9/11 and the consequences

Where were you on 9/11 2001 What are the warnings for the industry today

10 Sep 2021

Shani Wallis, TunnelTalk As with all major historic events, we can all recall where we were and what we were doing for events that have occurred in our lifetime. On the twentieth anniversary of that fateful day in September 2001, we share our recollections of that day and in relation to our work within the tunnelling and underground infrastructure construction industry. Perhaps you were involved in the construction of the original World Trade Center underground infrastructure in Lower Manhattan, or in its reconstruction, or perhaps its recovery after the damage caused to its underground car park by the truck bomb blast in 1993. I begin the exchange with my recollections and open a discussion about how resilient is our underground infrastructure to extreme terror, natural environment and devastating accidental events.

As a journalist reporting on underground construction projects, I was travelling in Russia on Tuesday 11 September 2001 visiting the Severomuiski railway project in Siberia ahead of preparing an article about its extraordinary accomplishment by all involved.

My hosts and I were in the project guesthouse watching the CNN news feed on the television, the Russian commentary making it difficult to hear the English reporting underneath. We watched in astonishment and, like so many, believed it a hoax or the trailer for a movie. Plans for the day were overtaken as we continued to watch in awe and disbelief as events unfolded.

For me personally it was shocking to recall that early that year I was in New York for the George A. Fox Conference and the Moles Dinner. During the trip, a colleague and I made a visit to the observation deck of the South Tower of the World Trade Center.

Nine months after the event, in July 2002, I was again in New York to visit the recovery works and the upgrade of the Exchange Place Station in New Jersey and the twin subway tunnels under the Hudson River into reconstruction of the station that were built into the lower levels of the World Trade Center. Ray Sandiford, who was Chief Geological Engineer at the time with the Engineering/Architectural Design Division of the Port Authority, owner of the subway infrastructure hosted the visit and provided access to the site following a process of tight security and vetting of all visitors.

By that time the debris of the collapse of the towers had been cleared and the scale of the diaphragm walls and the space support for the foundations for both towers, referred to colloquially as the bathtub, was revealed.

Overcoming adversity in Siberia – TunnelTalk, April 2002 PATH prepares for a new era – TunnelTalk, September 2002 Ground Zero revival of Manhattan – TunnelTalk, September 2013

Twelve years later, in June 2013, a return visit was arranged to report on the reconstruction work to build the new Freedom Tower, create the memorial to those who lost their lives on the day, and tour progress on the new subway station as part of the World Trade Center Transportation Hub. Again hosted by Ray Sandiford, the visit was a career highlight and my thanks are extended to Ray and those who joined us on the visits of both 2002 and 2013.

From left: Prepared for a trip underground at Severomuiski ; In Ground Zero bathtub 2002 ; Touring the new metro station 2013

In recalling the events of September 2001, the question for our industry and others, is how resilient is our public infrastructure to the threat of attacks and to the consequences of extreme environmental events.

Several major cities have be targets for atrocious terror attacks. As well as New York, underground public transportation infrastructure and facilities in London, Moscow, Tokyo, Paris and others, have experienced attacks of different kinds.

At its World Tunnel Congress in Budapest in 2009, the International Tunnelling and Underground Space Association (ITA) convened a working group session to discuss the vulnerability of underground infrastructure and examine feasible industry responses to the ever­present threat. The ITA also established its Committee on Underground Space (ITACUS) in 2009 to promote the development of the underground dimension to address the increasing urbanisation of the population of the world and in search of urban resilience for mega cities.

Laser light memorial for Ground Zero disaster

Fire in the underground environment has been the source of many hard lessons learnt. Fires in the Eurotunnel railway, in the Mont Blanc and St Gotthard highway tunnels, in metro stations, most devastatingly at the Kings Cross Station of the London Underground on the evening of 18 November 1987, have led to changes in design, construction and operational procedures and legislation. Many new Metro bomb attacks heighten alert – TunnelTalk, March 2010 ITA post congress analysis – TunnelTalk, June 2009 regulations mandated that they be applied retrospectively In search of resilient cities – TunnelTalk, December 2011 to existing underground facilities. The continuing search to Superstorm devastates New York region – TunnelTalk, October 2012 improve the fire­life safety of underground infrastructure is Evacuating along elevated platforms – TunnelTalk, May 2018 the focus of the ITACOSUF Committee on Operational Solutions for safer public transport – TunnelTalk, September 2016 Safety of Underground Facilities of the ITA. There is now the added growing recurrence of natural environmental flooding events that are being attributed to the effects of global climate change. While the underground is a natural refuge during an earthquake, with underground infrastructure suffering little or no damage amid devastation on the surface, few in the industry can fail to have been alarmed at the harrowing images of recent major storm events flooding the metro systems in Zhengzhou, China; London (although not into the underground structures); and in New York.

Superstorm Sandy provided an earlier warning to New York and New Jersey in November 2012 when subsurface road, rail and subway infrastructure was inundated.

The metro system in Zhengzhou is about 10 years old and resilience against extreme flooding events must have been low on the operating risk register. It cannot be for any metro or underground road or rail projects for the future. Retrofitting defence systems to increase resilience against potential flooding events will be expensive.

The behaviour of humans in the event of an emergency in an underground environment must also be at included in reviewing the design for operation of existing and future underground infrastructure. Panic is the natural response to anything out of the ordinary and as professionals engaged in the underground industry we know well the realities and risks of being in the underground environment. We are a tuned to it but must remember that it is an unfamiliar space for new recruits, visitors and the public as the end users. All these concerns are brought to mind in remembering that day of terror and destruction in Manhattan in September 2001.

TunnelTalk References Inflatable protection against inundation – TunnelTalk, December 2012 Probability of road trauma in NorthConnex highway – TunnelTalk, September 2020 Fire fighting system unveiled by Eurotunnel – TunnelTalk, February 2011 Exit spacing influence on ventilation choices – TunnelTalk May 2012 Sprinkler limitations for tunnel fire fighting – TunnelTalk, September 2011 Effectiveness of sprinklers for fire suppression – TunnelTalk, August 2017 Mandating highway tunnel inspections – TunnelTalk, December 2008 Find further research articles on our fully searchable Archive

From Left: Recent metro flooding in China and New York Below: Passenger flow through Piccadilly Circus, London