Tunnel Business Magazine

FEB 2018

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TUNNELINGONLINE.COM TBM: TUNNEL BUSINESS MAGAZINE // FEBRUARY 2018 principle that he has a duty to facilitate rather than prevent the proper perfor- mance of the contract. When the GBR is included in the contract, becoming the contractually accepted interpretation of the site data, the baselines serve as contractual refer- ences to establish where conditions en- countered during construction that are materially more adverse, onerous and time consuming, may be considered as 'unforeseen'. Then, the contract should also include a 'Differing Site Conditions Clause' (DSC) that allocates the risk of such changed conditions to the em- ployer. A Critical View of Geotechnical Baseline Reports The use of a GBR must be associated with express contract provisions to deal with changed conditions, or the parties will face an uncertain recourse to the governing law of the contract to resolve disputes, defeating the purpose of defin- ing both what is considered 'unforesee- able' and the remedies available under the contract. The contents of the GBR should be balanced and realistic, since 'overly conservative baselines for items such as obstructions (…) can result in overly conservative and c 2008). Over cautiously drafted base- lines may cause the Contractor to bear the total responsibility of the ground risk, resulting in a higher bidding price. The contrary would also be deleterious, when an over simplified baseline would absolve the contractor from otherwise foreseeable risks. Another good reason to give a bal- anced position to the GBR is that of moti- vating each party to resolve the difficul- ties that eventuate during construction within their capability and in the inter- est of the project that should be complet- ed on time and within the budget. The description should be detailed enough to encompass the range of con- ditions that might occur in a project. On the other hand, a vague or broad description of ground conditions would not eliminate uncertainties on risk al- location but, after any event, it would leave room for its interpretation with inevitable hindsight knowledge. This would create fertile ground for denial of responsibility and disputes, especially when there is an expensive bill to pay as a consequence of adverse ground con- ditions. Therefore, baselines and DSC should be 'most clearly and unambigu- ously expressed' (W&S Pollock & Co. v ae, 1922). Another controversial point is when the DSC includes terms that are related to performance, e.g. ad- vance rate of excavation, as they may ambiguous and lead to discussions. If the description of geotechnical con- ditions in the GBR falls in contradiction with other contract documents, there could be conflicting interpretations and disputes. For example, geotechnical in- vestigations may include many reports that may be difficult to integrate in a sin- gle interpretative work. However, this is the very reason for putting the common seal to a single GBR, warranted and re- lied upon by the parties. Above all, since GBR is the formal rep- resentation of the ground conditions on which the contract price is founded, it should not be manipulated in any direc- tion, to avoid allegations of misstatement or misrepresentation. It is difficult to write an appropri- ate GBR linked with DSC that define in clear terms those circumstances that ought to be foreseen and provide a practical mechanism to measure dif- ferences, meting out the relevant rem- edies. A potential weakness of the GBR lies in this very point. What Should a Geotechnical Baseline Report Include? The GBR should include in clear terms the results of site investigations, but should also be drafted as a practical mechanism to measure actual conditions and compare them with those presented in the report. It is impossible to predict with certain- ty what lies beneath the surface in any given position, unless the investigations are carried out on that very spot. That is the reason why ground conditions are best expressed in terms of characteriza- tion and probability. The GBR should take a practical ap- proach in defining the site conditions; it should focus not only on the ground but also on the method of work. For instance, in tunneling, this document could identify the expected geotechni- cal classification, the method of clas- sification, and the distribution of the types of rock classes along the tunnel profile. If the method of work is linked to the baseline conditions established in the contract, it becomes evident when changed site conditions lead the parties into a variation. Geotechnical Baseline Reports and Dispute Resolution '… The CIRIA working party recom- mended that a set of Reference Condi- tions be established by the engineer and, by discussion with, and modifica- tion by the contractor, these to be used as a basis for settlement of disputes' (J. Baileys, 2007). Bidders could be required to disclose the parameters used to calculate the bidding/contract price, that become the reference in case of disputes. If the con- tractor's concern is that the employer may disclose this information to other tenderers, a means to dispel it is that of depositing the bidding documents as Es- crow Bidding Documents, or EBD to be used only when necessary, e.g. in case of disputes. Also employers may fear that ground information is used to the con- tractor's advantage. By contrast, the GBR is a document that is known by all and, when used at the bidding stage, places all contenders on level ground, promot- ing a conscious and keen tender pricing. As the contract progress unfolds, the parties can measure the difference be- tween the reference conditions included in the GBR and the actual conditions met on the ground. Finally, the GBR can make the parties lay out clear conditions that prevent 'the "pinch points" that pro- vide fertile ground for the growth of le- gal risk …' (Capper, 1994). Conclusions The GBR 'carries clear definition of risks and their allocations' and 'contains an effective means to settle disputes as risks materialise' (H. Tang, 2001). As such, it is an effective tool for the man- agement of differing ground conditions, provided that the GBR is incorporated in the contract as a warranty and with- out disclaimers. Finally, since 'for the success of any construction contract the risk must be acknowledged and clearly allocated' (CIRIA, 1983), the GBR provides an an- swer as to what ground conditions are allocated to the contractor, thus con- tributing to the successful management of a contract. Eugenio Zoppis is a PhD Researcher at King's College in London. He has engineering and legal academic background, and has experience as project manager for Salini Impregilo working on major roads, tunnels, and hydroelectric projects. 3 4 F E A T U R E S T O RY

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