Strand Tendons for the The Gerald Desmond Stay Cable Bridge

Context

The Gerald Desmond Bridge crosses the Back Channel in the Port of Long Beach, California and so an important connection to the city center. Thanks to a 62.5m (205ft) clearance, the bridge is also suitable for large cargo ships. The two pylons are approx. 157m (515ft) high, and, once completed, the new Gerald Desmond Bridge will be the USA’s second highest stay cable bridge. The bridge deck has a 610m (2,000ft) long main span and is supported by 40 stay cables at each of the two pylons.

Scope

In total, over 3,000t of bonded DYWIDAG Strand Tendons of different types ranging from 4-0.6" to 37-0.6" with MA Anchorages have been installed in the bridge. The scope also includes the installation of all anchorages, duct and strand as well as stressing and grouting.

Solution

For the high-level approach structures that are being built using the incremental launching method with Movable ScaffoldingSystems (MSS), DYWIDAG is also installing the strand tendons and performing the stressing and grouting operations as well as the complete installation of the transverse deck post-tensioning.

When using the incremental launching method, stressing operations follow concrete placement by just 48 hours. Therefore, the equipment must be provided just-in-time in order to ensure the completion of the stressing and grouting work within the tight launch schedule.

The typical spans are constructed using 4 to 5 Type 27-0.6" DYWIDAG Strand Tendons, running full-length in each girder web. Additional, part-length, typically Type 27-0.6" or 37-0.6" DYWIDAG Strand Tendons pass longitudinally through the top deck. The top decks are transversely post-tensioned using Type 4-0.6" DYWIDAG Strand Tendons in flat ducts with Type FA Flat Anchorages. Several structures feature part-length DYWIDAG Strand Tendons that necessitated stressing from the interior of the box girder. This requires close collaboration with the contractor.

Cast-on-falsework construction is common in the western USA, and DYWIDAG is one of the most experienced subcontractors in this market. The extensive experience of DYWIDAG’s field crews ensures a safe and efficient installation within the tight schedule.

Thanks to the fact that DYWIDAG’s Long Beach facility is located at a distance of only 16km (10min) from the jobsite, DYWIDAG was able to rapidly respond to the contractor’s changing needs at all times in this major project. Furthermore, due to the wide array of available equipment, DYWIDAG was able to supply the matching equipment to the jobsite at all times without any delays. The continuous coordination between multiplework locations on the project site as well as the Long Beach plant ensures a seamless flow of materials, equipment and manpower.