“Computational Civil Engineering - "Intersections" International Journal

142 C. NutiuAs the degree of accuracy is very high with these procedures of data processingand assessment, the topographical-geodetical methods represent a fundamentalsystem in the process of construction analysis.3. TYPES OF SUPPORTING NETWORKS IN OBSERVATION OFCONSTRUCTION STRUCTURESWhen processing the linear and angular measurements, either the vector of verticalor horizontal displacement can be obtained, or, first, the values of the componentslaid on the orthogonal axes, then the value for the displacement vector.The microtriangulation method is used to observe in time the behaviour of massiveconstruction structures (dams, locks, viaducts, bridges, monumental edifices) andthe terrain pertaining to these.The valuation of the vector for the horizontal displacement and constructionsettlement involves repeated measurements of the microtriangulation network,maintaining the same accuracy used when the network was set. The compensationcalculations must be rigorously performed, using the method of smallest squares,for obtaining the most probable values for the coordinates of the network points.The network consists of the following points:• Control points - named also settling benchmarks, they are mounted on theconstruction structure that is to be observed. They are marked with beaconsof different shapes and made of chrome-plated bronze for protectionagainst corrosion. The research showed that the best beacons are discshaped.• Observation points – from here repeated observations are made towards thecontrol points placed on the construction structure.• Fiducial points - from here the changes in position for the observationpoints are identified; they are placed on solid ground, 200-300 m awayfrom the observed construction to eliminate any impingement of the latter.• Orienting points - are placed at long distances, on grounds with a highdegree of stability, mentioned in the geotechnical studies.The microtriangulation network can have the following structures: simple network,partial network and full network. In the below representations there are thenotations as follows:B 1 , B 2 .…B n - benchmarks set on the objectS 1 , S 2 .….S n - observation stationsC 1 , C 2 .…C n - control pointsO 1 , O 2 ….O n - orienting points