Frequently Asked Questions
How much do ECO-SPAN® bridges cost?
Price depends on many factors. The fastest way to get an accurate estimate is to fill out our online form and request a price.
What sizes are available?
Standard spans range from 12 to 80 feet and beyond. Rise of the precast units varies with span and can be increased using precast or cast-in-place pedestal walls. See Technical Detail sheet for standard sizes.
How wide are the arch units?
The standard width or laying length of the pieces varies from 4 to 8 feet depending on span. Shorter non-standard lengths are also available. See Technical Details sheet for standard lengths.
Can arch units be skewed?
The maximum skew angle of the arch units varies depending on span. When roadway skew exceeds maximum arch unit skew, the ends of the bridge may be squared off if right-of-way limits permit.
What are the minimum and maximum earth fill heights over the arch units?
Minimum recommended fill is the full roadway cross-section including base material (typically around 1 foot) to minimize the potential for reflective pavement cracking at arch joints. ECO-SPAN® arches have been designed for over 100 feet of cover.
What vehicles can be supported by ECO-SPAN® arch units?
Concrete arches are known for their significant load-carrying capacity. Arches are typically designed for AASHTO LRFD HL-93 live load but have potential for much more. Precast arches can be designed to support aircraft (767), trains (Cooper E-80), and various off-road construction equipment.
Is design support available?
Design and technical support is provided by the Pretek Group. Basic drawings of the system are available at no charge. More detailed designs are available in most areas for a nominal fee. Pretek engineers work as an extension of the project design team. Their expertise often saves significant time and money.
What information is needed for a contractor to bid a project involving an ECO-SPAN® arch?
Bid drawings and specifications should include size (span, rise, length, wingwall lengths and angles), cover and live load requirements, and geotechnical recommendations prepared by a qualified firm. Bearing capacity of the soil and minimum foundation depth for scour should be included.
It is often most efficient to leave foundation design to Pretek and other suppliers. This minimizes up-front engineering costs and allows suppliers to provide designs specifically for their products.
Do joints need to be grouted?
No. Joints are simply butt joints with 1/4 inch to 1/2 inch nominal width. 1-inch nominal butyl material spans the gap and fills the chamfered edges on adjacent units. 9-inch (minimum) self-adhesive wrap seals the joints. See Technical Details sheet for standard joint detail.
Are joints water-tight?
The standard butyl and wrap configuration described above provides a “soil-tight” joint. Contractors can make the structure water tight using sheet membrane or spray-on systems. These have been used successfully on many tunnel and underpass applications.