The light at the end of the tunnel: managing challenges at Heathrow Express Project

Revision as of 00:56, 14 September 2016

• • • WIP***

The Heathrow Express Tunnel Project was intended as a way to connect Heathrow airport with Paddington station in central London. The project, managed and bided by the British Airport Authority (BAA), was to be constructed by Balfour Beaty (BB), a major and well-known construction firm. As part of the design, BB wanted to introduce the use of a construction technique named New Austrian Tunneling Method (NATM) for the first time in the UK. Consequently, they recruited the services of the technique’s Austrian expert firm Geoconsult. The project was planned to start in 1994.

The project management faced a multitude of difficulties from the start. Among them were a restrictive economic environment, a rigid and complex organization and technical problems with the implementation of a poorly understood technology (NATM). Several decisions taken directly as a result of this scenario jeopardized the entire project and led to the tunnel collapse occurred in the night of October 21st, 1994.

The jointly project management confronted the emergency introducing organizational changes to overcome the disastrous situation; under a new structure, the team gradually repaired the tunnel and finished the project. The namely “Solution team” developed a 12-month plan which included a conservative-approach solution with the construction of a cofferdam (at the time, the greatest ever constructed in Britain). They also recommended continue using NATAM technique for the tunnel construction, after an investigation carried out by the Health and Safety Executive (HSE) certified the safety of the method.^[1]

Ultimately, the plan succeeded, and the delay was reduced from 12 to only 6 months, and the project-works were concluded in 1998. Subsequently, an HSE investigation on both BB and Geoconsult led to their indictment and prosecution. They were charged with £1,3 million and £600.000 respectively. The case refaced the way to approach construction projects in Britain, including additional requirements and standards for NATM’s tunnel-projects.^[2]

Context

Project description

The Heathrow Central Terminal Area (CTA) and Terminal 4 stations of Heathrow airport required an efficient way to communicate them to Paddington Station in Central London. The airport’s owner, then a public company named British Airport Authority (BAA), adjudicated the project to the lowest bid (around £60 million) made by Balfour Beaty (BB) under the design proposed by the British building contractor Mott MacDonald. They were required to construct the 8.8 km tunnel and decided to propose the adoption of a technique that had been in use for similar projects, called New Austrian Tunneling Method. The method was seen as a technological solution to cape with the financial restrictions imposed by the budget.

New Austrian Tunneling Method

The New Austrian Tunneling Method (NATM) was developed by Profr. L. von Rabcewicz in a series of articles published in 1964 and 1965. The technique proposed ways to stabilize tunnels under construction using strata and a layer of concrete sprayed. This is why the technique is also named “shotcrete” or “sprayed concrete”. It was first used in the construction of Frankfurt Metro in 1968. The Austrian Society of Engineers and Architects define it as “a method where the surrounding rock or soil formations are integrated into an overall ring-like support structure”^[1]. The method was tested for its viability in the clay soil at Heathrow in 1992, confirming the possibility of being used. The method was subsequently used in several metro lines, but its first extensive use in a work managed by a UK firm was in the Heathrow Express.

Contract and Organization

Figure 1. Organizational chart appointed for the project administration^[2]

Balfour Beatty (BB) chose to use the New Engineering Contract (NEC), a new set of contract standards at the time; its first version was released in 1993. The aim of NEC is facilitate the management of the work using plain and simple language to describe the activities that each party must carry out, while enhancing the collaboration across the project stakeholders^[3].

BAA set a project management team in line with the NEC requirements: the HEX management team included representatives from BAA, BB, Mott MacDonald and Taylor Woodrow (a British construction company that would function as construction manager). Figure 1 shows the organizational chart of the project, including the role of the Austrian firm Geoconsult, which was not included in the management and was considered a consultant to the engineering division of BB.

Challenge

Challenge

Challenge

Solution

Implication

Implication

References

1. ↑ ^{1.0 1.1} Health and Safety Executive. Safety of the New Austrian Tunneling Method (NATM) Tunnels. London, UK, 1996. Retrieved 14Mar2016 from HSE Available online version
2. ↑ ^{2.0 2.1} Wallis, S. (1999). Heathrow failures highlight NATM (abuse?) misunderstandings. Tunnel, 3/99, 66–72. Retrieved on 30Mar2016 from Available online version
3. ↑ NEC history, consulted on 13Sep2016