Better Bridges: Home Sweet Home
to the bridges themselves,” Crook says. “This walks the designer through what to consider. We are essentially building habitats for different bat species.”
At Better Roads press time, 88 bridges in the program were in compliance with bat habitation environmental performance standards, according to ODOT. The agency has verified that its bat habitats have been successful. With the creation of a crevice habitat — one of three types of bat habitats on bridge structures — in the shallow box-beam bridge replacements to provide a roost for mouse-eared bats, inspectors found piles of guano, or bat waste, directly beneath the crevices shortly after construction. This served as evidence that bats were using the structures, the agency says. The other two types of bat habitats that can be incorporated into a bridge include a cave-like or an “Oregon wedge” design. With a crevice habitat, an integrated habitat is built into the concrete of the structure. This is a crevice type of habitat that incorporates box-
beam girders or pre-cast concrete. A gap is placed between the boxes to provide a crevice that runs along the span of the bridge. “We can size the crevice appropriately for an ideal bat habitat,” Crook says, adding that 1/2 inch to 1-1/2 inches is standard for the crevice. A cave-like, or cavernous habitat, is idea for the brown bat. An actual box is built into a span between box girders to provide an open area. The “Oregon wedge” is a simple plywood box designed to accommodate hundreds of bats at a time. The vertical box is typically affixed to the side of a bridge with a 1/2-inch crack, so bats can crawl up inside of it. “This gives them a place to shelter and roost,” Crook says. The box can be placed in a beam or on the outside of it. Placing it in a beam is advantageous because it is darker and there is less temperature swing. However, the advantage to placing the box on the southern outer side is the quicker heat up of the concrete during the winter. Bats like to thermoregulate; they need to maintain a certain body temperature. “Even though they roost in >>>
Pile Installation Recorder (PIR)
Automated Monitoring Equipment displays grout volume versus depth
Install Superb Augered Cast-In-Place Piles
BRIDGE CROSSINGS NON-CONDUCTIVE PIPE ROLLERS
Prevent the passing of current from the pipeline to bridge structure, rebars, etc.
* Free catalogue of pipeline Bridge Crossing Products.
Complies with FHWA GEC-8
Quality Assurance for Deep Foundations Cleveland, OH USA +1 216-831-6131
Maintain same support strength of pipe hanger system. Eliminate chaﬁng and rusting pipe caused by iron rolls. Eliminate electrical grounding of the pipeline to the bridge. Eliminate insulating joints at each end of bridge, and include the suspended line as part of a cathodically protected pipeline, i.e. continuity of cathodic protection. Absorb vibration from trafﬁce or other sources, saving wear and tear on pipe hanger parts. Highest speciﬁcation polyurethane compound is cast around an integral steel sleeve to form a full length bearing for the axle. Direct replacement for cast iron roll.
P.O. Box 540 Westtown, PA 19395 Fax 610-344-7519
Better Roads May 2011 37