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

Image 1. A view of the site of the collapse at Heathrow Express tunnel in 1994

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 on the Terminal 4, after an investigation carried out by the Health and Safety Executive (HSE) certified the safety of the method.

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.

This article aims to make an overview of this project, considering its importance over an entire industry that needed to adapt and innovate to stay competitive. The case is a good reference for project practitioners into how a complex and disastrous situation can be overturned and learned from.

Context

Figure 1. Heathrow Express System

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 L. von Rabcewicz, Leopold Müller and Franz Pacher 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”. The method was tested for its viability in the clay soil at Heathrow in 1992, confirming the possibility of being used. The method was being also used in several metro lines including the Jubilee Line Extension Project (JLEP) for the construction of tunnels near Waterloo and London Bridge stations, although in not such an extensive manner as in the Heathrow Express project .

Contract and Organization

Figure 2. Organizational chart of the project

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.

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 2 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.

Challenges

As in every project, several challenges raised before and during the project. Some of them would be directly responsible for the collapse at CTA; henceforth are described the ones considered as most relevant.

Project Budget

Arguably, the main driver point of the activities for this project was the budget cost; it is important to contextualize the project on a moment in time when British economy was stagnated and had suffered a recession (1991-1992). The banks and insurance companies had a risk-averse policy, within a diminishing infrastructure investment environment, made several projects to be postponed. Although BAA had enough resources to allocate for the financing of Heathrow tunnel, the choosing of the lowest bid meant that the contractor looked for all available options to reduce costs and maintain its adjusted markup.

New Engineering Contract specifications

One of the principle challenges the organization faced was the adoption of NATM technology in the context of British construction industry. This industry was characterized as being highly dependent on standards and codes, "with a high number of disputes being settled through litigation". Hence, the introduction of the NEC was important to increase the productivity of the sector.

The NEC describes thoroughly the engaged activities to be carried out by each party, and it does using simple wording. One of the central aspects of the NEC was the so-called “self-certification”, which meant that the contractor was in charge of review the quality and advance of their own work. This aspect was considered essential to reduce the bureaucratic charge of the daily management for the HEX team, which in turn would be free to oversee the project itself.

A second and complimentary NEC aspect that represented a major challenge was the “early warning principle”, which stated that the contractor was obliged to inform immediately to the client of any problems presented on the works. In theory this would be done through several middle management reports that would reach the HEX management group, and finally they would evaluate if was needed to inform the client (BAA). However, the reality was that many of the reports which described several problems documented during the CTA tunnel construction were discarded or mismanaged by either the middle managers or the HEX management group.

Technology transfer

One way of obtain those reductions was the introduction of the NATM technology instead of more traditional tunnel construction techniques. Hence, bringing Geoconsult as consultants and supervisors within the construction site was a key move that also impacted on the project finances. However, is worthy to mention that the original offering by Geoconsult to have deployed 3 full-time engineers trained and experienced on NATM construction was reduced to only one, which was charged with the responsibility of “act as site liaison with Geoconsult's design office in Austria, prepare the NATM working sheets as required, interpret monitoring data, and advise Balfour Beatty accordingly”. Three engineers from BB (with scarcely if any training on NATM use) were to function as the missing QA supervisors to assist Geoconsult’s on-site engineer.

Project Organization

The project organization, as mentioned before, was complex. The Hex management group had to concentrate mostly on the financial aspects while BB, as main contractor, focused on the project daily programmed work and its quality. The stream of information was not carried in the most efficient manner, and even when the documentation demonstrated that although key measures were being recorded, the interpretation and decision process that should have taken into account them was not always in place. Furthermore, a lack of communication between the management and the operations represented a key factor to mismanagement of the data that showed early alarm signs.

Project Quality Review process

Video 1. Geoconsult's history, overview of NATM and the CTA collapse

An intense and tight schedule called for minor mistakes on the work execution to keep within construction timelines. When the responsibility of the quality review was transferred to BB engineering department, quality assurance was put into the “to do” list of an already stressed organization, which did not saw it as a priority activity.

Reworks started to pile up, specially requested by Geoconsult’s field engineer whom raised several concerns about the quality of the workmanship and asked for additional works to ensure the tunnel structural integrity. However, his role inside the project structure left him with almost no decision power and dependent on Geoconsult pressure exertion over BB, something that later would be accounted as “poorly done”. During the prosecution trial, one argument held upon the defendants was that BB managers failed to acknowledge the continuous need of reworks based on the review of the works quality . Some signals on the imminent collapse were documented up to 14 days in advance of the event, according to witness expert Sir Alan Muir Wood. The prosecution showed this mentality using a written communication of the by BB director to the Hex Management team, in which he says: “The primary function of the NATM engineers is not quality control. Quality control is the responsibility of the construction teams. This is in accordance with our self-certification scheme, we repeat we have continuous NATM engineering supervision and we do not have project-wide quality problems as you suggest”. Video 1 renders the point of view of Geoconsult regarding the project and the final verdict of the trial.

