The Challenge

The Selenyum is a 20,000m2 luxury residential, commercial and office complex built on a steep hillside. A road and car park was to be created on top, requiring a 15m high retaining wall structure of sufficient strength and durability. Severe space limitations dictated a steep wall (75+°) with a very small footprint on the bottom of the slope (8m). In addition, the wall had to meet very stringent seismic building codes. Construction logistics as well as project duration and costs were additional yet crucial considerations.

Conventional Solution

The logistics and expensive costs of high reinforced concrete retaining walls and to meet the local earthquake building codes were prohibitive, in addition to being unaesthetic. Solutions utilizing segmental retaining walls entailed complicated site logistics while walls at these heights even if reinforced are problematic. Furthermore, concrete joints typically used to cement the modular blocks are subject to cracking even under mild seismic activity.

Neoloy Geocell Solution

Neoloy Geocells have been uniquely designed, comprising of three 5m terraced walls built on the steep slope at a 75o angle. The footprint of the entire wall structure at the base is only 8m (on soft foundation soil). The bottom and middle reinforced walls have 5 rows of large-diameter 20 cm high cells. Each layer is covered with geogrids for reinforcement and backfilled and compacted with local high quality crushed stone. Typical horizontal length of the walls is an average of 70 meters. The top 5m wall is an unreinforced gravity wall of varying width.

The tri-planar tensile reinforcement of the Neoloy Geocell system – even with low strength uni-axial geogrids – not only provided the required engineering strength for the 15m height and loads. Neoloy also provides flexible strength and reinforcement to withstand extreme seismic motions and meet local earthquake design codes in full.