London's "Cheesegrater" skyscraper completes innovative design and construction process
By Stu Robarts
August 22, 2014
London's skyline appears to reach ever higher to the sky. Earlier this year it was claimed that 230 new towers were being planned in the city. That figure includes the Leadenhall Building, which sits close to the Gherkin and has a tapering profile so as not to impede views of St. Paul's Cathedral.
Designed by Rogers Stirk Harbour + Partners (RSH+P), the tapering profile of the building gave rise to its nickname "The Cheesegrater." It was designed like this to meet requirements for respecting views of St. Paul’s Cathedral from Fleet Street in particular.
RSH+P has worked on a host of major projects in London, including the design of the Lloyd's of London building (opposite which the Leadenhall Building stands), the Billingsgate Market transformation and the Canary Wharf Riverside South development. The firm was also involved in the London As It Could Be Now open ideas contest, that gave rise to the Thames Baths Project.
The Leadenhall Building is another high-profile project for RSH+P. At 736 ft (224 m), it is one of the tallest buildings in London and provides 610,000 sq ft (57,000 sq m) of floor space over 46 floors. Passengers will be ferried between floors by what are claimed to be the fastest panoramic lifts in Europe, traveling at up to 8 m/s (26 ft/s) and traversing 45 floors in 30 seconds.
The building was designed and built to British Land's Sustainability Brief for Developments, a standard that aims to generate positive environmental and social outcomes through responsible design and construction. The Leadenhall Building Development Company (LBDC) claims that the construction of the building contributed £376 million (US$625 million) of Gross Value Added to the UK economy.
A variety of environmental factors were taken into account with the design, construction and running of the building. Offices are protected from direct sunlight by solar-responsive venetian blinds, low-flow water fittings are used throughout the building, and a total of 293 meters have been installed to monitor energy usage. All timber used for the construction was from FSC-certified sustainable sources and the LBDC claims that 97 percent of construction waste was recycled. As a result of these efforts, the building has received a BREEAM excellent sustainability rating.
The construction process for the building was also noteworthy. The construction was planned using a digital 3D version of the building that incorporated detailed information about every component. Using this means of preparation, the building was "virtually" constructed in computer simulations 37 times before being built. Once construction commenced, RFID data tags were used to track components of the building through manufacture, supply and installation.
Using the main contractor Laing O’Rourke’s Design for Manufacturing and Assembly methodology, an estimated 85 percent of the building was constructed outside of London, with the various steel components transported onto site and assembled "like a giant Meccano set." The building required 24 m (79 ft) beams to be transported onto site, which is the longest load that can be transported into the City of London, and required a police escort when on motorways. They were only allowed to enter the city between 1am and 5am. The megaframe of the building was divided into eight sections, each 28 meters (92 ft) high and comprising seven floors. Nearly 3,000 threaded steel rods, or "megabolts," hold the steel parts together.
The Leadenhall building recently reached practical completion, but it will officially open next spring.
The video below, commissioned by RSH+P, shows the first six months of construction of the Leadenhall Building.