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Sharing It Around

Crossrail Central has been helping ground investigation contractors share best safety practice on the £15.9bn mega-project.

Ground investigation contractors on London’s £15.9bn Crossrail project are implementing new safety measures as a result of reviews led by delivery partner Crossrail Central.

The joint venture, comprising Bechtel, Halcrow and Systra, won the £400M contract to project manage the central London section of the rail link in April 2009 and since then has had responsibility for ground investigation.

Following its appointment it has been working closely with the existing ground investigation contractors Fugro Engineering Services, Soil Mechanics and Vinci Soil Engineering, to ensure that the project is using best health and safety practice from the very start of work.

Ground investigation work for Crossrail first began in 1992, when the original scheme was in the planning stage.

After several years on hold, the project restarted in 2001 and since then more than 15km of boreholes have been drilled by the three firms.

The introduction of Crossrail Central to the project team has presented all parties with a new opportunity to review health and safety procedures and share experiences.

The entire team is driven by the aspiration to achieve zero accidents on the project as part of the Target Zero campaign.

At its core is the belief that every accident is preventable.

“We have revisited methods, behaviour and culture in our quest to identify safer techniques and systems”

To work towards this, a key objective of the project team was to provide access to the bank of knowledge accumulated by the design and management team in the early stages, so that ground investigation contractors reaped the same benefits as the main contractors.

Because ground investigation is undertaken at the early stages of major construction projects, ground investigation contractors are not always exposed to well-established safety campaigns and initiatives developed as the project progresses.

This has meant that the ground investigation industry has often not benefited fully from the knowledge held by experienced clients and project managers.

“The safety culture at Crossrail has refocused Soil Mechanics’ view of safety. We have had an opportunity to communicate more closely with other contractors in the industry and jointly share our understanding of best practice,” explains Soil Mechanics associate director Bob Brewer.

“We have revisited methods, behaviour and culture in our quest to identify safer techniques and systems, which, after validation by field testing, will be employed as best practice,” he says.

The safety challenges faced by Crossrail at ground investigation stage are not markedly different from those faced elsewhere on major projects, but the scale of the scheme and the number of parties involved presents an obvious opportunity to pool resources and ideas, then push for best practice improvements in working methods and behaviours.

This knowledge development and new methods adopted could benefit the whole industry.

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Fugro Engineering Services director, Christian Grundy, recognises the key role that Crossrail Central has played in the effective management of health and safety and agrees that such an approach has wider benefits.

“Support from key clients such as Crossrail is an essential part of our health and safety strategy and we very much appreciate the lead that Crossrail has taken to encourage genuine cooperation and information exchange. This will be of significant benefit to the industry as a whole.”

In practical terms, the teams have recently held a series of safety workshops with the ground investigation contractors and design engineers looking at both behavioural safety and working methods.

These sessions allowed all parties to raise safety issues, share ideas and discuss experiences from working on Crossrail and other projects.

Crossrail Central challenged the current working methods and industry practices in areas collectively identified as requiring improvement, such as working at height on drilling rigs, excavations near buried services and communication of information.

A subsequent safety seminar was then held at which the contractors shared new proposals for best practice focusing on these areas.

The result was that Crossrail incorporated a number of proposals into the Crossrail minimum best practice standards.

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For example working at height on cable percussion rigs and rotary rigs has been common in the industry due to the need to attach pulley blocks for pulling casings, replacing ropes on fly wheels and maintenance and re-fuelling.

Crossrail challenged contractors to eliminate the need to climb the rigs where possible.

Each contractor had safe climbing systems in place but the workshops enabled the firms to pool their operational procedures to develop an agreed best practice approach.

The new methodology includes:

  • Modifications to cable tool rigs, including the introduction of steel pins across the crown wheel and the use of a “whip prevention loop” below the crown wheel to prevent the rope from jumping and therefore eliminating the need for operatives to climb the rigs.
  • Using a second winch on cable percussion rigs (newer rig models) to allow the drill mast to be lowered.
  • Improved initial set up of cable percussion rigs, by attaching the pulley block before raising the rig, to avoid the need to access the top of the rig for pulling casing.
  • Using safe working platforms to access height on all rigs, where available.
  • Modification to rotary rigs adding dedicated access ladders and barriers to allow safe working.

The introduction of a permit to work at height requirement when such activity cannot be avoided and other access methods are impractical.

The permit acts as a hold point to assess whether working at height can be avoided and if not, to ensure everything is in place in accordance with the method statements and rescue plan to ensure safe access, egress and working through the use of harnesses/fall arrest systems.

“Support from key clients such as Crossrail is an essential part of our health and safety strategy and we very much appreciate the lead that Crossrail has taken to encourage genuine cooperation and information exchange.”

The cumulative impact of these improvements has been that the ground investigation contractors have significantly reduced the need to climb rigs.

In other areas changes have been introduced to working procedures for excavations near buried services and to the way in which information is communicated.

For excavations near services the use of permits to dig is a recommendation under the Health & Safety Executive’s HSG47 guidance on avoiding danger from underground services.

But Crossrail has now put in place additional requirements that permits are now to be signed at the start of each shift by streetworks-accredited personnel under the New Roads Street Works Act (NRSWA), and that streetworks-accredited personnel are now required to supervise and excavate inspection pits irrespective of whether they are in a highway.

In terms of improving communications, borehole-specific information packs are now required for each exploratory location.

They contain comprehensive information including location plans, utility drawings, specific risk assessments, work and sampling instructions, traffic management plans, consents and permit forms. 

Using one briefing pack ensures that all the safety critical information is easily accessible for the crews on site.

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During previous phases of the work, some of the information was held at a central site compound and therefore not immediately available to those in the field.

Another minimum standard is a daily briefing to ensure people are aware of hazards or risks on site.

For ground investigation works, an additional borehole specific briefing is now held at each exploratory position before any works start.

This involves talking through the borehole information pack.

These minimum best practice standards have since been implemented as a contractual requirement across all Crossrail ground investigation sites in addition to other Crossrail initiatives.

Early feedback from management and from site level has been positive.

“As a result of Crossrail’s initiatives, I believe there has been, an even sharper focus from us all on keeping everybody safe,” says Digby Harman, regional manager of Vinci Soil Engineering.

Crossrail Central has also established bi-monthly safety forums in which it continues to work closely with contractors to maintain the open dialogue, champion safety initiatives and challenge the working methods in other key areas.

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Looking ahead, Crossrail will be promoting safety improvements implemented by contractors on the project at a number of forthcoming safety events, including the Equipe 3A’s technical seminar “Health & Safety in Geotechnics”.

Crossrail is also organising a joint Crossrail-Transport for London (TfL) safety forum to share best practice and promote Crossrail’s best practice safety standard.

“It is vital that improvements adopted by our contractors and valuable lessons learned are not lost when our ground investigation work is over,” says Crossrail Central ground investigation manager, Chris Goatman.

“We aim to maintain and build upon the safety improvements already adopted and leave a lasting safety legacy that will help future construction projects.”

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