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Risk Management and Contracting Practices Chair: J. Reilly, John Reilly Associates, USA ITA Co-chair: A. Dix, ITA WG 3 Animateur, Australia 08:30-08:50 Resolving Difﬁcult Public Transportation Tunneling Problems through the Conduct of Industry Peer Reviews M. P. Schroeder, American Public Transportation Association Challenges have emerged as subway systems age and as new tunnels are bored in congested corridors or in high -risk environments. To help public transportation agencies address tunneling challenges, the American Public Transportation Association has convened numerous independent industry peer reviews composed of top experts in their ﬁelds to come together and provide recommendations and solutions. This paper provides case histories of peer reviews that include topics such as boring through toxic soils, boring underneath existing tunnels, retroﬁt of tunnel ventilation systems, and mitigation of water intrusion. Peer reviews are applicable to all tunnel projects worldwide. The paper will highlight the conditions of these challenges, peer review recommendations, steps taken to reach agreement, and the successes that resulted, which led to major changes, new legislation and reduction of risk.
08:50-09:10 Risk Management in Tunneling: A Review of Current Practices and Needs for Future Development from the Designer's Perspective P. Grasso, M. Pescara and L. Soldo, Geodata Engineering Risk management in tunneling is more important today than it was a few years ago, considering increasing demands for safety and environmental and socio-economic sustainability, which are now required by citizens, owners, lenders, and insurers. Moreover, our current risk management philosophy should not only address risk avoidance and mitigation, but should also be used as a means of value creation, beneﬁting the overall project. Given the strategic implications of risk management, the authors intend to present, in this paper, a comprehensive overview of references and experiences from current practice—e.g., what is missing or weak, as well as possible or necessary developments that can have a key role in implementing effective risk management, particularly for a project’s design and construction phases.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 09:10-09:30 Multiphase Risk Management Method (MRMM) and its Application in Quasi Rectangular Shield Tunnel in China A. Chen and Y. Bai, Tongji University; Y. Zhu and G. Li, Xiangdong, Shanghai Tunnel Engineering Co, Ltd., L. Hu, Tongji University It is well known that tunnelling involves a high degree of risk.
Conventional risk management only evaluates risks and chooses mitigation measures before the start of a project. However, mitigation measures also introduce risks, which are ignored in the conventional risk control process when choosing different measures. The Multiphase Risk Management Method (MRMM) takes the risk of mitigation measures and dynamic risk control into consideration. This paper introduces this new method and provides a ﬂow chart for better understanding. A case study of the MRMM is given based on Ningbo Metro Line 3, the ﬁrst quasi rectangle shield tunnel in China.
09:30-09:50 Use of Numerical Modelling and GIS to Analyse and Share the Risks Related to Urban Tunnelling Greater Paris – Red Line – South Section S. Mahdi and F. Houmymid, SYSTRA and E. Chiriotti The Greater Paris projects involves the creation of a 200km extension of the actual public transport network on the close outskirt of Paris. In 2011, SYSTRA has been awarded the Engineering studies of a 20km underground section in the densely urbanized southeast quarter of the Parisian suburb. In order to both guide the TBM technology choice and identify and mitigate the risk due to soil settlement during tunnel boring, several analysis have been carried out and integrated into a Geographical Information System to share and manage this risk during the successive design phases of the project. The geological context‘s complexity and the Owner‘s requirements have led to the necessity of using an innovative analysis approach, leveraging both the numerical modelling analysis’s accuracy and the analytical method‘s ease of programming and implementation in a GIS, by the mean of the calibration of the analytical approach’ parameters on the FEM results.
09:50-10:10 Risk Management – Correlation and Dependencies for Planning, Design and Construction P. Sander, Riskconsult GmbH; A. Moergeli, Moergeli Consulting, Llc. And J. Reilly, John Reilly International While the basic elements of risk management, including probability, consequences, risk registers, mitigation measures, etc., are now well understood, the process to include correlation, dependencies and linkage of risks and risk scenarios is less well deﬁned and not well understood. To perform accurate and WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL complete risk analysis and risk management, it is necessary to include correlation, dependencies and linkage between risk events, as well as risks that may occur multiple times. In this way, owners and contractors can more accurately determine risk-based costs, risk impacts and risk mitigation strategies. This paper will outline methods to deal with correlation, dependencies and linkage and will consider risks that may occur multiple times.
