Bridge across the Adda river in Stazzona (SO) - diagnosis and vulnerability assessment

Activities were planned according to the program summarized herewith:

• collection and analysis of the historical documentation available and comparison with the on site situation;
• visual  inspection of conservation status and of cracking and deformation pattern;
• magnetometric analysis for the detection of rebars within R.C. beams (B.S. 1881-204:1988);
• mechanical characterisation of materials through laboratory tests such as determination of compressive strength of concrete coring and determination of traction strength of steel bars;
• extension of the results of the laboratory tests through NDT such as ultrasonic velocity measurements (UNI EN 12504-4:2005), ultrasonic tomography, pull out tests on concrete beams (UNI EN 12504-3:2005);
• determination of carbonation depth on concrete coring and on dust sampling (UNI 9944:1992 - method 2.1 and 2.3)
• mapping of corrosion potential (UNI 10174:1993);
• determination of structural stratigraphy through coring and endoscopic visual inspection.

On the basis of the information collected, the structural safety assessment was carried out, identifying the category of the bridge in compliance with the current Italian Seismic Code, and estimating the maximum allowable load the bridge can carry.