A 90-tonne vessel travelling from Jubail to an inland plant looks like a transport problem. It is really a planning problem that ends with a transport job. By the time the trailer is loaded, every meaningful decision has already been made.
The route survey
Someone physically drives the route. Not a map review. A drive, with a measuring wheel and a camera. We record bridge clearances, road widths, turning radii, roundabout geometry, overhead power lines, surface conditions and the load capacity of every structure the convoy must cross.
Surveys occasionally return the answer nobody wants: this piece cannot travel this way at this size. Finding that out during planning is inconvenient. Finding it out at two in the morning with a police escort waiting is considerably worse.
Equipment selection
Axle load calculations determine the trailer configuration. Spreading weight across more axle lines reduces the load imposed on each bridge, which sometimes turns an impossible route into a viable one. Hydraulic modular trailers can be built up to match the piece rather than the piece being forced onto a fixed trailer.
Permits and escorts
Abnormal load permits are issued against specific dimensions, weights, routes and travel windows. Many movements are restricted to night hours. Police escorts and pilot vehicles are arranged around those windows, and each authority along the route may impose its own conditions.
The method statement
Before anything moves, a written method statement sets out the lifting plan, lashing arrangement, convoy composition, communication protocol and contingency actions. Everyone involved works from the same document, which is the point.
A well-planned heavy lift is uneventful. If it becomes interesting, something was missed during planning.
