A 91 m clear span in a modular steel bridge removes the pier — and with it, river-bed works, seasonal windows and the largest part of the civil cost. This page documents the configuration, the load test and what it changes on site.
Why 91 m matters commercially
Most modular bridge suppliers work between 30 m and 60 m. Beyond that, the standard answer is an intermediate pier: sheet piles, concrete, dewatering, a dry-season window and a second mobilisation. On a river crossing in a remote region, that pier often costs more than the bridge steel.
A 91 m single span deletes that line item. The structure is launched from one bank by cantilever, so no crane access is needed on the far side and no work happens in the water.
Configuration and technical data
| Parameter | Value |
|---|---|
| Panel type | D-type modular panel (deep truss) |
| Maximum single span | 91 m |
| Panel depth | 2.4 m |
| Carriageway width | 4.2 m single lane (widenable with additional transoms) |
| Design load | HS20-44 / Class 60, custom classes on request |
| Steel grade | Q345B / S355 equivalent |
| Corrosion protection | Hot-dip galvanised to ISO 1461 |
| Launch method | Cantilever launch with nose and rollers; jack-down at far bank |
| Verification | Full-scale load test completed before delivery |
| Shipping | Standard 40 ft containers, marked per erection sequence |
How the span compares
| System | Typical max single span | Pier required? |
|---|---|---|
| Compact 100 panel | 15–24 m | Often |
| Compact 200 panel | 21–30 m | Usually above 30 m |
| Standard Bailey (double-double) | 30–45 m | Yes above 45 m |
| D-type modular (Evercross) | 91 m | No pier |
Load test — what was verified
The 91 m arrangement was assembled full-scale and loaded to verify deflection, panel joint behaviour and transom stress under the design load case. Results were recorded against the calculated model; the test report, together with the erection drawings, is issued to the client before shipment.
When a 91 m span is the wrong answer
Honestly: sometimes it is. If the banks are low and the river is dry for eight months, two 45 m spans with a simple pier can be cheaper. If the site has no launching space on the near bank, a shorter span with a crane erection is faster. We will tell you when the long span does not pay — the layout study is free.
Frequently asked
How long does a 91 m span take to install?
With a crew of 25–30 and one small crane for unloading, a 91 m cantilever launch typically takes 10–18 days on site, including decking and approach works. Pre-assembly on the bank reduces this.
How many containers does it ship in?
Approximately 8–11 × 40 ft containers depending on deck type, kerbs and launching nose. The packing list is sequenced to the erection order so nothing is opened twice.
Can it carry mining haul trucks?
Yes — the arrangement is re-analysed for the actual axle loads and spacing rather than being quoted from a catalogue class. Send the truck specification and we return a revised panel arrangement.
What about wind and seismic loads?
Site wind speed and seismic zone are taken from the project location and applied in the structural check; the report is issued with the drawings.