Fort Lauderdale 17th Street

Diagram of the balanced cantilever method.

Diagram of the progressive cantilever method.

A temporary Dutch style bridge was built for use during construction of the permanent bridge.

The new 17th Street Causeway Bridge in Fort Lauderdale increases the vertical clearance and the channel width.

Variable depth segmental approaches.

The new 17th Street Causeway Bridge in Fort Lauderdale, Florida, was constructed along the alignment of the previous drawbridge. The cost of the transformation was $62 million. The new bridge was completed in 2001 and offers bike lanes, an emergency lane and pedestrian overlooks. While work was carried out on the new permanent bridge, a temporary Dutch style bridge was put in place to maintain traffic flow.

The cost of the permanent bridge was $62 million, and the temporary bridge $6 million. The new bridge increases the vertical clearance from 25ft to 55ft and the channel width from 100ft to 125ft. The 17th Street approach spans are made of twin variable depth – constant slope concrete segmental bridges, built using a combination of balanced cantilever and progressive cantilever construction methods.

CARINA PIER

The Carina Pier at the bridge’s midspan houses the counterweights that raise the bascule leaves vessels need to pass through the bridge. This allows for a simple rigid connection to the segmental approach spans.

WEST APPROACH SPAN – BALANCED CANTILEVER

The west approach span was constructed using the balanced cantilever method. Construction started by placing a pier segment on top of the pier then erecting the next two segments, one on either side of the pier segment. As the structure grew, by placing one segment at a time on each side of the pier, a balanced cantilever was formed. This cycle was repeated until the cantilevers reached midspan.

EAST APPROACH SPAN – PROGRESSIVE CANTILEVER

It was not practical to use cantilever construction off the back of the Carina Pier, thus temporary towers were placed in the waterway to prop the cantilever, allowing the completion of the span adjacent to the pier. The progressive cantilever method consisted of initially building part of the span by the balanced cantilever method. Once the cantilever exceeded half the previous span, a temporary tower or prop was added. Segments were added to the long span side of the pier with the temporary tower carrying out the balance loads.

TEMPORARY DUTCH-STYLE BASCULE BRIDGE

To avoid unnecessary congestion, a temporary Dutch style bridge was built for use during construction of the permanent bridge. This movable span employed a counterweight positioned on an A-frame to raise the bridge’s 160t bascule leaf.

LEAD CONTRACTORS

Figg Engineers, Inc. designed the concrete segmental approaches. EC Driver designed the bascule main span and was the prime consultant for the final design of the Carina Pier, the temporary bridge, the bascule bridge and maintenance of traffic. Traylor Bros, Inc. was the prime contractor for the construction of the permanent bridge and Gimrock was contracted for construction of the temporary bridge.

The CEI Team consisted of Parsons Brinckerhoff Construction Services (as the prime contractors), Greenhorne & O’Mara, Williams Earth Sciences Inc., David Fiero & Associates, TRS Consulting, Inc. and Law Engineering. SuperStructure construction engineers were Finley McNary Engineers, Inc.

The design team consisted of Parsons Brinckerhoff carrying out the feasibility study, Keith & Schnars in charge of roadway design and Edward D. Stone & Associates in charge of the landscape architecture, underdeck parking and pedestrian facilities. Helman Hurley Charvat Peacock Architects, Inc. did the work on bridge aesthetics, while David A. Mintz, Inc. did the work on aesthetic lighting. Geotechnical services were carried out by Schmertmann & Crapps and Arkitex2, Inc. completed the architectural design.