515 Congress Garage Roof Strengthening
Garage roof strengthening combining joist flexure, beam shear and a distinct reinforcement detail beside a new opening.
Delta Structural Technology completed carbon fiber strengthening at the garage roof of 515 Congress Avenue in Austin. The composite design combined longitudinal reinforcement at concrete joists with shear reinforcement at a beam. Joists adjacent to a new opening received a distinct strengthening detail. The project joined multiple reinforcement arrangements within one existing roof structure, with member locations, fiber directions and anchor requirements defined in the shop drawings.
- Market
- Parking
- Services
- CFRP joist flexure and beam shear strengthening
- Location
- Austin, Texas
- Structural members
- Concrete Beam StrengtheningJoist
Project challenge
The roof strengthening could not use one uniform treatment throughout the framing. Typical joists, joists beside the opening and the designated beam carried different reinforcement requirements. The joist details placed longitudinal strips at the bottom and side faces, while the beam detail used vertical strips. Intersecting joists and supports also shaped the reinforcement layout and the anchorage needed at the existing concrete members.
Project approach
The Simpson Strong-Tie design, based on Dunaway Associates documents, specified externally bonded carbon fiber and composite anchors. Longitudinal strips addressed joist flexure, with a separate detail for the joists beside the new opening. The beam shear detail used vertical L-shaped strips and anchors. Installation requirements covered concrete preparation, epoxy saturation, placement of the fabric and removal of trapped air. Field photographs show installed longitudinal reinforcement along the existing joists and overhead access during the work.
Delivery and coordination
The drawings connected each reinforcement detail to a location in the roof framing plan. A later engineering letter permitted alternative combinations of CUCF22 and CUCF44 fabric for the two joists with the higher layer requirement, making material selection part of the engineering coordination. The installation specifications also called for field monitoring, material samples and bond testing after cure. Those requirements tied layout and material handling to the composite system’s quality-control process.
Project significance
515 Congress illustrates a retrofit that combines flexural joist reinforcement and beam shear strengthening around existing roof geometry. Its distinguishing features are the separate detail beside a new opening and the engineered fabric alternatives for selected joists. The project shows how a composite system can be tailored member by member within one reinforcement plan.
