Geokon 1300, Instruction Manual

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1. INTRODUCTION
1.1. Theory of Operation
The Geokon Model A-9 Retrievable Extensometer is designed primarily for short term
measurements of deformation in boreholes in concrete, rock, etc. The system is used in both
precast and cast-in-place concrete piles in plate load tests in rock and anywhere where
deformations need to be measured in boreholes, either drilled or cast in to the structure being
analyzed.
The system consists of pneumatically actuated anchors with spring loaded transducers that are
connected to one another in series by a single connecting rod. When installed, the anchors are
fixed in place and the transducers measure the deformation between the anchor positions. The
connecting rods are held in tension to eliminate errors due to bowing and friction. Connecting
rods of fiberglass, graphite epoxy, and stainless steel are available. The standard system is
designed to be used in a nominal 2" ID pipe; either plastic or steel.
Anchor
Transducer
Transducer Shaft
Swagelok for Connecting Rod
Nylon Inflation Line
Pistons (8 places) Transducer Cable
Cable & Tube Slot (4 places)
Connecting Rod
Top View
2.0"
51 mm
16.875"
429 mm
Figure 1 - Model A-9 Retrievable Extensometer Anchor