Meixi Urban Helix Structure in Changsha, China

KSP Jürgen Engel Architekten, together with Weiske + Partner structural engineers, developed different ideas for the project in 2013. The decision was made in favor of the helix in its present form. The engineers from Weiske + Partner used FEA software RFEM for the structural analysis of the spatial structure.

Structure

A pedestrian-accessible ramp with a width of 6 m (20 ft) spirals upward around the exterior of the inclined columns. At the lookout height of 30 m (99 ft), the helix has a total diameter of 88 m (289 ft). A ramp running in the opposite direction on the inside of the columns leads downwards. The structure has a total length of less than 1 km (0.62 mi) and ends in a public park. 

The ramps consist of bending and torsion-resistant steel pipes which are supported at the face of the 32 steel columns. Because the ramp is supported on both the interior and exterior of the columns, the eccentric loads are largely compensated. This meant that the columns could be made of relatively slender hollow box sections. The tapered columns consist of a wider base diameter and are fixed at the footing to a circular foundation on large bored piles. 

The lateral support of the helix structure includes filigree tension cables spanning between the columns. The cables' flat inclination reduces the horizontal stiffness of the structure, resulting in smaller seismic load reaction forces.