Collapse

Figure 3. CTA affected area

The CTA tunnel collapse occurred in the night of October 21st, 1994. The night shift workers that were doing crack repairing around 7 pm started to notice the enlargement of cracks on the walls; they also noticed that they kept growing faster, and even extended to the zones where they have already been repaired; parts of concrete and wire mesh started to fell. The order to evacuate the tunnels came about midnight of October 22nd, and the tunnel collapse started around 1 am. It continued for the next two days, damaging not only the tunnels but also the structures in the surface above them. The Figure 3 illustrates the affected zones and marked where surface craters appeared.

There were no fatal causalities nor injured on the event, which occurred on a very busy part of the airport, but happened in the middle of the night. Nonetheless, when the case was presented to the courts by the prosecution, it was treated as a criminal case due the potential harmful to human lives. In the middle of the media response, the HSE ordered a full investigation and called to stop all other NATM-based constructions until the safety of the technique was properly assessed.

Due the magnitude of the collapse, the insurance company representing the project pressed to settle the responsibilities of each part in court, in the hope to avoid large expenses. Henceforth, the requirements of insurance companies for this type of projects would be hardened, demanding the implementation of management mechanisms to ensure project safety.

An additional problem was the interruption of transport to and from Heathrow airport by the Picaddilly metro line. This was overcome with the creation of the Heathrow Junction railway station, a temporary station that served until the completion of the project on June 1998 .

Solution

Video 2. Footage from the CTA collapse, 24Oct1994

The HEX team had to overcome the difficulties by restructuring the information flow inside the project, the development of a solution to the crisis and implementing a different overview to the quality assurance process. The first was approached by making the HEX team to be in a closer contact with daily work advances by having group meetings with the middle management involved in the construction site. The second was the creation of a task force denominated "Solution team". This entity's main purpose was to generate a feasible, efficient and affordable path to reconstruct the tunnel and retake the project.

The latter aspect changed by the incorporation of external overview over the quality. This was somewhat mandatory, since the involvement of the HSE was increased as part of the investigations on site. With the urgent need of resources came the budget and contract restructure negotation. The controversies around the use of NEC were postponed, while the contract was adjusted to a more traditional version, with a higher involvement of BAA. From the technological point of view, the "solution" team proposed a conservative plan, based primarily on . This approach came as no surprise, since the most important objective was to remediate the problem as fast and save as possible while incurring in the lowest possible cost. The “solution” team offered a 12-month integral plan that addressed not only the construction issues, but reshaped the organization structure, especially the internal communication.

Technological solution

A cofferdam to free the collapsed area in the tunnel was projected; the size of the work made the cofferdam the largest ever constructed in the U.K. up to that moment. Despite the previous problems, and in line with the report of the HSE whom considered that “[p]rovided careful account is taken of all the issues in …[the HSE report]… review, it has proved possible for NATM work to proceed in safety...", the "Solution" team supported the decision to continue with the use of the same technology for the construction of the tunnels at Terminal 4.

Organizational solution

As for the organization, the “solution” team brought a new mentality to the project. The narrative changed to be one focused on the cost-reduction, and was redirected towards one of motivation to finish the project on quality and safety as key drivers. Since any collapse responsibility would be acknowledged by the competent judiciary authority, there was no point in doing a witch hunt. Therefore, the Hex management group promoted a culture of no-blame, which did not mean to overlook responsibilities but rather prevent a division within the project structure. This helped to align all parties into a single goal.

Information flow

The communication strategy was modified too. All decisions were transmitted through formal notifications and the receivers had to confirm that they have been informed. This process could take more time but in turn made increase the worker’s involvement on the projects since they could know exactly what was expected from them. One initiative was to held weekly project advance meetings to review the status with all involved parties.

Decision making process

The decision process was opened to allow the participation of the operation and construction departments to provide their feedback. The approach had two clear intentions: to empower workers and deepen their involvement on the project development, and to increase the early notification of potential issues so they could be adequately addressed. Altogether was combined with a culture of documentation, where all parties became accountable of the inputs and decision taken by the elaboration of a signed minute of the weekly project meetings.

The project advanced under this management at good pace, and the conservative solution worked: the cofferdam helped to clean the collapsed sections of the tunnel. Meanwhile, the HSE had concluded the assessment of the NATM technique safety and issued a series of recommendations for its use; they also concluded that “…[t]he existing statutory provisions, and in particular CDM, provide a comprehensive system for the regulatory control of risk including the assessment of competencies. HSE concludes there is no need for further legislation specifically to address the risks arising from NATM”. The other projects that used the technique restarted in the U.K.. By middle 1996 the works of tunnel refurbishment continued according to the original plan, and the gap started to reduce from a 12-month towards end up in only a 6-month delay from the projected deadline. Finally, the trains started to operate on June 23rd, 1998.

