A complete bridge is on its way to a site deep in a NSW forest. As well as the steel girders & crossbracing, deck slabs, rubber pads and fixings, the kit includes a pair of steel mesh abutment cages. On arrival at site the components can be lifted into place and bolted together in a few hours, no welding is needed.
Usually, the lifting can be done by the excavator that prepares the site. And the excavator is ideal for filling the abutment cage compartments with rocks, forming stable supports based on the well-established principle of gabions. Small mesh pockets built into the abutment cages form voids which accommodate the hold-down bolts. Hence only a small amount of concrete is needed is to fill the voids and embed the hold-down bolts monolithically with the surrounding rocks.
“Off the shelf” bridges like this are ideal for emergencies such as flood, fire, accident, earthquake, etc., enabling access to be restored quickly. Some local councils have purchased bridge kits for this reason, and also for use as a temporary bypass during major construction works. Bolted fixings means that these bridges can be dismantled easily for transport and reuse on another site, highly suitable for logging access roads in forests. On the other hand they may also be used for permanent bridges erected on prepared footings, eg. piles.
