Engineers Surveyors Designers
Structural Engineering
Project: Biobasin Walkway Bridges
This project involved the design of 5 walkway bridges and 3 conduit bridges to replace existing biobasin walkway bridges in the Rhone - Poulenc AG Company Institute Plant. The structure lengths ranged from 42'-0" to 62'-0".
The bridges were designed as fiberglass trusses with a fiberglass grating floor system. Pulltruded FRP structural shapes were utilized for the design of the truss, stringers, handrail, and toe plates.
The owner specified the materials utilized for the design and construction of the bridge to be fire-retardent vinyl ester resin, UV inhibitor, a surfacing veil of non-woven fabric, and a finish coating of urethane.
The walkway bridges were designed for a floor live load of 100 psf over the total area of the bridge with a 2,000 lb concentrated load placed for maximum member stress.
The conduit bridges were designed for a floor live load of 40 psf over the total area of the bridge with a 200 lb concentrated load placed in the center of the bridge.
Total deflection of the structures was limited to L/240. Given the high modulus of elasticity and the high strength of the fiberglass shapes, the controlling factor driving the design was the deflection criteria.
Design in structural fiberglass is focuses primarily on connections do to the limited methods of connection available to the designer. Bolted connections relying on bearing and shear for the transfer of member forces is the primary method of connection. Epoxy and other adhesives are not permitted due to the unreliability of the connection.
The bridges were designed as fiberglass trusses with a fiberglass grating floor system. Pulltruded FRP structural shapes were utilized for the design of the truss, stringers, handrail, and toe plates.
The owner specified the materials utilized for the design and construction of the bridge to be fire-retardent vinyl ester resin, UV inhibitor, a surfacing veil of non-woven fabric, and a finish coating of urethane.
The walkway bridges were designed for a floor live load of 100 psf over the total area of the bridge with a 2,000 lb concentrated load placed for maximum member stress.
The conduit bridges were designed for a floor live load of 40 psf over the total area of the bridge with a 200 lb concentrated load placed in the center of the bridge.
Total deflection of the structures was limited to L/240. Given the high modulus of elasticity and the high strength of the fiberglass shapes, the controlling factor driving the design was the deflection criteria.
Design in structural fiberglass is focuses primarily on connections do to the limited methods of connection available to the designer. Bolted connections relying on bearing and shear for the transfer of member forces is the primary method of connection. Epoxy and other adhesives are not permitted due to the unreliability of the connection.
Key Personnel:
Project Manager - Roger K. Randolph, P.E.