Implication

In the words of Justice Peter Cresswell during the trial: "This was one of the worst civil engineering disasters in the United Kingdom in the last quarter of a century”. And it was so not only by the magnitude of the collapse and the works, but also in the way the project was handled. For an industry of the size and background like the British construction industry, the failure represented an eye opener in several senses:

• The professionalism of the industry was challenged, and key actors of the industry like BB and Mott-MacDonald had to face their reputation impacted for allegations of lack of supervision and poor project management. The adjustment of revised Management practices and the different use of construction contracts would help to overturn such image.

• An overconfidence and difficulty to adapt to business challenges was revealed, including a disregard to understand and adapt technologies. In that sense, is important to review how professional associations such as the Institution of Civil Engineers (ICE) responded to the event. In the case of ICE, they issued he guideline “Sprayed Concrete Linings (NATM) for tunnels in soft ground” (1996), which helped to standardize somewhat the use of NATM technology in the U.K..

• The monetary orientation of the project management damaged the necessary quality assurance and risk assessment that is required in construction works. After the collapse, there was a hardening on the risk management regulation on construction works. An example of this change was the project for the construction of Terminal 5.

• It showed that the HSE supervision was far from the expected. No warnings were issued by inspections carried out at the construction site. During the trial against BB and Geoconsult, the entity also was accused of being partial and biased on their account of facts, and received a small compensation from the total amount of the imposed fines.

• The industry as a whole and the government recognized the need to implement new working standards to maintain Britain as a leader on the construction sector. One of such was the document “Rethinking Construction: The Report of the Construction Task Force” (1998), that provided the outlines for the industry reconfiguration during the early 2000-decade.

In the end, is interesting the ability of the project management to reconvene the work and correct most of the issues that led to the collapse. The main differentiator in this project was not the introduction of a new technology, but the intensive process of Management adaptation to a new reality and the capability of identify the key aspects to be corrected on a large and complex organization. If anything, is a great example of how to convert a tremendous disaster into an industry revolution.

Annotated Bibliography

• * * WIP * * *

From the list of reviewed material to document this article, in the author's opinion, the following 3 are the best sources by far to get a better understanding of this case and it implications. Two of them can be easily accessed through their online versions:

• Health and Safety Executive (1996). Safety of the New Austrian Tunneling Method (NATM) Tunnels. London, U.K. retrieved 14Mar2016 from http://www.hse.gov.uk/pubns/natm.pdf

This assessment contains generalities about Sprayed Concrete Lining (SCL)-NATM method from a technical point of view. It was prepared by the HSE in response to the CTA collapse. It also contains a review of the state of the art of the technique, and provides a history of the evolution and use of method in projects around the world (including a list of similar incidents). Finally, it offers HSE recommendations on the use of the technique. Is a good initial point to understand the technology.

• Wallis, S. (1999). Heathrow failures highlight NATM (abuse?) misunderstandings. Tunnel, 3/99, 66–72. retrieved on 30Mar2016 from http://www.tunneltalk.com/images/laneCoveCollapse/Ref5-Heathrow-failures-highlight-NATM-misunderstandings-Shani-Wallis.pdf.

This online divulgation article offers the journalistic approach to the review of the case. It offers a general overview of the case, based from the chronicle of the prosecution trial against BB and Geoconsult, taking quotes and facts from the people involved in them. The article also offers a contextualization of the case and some of their repercussions. The author considers this the best initial approach to understand the key steps leading to the collapse coming from a specialized but not technical source.

As for the third, this is a confidential article accessible only for academic purposes:

• Aalvik, M., Cruz Contreras, J. J., Guerra, P., Jónsdóttir, S. L., van der Mieden, J., Tange I. & Vinggaard Kjeldsen, C. (2016). Influence of the Heathrow Express tunnel collapse on the British tunneling industry. Article prepared as part of the “Management of Change In Engineering Systems” Course spring 2016, Denmark's Tekniske Universitet (DTU)

This academic article was prepared as part of the course Management of Change In Engineering Systems from Denmark's Tekniske Universitet (DTU). The article takes on the case from the perspective of the management of change and analyzes the decisions taken by the management before, during and after the collapse using two models: Kotter’s integrative model of organizational dynamics; and Cummings & Worley's typology of interventions. The article makes a review of the documents mentioned in this wiki article, and it also report on the interviews held with two members of the project (both started at the project after the collapse). Due the confidential character of the opinions expressed by the interviewees and according to their desires, the article cannot be distributed for publication.

Additional references like...

• The HSE report on the case

• The Terminal 5 project

• ICL guideline to the use of NATM