At AWA Structural Engineers, we specialise in bridge design and assessment, where the role of the structural engineer is paramount. Unlike building projects, bridges are rarely designed with the involvement of architects, meaning the responsibility lies with Civil or Structural Engineers to lead the entire process. This is where our extensive experience comes into play – our proven track record ensures that your project is not only structurally sound but also navigates the complex approval process smoothly and efficiently.
The bridge design process is meticulous and strategic and begins with understanding the client’s needs and stakeholder limitations. For every footbridge, access bridge, or accommodation bridge, it is essential to evaluate whether a new bridge is necessary, if an existing one can be assessed or even if an alternative route around can be found. A ground investigation, topographical survey and utility survey will all be required to inform the design. Planning consent and ecology surveys may also be necessary.
Bridges that may be adopted after construction by a local authority (therefore not remaining private) or convey public rights of way, will require early engagement with the local authority to establish their approval process. This usually involves the production of an AIP (Approval in Principle) document, which outlines what you are planning to build and how you will go about designing and constructing it. For bridges over watercourses, railways, or private land, additional approvals from entities like the Environment Agency National Permitting Service, Ordinary Watercourse Consent, Canal & River Trust, Network Rail and Defence Infrastructure Organisation may be required.
The design phase combines hand calculations and computer analysis to develop an optimal structural solution, which is then conveyed through detailed drawings for the contractor. Throughout construction, the designer provides clarification via RFIs (Requests for Information) and updates drawings to reflect any design changes.
In bridge construction, the choice of materials – whether concrete, steel, or timber – is determined by the specific performance requirements and design goals of the bridge. Concrete is commonly used for access bridges due to its strength and durability, while steel and timber are often chosen for footbridges for their aesthetic appeal and flexibility. Key components include bearings, which allow for thermal expansion and contraction, and parapets to protect users.
Assessing existing bridges is crucial to ensure their safety and integrity. This process begins with a visual inspection to evaluate the bridge’s condition and may involve more detailed assessments like load capacity calculations. In the UK, highways document CS 450 mandates periodic inspections to identify deficiencies and plan remedial works. Techniques range from visual surveys to intrusive methods like concrete core sampling and non-intrusive methods like ultrasonic thickness gauging.
At AWA Structural Engineering we have experience in innovative solutions like bespoke precast concrete elements, which enhance product quality and reduce on site programme time. These elements are designed for ease of installation, even in challenging site conditions. For instance, designing ‘stitches’ that tie large sections together on-site with small in-situ concrete joints or proprietary couplers allows for manageable handling and installation.
Sustainability is integral to our bridge design and assessment processes. We prioritise using familiar materials efficiently and maximising design life through clever detailing. This approach ensures minimal disturbance to the environment, especially when building over watercourses. We consider the bridge’s load over its lifespan and how water and soil movement will interact with the structure.
Bridge design and assessment must adhere to stringent regulatory and safety standards outlined in the DMRB (Design Manual for Roads and Bridges) and the MCHW (Manual of Contract Documents for Highway Works). Bridges are designed and detailed according to the Eurocode design suite, which replaced British Standards 15 years ago. Compliance with CDM 2015 (Construction Design and Management regulations) is essential, assigning specific duties to clients, contractors, and designers to ensure risk reduction and effective planning.
Emerging trends in bridge engineering, such as the use of Fibre-Reinforced Polymer (FRP) and the adoption of Eurocodes for both design and assessment, promise exciting advancements. These innovations will likely enhance the durability, efficiency, and sustainability of future bridge projects.
Collaboration with clients is key to meeting their needs and requirements. Our extensive experience in obtaining stakeholder approval helps us navigate the often complex and slow approval process. Unlike building structures, bridge projects are led by Civil or Structural Engineers, making our experience and niche expertise invaluable.
If you have a bridge project that needs our involvement, don’t hesitate to get in touch, you can call us on 01794 524447 or email mail@awaengineers.com
AWA is a structural engineering and civil engineering consultancy established in 1987, with a hard-won but deserved reputation for delivering excellence in our profession.
Our philosophy is simple: we put people first. This has resulted in a high number of repeat clients and an impressive track record of successful award-winning projects. We are proud to be professional, and approachable; we believe this makes us the ideal partner for your project.
AWA has chartered engineers in our offices located in Romsey, Hampshire and Bath, Somerset. We deliver services to clients across the South, South East and South West.
Our team includes both chartered structural engineers and chartered civil engineers committed to continuous professional development ensuring you benefit from up to date industry expertise, whatever your project entails.
To find out more about how AWA can help with your project, get in touch today. Call 01794 524447 (Romsey) or 01225 251498 (Bath) to speak to a member of our team. Alternatively, email mail@awaengineers.com and one of the team will be in touch.
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