Climbing Slovenia's tallest structure

Concrete Construction, Oct, 2004

DARS, the Slovenian motorway company, planned a visually pleasing structure with spans of up to 140 meters and a maximum height of 87.50 meters. The result, Crni Kal Viaduct, is Slovenia's longest motorway and tallest structure. Starting in 2005, traffic will be speeding along its 1065-meter-long bridge on two separate carriageway superstructures that rest on a total of eleven piers.

The project planner, Dipl.-Ing. Marjan Pipenbaher of Ponting Maribor, designed complicated Y-piers with constantly varying geometry. The brickwork pattern in the concrete had to be of the highest quality while following the geometry of the piers.

Doka automatic climbing formwork was used for six of the most complicated piers. The formwork elements for the outwardly splayed surfaces were sized to accommodate the greatest increase in the width of the pier head. This made it possible to stagger the brickwork pattern toward the outside. Each 4-meter-high section required a formwork alteration. Once set, the climbing operation for each section took only 9 minutes.

The recessed central part of the pier, the web, was climbed vertically. The necessary adjustment was made with coordinated box-outs. The contractors used a Doka balanced cantilever method to construct the superstructure. The Ljubljana to Koper motorway should open for traffic on time in 2005.

PROJECT PARTICIPANTS

* Project Planner: Ponting Maribor

* Contractors: Joint venture of the Slovenian firms SCT and Primorje

If you have an interesting project for us to consider, write to Project of the Month Editor, CONCRETE CONSTRUCTION, 426 S. Westgate, Addison, IL 60101; fax 630-543-3112; e-mail: cceditor@hanleywood.com