foundations, utilities or other geotechnical hazards Engineering Group of the Geological Society 15th September 2009 Example of a baseline statement (1) • Tunnel in glacial till • Boulders of rock are to be anticipated • Estimated 100 to 300 boulders • Set baseline at 300 boulders – the risk of unforeseen ground conditions is removed GPC6, C-2012668-02, Task Order #39 Dallas CBD Second Light Rail Alignment (D2 Subway) Concept Design . 0064‐M06‐032 Virginia Department of Transportation. As described in more detail in the following sections, the underground portions of the project include the bored More details are available in the paper presented by the authors at the June 2017 RETC conference in … �n��V�i�b��w�ݬ���z�3p�e��t��Z�^�ų�,�q�m��k�}�tJ�����)gs�`��ށ{o���D*��̮�D�eS���y�?˰�t�s� ������d֖�:�*��խ7��n��C��>q�9�r�*7�zWY�p��������+�Yݕ�,��-����I��c��G\�R���Xc/%�A��w�Zq���:�H��2��$I�����%#h)=�Y�@g��Bv/x_������~�����B��".zL�9Ƃ�4 ��|�y8��{b$ 0�W*@��|�z��#�HH4�+�B�I��د@�;G�p��x�@;t���e. 1 Introduction and background 1.1 Introduction This document sets out to record Crossrail’s experience of the use of Geotechnical Baseline Reports (GBRs) in its construction contracts. General Planning Consultant Six Managed by HDR Next, we turn our attention to the fossils recovered during tunnel construction. Present the results of geotechnical investigations conducted for the project in a factual manner. 2. Geotechnical Baseline Report Table of Contents WESTSIDE SUBWAY EXTENSION PROJECT A mendment 3 October 15, 2013 Page i May 22, 2013 Table of Contents Disclosure of the available site data by the employer falls in line with the principle that he has a duty to facilitate rather than prevent the proper performance of the contract. This paper intends to demonstrate that the incorporation of ground baseline conditions/report in contracts is an effective tool for managing the ground risk in construction projects, for reducing costs and for dispute prevention or settlement. As such, those conditions should be considered as the basis, or the baseline, for risk evaluation and pricing. The description should be detailed enough to encompass the range of conditions that might occur in a project. 0 Introduction The Big Sand Wash Reservoir Enlargement project forms a major part of the Lake Fork Section 203(a) Uinta Basin Replacement Project. 1771 0 obj <>stream Disputes Review Board . Tunnel projects are linear and can extend for miles . 12374.001 -4- 2.0 GEOTECHNI CAL CONDITIONS Presented below are “baseline” site geologic/geotechnical conditions based on review of pertinent literature and the site-specific field exploration (Leighton, 2020). During construction, the baseline may be compared with actual conditions, in order to determine if and how much these circumstances are more unfavorable than expected, and to evaluate the appropriate compensation. 100 pp. When the GBR is included in the contract, becoming the contractually accepted interpretation of the site data, the baselines serve as contractual references to establish where conditions encountered during construction that are materially more adverse, onerous and time consuming, may be considered as ‘unforeseen’. Road tunnel, highway tunnel, geotechnical investigation, geotechnical baseline report, cut-and-cover tunnel, drill-and-blast, mined tunnel, bored tunnel, rock tunneling, soft ground tunneling, sequential excavation method (SEM), immersed tunnel, jacked box tunnel, seismic consideration, This Geotechnical Baseline Report (GBR) summarizes the geotechnical basis for design and construction of the Cowmire and Coldwater Stormwater Tunnels and is intended for use by bidders as an aid in bid preparation. The Geotechnical Baseline Report (GBR)is intended to form the basis for establishing the ground related risks in the design and construction for the execution of Underground Works, and as such is critical in providing a balanced allocation of risk between the Parties. management of such risks is essential and critical, and for the Tsuen Wan Drainage Tunnel (TWDT) was implemented by the inclusion of the Geotechnical Baseline Report (GBR) into Tender Documentation. The court upheld the principle of certainty of price and performance. Although originally developed for use on large diameter tunneling projects, GBRs have been implemented on a number of microtunneling projects. endstream endobj 1757 0 obj <>/Metadata 168 0 R/OCProperties<>/OCGs[1765 0 R]>>/Outlines 243 0 R/PageLayout/SinglePage/Pages 1747 0 R/StructTreeRoot 320 0 R/Type/Catalog>> endobj 1758 0 obj <>/ExtGState<>/Font<>/XObject<>>>/Rotate 0/StructParents 0/Tabs/S/Type/Page>> endobj 1759 0 obj <>stream The comments in this report relate to those alignments. Next, we turn our attention to the fossils recovered during tunnel construction. When the GBR is part of the contract, it sets the range of adverse physical ground conditions that ought to be provided for and included in the contract price. 