Design and install stainless steel flagpoles with flags

We designed and installed two 18.5m stainless steel flagpoles with flags on the Shell Tower as part of a building refurbishment scheme by Overbury plc.

The Shell Centre is one of two central offices of oil major Shell and is a prominent feature on the South Bank of the River Thames in London. Standing at 107 metres tall it was the first London office tower to exceed the height of the Victoria Tower of the Palace of Westminster. On completion the building also held the record for the largest office building, by floor space, in Europe.

The original steel flagpoles on the East and West elevations of the tower had exceeded their service life and were to be replaced as part of a building refurbishment program. The appearance of the replacement flagpoles needed to be as close to the original as possible incorporating as much of the existing structural fixtures where possible. The client’s main requirement was to remove the need for steeplejacks to climb the pole for maintenance and servicing as it was unsafe and expensive.

Removal and recycling

The corroded poles were cut down and removed for recycling. The existing brackets could be saved and reused. They were restored, NDT tested, re-galvanised and power coated. They were now ready to house the new stainless-steel poles, which were selected for their longer life span and lower maintenance requirements over materials such as mild steel.

Design

To negate the need for climbing the poles for maintenance and servicing a unique solution was needed that allowed the poles to be lowered at roof level. Harrison’s design engineers and consultants developed a winch operated cantilever that allowed the poles to pivot onto the roof.  The hinge systems were concealed at roof level, so they could not be seen from the ground and did not spoil the design aesthetic of the sleek poles.

An internal flag mechanism was also added that allowed the flag to be raised and lowered easily.

A full design report was provided with calculations additionally checked by a third party engineering consultancy.

Installation

The poles were manufactured in sections and assembled on site. They were lifted 27 storeys into place using a specially designed lifting system. All works were supported with detailed risk assessments and method statements in line with the end user’s stringent health and safety requirements.