Practical result comparisons – with or without these elements – will be presented.
10:10-10:40 Break 10:40-11:00 Risk Management of Long and Deep Tunnels – the European Experience Y. Boissonnas and M. Bettelini, Amberg Engineering Ltd The operational safety of long and very long rail tunnels represents a key issue in all development stages, including design, construction, commissioning and operation. The spectrum of potential threats is very broad and challenging. These issues can only be mastered by means of a proper combination of a number of safety measures at various levels. This paper focuses on the speciﬁc safety issues and the extremely challenging conditions characterizing very long and deep tunnels. They include a signiﬁcantly increased risk during operation that the incident train cannot exit the tunnel by its own means, long self-rescue and rescue distances, the presence of a number of trains, possibly mixed trafﬁc as well as signiﬁcant thermal issues. Amberg Engineering is strongly involved in the design and construction of most long and very long rail tunnels in Europe, including in particular the Gotthard Base Tunnel (GBT), Lyon-Turin Base Tunnel (LTF) and the Brenner Base Tunnel (BBT). The combined experience arising from these tunnels forms an invaluable body of expertise, which is summarized in this paper. The focus is on shared issues with practical relevant examples and project-speciﬁc solutions. Special attention will be devoted to the 57 km long Gotthard Base Tunnel, which will be operational by mid-2016 and will be the longest infrastructure tunnel worldwide.
11:00-11:20 Risk Management for Soft Ground Tunnels in New York A. Thompson and F. Perrone, Mott MacDonald As part of the Metropolitan Transportation Authority’s $10.5bn East Side Access Project in New York, 3,200 m of tunnel had to be constructed in rock, mix face and soft ground conditions beneath one of the largest passenger railroad junctions in North America, handling over 780 trains per day. The use of risk based decision making tools was essential in developing the bespoke contract framework that was adopted as well as making informed decisions once excavation commenced. This paper will outline the risk management process adopted, discuss the risks and mitigation strategies adopted and comment on the impacts of this approach on the as built Project cost and schedule. In particular, the paper will outline the unique approach used to establish the 22 – 28 APRIL | MOSCONE CENTER | WTC2016 baseline against which the Contractors performance would be measured as the selection of a Slurry TBM to excavate the tunnels was considered to compromise the effective use of a Geotechnical Baseline Report.
11:20-11:40 Avoiding Disputes on Challenging Ground Conditions in the Lake Mead Intake No. 3 TBM Starter Tunnel J. Nickerson, Salini-Impregilo, S.A. Healy and M. Jensen and E. Moonin, Southern Nevada Water Authority This paper will explain how the Contractor and Owner avoided a contractual dispute involving characterization, impacts, and ﬁnal remedy for challenging ground conditions encountered during drill and blast excavation of the starter tunnel required for launch of the tunnel boring machine (TBM ). During excavation more than 600 feet underground, the Contractor encountered a large complex fault zone subject to more than 14 bar of water pressure. Successive ground inﬂows from the fault complex over a six -month period presented signiﬁcant technical and partnership challenges for the team and ultimately delayed the project by nearly one year. This paper will discuss how the Contractor, Owner, and their respective consultants worked together to address these challenges, make decisions, and ultimately move the project to successful completion.