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. Historical Perspective Assessing Geotechnical Risk Risk Sharing Philosophy GBR Fundamentals Case Histories 2 ... borings and profile showing tunnel outline • Interpretive Geotechnical Report in the Contract • Over-consolidated clays - the Cretaceous Patapsco formation. Disputes Review Board . Shield Tunnel Boring Machine (TBM), highlighting the use of detailed geotechnical characterisation as the primary driver for offsetting risk from unforeseen or changing ground conditions during tunnelling. ‘… The CIRIA working party recommended that a set of Reference Conditions be established by the engineer and, by discussion with, and modification by the contractor, these to be used as a basis for settlement of disputes’ (J. Baileys, 2007). Also employers may fear that ground information is used to the contractor’s advantage. Under English jurisdiction, the contractor bears the risk of changed ground conditions unless it is otherwise expressly provided for in the contract. RELATED: Risk Management Professionals Convene in DC. • Preparation of a Geotechnical Baseline Report (GBR) to define the baseline conditions on which contractors will base their bids and select their means, methods and … Copyright 2019 Benjamin Media, Inc.     |. 1756 0 obj <> endobj On the other hand, a vague or broad description of ground conditions would not eliminate uncertainties on risk allocation but, after any event, it would leave room for its interpretation with inevitable hindsight knowledge. Through his career John has been retained to undertake forensic investigations of geotechnical failures and expert reviews of underground construction claims on more than 50 projects. A potential weakness of the GBR lies in this very point. It is difficult to write an appropriate GBR linked with DSC that define in clear terms those circumstances that ought to be foreseen and provide a practical mechanism to measure differences, meting out the relevant remedies. The GBR should take a practical approach in defining the site conditions; it should focus not only on the ground but also on the method of work. The Geotechnical Baseline Report (GBR)is intended to form the basis for establishing the ground related risks in the design and construction for the execution of Underground Works, and as such is critical in providing a balanced allocation of risk between the Parties. 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 given and accepted’, data and reports on ground conditions may be considered a term or a warranty when they are expressly incorporated in the contract, as long as there is no uncertain language and there are no waivers or disclaimers. Anything can be expected when dealing with ground conditions, and since contracts cannot specify all future eventualities, they should at least incorporate a contractual mechanism to determine how to deal with them. This information is coupled with construction methods and geology of the construction site, as well as considerations for construction. Figure 1 shows the approximate location of the crossing. • Geotechnical Baseline Report ... borings and profile showing tunnel outline • Interpretive Geotechnical Report in the Contract • Over-consolidated clays - the Cretaceous Patapsco formation. 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, promoting a conscious and keen tender pricing. ... Geotechnical Data Report. The Joint Code of Practice for Risk Management of Tunnel Works (2003) defines Geotechnical Baseline Conditions as follows: Definitive statements about (…) the ground (…) and groundwater together with geotechnical properties of the ground which serve as the basis for construction Contract tendering purposes and for subsequent application of the contract with respect to the conditions actually encountered during Tunnel Works. The Geotechnical Baseline Report (GBR) is a statement representing the known ground conditions in a project site. GEOTECHNICAL BASELINE REPORT FOR OUTLET WORKS CVO/BSW GEOTECHNICAL BASELINE REPORT.DOC 1-1 1. In the case Mitsui v Attorney General of Hong Kong under a remeasurement contract where actual quantities were in different proportions from those estimated 