Civils Project of the Year 2023

Cardiff Central Square - Knights Brown Construction, Cardiff Council, Arup, Welsh Government, Greenblue, Ryan Landscapes


Category sponsored by Hugh James

As part of its broader strategy to enhance sustainable transport infrastructure, Cardiff Council issued a tender for a scheme designed to encourage modal shift from private vehicles to sustainable transport. The scheme was subject to the latest SAB Schedule 3 Legislation and aligns with the Adopted Local Development Plan 2006-2026's objectives for sustainable travel. By facilitating the use of more sustainable modes of transportation, the scheme aims to reduce carbon emissions and support the development of key areas in the city centre. It also aims to contribute to improving air quality and ensuring compliance with relevant national and local regulations governing air pollution.

The primary objective of the project was to accommodate the new Cardiff City Centre transport interchange and Central Square development. To achieve this, through-traffic was removed from Westgate Street by the introduction of a new bus gate. Furthermore, a new highway layout was implemented, improving connectivity between the existing bus network and the newly developed transport interchange, Central Square, Central Station, and the city centre enterprise zone. The project involved the reconstruction of almost 1km of new carriageway in the city centre, along with over 6,500m2 of granite footpath paving. Pedestrian safety has been significantly improved through the implementation of wider footpaths, upgraded pedestrian crossing facilities, and a reduced speed limit of 20mph. As a result, there has been an overall enhancement of the public realm in and around the Central Square development and outside the Principality Stadium. Additionally, the project included the provision of more than 500m of segregated cycle infrastructure, linking the area to the proposed cycleway on Castle Street and Taff Trail routes. The designated cycle routes have been designed to ensure the safety of all road users, including the installation of new cycleway signals. Notably, the UK's first cycleway pedestrian crossing was installed to enable safe crossing of the cycleway by individuals who are blind or partially sighted.

The revised highway alignment necessitated the installation of a new drainage system, which included a large surface water sewer with an outfall to the River Taff. Additionally, several SuDS systems were implemented, comprising of multiple innovative retrofitted tree pits and rain gardens. These systems were designed to alleviate surface water flooding, improve water quality, and enhance the environmental amenity and biodiversity value.

Undertaking projects in the city centre can be particularly challenging, given the high numbers of vehicles and pedestrians, the high-profile nature of the work, and the involvement of multiple stakeholders. The project neighboured major business and organisations including the BBC, Cardiff University, Media Wales, HMRC and numerous other businesses. Ensuring effective communication and collaboration with these key stakeholders was critical to the successful completion of the project.