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Fortec Double Tee Anchor

Parking Garage Flange Connector

Fortec Double Tee Anchor

Parking Garage Flange Connector

The new, non-corrosive, easy-to-install anchor that stabilizes parking garage flange movement

Fortec Stabilization has performed full scale testing of the new Fortec Double Tee Anchor to repair an active parking garage with typical flange failures. The parking deck’s Double-T beams are 60-feet long, 8-feet wide with a 4 inch, non-topped deck. The Fortec Double Tee Anchor is formed using carbon fiber in a U-shaped polymer composite, precured and surface prepped for installation.

As owners and operators of parking structures know well, standard steel welded flange connections typically fail. Load forces cause premature failure of welded flange connectors either in the connector or more commonly in the concrete flange surrounding the connector. The welded connection is too rigid and causes fatigue failure in the weld or cracking of the concrete surrounding the connector’s embedded anchors.

Current composite and steel repair methods also create a rigid joint having similar failures to the original connectors. Without allowing for a nominal amount of movement or flex, the connection is prone to failure. The lack of ductility in these repairs repeats fatigue failure in the concrete or the connector. Fortec Double Tee Anchors significantly reduce movement of the concrete beams while allowing for a small amount of flex in the joint creating a load transfer system through the carbon fiber and arrest fatigue stress in the concrete and the connector.

Full Scale Testing

  • First, a dial indicator was bonded to the bottom of a Double-T flange at a joint.
  • A 2017 Ford F-150 crew cab was driven over the Double-T flange joint. The front axle deflected the flange joint and a deflection reading was recorded.
  • Fortec Double Tee Anchors were installed 3 feet on center in the middle third of the Double-T beam and at 6 feet spacing towards the ends of the beam.
  • One-inch diameter holes were drilled on each side of the joint to depth of 2-inches. The holes were filled with epoxy paste and Fortec Double Tee Anchors were inserted.
  • The bonded assembly was allowed to cure and test resumed over the joint with the F-150.
Total joint movement observed with dial indicator:

The test joint deflected 5 times less with Fortec Double Tee Anchor installed. This system is designed so that only the ends of the Fortec Double Tee Anchor are inserted into the concrete flange allowing the middle of the U-shape to take the strain of the expected loads, and thus not putting stress into the existing concrete. For aesthetics, the carbon can be painted to match the color of concrete or other finish. The Fortec Double Tee Anchor is low profile and does not affect the ceiling clearance of a typical Double-T beam.

Engineered Solutions

Fortec designed the carbon fiber composite profile using FEA models to evaluate horizontal (racking) and vertical (vehicle loads) forces. Physical testing has been performed to withstand over 10 times the movement of an unsupported flange. In addition, cycle testing has also been performed at 4 times the installed strain for 10,000,000 cycles.

184 West 64th Street, Holland, MI 49423
Tel: 616-355-1421 Fax: 616-355-1428


Patents pending.