Calculation of tube concrete elements with strengthened cores by numerical method Oleksandr Palyvoda, Dmytro Yermolenko, Oksana Demchenko, Oleksandr Andriichuk and Oleksandr Nyzhnyk E3S Web Conf., 166 (2020) 08002 Published online: 22 April 2020 DOI: 10.1051/e3sconf/202016608002