A1 - Szewczyk, Piotr A1 - Szumigała, Maciej A2 - Kuczyński, Tadeusz - red. PB - Zielona Góra: Oficyna Wydawnicza Uniwersytetu Zielonogórskiego N2 - This paper presents the numerical modelling of strengthening a steel-concrete composite beam. The main assumption is that the strengthening is not the effect of the state of a failure of a structure, but it resulted from the need to increase the load-bearing capacity and stiffness of the structure (for example: due to a change in the use of the object). N2 - The expected solution is strengthening without the necessity to completely unload the structures (to reduce the scope of works, the cost of modernization and to shorten the time). The problem is presented on the example of a composite beam which was strengthened through welding a steel plate to the lower flange of the steel beam. The paper describes how energy parameters are used to evaluate the efficiency of structures' strengthening and proposes an appropriate solution. KW - metoda elementów skończonych KW - belki zespolone KW - wzmacnianie KW - analiza nieliniowa KW - Finite Element Method (FEM) KW - composite beams KW - strengthening KW - non-linear analysis T1 - Numerical modelling of the strengthening process of steel-concrete composite beams = Numeryczne modelowanie procesu wzmacniania stalowo-betonowych belek zespolonych