Syntegrity – Structural and civil design consultants in India since 1999
How is a foot over bridge designed in Mumbai, from survey to opening?
A foot over bridge (FOB) in Mumbai is designed in six stages: deciding where people actually need to cross, surveying the site and its utilities, fixing the layout and getting it approved, choosing the structural system, completing the detailed design and drawings, and supporting the contractor until the bridge opens. Most of the difficulty is not the span itself but fitting stairs, lifts and foundations into crowded footpaths, keeping traffic, trains or metro services running during erection, and satisfying several authorities at once.
1. Where do people need to cross?
A FOB is only useful if pedestrians choose it over crossing at grade. The design starts with the destinations it must join (a metro or railway station, a bus stop, a skywalk, a residential area across a highway or nalla), the expected footfall at peak hours, and where landings can physically fit. Landing positions decide the length of the bridge, the number of staircases and whether lifts or escalators are needed.
2. What is surveyed before design?
- Topographic survey of the crossing, road or track levels, and the landing areas.
- Utility survey: water mains, sewers, storm-water drains, power and telecom cables. In Mumbai these often decide where a foundation can go.
- Geotechnical investigation: boreholes to choose between open and pile foundations.
- Clearances required over the road, railway, metro corridor or waterway being crossed.
3. Layout and approvals
The General Arrangement Drawing (GAD) fixes the alignment, spans, levels, clearances, staircases and lifts. It is reviewed by the owner (for example BMC, MMRDA or a metro or railway authority) and by every agency whose land or service the bridge touches: the traffic police for road crossings, the railway for crossings over tracks, and the metro operator where the bridge connects to a station. Settling the GAD early avoids redesign later.
4. Steel or concrete?
Most urban FOBs in Mumbai use steel superstructures (trusses or plate/box girders) on RCC piers. Steel spans can be fabricated off site and lifted into place in short night-time blocks, which matters when the bridge crosses a highway, a railway or a live metro corridor. Concrete is used for piers, foundations and sometimes staircases. The choice depends on span, erection access, maintenance and the owner’s preference.
5. Detailed design: what is checked
- Loads: pedestrian crowd loading, self-weight, roofing and finishes, wind, temperature and earthquake, following the applicable Indian codes (IRC and IS).
- Vibration: footbridges must be checked so that walking crowds do not make the deck feel lively.
- Piers and foundations, including protection of piers next to traffic.
- Erection stages: the structure must be safe while it is being lifted and before it is complete.
- Accessibility and finishes: stair and ramp geometry, lifts, handrails, roofing, lighting and drainage.
The output is a set of calculations and construction drawings. On public projects these are often reviewed by an independent proof checker before construction.
6. Construction support
During construction the designer answers site queries, reviews the contractor’s fabrication and erection proposals, and adapts details when underground utilities or site conditions differ from the survey. This stage is where many FOB schedules are won or lost.
Examples from Syntegrity’s work
- FOB at JVLR for Mumbai Metro Line 6 (MMRDA, approx. 175 m): detailed design and construction support; under construction.
- FOB connecting Airport T2 to Metro Line 3 and Line 7A (MMRDA): detailed design and construction support; completed 2024.
- FOB for T2 connectivity at CSMIA (MMRCL): detailed design and construction support; completed 2024.
- Three railway FOBs at Bhuj station (Western Railway): detailed design; completed 2023.
- FOB across the nallah at Shankar Lane, Kandivali (BMC): detailed design and construction support; completed 2020.
See all our bridge and FOB projects.
Frequently asked questions
Who approves a foot over bridge in Mumbai? The owning authority (usually BMC, MMRDA, MMRCL or the railway), plus each agency whose road, track or station the bridge touches, such as the traffic police or the railway.
Why are most Mumbai FOBs made of steel? Steel spans can be made in a workshop and lifted into place in short night blocks, so roads, trains and metro services keep running.
Does a FOB need lifts? Where a FOB serves a station or heavy footfall, owners increasingly ask for lifts or escalators so that elderly and disabled people can use it. The decision is made at the layout stage because it changes the landings and foundations.
Planning a foot over bridge?
Syntegrity Consulting has designed foot over bridges for BMC, MMRDA, MMRCL and Western Railway. Email info@syntegrity.co.in with the location and the crossing you need.