Design and install two replacement flagpoles

Harrisons recently completed another project on a significant historical monument, Pembroke Castle – a Grade 1-listed Medieval Castle in Pembrokeshire, Wales.

Our clients had requested two replacement flagpoles for the towers on the Great Gate House. The top of the towers are completed with the traditional medieval battlements. The original flagpoles had been positioned in the centre of each tower, then secured at the base into an elevated plinth and to the internal sides of the battlement via four stay wires. Due to the height and position of the crenellations it was not possible to lower the poles from the base. Lowering the poles is necessary for flagpole servicing.

Harrisons had to identify and design a means to safely raise and lower the two poles for service and maintenance through the crenellations. Specifically, each pole is required to be lowered to the horizontal and accessed by the maintenance team.

Our design and engineering team created a steel pillar for both flagpoles, secured into the existing plinth. The design was complete with a detachable winch arm and mechanism. The plinth elevated the hinging point of the pole above the base of the crenellation. The winch mechanism offers a safe and controlled means of raising and lowering the flagpole.

The new flagpoles were also completed with replacement detachable guy wires and collars. This offers additional structural support due to their exposed location.

As with all special projects, the initial concept design was discussed and reviewed with the client. Upon confirmation of the concept design we completed a series of engineering calculations to ensure the suitability of the design. These included wind calculations and FEA modelling where necessary. We then commenced in-house fabrication of the steelwork and manufacture of the two flagpoles.