Completing the legacy of the London Olympics

But behind the locked gates, the 500-acre site in Lower Lea Valley, east London, remained a hive of activity with more than 1,000 construction workers on site each day to deliver the Olympic legacy project to convert the sports venues, remove temporary arenas, build a new road network and double the amount of parkland.

Delivered in phases until August 2014, the £292m transformation of the site into the Queen Elizabeth Olympic Park is being led by client the London Legacy Development Corporation (LLDC) together with tier one contractors BAM Nuttall, Balfour Beatty, Skanska and ISG, and former Olympic Games project manager Mace.

The project comprises three distinct elements LLDC has labelled “clear, connect and complete” and involves clearing away temporary venues, connecting up the park by modifying bridges, cycle ways, footways and highways and completing the site’s permanent venues for legacy use. Complex construction challenges have included the removal of two “wings” of spectator seating from Zaha Hadid’s Aquatics Centre, and several large temporary bridges that crossed roads, rivers and railways.

A significant milestone was reached last month when large areas of the North Park were handed over to event organiser Live Nation in preparation for the Wireless and Hard Rock Calling music festivals this summer. Featuring new roads, pathways, parkland and cycle tracks, this area will also include the Copper Box, a conversion of the former Handball Arena, to create London’s third-largest sports and leisure arena with capacity for 7,500 visitors, which is due to open at the end of July.

In many ways, the legacy transformation represents an extension of work done in preparation for the Olympics, explains Colin Naish, executive director of infrastructure at LLDC. “Our overall approach has been driven by getting the Park open as quickly as possible, while completing the work as efficiently, effectively and safely as possible,” says Naish. “We adopted much of our learning from the good work carried out by the Olympic Delivery Authority [ODA], and have embedded the same principles in our management and delivery approach, but scaled it down and made it more appropriate to the work here.”

One year on, during CM’s visit, the overall impression of the Olympic Park is of a work in progress, characterised by vast swathes of open land and pockets of green landscaping, dismantling work and construction activity. The absence of crowds of spectators and the removal of venues such as the Basketball Arena, Water Polo Complex and Hockey Arena give some areas of the Park an air of waiting for something to happen. But this contrasts with zones of bustling construction activity, such as outside the Velodrome, where a BMX course, 1-mile road cycle circuit and 6km mountain bike trail are being created, and along the newly constructed Waterden Road, which creates a new direct Hackney-Stratford route across the Park.

Construction and civils company BAM Nuttall is the largest presence on site, having won two separate contracts to deliver £70m worth of infrastructure in the North Park and South Plaza. Contracts for the transformation of individual venues have been awarded to ISG (Velodrome) and Balfour Beatty (Aquatics Centre); a £150m contract to convert the Olympic Stadium has yet to be awarded.

Taking on one of the largest projects in Europe has required a strict approach to managing communication between all project stakeholders, explains Doug Mills, project manager at BAM Nuttall. “The Games phase of construction, which we were also involved in, demonstrated the importance of interfacing with all third-party stakeholders and clients and we have taken a similar approach into the transformation phase,” says Mills. “It’s also vital on a job of this size to ensure that operatives on the ground are getting the right message from management teams and that management teams learn of any site issues from the guys on the ground.”

Weekly meetings on safety, health, environment and leadership are being held to enable project directors from contractors, project managers and the LLDC to examine progress and trends on sites and discuss how to proactively monitor and manage issues.

Under the “connect” remit, BAM is modifying about 9.5km of the Games-time road network, and reconfiguring 30 Games-time bridges and underpasses to improve public access.

Improving access

The latter has involved the tricky removal of several temporary Games-time bridges, positioned over roads, waterways and railway lines to accommodate the huge crowds moving between venues that are now surplus to requirements. Each of the 15m to 20m-wide temporary bridges was designed to be easily extracted, although in some cases a permanent bridge will connect the Park with the surrounding communities.

