New York connections

Like the spectacular Verrazzano Narrows Bridge before it – connecting the New York City boroughs of Brooklyn and Staten Island and for which mageba delivered a complex expansion joint replacement solution in 2017 – we are proud to now be doing the same for the iconic Queensboro Bridge which connects the boroughs of Manhattan and Queens.

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

The Queensboro Bridge crosses the East River in New York City, connecting two of the city’s five boroughs – Manhattan and Queens

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The Queensboro Bridge is a New York City landmark since it was opened to traffic in 1909

The smaller three-gap TENSA®MODULAR expansion joints of the approach structures have already been delivered and installed

The installation of the new joints in the approach structures was relatively straightforward, as the joints could be concreted in place on the concrete superstructures

Design representation (cross section, view from above) of a TENSA®MODULAR joint as designed for the Queensboro Bridge’s main steelwork structure, showing how its design required to be integrated into that of the connecting bridge deck panels

Design representation (end of joint, view from beneath) of a TENSA®MODULAR expansion joint with pre-integrated connecting bridge deck panels

The connecting elements of the bridge deck, pre-assembled on the expansion joints in the factory, required precise detailing – using field templates to transfer hole locations – to ensure flawless connections to the existing structure

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The Verrazzano Narrows Bridge – the world’s longest suspension bridge from 1964 until 1981 and still a vital New York City inter-borough connection

An installed TENSA®FINGER joint of the Verrazzano Narrows Bridge, with an extraordinary movement capacity of 2,700 mm (approx. 9 ft)

Like the modular expansion joints of the Queensboro Bridge, the sliding finger joints of the Verrazzano Narrows Bridge had to be precisely tailored to suit the bridge deck’s steelwork