Assessment of stability and safety of huge structures such as dams, bridges, nuclear power plants ,etc during and after construction, have been proved to be very important and necessary.
Since structures performance is affected by Earth crust displacements, due to structural loads on the surrounding area as well as other ambient factors, therefore periodic monitoring of structures is of great importance to control the stability of them and preventing the possible human and financial losses.
There are two methods for periodic monitoring of structure’s permanent deformation: Geotechnical method based on geotechnical instrumentation, and Geodetic monitoring survey method.
Since in geotechnical instrumentation method, the instruments are installed within the structure, the results give merely localized but precise displacement information of part of structure versus its surrounding though, it doesn’t show total structure’s behavior versus its surrounding area which is not necessarily affected by the structure forces. Conversely in Geodetic monitoring survey method (Micro geodesy) the displacements are more reliable, as it yields global information of behavior of deformable structure applying modern and precise surveying equipment. As for structural deformation monitoring purposes, both methods are recommended according to international standards and experts involved in this discipline.

A deformation monitoring project includes following phases (steps):

• Designing and pre-analysis of geodetic control networks(off and on the structure)
• Construction of pillars and geodetic target points
• Conducting Geodetic observations
• Processing the observations and network adjustment.
• Determination and Analysis of displacements