Installation Guide for Arch Bridge 2.0m and 3.0m
There are specific seasonal windows to consider when installing a stream crossing. We recommend seeking the input of local fisheries, forest and engineering professionals. Be sure to inquire with local authorities before installing a bridge. We have provided step-by-step instructions below to guide you in the EnviroArch installation process.
Heavy Equipment: Our robust EnviroArch products can be managed by a single 20-tonne excavator, and can be lifted and packed, or drug across gravel surfaces to reach its destination.
Lifting Rigging: Be sure to utilize properly rated, inspected and maintained lifting rigging. EnviroBridge will supply suitable two- or four-way cables upon request. The net weight of your purchased EnviroArch will be stamped on the end wall for reference.
Compaction: A vibratory compaction of the backfilled material will be required to complete installation.
Aggregates: In some cases it may be necessary to import a more suitable gravel product to use as backfill, and/or rock (rip-rap) to use as armouring. We suggest inspecting a site prior to installation to determine the availability of these two materials.
Other Materials: Geotextile fabric is recommended for ground stability and silt control. Be prepared to cover an area of approximately 8m x 5m.
EnviroArch built-in footings make installation significantly faster and less intrusive than comparable bottomless crossings. Here are key factors to consider when preparing a site for an EnviroArch crossing: Endeavour to maintain the natural slope and condition of the creek bed, assess the bearing capacity of the ground underneath the I-beam footings and correct any unevenness. EnviroArch footings will perform well on most native soils, as long as the bearing capacity is even along the entire length of the crossing.
When the installation site is properly prepared, placement of an EnviroArch is very simple. Using suitable lifting rigging, lift and swing the arch over the center of the creek channel. Check the alignment and proceed with the backfill.
Place a geotextile fabric over the structure prior to beginning the backfill process (this will protect the critical backfill). Note that the geotextile should be placed on the outside of the structure, over one layer of structural fill. To protect the structure from hydraulic scour, a layer of angular amour rock (rip-rap) should be placed around the perimeter of the end walls. Continue to backfill and compact in lifts of 300mm to 600 mm, until the desired final road grade is reached. We recommend a minimum of 300mm of fill over the structure to prevent damage from road maintenance over time.
If the structure is to be removed and reused, begin by excavating as much material as possible from both sides of the structure. Keep in mind that the steel arch itself can support the weight of your heavy equipment even without structural fill. Remove the geotextile if present and lift the structure out of the watercourse. The main objective in removing any structure over a watercourse should be to prevent as much silt and foreign material from entering the streambed as possible.