This bridge is Ohio's largest project to date, and includes almost 4.5km of precast concrete segmental approaches, ramps and a cable-stayed bridge, adding up to a total of 111,483m2 of bridge deck. The river crossing's single tower is flanked by two 186.7m spans, and the bridge will carry traffic high above the Maumee River, providing vertical navigation clearance of 37.8m. The existing bascule bridge will be used for local traffic once the new bridge opens, improving traffic flow both for interstate travellers and commercial shipping traffic which uses the Port of Toledo.

The construction contract for the project, with a low-bid value of US$220 million, was awarded to Fru-Con Construction Corporation in March 2002. Erection of the four ramp structures providing access to and from the I-280 bridge was completed in July last year. An overhead gantry, smaller than those employed for construction of the approach superstructure, was used for the span-by-span erection of the 74 ramp spans. The two ramps on the south end of the project were completed first, after which the gantry was relocated to the north end of the project where the remaining two ramp structures were completed.

In addition, all foundation work is complete, including 181 cast-in-place piers and 248 drilled shafts, ranging in size from 1.8m diameter to 2.4m diameter. The drilled shafts are up to 35m deep in the ground and were installed using two Leffer casing machines. The cast-in-place piers are up to 34m tall and have an eight-sided rectilinear cross-section which corresponds with the angular shape of the tower.

Casting of the 3,050 segments and delta frames was finished last April, at the 16.2Ha casting yard near the site; and on 17 October last year, another milestone was reached when a ceremony celebrating the topping-out of the 122m-high tower was held. Three precast sections, totalling 14.5t, were positioned on the cast-in-place tower, bringing tower construction to completion. At the time of writing, erection of precast segments using the span by span method was in progress at three locations, using three pieces of special equipment.

An overhead gantry originally supplied by Paolo de Nicola and modified by Fru-Con, is being used to erect spans for the southbound approach bridge south of the main span. Upon completion of this task, the gantry will be side-shifted to the northbound bridge to proceed with erection of the span-by-span backspans for the northbound portion of the main span section. Erection of these backspans, supported by temporary piers, should be completed by mid-2006. Once this part is complete, the gantry will be moved southwards to erect the remaining 14 spans of the northbound approach structure south of the main span, due to be finished later this year.

A second overhead gantry, this one supplied by Strukturas, is currently erecting approach spans for the southbound structure, north of the Maumee River. This gantry will work its way southward, span-by-span, and is expected to complete all 30 southbound approach spans north of the river this spring. It will then be repositioned at the north abutment to erect 20 of the northbound approach spans

Also in use is an underslung launcher, which is being used to erect the southbound backspans of the main span section. Once these are complete, the launcher will be relocated to the northbound approach structure north of the Maumee River, where it will erect the ten approach spans closest to the river crossing. Erection work with the underslung launcher is programmed to be completed this summer.

After both the northbound and southbound back spans of the main span section are erected, using six temporary piers and the span-by-span erection method, construction of the main cantilever will start. Erection of this 187m-long cantilever will move in one direction from the main tower to the north bank of the Maumee River. Precast superstructure segments and delta frames will be delivered to the cantilever from the completed approach spans south of the tower and lifted into place using stiff-leg derrick cranes anchored to the completed portion of the cantilever. Cantilever erection will progress in a systematic fashion: the derrick cranes will erect three cantilever segments each on the northbound and southbound sides, a delta frame will be erected, and then a stay cable will be stressed. Upon completion of the stay cable installation and stressing, the derrick cranes will be moved forward on movable sleds to begin the next erection cycle.

Construction of the main-span cantilever is expected to be completed by the end of this year. Shortly afterwards, Interstate traffic running in both directions will then be temporarily shifted onto the newly-completed southbound structure. The northbound approaches are expected to be complete by the middle of 2007.

The Veterans Glass City Skyway uses a cradle system designed to carry the cable stay strands as continuous elements from bridge deck through the tower and back to bridge deck, eliminating anchorages in the tower (Bd&e issue no 27). The 20 stays vary in size from 82 to 156 strands, and each cable strand passes through its own individual stainless steel sleeve in the cradle assembly and is housed in stainless steel sheathing for its free length. Stainless steel was selected for the stay cable sheathing due to its minimal long-term maintenance needs and as an aesthetic complement to the bridge's 'glass' theme. The cradle system, designed and patented by Figg, has numerous advantages; most importantly it provides the ability to remove, inspect, and replace individual stay-cable strands. This also gives owners the opportunity in future to replace the original strands with materials currently under development, such as carbon-fibre reinforced polymers. Use of the cradle eliminated the need for anchorages in the tower, along with the associated required internal space for access, permitting a reduction in the size of the tower. The tower would have been at least 3m wider with traditional anchor systems.

The tower is the second tallest structure in Toledo and incorporates glass curtain walls backlit by multi-coloured LED fixtures on the top 56m of its height. Glass panels form the four diagonal faces of the upper tower. Each glass light has seven distinct glass and laminate layers totalling more than 32mm in thickness. One of these layers is partially mirrored, allowing the glass to transmit coloured light from the LED system at night and reflect the sky during the daytime. Ohio DOT performed ballistics tests, uniform pressure and deflection tests and water infiltration tests on the proposed glazing system and constructed a 13.7m tall full-scale mock-up before the construction contract was awarded.

The LED lighting consists of nearly 100 units spaced at 635mm behind each of the glass faces. Each one emits variable intensities of red, green and blue light. When this light is reflected on the curved and painted concrete surface behind the glass, these three constituent shades combine to generate millions of colours. Each LED fixture is programmable and the entire system can be remotely-controlled using a laptop computer, providing ODOT with the opportunity to display both static and moving shows at various times of the year, to mark selected holidays or as a part of special events in the Toledo area.

The prismatic effect of the tower glass, stainless-steel stay sheathing, LED tower lighting and the bridge shapes were developed in close cooperation with a local community-based task force. Final selections were based on preferences expressed in the community workshops, led by Figg. The bridge aesthetics contribute to the creation of a distinctive appearance for this landmark in Toledo's skyline.

Owner: Ohio Department of Transportation

Consultant: Figg

Contractor: Fru-Con

Project manager: HNTB

Post-tensioning and cable-stay subcontractor: DSI

Jeff Baker is construction manager for the Ohio Department of Transportation, District 2 and Wade Bonzon is field engineer for Figg.

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