11:40-12:00 Risk Sharing Principles in Tunnel Contracts E. Grøv, SINTEF/NTNU Tunneling is related to handling of uncertainties, risks associated with geological conditions are signiﬁcant, ‘unexpected geological conditions’ often claimed. Unit rates contracts are bid-build model sharing risk between owner and contractor, owner retains risk for geological conditions while contractor carries risk for performance efﬁciency. Actual quantities may differ from the contract’s BoQ, a ﬂexible contract is required to enable adjustments. Variations of quantities involve a clause to adjust construction time. Unit price contracts deals with ‘unexpected geological conditions’, if ‘unexpected’ element results in variations in quantities. Work activities have quantities and ‘standard capacities’ for regulation of construction time. Variations in quantities are expected in tunnelling and hardly deserve the term ‘unexpected’. If unforeseen geological features necessitate work not included in the BoQ, the contract must be supplemented. Fixed price contracts may not provide the intended predictable cost. ‘Adjustable ﬁxed price’ contracts, combining unit rate and ﬁxed price, may prove suitable.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL 12:00-12:20 Road-Testing the ITA Contractual Practices Checklist A. Hodgkinson, SoftXS GmbH; D. Caiden, Arup and P. Fortsakis, Deutsche Bahn International The “ITA Contractual Framework Checklist for Subsurface Construction Contracts” was produced by ITA Working Group 3 (WG3) Contractual Practices in 2010 and recently updated (2015).
It identiﬁes key contractual areas seen as ensuring successful subsurface construction. The Checklist was prepared because existing standard forms of construction guidelines and contracts do not adequately explain how to deal with the peculiarities of subsurface works. The Checklist was based on the collective knowledge of the members of WG3, who together have worldwide underground project experience. To determine if actual project results correspond to the Checklist recommendations, the authors had selected industry practitioners take a survey on their project experiences. The authors present and analysis the resulting data, which shows positive correlations between project characteristics, contractual details and project results.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 Posters (On display in the exhibit hall during exhibit hours. Authors will be at their poster from 13:00-14:00 for discussion.) Should the TBM Operators be Certiﬁed?
D. Ifrim, Mott Macdonald and S. Skelhorn, McNally International A tunnel project poses many challenges; the operation of the Tunnel Boring Machine (TBM) being one of them. Mechanized tunneling is known as a safe and effective alternative to other methods in terms of schedule and cost; however, efﬁciency can be severely affected by a bad TBM selection and qualiﬁcation and employment of inexperienced operators. The success of a mechanized tunneling project involves a comprehensive and interdisciplinary consideration of all contributing factors such as TBM technical speciﬁcation and selection, TBM design and procurement including ancillary equipment and tunnel linings. The tunnel equipment selection along with the operation can make or break the project. The objective of this paper is to address the importance of the skills and qualiﬁcations of the TBM crew with particularity to the TBM Operator. The study includes the Owner and Consultant involvement in the selection and pre-qualiﬁcation of the TBM crew and speciﬁcally the TBM operator as well as the role of Contractor and TBM manufacturer in TBM operator training. This paper also analyzes the possibility of issuing a TBM operator certiﬁcation, and discusses the beneﬁts and signiﬁcance of periodic training and certiﬁcation programs.
Quality Management System on Sound Transit Underground Construction Projects M. Saleem, Sound Transit; I. Banerjee, CH2M Hill Inc; K. Sapp, Jay Dee Contractors, Inc and J. Salley CH2M Hill Inc On underground construction projects, effective Quality Management is essential for ensuring facility durability, life cycle performance and low maintainability. Furthermore, follow on contracts also rely on an effective quality management system for interface congruency. An effective Quality Management System (QMS) is also essential in mitigating risks and meeting schedule and budget performance objectives. For the past 15 plus years Central Puget Sound Regional Transit Authority’s Link Light Rail extension has successfully completed over 10 miles of twin bore tunneling and associated underground features including cross passages, deep sump structures and shafts. After the completion of each segment, lessons learned have successfully been implemented to improve the quality of delivered projects.
This paper presents the Sound Transit QMS with regard to a number of project elements of tunnel construction projects, with speciﬁc focus on quality performance of slurry wall construction, TBM tunnel excavation assessment, segment production and segmental lining installation, and other associated construction features. A collaborated total QMS will be presented in this paper that will serve as a guide for successful implementation of Quality Assurance and Quality Control processes.