Zero Percent Finance

By using our site you accept the terms of our cookie policy

BSI Kitemark

Riverside Drive Bridge Underpass, Aberdeen



  • Appointed as principal project contractor

  • 4m high x 5m wide double leaf steel Manual Flood Gate to protect homes & businesses adjacent to bridge underpass

  • Completed on time and within budget

This project saw UK Flood Barriers secure its first ever appointment as a principal project contractor. The team undertook the survey, design, manufacture, civils/drainage construction, installation and final project handover of a double leaf, steel Manual Flood Gate to protect properties adjacent to a bridge underpass in Aberdeen. Previously, water from the swollen River Dee has flooded through the underpass, flooding local businesses and residential properties.

Initial Contact

Aberdeen City Council (Structures, Flooding and Coastal Engineering Department) contacted UK Flood Barriers in June 2016 for some initial feasibility advice on a flood defence solution to protect the bridge underpass.

After full consideration, UKFB Engineers confirmed a flood defence project was entirely feasible, however given the nature of the environment; a completely bespoke flood gate design would be required.

Initial concept drawings, including a 3D visual, were produced for a double leaf, mitred swing hinge steel Manual Flood Gate.

Riverside Drive Underpass Aberdeen

Underpass before work began

In line with the client’s project specification, UKFB confirmed it could deliver the full design and build package, acting as principal contractor and completing all structural and civils design in house.

Following the client’s tender evaluation process UKFB was awarded the contract. Work began on-site in June 2017, and was completed on 14th September 2017.


As well as an initial site survey, a category B service survey, a site measurement survey and a surrounding area survey was also undertaken. SUMO and Betts Ecology also undertook an eco-systems survey to check that no wildlife or eco systems were in danger during site works.

Designing the gate

When designing the gate, which measures 4m high by 5m wide, there were several things for the UKFB Design & Build team to take into consideration. The gate needed to be held open at 120 degrees, so the space between the gate leaf and the wing of the bridge is wide enough to not cause entrapment of a person. Bespoke posts were designed to secure the gates open at this angle.


Post to secure gate in open position

In addition, to fulfil the client’s requirement to enable full closure of the underpass, sealing was incorporated at the head of the gate, to provide full height protection. A bespoke, removable channel also was designed which allows for seals to be removed and replaced as and when necessary without the need to remove the gate from its hinges

Throughout the design development process, there were regular face to face design meetings so that both the UKFB team and the council team could consider and review all construction drawings.

The Manual Flood Gate designed by UKFB was manufactured by a Worcestershire steel specialist, with manufacture taking 10 weeks. The gate was finished in bottle green anti-corrosive paint (RAL colour 6007), as specified by Aberdeen Council.

Civils Work

To ensure the location where the flood gates were to be installed was structurally sound, appropriate civils works were undertaken by an experienced on site team. 

All finished surface levels were completed to allow water to run off towards the river away from the gate. A soakaway allows excess water to drain naturally into the ground and stop any ponding under the bridge.

To remove any run off water and to cover any small leakage rate through the gate, a drainage channel was installed and connected to two sump & pump units to discharge any water back onto the river side of the gate.


To house a power supply connector for the sump & pumps generator, a bespoke connection cabinet was made and installed at a safe level on  the bridge top. In order to maintain the integrity of finished surfaces, the core surfacing between the underpass and the nearby cycle path was reinstated.


Bespoke connection cabinet

Challenges of the project

Working in such a demanding environment with a busy road running above the site presented a number of challenges.

Due to the location of the bridge, site lifting would be difficult. To overcome this, UKFB appointed a highly experienced transport company, Vic Haines, that UKFB have worked with previously. Using swivel lifting eyes and an experienced site team, all lifting was carried out effectively with great precision.

During initial site excavation, old drainage pipes were uncovered near the Flood Gate. These were investigated further to ensure there was no connectivity to the protected side of the gate.

UKFB’s experienced site team was in regular communication with the design team to ensure no snags occurred on site. Any changes or modifications throughout the process were coordinated with the on-site team, to ensure successful delivery of the project.

Health & Safety

 In its role as principal contractor, UKFB took on full responsibility for co-ordinating the safety management of the construction activities and sub-contractors as required by the CDM Regulations 2015.  


Upon completion of installation, the gates were water tested up to 600mm using the council’s water bowsers. Pumps were also tested to ensure that the pipe work pumped water efficiently.

A training session was carried out with the client’s workforce to demonstrate how to operate the gate effectively in both open and closed positions. They were also fully briefed on the gate testing process and how to make regular maintenance check-ups on site.


This project, represented UKFB’s first ever attempt to deliver a fully protected, closed off bridge/ pedestrian underpass. Our specialist team had the necessary experience and knowledge to deliver on time and within budget to the clients’ satisfaction.

As principal contractor, UKFB utilised and managed several support contractors on this project. They included; JR Donald (tarmac), Leiths Group (concrete), Reilly Concrete Pumping Ltd (concrete pump), Garic (welfare and fencing), Ramsey & Chalmers (reinforced concrete), Vic Haines (lifting and transport) and Barnsley Marshall (engineering calculations stamps).

The end to end on site delivery process was recorded using a time-lapse camera to ensure this unique flood defence installation was visually documented – watch the video here: 

Photo Gallery

Click through the gallery of photos here:

Riverside Drive Underpass Aberdeen

Finished Gates in open position


Finished Gates in closed position


Finished Gates in closed position - view from the underpass

iso 14001

ISO 14001:2015

ISO 9001

ISO 9001:2008

bsi kitemark

Kitemark Certified Survey & Installation

chas accredited

Chas Accredited

Guarantee Protection through GGFI

Guarantee Protection through GGFI


UK Register of
Pre-qualified construction services

UK Flood Partnership
Business In The Community