Bridges.
Structural design for pedestrian bridges, road crossings
and major infrastructure spans.
Spanning obstacles.
Engineered to last a century.
Bridges are among the most technically demanding structures in civil engineering — exposed to dynamic traffic loads, environmental forces and fatigue over decades of continuous use.
IGG provides complete structural engineering for bridges of all types and spans. From small pedestrian footbridges to multi-span road crossings, we handle conceptual structural design, full 3D finite element analysis, deck and substructure design, bearing and expansion joint specification, and complete documentation for permitting and construction — all to Eurocode standards. Bridge design is a core speciality of our team, with particular expertise in steel and composite bridge structures.
Start Your Project- Conceptual structural system selection
- Steel beam & plate girder deck design
- Reinforced & prestressed concrete deck
- Composite steel-concrete deck design
- Abutment & pier substructure design
- Foundation design (spread, pile, caisson)
- Traffic load analysis to EN 1991-2
- Dynamic analysis & fatigue assessment
- Bearing & expansion joint specification
- Inspection & maintenance access design
- Seismic bridge design (EC8-2)
- Permit & construction documentation
Dynamic. Exposed. Permanent.
Bridge engineering demands more.
Traffic Load Models
EN 1991-2 defines complex traffic load models — LM1, LM2, LM3 and LM4 — representing different vehicle configurations and crowd loads. We apply the correct model for each bridge class, including load positioning to produce the governing effects in every structural element.
Fatigue Under Cyclic Loading
Bridges experience millions of load cycles over their design life. Steel connections, welded details and shear connectors are checked for fatigue using damage equivalent loads per EN 1993-1-9, ensuring structural integrity throughout a 100-year service life.
Dynamic Response & Resonance
Pedestrian bridges and slender spans can be susceptible to dynamic excitation from footfall or wind-induced vibration. We calculate natural frequencies, assess resonance risk and — where required — specify damping solutions to maintain comfort and safety.
Substructure & Foundation
Abutments, piers and foundations must resist large horizontal forces from traffic braking, thermal expansion, seismic action and earth pressure. We design the complete substructure system and coordinate geotechnical data directly into the structural model.
Thermal & Creep Effects
Bridge decks expand and contract significantly with temperature change. We design the bearing and expansion joint system to accommodate these movements while correctly modelling thermal restraint forces in continuous and integral bridge decks.
Erection & Construction Sequence
The structural behaviour of a bridge during construction — before composite action is achieved or before continuity is established — can govern member design. We analyse critical erection stages and specify temporary works requirements to ensure safe construction.
What we design.
Pedestrian Bridges
Steel, timber and concrete footbridges — from simple beam spans to architecturally expressive feature structures.
Road Bridges
Single and multi-span road crossings in reinforced concrete, prestressed concrete and composite steel-concrete.
Railway Bridges
Heavy rail and light rail bridges designed to the demanding dynamic and fatigue requirements of rail loading.
Culverts & Underpasses
Box culverts, arch structures and pedestrian underpasses — buried or semi-buried concrete and steel structures.
Have a bridge project?
Send us your brief and we'll scope it within 24 hours.