Archive for Bridges

Tapered Rectangular Conical Structure

Shin Seoncheong, South Korea – Tapered Rectangular Chimney

Global Chimneys Co. Ltd. hired Gleitbau GmbH of Salzburg Austria, to slipform this new chimney structure. The sliding operation was performed during 2017. The tapered rectangular shape makes for a unique and spectacular tower-like structure, made possible by the latest advances in slipform technology. The overall height is 148 m and the base dimensions of 20 m x 20 m taper off to 12 m x 12 m at the top. The wall thickness reduces from 0.90 m at the bottom to 0.35 m at the top.

Tapered Tower
Tapered Rectangular Chimney – Height 148 m

While this particular structure is a chimney, its shape could equally be applied to a tall bridge pier, especially in regions with high seismic activity. The tapered shape would increase the flexural stiffness of such a pier, reduce transverse superstructure deflections and enhance the dynamic performance of the overall bridge. Slipforming is the only building method that can economically produce such a tapered, rectangular shape. The technology was developed and perfected for the slip form construction of offshore gravity base structures and then extended to include almost any kind of vertical concrete structure.

Some basic drawings about the slip form system of construction can be found here. Slipforming has proven to be a very dynamic and capable technology, rapidly adapting to changing market needs and able to create structures that were unthinkable just a few years ago.

Gleitbau GmbH is a leading slipform contractor in North America and around the world, executing more than 100 slipform projects per year. The company was founded in 1961 and became an industry leader during the 1970s and 1980s through its offshore work in the North Sea. Gleitbau GBG typically supplies the slipform system, engineering, concrete mix design, geometry control and technical supervision, mostly to general contractors. Heavy lifting services are also provided, many times in conjunction with slipforming. For more information, please contact Michael Veegh.

Bridge Pylons

St. Petersburg, Russia

bridge pylons

Petrovsky Fairway Cable-Stayed Bridge, St. Petersburg, Russia

Pictured here are the bridge pylons for the Petrovsky Fairway cable-stayed bridge, which is a crucial link in the St. Petersburg Western High Speed Diameter Project. This is the largest PPP road construction project in the world today and the first urban high-speed toll motorway in Russia.

Elba Yaritim Sondazh Inshaat, the general contractor on this project, hired Gleitbau GmbH to slipform the two bridge pylons. The pylons are approximately 114 m tall with outside dimensions of roughly 5.0 m x 6.0 m per leg. The pylons were completed in 2014. Slipforming was chosen because of the speed of construction and the resulting structural durability, as the towers have no construction joints or form-tie holes.

Anchorage Area

The cable anchorage area required the installation of welded steel boxes, which nowadays is the preferred method for defining the intricate stay pipe and bearing plate geometry for each cable.

The slipform was stopped at the underside of the first welded box, to insert steel supports into the wet concrete. These supports were then used for leveling and orienting the box in relation to the bridge.

At that point, the inside form was abandoned and slipforming continued with the outside form only, which ran flush with the ends of the stay pipes. These pipes were cut at compound angles to match the concrete surface.

As the slipform climbed, steel boxes were added. Bolts were used initially for connecting and adjusting the boxes, followed by final welding.

This particular design anchored the stay cables inside the tower. No cable saddles were used. The entire pylon was slipformed at an average speed of 3m / day, including the anchorage area.

Gleitbau GmbH is a leading slipform contractor with projects all over the world, including North America. The company was formed in 1961 and completes between 80 – 100 slipform projects every year. The scope of work normally includes the supply of custom slipform equipment, engineering, geometry control and supervision of the slipforming operation. For more information, please contact Michael Veegh.

bridge pylons

Bridge pylons being slipformed