Soil-Structure Interaction, Test Site No. 3

Forced vibration of field test structure at Garner Valley Downhole Array (GVDA) site to investigate soil-structure-interaction (SSI) systems. The GVDA site is unique compared to the previous two test sites (experiment nos. 25 and 26) in that it was previously improved with a similar type test structure that was instrumented to record the effect of structure-soil-structure interaction. In this experiment’s documentation, the test structure is referred to as 'Mini-Me' and the aforementioned pre-existing structure at GVDA is referred to as 'Dr. Evil.'

Mini-Me is a rectangular shaped steel moment frame with removable cross-bracing consisting of reinforced concrete roof and foundation. Braced and unbraced conditions were investigated as part of this experiment. The foundation mat is not embedded and has dimensions of 4.28 m (14 ft) by 2.13 m (7 ft) and a thickness of 0.61 m (2 ft). The height of the structure is 3 m (9.8 ft) above ground and the upper deck (roof) has similar dimensions as the foundation mat, with the exception of the thickness which is 25.4 cm (10 in). Mini-Me was instrumented with 24 accelerometers.

Dr. Evil is a square shaped steel moment frame with removable cross-bracing consisting of reinforced concrete roof and foundation. During the testing period of this test Dr. Evil was unbraced. The foundation mat is not embedded and has dimensions of 4.05 m (13.3 ft) by 4.05 m (13.3 ft) and a thickness of 0.82 m (2.7 ft). The height of the structure is 4.6 m (15 ft) above ground and the upper deck (roof) has similar dimensions as the foundation mat, with the exception of the thickness which is 40.6 cm (16 in). Dr. Evil was instrumented with 12 accelerometers.

Six field accelerometers were placed about 0.305 m (1 foot) underground in the vicinity of Mini-Me to represent free-field measurements. The structural drawings for Mini-Me and sensor location plan are provided in the drawing section of this experiment.

Mini-Me was subjected to force vibration testing using two types of shakers. A small shaker referred here as ‘Atom-Ant’ was used for x, y and torsion modal forced vibration testing at the roof and top of foundation mat levels. A larger shaker referred to as ‘Mighty Mouse’ was used for x and y modal forced vibration testing at the roof level.