Rope and Sling Specialists Ltd. (RSS) has completed load tests on three lifting frames for mechanical handling specialist SCX Group, which has been selected to provide a retractable pitch for Premier League football team Tottenham Hotspur's new stadium on White Hart Lane, London. One of the aforementioned frames will be used there during installation of pitch trays.
The new stadium (the Northumberland Development Project), scheduled for completion later this year in time for the 2018-2019 season, will boast nearly 62,000 seats and includes nine floors. Spurs have agreed a 10-year partnership that will see NFL International Series (American football) matches played at the new stadium.
Integral to the multi-purpose design is a retractable grass field with an artificial surface underneath that will be used for NFL games. SCX Special Projects' concept features rails for the retractable pitch, hidden safely beneath its surface. The real turf pitch will roll into the stadium in three sections; each weighs over 3,000t and is driven by 68 powerful electric motors that will roll it along rails on 168 wheels. These wheels were tested in-house by RSS in 10t increments up to 85t, employing the company's 120t Enerpac hydraulic press, complete with gauge.
The whole pitch, which is split lengthways, can be rolled out in just 25 minutes. Once parked alongside the central section, the side sections will move inwards. When the sections are in position, hydraulic actuators open flaps so the touchline can be raised up to pitch level. Then, tunnel ramps are raised before the flaps are closed and the stadium is ready for action.
RSS, a lifting and rigging equipment supplier, was presented with a scope of work by SCX to test three frames, one of which was to be used for installation of pitch trays at the White Hart Lane construction project and needed to be uprated from 27t to 35t working load limit (WLL). RSS completed two load tests on the frame—one at the new WLL and another with a proof load of 46t.
A 150t capacity mobile crane from PP Engineering; four 35t, 12,000mm wire rope slings; soft eyes for each end; and four 25t alloy bow shackles combined to complete the lifts. Railway sleepers were used to level the load for the tests.
Mick Gill, senior testing engineer, explained that the lifting eyes were at 11,600mm so 12,000mm wires created a 60-degree angle. For the final test the total weight to be lifted, including the 6t frame was 52t.
RSS used the pitch trays and moving assemblies to be employed during retraction as test weights—so the frame was used as intended onsite—to create a uniformly distributed load. There will be 99 of these trays installed by the frame at White Hart Lane. Gill combined with Gary Coleman, site engineer at RSS (both are based at the company's Rotherham depot), to complete the 10-hour project.
Steve Hutin, managing director at RSS, concluded: "Tottenham isn't my team but this is a truly iconic project to be associated with; Mick and Gary should be proud of their involvement. When I'm watching matches on the television at White Hart Lane next season I'll be thinking of the integral role RSS played in keeping the project on track."