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 expressly or impliedly included in the original contract and, therefore, are not included in the contract price, are generally termed variations, …’ [emphasis added]. Geotechnical Baseline Report . S-000900-0109-3 HOUSTON, TEXAS 1.0 INTRODUCTION 1.1 General The report submitted herein presents the results of Aviles Engineering Corporation’s (AEC) geotechnical 2 Page 6, Field Trip Guide "Tunneling Through a Miocene Plate Boundary" by Chris Risden and Ivy Morrison. Therefore, baselines and DSC should be ‘most clearly and unambiguously expressed’ (W&S Pollock & Co. v McCrae, 1922). the project geotechnical engineer and prepared the Geotechnical Data Report and Geotechnical Baseline Report. The purpose of this Geotechnical Baseline Report (GBR) is to present an interpretative summary of the results of the geotechnical investigation completed for the proposed trenchless sections, and associated shafts, for West Anthem Gravity Sewer Improvements Project (Project), in Phoenix, Arizona. Independent geotechnical consultants have prepared these (pre-bid) reports for the last 70 years or more. This report details proposed work for the Waller Creek inlet tunnel, inlet shaft, and debris channel. Tunnel projects are linear and can extend for miles We prepare a Geotechnical Baseline Report to • Describe the anticipated subsurface conditions and how they will influence the construction • Describe how they influenced the design • Identify the key subsurface risks on the project • Describe how those risks are allocated between the Final Geotechnical Baseline Report 1.0 - Introduction REGIONAL CONNECTOR TRANSIT CORRIDOR PROJECT April 20, 2012 Page 2 1.2 Scope of the Geotechnical Baseline Report This GBR pertains to the underground portions of the RCTC project. �U�{�!�� ���� Tunnelling in Difficult Ground: How the Geotechnical Baseline Report Helps R. Perlo, M. Swales and T. Kane Above all, since GBR is the formal representation of the ground conditions on which the contract price is founded, it should not be manipulated in any direction, to avoid allegations of misstatement or misrepresentation. If a ground conditions report is not expressly incorporated in the contract, it is not considered a term of the contract 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 performance requirements of Thorn v London Corporation apply to the contractor. Thank you and be well. This Report was Prepared for DART . Differing Site Conditions Clause . Submitted herewith is the Phase 1 Geotechnical Baseline Report for the proposed improvements to LBJ Freeway. 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 costly bids’ (SME, 2008). Tunnel projects are linear and can extend for miles We prepare a Geotechnical Baseline Report to • Describe the anticipated subsurface conditions and how they will influence the construction • Describe how they influenced the design • Identify the key subsurface risks on the project • Describe how those risks are allocated between the 1 Page 69, Caldecott Improvement Project: Geotechnical Baseline Report, prepared by Jacobs Associates, June 2009. Conversely, site conditions differing from those considered in the GBR are deemed to be ‘unforeseen’ under the contract and ae carried out at the employer’s risk. The use of Geotechnical Baseline Reports (GBRs) for contractually de ning anticipated ground conditions has become a widely accepted practice in the tunneling industry. California High-Speed Rail Authority, 2016, San Jose to Merced Project Section, Draft Preliminary Geotechnical Data Report for Tunnel Subsection, September. 7 8 Underground “Facts of Life” means, methods, and . The GBR ‘carries clear definition of risks and their allocations’ and ‘contains an effective means to settle disputes as risks materialise’ (H. Tang, 2001). shown in Geotechnical Investigation Plan Drawings 108-119 (Appendix A). A geotechnical investigation program for a tunnel project must use appropriate means and methods to obtain necessary characteristics and properties as basis for planning, design Pre-bid reports prepared for contractors preceded the advent of GBRs. Finally, since ‘for the success of any construction contract the risk must be acknowledged and clearly allocated’ (CIRIA, 1983), the GBR provides an answer as to what ground conditions are allocated to the contractor, thus contributing to the successful management of a contract. ��%l8:X�; ���Q٨,$���A��@�@F�� ��|���3g&!