THE CONCRETE BRIDGE MAGAZINE

SUMMER 2017

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

Issue link: http://www.aspiremagazinebyengineers.com/i/844035

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C O N C R E T E B R I D G E T E C H N O L O G Y 28 | ASPIRE Summer 2017 On February 20, 2017, one lane of traffic in each direction was relocated to the new upper level of the Bayonne Bridge. With the traffic relocated to what will become the northbound structures, demolition of the existing arch floor commenced. The Port Authority of New York & New Jersey planned the construction of the Bayonne Bridge Navigational Clearance Program to coincide with the expansion of the Panama Canal, so that the new generation of larger container vessels had sufficient clearance to pass under the bridge and access the Ports of Elizabeth and Newark. Accordingly, every effort was made to expedite the elimination of the existing arch floor of the Bayonne Bridge, thus increasing the air draft from 151 to 215 ft. For this to occur, both the arch structure and the northbound approach structures had to be ready to transfer traffic onto the elevated roadway. This article highlights some of the design features used to expedite the construction schedule. These include using combined precast concrete pier caps, a pipe strut to brace the taller Type 1 piers Bayonne Bridge—Design and Construction Features by Joseph LoBuono and Chester Werts, HDR Traffic relocated to the new upper level of the Bayonne Bridge using the northbound approach structure. All Photos and Figures: HDR. Precast concrete pier types. during construction, split superstructure pier segments, and balanced-cantilever construction at expansion joints. Approach Substructure The geometry of the precast concrete columns and pier caps was created to complement the original architecture of the 1931 Bayonne Bridge piers, while providing an efficient structural section that could be cast, transported, and erected as expeditiously as possible. Approach- structure piers can be divided into three groups: Type 2 single piers used closer to the abutments, where the wider roadways shift the box-girders apart; short Type 1 combined piers, where the side-by- side structures transition to the typical roadway width; and tall Type 1 combined piers, where intermediate haunched cross beams connect the tall, slender columns at approximately midheight. Type 1 combined precast concrete pier caps were effectively used to accelerate the construction of the substructure in advance of the segmental superstructure construction. The three-piece precast concrete pier caps are supported by the flared-pier capital segment that forms the base of the pier cap arch when complete. Precast concrete pier segments are constructed similarly to the precast concrete segmental columns, with both vertical and horizontal post-tensioning (PT) bars temporarily clamping the segments together and providing the required compression on the epoxy adhesive joints until the final multistrand tendons are stressed. Transverse horizontal multistrand tendons provide capacity for the cantilevered pier cap segments, and looped column multi- strand tendons are stressed at the top of the pier cap. Precast concrete segmental construction of the pier caps expedited the construction schedule and was exceptionally conducive to the staged construction of the northbound and southbound roadways. Each pier cap could be quickly constructed independently of the adjacent cap. When the two side-by-side structures are completed, the cast-in-place reinforced concrete closure will be placed and the two pier caps will then be post-tensioned together forming a framed two-column pier.

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