Скачать или смотреть Tunnel Transit: Navigating a Precast Bridge Girder Through Tight Spaces

The Logistics of Oversized Load Navigation
Transporting bridge girders through confined spaces like tunnels represents one of the most complex challenges in heavy haulage, where engineering precision meets real-world navigation. This process requires solving the fundamental physical problem of moving rigid objects through fixed apertures with virtually no margin for error.

• Transport engineers conduct detailed laser scans of the entire route beforehand, creating precise 3D models that identify every potential clearance issue before the girder ever leaves the fabrication yard
• The specialized multi-axle transport trailer features independent steering systems that allow "crabbing" - moving diagonally - to better align with the tunnel entrance and navigate through the tightest sections
• During the actual transit, spotters walk alongside with laser measuring devices, continuously monitoring clearances that may be as small as 2-3 inches (5-7 cm) on each side
• The transport speed is maintained at a consistent crawl, typically 1-2 mph (1.5-3 km/h), to prevent pendulum effects that could develop with faster movement and cause catastrophic contact
• Some operations employ temporary retractable tunnel lining panels or adjustable suspension systems that can momentarily gain precious inches of clearance at the tightest points

In this slow, deliberate passage through the tunnel, we witness the marriage of monumental construction and minute precision - where a structure weighing hundreds of tons must be guided with the delicacy of threading a needle. This operation embodies the principle that true engineering achievement lies not only in creating massive components, but in the painstaking care taken to deliver them intact through spaces that barely contain them.