“Each temporary bridge is bespoke in design and construction, which required various approaches to removal,” says Mills. “In most cases we stripped off the decks, then lifted pairs of braced beams off, either in tandem or individually, using cranes.”

The largest lift was the concrete central pier weighing 260t, which had to be lifted across the busy North London Line railway, which traverses the inner suburbs of north London. BAM Nuttall negotiated with National Rail to have the line closed one weekend to enable a lift to take place using a 1,200-tonne crane.

Perhaps the most striking sight in the new Park is the Aquatics Centre, whose two flat-sided “wings” of temporary spectator seating have been removed for the first time to fully reveal architect Zaha Hadid’s rounded wing-shaped design.

The temporary stands increased spectator capacity from 2,500 to 7,500 during the Olympics, and their removal will enable the building’s conversion to a public swimming pool, due to open in spring next year.

Removal of structures included various temporary bridges around the Park

Taking down the two huge 172-tonne trusses that formed the spine of each of the seating stands proved particularly tough for contractor Balfour Beatty, due to the tightness of the site next to a canal and the fact that the trusses could not be taken apart until they had been lowered to the ground. Two cranes weighing 800 tonnes and 750 tonnes had to work in tandem to lift and lower each truss. About 3,000 sq m of glazing was installed along the two side elevations to allow natural light into the building’s three swimming pools and reinstate the original design.

Under the “clear” remit, BAM Nuttall has been tasked with removing temporary venues including the Athletes Training Centre at Eton Manor in the north of the Park, the Water Polo Complex, various Games-time security areas and spectator stands and the Basketball Arena.

The Basketball Arena was a complex structure built around a 30m-high steel portal frame, wrapped in 20,000 sq m of lightweight recyclable PVC plastic to create an undulating 3D pattern.

Working at height restrictions meant that the roof’s massive 96m-long main trusses each had to be taken down in one piece and dismantled on the ground. “The specific design of the trusses meant that four crawler cranes had to be used simultaneously to lift each truss to the ground,” says Mills. “Temporary venues aren’t something BAM Nuttall does very often and it was incredibly exciting dismantling the roof.”

The installation of new utilities has not played a major role in the Park’s transformation, as most legacy heating and cooling, gas, electricity, water and telecoms were included in the original masterplan. However, the large amount of landscape reprofiling and removal of Games-time concourse to create green parklands meant taking extra precautions to avoid damage to underground services. Apart from ground scanners and detailed service drawings, BAM Nuttall deployed vacuum excavators designed to suck up granular sub-surface materials without the risk of damage associated with conventional excavators or shovels.

As part of its environmental commitment, LLDC is aiming to reuse or recycle more than 90% of demolition waste on site; to date about 250,000 cum of soil has been reused across the Park, equivalent to 312,500 tonnes of material.

Waste tracking

To help keep track of what waste material is moved where on site, the contractor is utilising the innovative waste transfer management system PODFather from software company Valley Technology. This PDA-based software enables banksmen to scan barcodes on delivery vehicles to record details of their location and cargo and upload the details to the cloud or automatically print out waste transfer notices. “It’s all about lean thinking and lean construction,” says Mills. “If we are having material delivered or if we are excavating material and moving it to another area of site, we can trace where it has gone. The system works in real time so we can track material movements around site from a computer.”

As transformation work continues apace, LLDC already has its eye on future milestones. By the end of the year, the entire North Park should be complete, including a new cafe-hub building, the VeloPark cycle, BMX and mountain bike tracks; a new Hockey and Tennis Centre at Eton Manor; and reinstated football pitches at East Marsh.

By Easter 2014, the entire South Park, including the Aquatics Centre fit-out and landscaping, will be complete apart from the delayed Olympic Stadium conversion, which only recently gained planning permission. This will be converted following the Sainsbury’s Anniversary Games in July from a 80,000-capacity venue into a 60,000-seat stadium with a permanent roof designed for West Ham FC and various events and concerts.

The Olympic flame won’t burn in London for a while, but at least the promised legacy of the 2012 Games is being delivered for London to enjoy.