Design and development In July 2000, Canary Wharf Group formally announced the development of the Heron Quays site, on the southern boundary of the Canary Wharf estate. This would involve the construction of five buildings providing a total of of Grade A office space. During the development phase, the five buildings were designated HQ1 to HQ5, with 25 Bank Street designated as HQ2. 25 Bank Street, along with its neighbours HQ3 (
40 Bank Street) and HQ4 (50 Bank Street) were all designed by César Pelli in the
International style, featuring complementary external cladding of stainless steel, glass and stone.
Adamson Associates Architects served as the shell and core architect. 25 Bank Street and 40 Bank Street, which are of equal height, are conjoined by the West Winter Garden glass enclosed concourse and all provide enclosed access to an underground retail mall. The building is designed around a central concrete core containing elevators, washrooms and services; this is surrounded by office floors with stainless steel and glass curtain walls. There are 5 basement levels, a ground floor, mezzanine, and a further 32 levels numbered 1 to 33. There is no 13th floor. The lower levels, up to level 8, incorporate large podium areas on the south and west sides. This allows large trading floors to be accommodated, each with a floorplate. The south podium incorporates a secondary core. In July 2000 Enron Europe opened negotiations with Canary Wharf Group to take 130,060 sq m (1.4 m sq ft) of space on the Canary Wharf estate. The HQ1 and HQ2 sites were earmarked for use by Enron in a mixed use development that would include a mini-power station. This development was planned to supplement Enron's Victoria headquarters at 40 Grosvenor Place. The negotiations were discontinued early in 2001, prior to Enron's insolvency later that year.
Construction The construction of 25 Bank Street was undertaken by Canary Wharf Contractors, with an overall build time of 32 months. The geography of the site presented considerable access challenges in that it was surrounded by water on three sides, with two thirds of the fourth side in the former dock. A
coffer dam was constructed in the dock to enable the water to be pumped out and a road was built on top of the dam, with earth ramps to enable construction traffic to reach the construction site. River traffic was extensively used to minimise road deliveries; consignments of aggregates and structural steel were delivered by barge and a concrete batching plant was constructed on a barge anchored in the dock. At the end of the project the coffer dam was removed and the fill loaded onto barges for removal. The construction of the rectangular concrete core was subcontracted to Byrne Bros (Formwork) Ltd, who used the PERI ACS self climbing formwork system. This was the first time this system had been used in the UK. By using the
jumpform system, the subcontractor was able to use additional work platforms situated below the main work platform, so that multiple phases of work could be undertaken concurrently. The West Podium of 25 Bank Street is situated at a height of above a length of the
Docklands Light Railway (DLR), including Heron Quays station. To protect the DLR, which continued to operate throughout construction, a concrete slab was installed above the railway that formed the base of the West Podium. This would support the upper floors and also act as an assembly deck during construction operations. The five levels of the West Podium are suspended from transfer trusses at the higher levels. The building was topped out on 8 November 2002. George Iacobescu, Canary Wharf Group Chief Executive, and Jeremy Isaacs, chief executive of Lehman Brothers for Europe and Asia, both signed the final steel girder before it was hoisted into place. At that time, 25 Bank Street was London's 6th tallest skyscraper. Elevators engineering was undertaken by Lerch, Bates & Associates, Inc. A specialist lighting arrangement was installed to illuminate the crown of the building. This was designed by LightMatters and involved a total of 5,472 LED fixtures installed between the inner wall and the outer glass shell of the building's 32nd level. ==Occupancy==