�b�z&w�g� ۼ�$l��yإ�jf0��z�"��H�d`�� �� 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 conditions. INTRODUCTIONIn recent years, the use of geotechnical baseline reports (GBRs) on microtunneling projects has become increasingly popular. Another good reason to give a balanced position to the GBR is that of motivating each party to resolve the difficulties that eventuate during construction within their capability and in the interest of the project that should be completed on time and within the budget. It is impossible to predict with certainty what lies beneath the surface in any given position, unless the investigations are carried out on that very spot. In the ‘tufa’ case Bacal Construction (Midlands) Ltd. v Northampton Development 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 accord with the hypothesis upon which the contractors had been contracted’ and the risk, under differing circumstances, should be borne by the employer. Geotechnical Baseline Report . Hampton Roads Bridge‐Tunnel Expansion Page 1 Commonwealth of Virginia Project No. In Thorn v London Corporation, the court dismissed the contractor’s allegation that there would be an implied warranty as to plans and specifications providing the use of caissons that were not buildable due to adverse ground conditions, as ‘although it was the engineer who suggested building those caissons, the builder promised he would’. Furthermore, an undefined scope for ground conditions 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 included in the contract price. 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 defining both what is considered ‘unforeseeable’ and the remedies available under the contract. Final Geotechnical Baseline Report November 28, 2018. GEOTECHNICAL INVESTIGATION CITY OF HOUSTON SURFACE WATER TRANSMISSION PROGRAM CONTRACT 74A-1 WATERLINE COH WBS NO. This report includes: Geotechnical Baseline Report Revised August 28, 2020 Murrieta Road Transmission Pipeline Project No. endstream endobj startxref Finally, the GBR can make the parties lay out clear conditions that prevent ‘the “pinch points” that provide fertile ground for the growth of legal risk …’ (Capper, 1994). Debunking the baseline conundrum Dec 2015 Dr. Peter J. Tarkoy, USA. The Geotechnical Baseline Report (GBR) is a contract document and a risk allocation document provided to Proposers of DB projects that provides the primary contractual interpretation of geotechnical conditions, in addition to the factual data provided in … A connected purpose of GBR is risk management during contract implementation, since it can be used as the starting point to prepare a risk assessment and management plan as far as geotechnical conditions are concerned. Contract Documentation (as well as subcontract documentation for Tunnel Works as appropriate) shall include Ground Reference Conditions or Geotechnical Baseline Conditions prepared by the Client (or prepared on his behalf) or shall require each tenderer to submit with their tender their own assessment of Ground Reference Conditions or Geotechnical Baseline Conditions, the … Properly drafted GBRs reduce construction costs and set clear terms between the parties in the event of more adverse ground conditions, thus contributing to dispute avoidance. Geotechnical Baseline Conditions or Report (GBR) is a single ‘contract document containing measurable contractual descriptions of the geotechnical conditions to be anticipated (…) during construction’, (D. Page, 2009). Dallas, Texas . Description (cont’d) • Contractor proposed a self-built open face For instance, in tunneling, this document could identify the expected geotechnical classification, the method of classification, and the distribution of the types of rock classes along the tunnel profile. Proposed Tunnel System. The Role of Geotechnical Baseline Reports in Managing Project Risks. h�b```f``�������� �� @1�0`��#P�&�&mf�Z�+,�8t�&2_d\\��ə1�� ����fkF�UL,�,�L/�n�Pc1b�ex�>O��L�v�*�.--.�5��A��b���L�]3��C����0��U�� If the description of geotechnical conditions in the GBR falls in contradiction with other contract documents, there could be conflicting interpretations and disputes. 1 Page 69, Caldecott Improvement Project: Geotechnical Baseline Report, prepared by Jacobs Associates, June 2009. A Geotechnical Baseline Report (GBR) is a document included in the construction contract, which provides the parties to the contract with a mutual understanding of the subsurface site conditions (the baseline). h��TMo�0�+�,($Y�X�`��EZ�%F;�U���#eYs� �m$Q��IG�L��2M��ܯ91���P��R)���]��=����m���)�}9Zv��d�;����墲[;O�y�/��wϮ��������zk�{SF&���/�=�̮ w��Y. 1. The Ground Risk and Geotechnical Baseline Reports: A Legal Perspective, A Unified Industry-Wide Voice for the Future of Tunneling, Proving Ground: Twin Bores Provide Perfect Test Bed for BTrenchless, NUCA Calls On New Administration To Keep Its Focus On Infrastructure, Hobas Pipe USA Supports Critical San Antonio Infrastructure Project, NHEO Institute, Bechtel Partner To Advance Innovative Safety Practices, Bouygues-Barletta JV to Build Pawtucket Tunnel. Therefore, the first question is what conditions are expressly or impliedly foreseen under the contract. 