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| Climbing without crane in Lagos, Nigeria  A new, prestigious administrative building is currently being realised for the Nigerian Central Bank in the financial district of Lagos. For the construction of the 100-metre tall high-rise structure, the formwork units are hydraulically climbed with the help of PERI RCS self-climbing technology then, for reasons of space, only three cranes are available. Following on from the rapid pace of work, the building shell facade is scaffolded with PERI UP. Formwork and scaffolding from a single source, professional training for the construction site team by PERI as well as excellent cooperation between all construction management members provides a solid basis for safe and fast construction progress.With over 150 million inhabitants, Nigeria is the most populous country on the African continent and ranks among those countries with the richest deposits of oil and gas. Lagos is the largest city in country and is situated on the Atlantic coast; with its 14 million inhabitants, it is one of the mega-cities in Africa and the world alongside Cairo and Kinshasa, and is currently experiencing continued rapid growth in all areas. Furthermore, Lagos aims to become the new financial centre in Africa. The Central Bank of Nigeria (CBN), the most important financial institution in the country, is currently having a new, 100 m tall administration building constructed on Lagos Island in the heart of the financial district. The 21storey structure will provide the very latest workplaces for around 2,000 bank employees. Above this are three circular-shaped executive floors complete with a helicopter landing pad on the roof. A facade consisting of aluminium, glass and natural stone gives the complex an individual and distinctive face. The complicated foundations and – due to the very close proximity to the neighbouring buildings – the extremely cramped site conditions placed tremendous demands on building contractor Julius Berger Nigeria. These challenges were already taken into account during the planning phase which led the Wiesbadenbased formwork engineers of Bilfinger Berger Nigeria GmbH to decide in favour of the PERI selfclimbing technology and scaffolding solution. Together with the PERI planning team from Frankfurt and Weissenhorn, a concept was developed that took into consideration all individual project requirements. On the tightly-spaced construction site, only three cranes are available for the shell and finishing work. Therefore, the formwork engineers combined the VARIO GT 24 girder wall formwork with the RCS climbing system to create projectspecific climbing formwork units for realizing the centrallypositioned main core. These are rail-guided and can be moved with the use of a crane by means of mobile RCS self-climbing aggregates. On-site requirement of only a few selfclimbing devices and hydraulic aggregates reduces the costs incurred here for crane-independent climbing. The RCS climbing formwork, complete with working platform as well as two finishing and one concreting platform, have been designed for a standard storey height of 4.20 m. The PERI concept takes into account in particular the changing ground plans with tapered wall thickness from 55 cm to 30 cm along with bracket cantilevers in connection with the wall returns. For ensuring efficient construction of the narrow shaft dimensions with clear widths, in part, of only 2.50 m, the VARIO elements climb all four walls on only one RCS platform up to the next floor. Furthermore, the PERI specialists dimensioned the climbing formwork units so that they can be used almost unchanged over the complete height of the building in spite of the geometrical changes in the structure and without any additional assembly costs. Three additional stairwell cores positioned at the corners of the building are climbed on the basis of the CB climbing scaffold system with crane support. Core and stairwell formwork are climbed three to four cycles in advance. For the safe execution of the stonework on the building facade, the facade scaffolding is mounted parallel to the structural work. The PERI UP Rosett Flex modular scaffold has been optimally adapted here to perfectly suit to the complex geometry of the building. The scaffolding planning was created with the help of PERI CAD software and took into account the varying ground plans featuring numerous projections and recesses as well as the three crane towers with corresponding fixing struts. Planning work and verification for the scaffolding static took place here hand-in-hand. As a result, planning reliability and optimum material utilization could be achieved especially for those scaffold sections reaching up to 100 m in height. 2.50 m long scaffolding bays with 1.00 m working widths serve as the standard bay lengths. Required length, width and height adjustments are carried out in 25 or 50 cm increments. As the steel decks also have a width of 25 cm, an extremely flexible system scaffold is available – with adaptation possibilities which are usually only found in tube and coupler scaffolding. In addition, working safety levels are increased because the integrated lock against lifting ensures that the decking remains securely in place immediately after being installed and the platforms are completely covered without any dangerous gaps. The flexibility of the modular scaffold system simplifies geometrical adjustments: unforeseen specific local circumstances can comfortably be dealt with at any time with PERI UP Rosett Flex due to the metric grid dimensions – in the system itself and therefore without any negative safetyrelated effects. Furthermore, PERI UP is used on the site extremely versatile as reinforcement scaffolding and stair tower. write your comments about the article :: © 2012 Construction News :: home page |