictive and include further contingencies in his price beyond the limit of the conditions defined in the contract baseline. During construction, the baseline may be compared with actual conditions, in order to determine if and how much these circumstances are more unfavor- able than expected, and to evaluate the appropriate compensation. A connected purpose of GBR is risk management during contract implemen- tation, since it can be used as the starting point to prepare a risk assessment and management plan as far as geotechnical conditions are concerned. The Geotechnical Baseline Re- port and Its Place in the Contract Anything can be expected when deal- ing with ground conditions, and since contracts cannot specify all future even- tualities, they should at least incorporate a contractual mechanism to determine how to deal with them. Furthermore, an undefined scope for ground condi- tions that are to be expected under the contract is an open door to disputes, and the remedy is finding a way to define the parameters of what is or ought to be in- cluded in the contract price. As such, those conditions should be considered as the basis, or the baseline, for risk evaluation and pricing. In fact, before executing a contract, the tenderer needs to know 'with a sufficient degree of certainty' (J. Barber, 1989) the risk that he is going to price, while the employer needs to know what he is going to pay for. Disclosure of the available site data by the employer falls in line with the F E A T U R E S T O RY

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