Looking Back on Innovation

The Compression Truss Strengthening to carry the extended roof at the Queen Elizabeth Olympic Park Stadium is a prime example of the specialist access achievements of PHD.

PHD delivered a highly innovative access solution, ‘Workshops in the Sky’, which at the time became one of the UK’s most iconic access structures.

The Olympic Stadium was originally designed for Athletics, not having foreseen its post-Olympic Games dual purpose additional role as the venue for West Ham United FC. This required the roof to be extended by strengthening the perimeter truss and in so doing created a major engineering challenge.

The strengthening of the 840m perimeter truss included inspection, blasting, welding and painting processes, and increased the structure’s weight from 1400 tonnes to 4,130 tonnes, making the finish product, the largest cantilevered roof of its type.

The scaffold delivery challenge being significant, this was due primarily to limited imposed loads that could be applied onto the truss along with limited permissible leg loadings onto the terraces. This was also further challenged by the restricted time frame, as the Major of London had announced that some of the 2015 Rugby World Cup games were to be held at the stadium This reduced the deadline by 25 weeks for completion and required PHD to accelerate the scaffold programme by 12 weeks to achieve the opening match.

The limiting factors of traditional scaffolding ‘bottom-up’ tube and fitting approach, would require between 200-230 scaffolders working 24/7; this was not a viable option.

PHD produced a bespoke, radical ‘top-down slung’ solution born out of the methods harking back to the days of the Cinema and the proscenium arch. In addition, by utilising lightweight components PHD reduced the weight of the scaffold by 67% compared to conventional tube & fitting scaffold satisfying the loadings issue.

PHD suspended the scaffold at a height of 37m high from chains and crane strops encased in fire retardant sleeves tied off with lockable grab-hooks and shortening Clutches thus levelled the suspended platforms. The work was achieved safely with a mix of abseils access (to get the initial fixings) MEWPs, and experienced advanced scaffolders familiar with suspended access.

Even more importantly, PHD’s radical methodology of using chains to hang the supporting beams dramatically reduced the safety risks by obviating the need to use over 250,000 loose scaffold fittings, which in-turn created a safer working environment for all operatives working beneath.

Over 480 tonnes of lightweight systems was used in the erection of the “Scaffolding Pods” which provided contractors an enclosed fabricating shop work environment, allowing the strengthening works vital to the trusses to be carried out regardless of external weather conditions. PHD erected and dismantled the scaffold all within 4 months on time as per to schedule.

To date, ‘Workshops in the Sky’ is one of PHD’s featured projects showcasing our renowned experience of simplifying complex access requirements utilising bespoke solutions.