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Designing and manufacturing expansion joints for new bridges demands skill and experience – especially in the case of extraordinary bridges such as the Queensferry Crossing in Scotland which require correspondingly impressive solutions. But supplying expansion joints to replace old joints on existing structures has the added complexity of designing and fabricating the new components to suit the dimensions and deck connections of the existing joints, while developing the solution to minimise impacts on the bridge’s traffic. The design and fabrication challenge is especially demanding in the case of steel bridge superstructures, where new and existing steel components must come together very precisely. In such cases, it is sometimes sensible to replace not just the expansion joint, but also the connecting elements of the bridge superstructure – for example, as illustrated by the recent project to renovate the Verrazzano Narrows Bridge in New York, for which mageba delivered a comprehensive expansion joint replacement solution complete with integrated steel deck panels.
Now, just a few years later, we are delighted to again have the opportunity to show what we can do on the ongoing project to replace the expansion joints of the Queensboro Bridge – another critical element of New York City’s transportation infrastructure and a city icon since 1909. The new joints are of the TENSA®MODULAR type, and have up to eight gaps each, accommodating movements of up to 600 mm. The installation of the four three-gap expansion joints on the approach structures has already been completed – a relatively straightforward process since the new joints could be concreted in place. However, the ten joints needed for the main steelwork structure have been developed with new elements of the bridge’s orthotropic deck panels and deck splice plates integrated in the design, to be delivered to the bridge as pre-assembled units.
The project has required close collaboration between our designers and those of the bridge renovation team, in developing proposals that minimise the need to adapt the bridge structure or to change the standard design of the joint. The care and expertise of everyone involved will ensure flawless connections and avoid difficulties during installation on site, while also facilitating quick installation and thereby minimising the impact on traffic – a key priority in “the city that never sleeps”!
Bridge renovation design engineer: Thornton Tomasetti
Contractor: American Bridge
Owner: City of New York Department of Transportation Division Bridges