This article is devoted to the issues of observation and analysis of the stress-strain state and deflection of long-span roof truss structures during the construction of a sports facility. The analysis of data obtained using strain gauges and geodetic observations of deflections of roof trusses is considered. A calculation of the loads absorbed by the structure from the moment of assembling the trusses and installing the structure during the construction phase for 20 months is given. The work compares data on the stress-strain state and data on the deflection of roof truss structures over time, which makes it possible to determine the correspondence between the loads perceived by the structure and its deformations in order to identify defects in structural elements or inconsistencies during the assembly process of truss structures.