The Millennium Tower, at 202 m, is one of the tallest buildings in Europe. The structure is constructed on a preloaded piled raft foundation. The soil at the site was improved by vibrocompaction and the excavation was contained within a tieback diaphragm wall (12 dewatering wells lowered the high groundwater level from the adjacent Danube river).
The ground movements due to excavation, pumping and subsequent loading by the rising building were measured by an Extensometer installed close to vertical axis of the tower. The extensometer was fitted with 5 vibrating wire Displacement Transducers and connected to a Micro-10 Datalogger. The Extensometer Anchors were located at different levels between 26 m and 60 m depth.
A flatjack was inserted at the interface between each bored pile and the raft, and preloading was carried out using the raft and the weight of two sub-floors. The hydraulic pressure at 11 flatjacks was measured automatically during the loading cycles with vibrating wire Pressure Transducers and the Micro-10 datalogger.
Additionally, a central bored pile, located close to the extensometer, was instrumented with 12 vibrating wire Rebar Strain Meters, distributed in four arrays at approximately 2 m, 5 m, 8 m and 12 m depth, and connected to the datalogger to automatically determine the deformation of the pile at different levels with the preloading.
For additional information, please contact: Carlos Fischer | Scanrock, GmbH