Buildings: Watch production center

Case study: SOFO System

Large excavation
Harsh mud environment
Slurry containing Walls monitoring
Mat monitoring
Mixed steel?concrete structure monitoring

Project Description

Summary: Load monitoring on the mat foundation and slurry walls during construction works

Clients: Watch production centre

Place: Geneva Canton (Switzerland)

Period: 2001 - N/A

Installation: De Cerenvill G?thechnique, Smartec

Structure's short description: The excavation concerns a 145 x 165 m soil surface with a maximum excavation level of about ? 20 m in very soft and saturated clays. The designed retaining system is composed of a slurry wall braced at its top. The bracing leans on a 130 m diameter circular reinforced concrete beam supported by piles that are linked with a buried circular internal slurry wall located at the excavation?s bottom.

Aim of monitoring: The aims of the monitoring were to monitor the load on the circular internal slurry wall; sensors were placed tangentially on the rebar cage before the concrete pouring. Mat foundation was also monitored to control the thrusts of the external slurry wall.

Number of sensor: 50

Main Results: Circular internal slurry wall sensors show the strain was up to 3,5 N/mm2. Engineers saw the real evolution of the load during the excavation, monitoring the load transfers.

Mat foundation monitoring

Measurement of the rebar cage

Rebar cage of the internal slurry wall with 6 fiber optic sensors

Bibliography:

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