Civil, road & bridge
with the details that matter.
Bridges, tunnels, retaining structures, corridors, and site topography. We pair the capture method to the way your team will use the result.
What needs to be
measured first?
Bridges, tunnels, and corridors need geometry captured without closing a lane any longer than necessary. Scanning produces clearance envelopes, deformation baselines, and existing conditions for rehabilitation design, with aerial work covering approaches and site topography.
Every facility has a different risk surface. We start with access, geometry density, and the decision the capture needs to unlock — then choose between laser scanning, drone mapping, or both.
Talk through a scope- Bridge structures
- Tunnels
- Retaining walls
- Corridor topography
- Culverts
- Clearance surveys
Capturing a structure without owning the road
Bridge and corridor work is measured in minutes of access, not days. Everything about the capture plan — where setups go, what gets captured first, how much can be done from the shoulder — is decided by how long a lane can be closed and who controls the closure.
Deck, joints, and approaches
Riding surface, expansion joints, curb and barrier lines, drainage scuppers, and the approach slabs either side. Deck geometry drives overlay quantities and profile design, and it is the part most likely to be captured under a rolling or short-duration closure.
Superstructure from below
Girders, diaphragms, cross frames, connection plates, and the underside of the deck, plus bearing seats and the bearings themselves. Bearing position and condition geometry are what a rehabilitation design turns on, and they are only visible from underneath.
Substructure and the ground around it
Abutments, wingwalls, piers, pier caps, and the exposed portion of foundations, along with the channel banks or embankment. Anything below the waterline is outside what an optical instrument can reach and has to be handled another way.
Clearance envelope
The full swept volume under the structure — vertical clearance across every lane and at every point along the span, not just at the centreline. Bridges get struck at their low corner, and a single posted clearance figure conceals exactly where that corner is.
Corridor and site from the air
Approach roadway, drainage, right-of-way, adjacent structures, and the topography around the crossing, mapped aerially against surveyed control so the structure and its setting share a coordinate system.
Lane closures, flagging, and working over water
Access on infrastructure work is a permit and traffic control problem before it is a survey problem. Lane closures need a maintenance of traffic plan, agency approval, and usually a night window; rail crossings need track time and a flagger arranged well in advance; and work over water brings its own access equipment and safety requirements. The instrument-time on a bridge is often a small fraction of the total effort, which is why capture plans are written to make each closure count rather than to be efficient in the abstract.
Some structures can be captured with no closure at all. Setups from the shoulder, under the structure, and from adjacent ground cover a surprising amount, and aerial capture handles the deck surface and the corridor without occupying a lane. Where a full closure is unavoidable — typically for bearing seats, joints, and clearance work under traffic — the plan defines exactly what gets captured in that window and in what order, so nothing is being decided while a lane is shut.
More on how this works in practice is on our guide to scanning without a shutdown.
What bridge and corridor projects use
Infrastructure deliverables tend to be narrower than building ones. The question is usually a single measured quantity — a clearance, a profile, a deviation — supported by a dataset someone else can verify.
| The decision | What to ask for | Why that one |
|---|---|---|
| Rehabilitation or widening design | Point cloud plus existing conditions plans and sections | Designers need measurable geometry of a structure whose record drawings predate several repairs. |
| Clearance verification and permit routing | Clearance envelope sections across the full width | The controlling dimension is rarely at the centreline, and only a surface across the deck shows where it is. |
| Deformation or settlement monitoring | A baseline capture with documented control | Comparison over time only works if the first dataset states its control, method, and conditions precisely. |
| Corridor and site design | Aerial surface model, orthomosaic, and contours | Approaches, drainage, and right-of-way are corridor-scale questions rather than structure-scale ones. |
Formats and what each one is good for are covered on the deliverables page.
What catches infrastructure projects out
- Ignoring temperature — A steel bridge moves measurably through a day. Joint gaps open and close, bearings shift, and camber changes with the deck temperature, so any capture intended as a monitoring baseline has to record the conditions it was taken under or it cannot be meaningfully compared with the next one.
- Capturing the deck and calling it the bridge — Everything a rehabilitation actually addresses — bearings, bearing seats, diaphragms, connection details, substructure — is under the deck. A survey from above documents the surface being replaced and none of the structure being repaired.
- No tie to a project datum — Infrastructure design happens on a state plane coordinate system with a defined vertical datum. A capture registered only to itself has to be re-tied before it can be used, which is a survey cost that could have been avoided by agreeing the datum before mobilizing.
- Expecting geometry underwater or underground — Scour zones, submerged footings, and buried utilities are outside what a surface instrument records. Those scopes belong to divers, subsurface locating, and inspection specialists, and their results can be tied into the same control rather than assumed away.
What DOT and bridge engineers ask
Can you capture a bridge without closing a lane?
Frequently, yes. Setups from the shoulder, from underneath, and from adjacent ground cover most of the structure, and an aerial pass handles the deck surface and the approaches. Closures are usually reserved for work that has to happen in a travel lane — clearance sections across the full width, joint detail, and bearing seats where sightlines from the shoulder are blocked.
Can this be used for a load rating?
It supplies measured section geometry, member positions, and current condition geometry that a rating engineer can work from, which is a much better input than assumed dimensions from an old plan set. The rating itself is an engineering determination involving material properties and analysis, and that stays with the engineer performing it.
How do you handle a rail crossing?
On the railroad's terms. Track time, flagging, and clearances around live track are arranged through the railroad well ahead of the date, and the plan assumes the window will be exactly as long as it was granted. Where possible, geometry is captured from outside the railroad's limits so the on-track time is spent only on what genuinely requires it.
Can you produce a monitoring baseline?
Yes, and the value is entirely in the documentation around it. A useful baseline records the control network, the residuals, the instrument setup, the coordinate system, the date, and the ambient conditions, because a later comparison is only as trustworthy as the weakest of those. Without that record, two datasets can differ for reasons that have nothing to do with the structure.
Pair TLS interiors with drone exteriors for one coordinate story.
Roof, yard, tanks, structures, and the building envelope can live in the same project handoff when the control is planned upfront.
See existing conditionsMake the invisible
measurable.
Tell us what is inside, outside, and on the line. We will help you scope the capture and the handoff — in New York, New Jersey, or Connecticut.
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