Bridges, Tunnels and other Transportation Structures
Full Session with Abstracts
In 2015, a joint venture between Flatiron and Dragados was selected for the replacement of the existing Harbor Bridge in the Port of Corpus Christi (TX), one of the most important facilities in the Gulf of Mexico due to bulk cargo movements. In this paper, I shall provide an overall description of the project as well as of the means and methods selected for the construction of the New Harbor Bridge (NHB.)
The Harbor Bridge Replacement Project includes a total of 18 structures and two interchanges. The main bridge is designed by Figg Engineering with a 3289-ft cable-stayed bridge and a 1.4 miles length approach bridges. Its 1661-ft main span length is currently second in the world for its typology, only exceeded by the Third Panama Canal Bridge. The cable-stayed span is designed with a centered single plane of stays which splits the 149-ft width deck in two corridors. The north corridor includes a multi-use path which challenges the erection during the construction due to this unbalanced situation. All structures have been designed in concrete to comply with the project agreement. Both the schedule and the 175 year live cycle for the superstructure, force to have a concrete precast box section selected for the superstructure. The heavy superstructure defines the selected means and methods. All precast segments will be self-performed in a custom-made precast yard to guarantee quality and delivery in time.
As far as means and methods is concerned, for the erection of the cable-stayed superstructure, derricks were selected as the optimal equipment, feeding the segments from behind. The derricks also minimize the construction loads, optimizing temporary PT and any local reinforcement required. The pier table in the pylons, which fixes the superstructure to the tower, will be also precast and erected in balanced cantilever.
For the approach bridges, the width of the deck are 96’ for the north and 58’ for the south corridor, and the typical span lengths are 180’ or 205’. Due to important constraints in the ground, the erection of these spans will be done with an overhead gantry, designed and fabricated by DEAL and McNary Bergeron.
Finally, strong wind conditions and hurricanes have been taken into account during construction. These typical loads in the Gulf area govern in some cases the design of both the permanent structure and the lifting equipment, which have been mitigated with the proposed means and methods. These corrective measures are applicable in areas with strong winds or lateral loads, and for projects where heavy lifting equipment is used, where temporary stages could govern the design of the structure.