An arched bridge for the Denver Regional Transportation District’s light rail system was designed with arches that matched other nearby bridges.

One forming challenge was that the curve was designed with more than one radius and this same element needed to be repeated multiple times. Another concern was that the forms could not be supported by the ground because of flowing water and wet soil.

To address these concerns, Symons devised a plan to pour the straight support walls first and then use a combination of systems to create a set of arched forms that could be set up just once and rolled, much like Max‑A‑Form Box Culvert Traveler, from one pour to the next on a system of beams supported by 70K Anchor Brackets mounted to the walls.

The forming scheme utilized a combination of several Symons® by Dayton Superior form‑ ing systems. The Flex- Form forming system, an obvious choice for the curved areas, was complemented by Max-A-Form panels for the straight sections. These high-strength con‑ crete forming systems have a steel face that also provides a smooth finish.

The support for the arched form was accom‑ plished with a mixture of other systems. The Flex-Form panels were supported by horizontal Soldier Beams and Rigid Screw Jacks. Horizon‑ tal, diagonal and vertical Soldier Beams were attached with pivot brackets, Strut Jacks and Max‑A-Form outside corners.

To strip the forms, the contractor adjusted the Rigid Screw Jacks and Strut Jacks to lower the assembly onto 1'-6" soldier beams with custom-mounted rollers. Once lowered, come-alongs were attached to roll the entire assembly to the next bridge pour location.

The Flex-Form inside forms were tied to Max‑A‑Form outside forms with 1" lagstud through Flex‑Form tie bearing brackets and 5" Versiform walers secured to the Max-A-Form panels. Tie hardware consisted of Max-A-Form 7/8"x5"x7" flat washers and 1" contour nuts.

The contractor was impressed with how the various systems combined to produce a pro‑ ductive assembly that simplified construction by reducing setup and tear-down operations.

Flex-Form® System

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