Abstract
Beam spans are the most vulnerable elements ofthe bridge system, as they are exposed to directeffects of mobile load, environmental and climaticfactors (temperature and humidity effects, includingfreezing and thawing, shrinkage, humidity, etc.).Appearance of defects of the structure is inevitable;the refore civil engineers face a topical problem ofstrengthening of damaged structures of bridges. Thearticle discusses some results of calculated valuesand instrumental measurements of stress-strain state(SSS) of reinforced concrete beam span structuresof railway overpass under operational load caused bydifferent rolling stock units. The objective of this studyis to control stress-strain state of railway overpass foridentification and elimination of defects at earlystages. The calculation results obtained, carried outby finite-element method (FEM) in the programABAQUS/Standard correlate well with experimentaldata. These results can be used for monitoring thestate of artificial structures on main lines of JSC NCKTZ.