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. The Geotechnical Baseline Report (GBR) is a statement representing the known ground conditions in a project site. What is foreseen in the contract must be included in the price, but the obligations under changed conditions depend on the contract stipulations and the law governing the contract. When the GBR is part of the contract, it sets the range of adverse physical ground conditions that ought to be provided for and included in the contract price. Road tunnel, highway tunnel, geotechnical investigation, geotechnical baseline report, cut-and-cover tunnel, drill-and-blast, mined tunnel, bored tunnel, rock tunneling, soft ground tunneling, sequential excavation method (SEM), immersed tunnel, jacked box tunnel, seismic consideration, If the contractor’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 Escrow Bidding Documents, or EBD to be used only when necessary, e.g. Over cautiously drafted baselines may cause the Contractor to bear the total responsibility of the ground risk, resulting in a higher bidding price. 100 pp. As the contract progress unfolds, the parties can measure the difference between the reference conditions included in the GBR and the actual conditions met on the ground. February 26, 2020 . Geotechnical Baseline Reports (GBRs), John was co-author of many of the first GBRs written for underground projects in Ontario. 1.1 General. In fact GBR should be included as a representation, and not be merely provided ‘for information’. Specific details of the current vertical alignments are shown on Geological Section Drawings 252-255, 258-262 and 326-337 which are contained in Appendix B. ITA-AITES World Tunnel Congress, WTC2020 and 46th General Assembly Kuala Lumpur Convention Centre, Malaysia 15-21 May 2020 Considerations on the Practical Development of the Geotechnical Baseline Report (GBR) for the FIDIC Emerald Book and … GE‐004 Tunnel Soil Interpretative Report ... superseded by the Geotechnical Baseline Report (GBR). The Geotechnical Baseline Reports: General Concepts Geotechnical Baseline Conditions or Report (GBR) is a single ‘contract document containing measurable contractual descriptions of the geotechnical conditions to be anticipated (…) during construction’.23 The wording ‘contract document’ is added 18 [2002] EWHC 1270 (TCC); Const. The BNSF railroadcrossing and the associated launch and reception pit and shafts arethe subject of this Geotechnical Baseline Report (GBR). tunnel and facilitate installation and future maintenance of the pipeline. Technical Specifications Report. If the contractor comes across a more adverse condition Geotechnical Baseline Report for 20% Design . 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. ... volume of soil excavated along the length of the tunnel alignment will consist of cobbles and boulders." The Geotechnical Baseline Report (GBR) is a contract document and a risk allocation document provided to Proposers of DB projects that provides the primary contractual interpretation of geotechnical conditions, in addition to the factual data provided in the GDR, for Proposers to use as the basis for To better serve our many subscribers that are working from home during this time, we are offering digital issues of TBM: Tunnel Business Magazine. 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. ... Geotechnical Baseline Report. The rationale of this common law principle lies in the contract since, where the contractor has undertaken to complete a work and comply with contract drawings and specifications he bears the cost of performing the promises, irrespective of changed conditions, without entitlement to variations. Another controversial point is when the DSC includes terms that are related to performance, e.g. Bill Wang (Senior Geotechnical Engineer – Golder Associates), who assisted with preparation the report titled, West Gate Tunnel Project Technical Report D, Appendix A – Ground Movement Modelling Prediction – Tunnels and Portals 1521107-211-Rev0.

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