RETC delivered again this year with a session in New Orleans to suit everyone’s expectations. More than 1,200 delegates attended a program of technical presentations that shared specific experiences, explained new techniques and explored lessons learned. There was also a chance to visit an exhibition of more than 150 booths that presented the opportunity to interact with all elements of the tunneling industry supply chain.
The increasing success of the RETC as a biennial event in the United States was evident in the growing number of international delegates, an increasing number of presentations about projects in different parts of the world, and the need to overflow the exhibition space into two separate halls. The Sheraton venue hosted the event across four floors with the exhibition halls on floors three and five and two session rooms each on floors two and five. This resulted in time spent on the escalators between levels and was something that the SME organizers said would be avoided for future events. For all delegates the anticipated services for hosted receptions and lunches in the exhibition halls, and ample supply for sponsored coffee for session breaks, were available and appreciated.
A focus of this year’s RETC session was on design and planning of major projects and the development of variations in contracting practices to ensure advance and successful completion of complex and high-risk projects. The Contracting Practices session on Monday afternoon included presentations on the Construction Manager/General Contractor delivery method for the drill+blast widening of the I-70 twin highway tunnels in Colorado; successful partnering to overcome challenging construction of the Roosevelt Station for the Seattle Sound Transit Northgate LRT extension; an integrated design process to fast-track the First Street flood relief sewer tunnel as part of the Clean Rivers program in Washington DC; and partnering through risk management for successful completion of the high-risk Lake Mead No 3 water intake tunnel for the Southern Nevada Water Authority.
One of the most well-attended sessions provided an update on future projects planned for different parts of the United States. With a wave of current projects coming to a close, the construction industry is keen to understand the scope and technical requirements for the next series of major projects that are in the planning stages.
Three of six projects presented in the session are based in California.
First is the estimated $550 million effluent outfall conveyance tunnel for the Sanitation Districts of Los Angeles County, which is approaching the 60% design completion ahead of its design-bid-build procurement scheduled to start in late 2016.
Next was an update on the mega Bay Delta Tunnels Project in Northern California for the State of California Department of Water Resources, which centers on excavation of twin 30-mile x 40ft i.d. precast concrete water tunnels plus another 9 miles of smaller diameter feeder tunnels. Separating the civil construction elements of the mega project from the conservation elements is expected to allow each to progress at their own schedule with the main tunneling by up to 10 TBMs on the project operating at their peak in 2022. A construction period of 10–12 years is envisaged.
The third project presentation for California was revival of the BART to San Jose Phase II project, which includes 5 miles of twin bored transit tunnels and underground stations beneath San Jose. On hold since 2009, the Santa Clara County Valley Transportation Authority is initiating efforts to prepare supplemental Federal and State environmental clearance documents and establish a schedule for design and construction of the long-planned extension.
Two of the session papers described major water projects for the Albany Park Stormwater Diversion Tunnel in Chicago, and the critical bypass tunnel under the Hudson River in New York to secure the city’s fresh water supply that will enable the decommissioning of a section of the force main that is leaking badly.
The sixth presentation of the session described the scope of the 14-mile Red Line extension of the Maryland LRT system with two TBM underground sections, the 1.2 mile Cooks Lane Tunnel and the 3.4-mile section with five underground stations beneath downtown Baltimore.
Within the 20 technical sessions, held in a program of four run simultaneously across three morning and two afternoon periods from Monday to Wednesday, there were presentations to meet a wide range of interest, experience, development and expertise. These ranged from hard rock tunneling to excavation of large-span caverns; from trenchless tunneling and rehabilitation to geotechnical considerations; and from pressure face TBM case histories to ground support and final linings; SEM/NATM; new and innovative technologies; and risk management. The discussion about spray-applied waterproofing and sheet membrane waterproofing systems was developed within the context of their application and long-term durability. The debate about steel fiber and macro synthetic fiber for reinforcement of precast segments and shotcrete linings ran through several presentations.
International experience was well represented, with papers from New Zealand, about the Waterview highway TBM project in Auckland and the city’s new rail link tunnel project; Turkey, with presentations about the new highway TBM bored tunnel under the Bosphorus and advance of the Kargi hydro tunnel by TBM and drill+blast through extreme fractured and squeezing ground; several papers about projects in Australia; a case study of tunneling for the Crossrail project in London from the UK; and details of the PPP mode of procurement for Lines 2 and 4 for the Lima Metro from Peru.
Copies of the conference proceedings, both in printed and DVD format, are available from the SME priced US$139 for UCA members and US$179 for non-members.
The series of short courses held on Sunday ahead of the main program concentrated on three major topics – Shaft Construction and Design; Underground Blasting Technology and Risk Management; and Grouting in Underground Construction. The grouting course convened by Dr Ray Henn came in for particular praise and was described as “brilliant”.
Two workshop sessions were also held on Sunday. One of these advanced the discussions started at the previous RETC in 2013 on issues regarding risk and uncertainty in tunneling. Convened by Russell Clough, and including panelists representing all elements of the industry, including TunnelTalk as a representative of the media, the discussions examined a series of questions as part of efforts to better understand uncertainties and human behavior in the planning and building of projects. Questions included: In ambiguous and risky situations, how do we recognize biases, opinions and beliefs that hinder us from making the best choices? Why do others have such different views of logical and rational decisions? How do we improve critical thinking skills? How do we minimize the cost escalations and the damaging publicity that this attracts? This proved a very interesting and enlightening discussion.
The second Sunday session considered tunnel safety and the engaging of future generations of engineers and professionals in the underground construction industry. One presentation considered the process of eliminating risky behavior from the workplace, while another provided strategies to encourage growth and increased awareness about the need to expand the education programs for specific tunneling and underground construction engineers.
As part of continuing efforts to attract and retain new recruits to the industry there were two special networking sessions. One for Young Members of the UCA (Underground Construction Association of the USA) and for fellow Young Members visiting from other countries; and the other a networking breakfast for the Women in Tunneling group. Both provided the opportunity to socialize and expand the circle of friends and colleagues and share workplace experiences.
The exhibition areas were open at specific times and to avoid conflict with other aspects of the program, and to ensure delegate attendance at the technical sessions. When open, and starting with a two hour hosted exhibition reception on Monday evening from 5–7pm, the exhibition halls were a buzz of activity and discussions. Among the many stands, representing consultants, constructors and major suppliers to the international industry, TunnelTalk was represented by its Publisher Shani Wallis, its Business Development Manager, Katrina Santa Maria and its Advertisement Sales Executive Christie O’Reilly, and welcomed many visitors and friends to its stand in the main exhibition hall.
After the busy and successful days of conferencing in New Orleans, everyone looks forward to the NAT event next year in San Francisco, that will include the UCA’s hosting of the ITA General Assembly and its World Tunnel Congress for 2016; and to the next in the RETC series in San Diego in June 2017.