Geokon 4425, Instruction Manual, Page: 20 / 27

14
From Equation 3:
Dtemperature = + 17.5(0.0087 + 0.2 × 10-6 × 30,000 + 0.0178) = + 0.568 mm
From Equation 5:
Dcorrected = + 4.566 + 0.568 = + 5.134 mm
From Equation 7:
Drodstretch = 5.95 × 5.045 × 30,000 / 31.67 × 0.117 × 10 6 = +0.243 mm
From Equation 8: (Not required if the convergence meter is vertical)
Dsag =[30
3
x 0.481
2
/24 x 133 x 133] -[30
3
x 0,481
2
/24 x 163 x 163] = + 4.918 mm
From Equation 9:
The true extension:
Dcorrected = + 4.566 + 0.568 +0.243 + 4.918 = + 10.29 mm
4.5 Environmental Factors
Since the purpose of the convergence meter installation is to monitor site conditions, factors that
may affect these conditions should always be observed and recorded. Seemingly minor effects
may have a real influence on the behavior of the structure being monitored and may give an early
indication of potential problems. Some of these factors include, but are not limited to, blasting,
rainfall, tidal levels, excavation and fill levels and sequences, traffic, temperature and barometric
changes, changes in personnel, nearby construction activities, seasonal changes, etc.