TY JOUR TI THE ISSUE OF SECURITY CROSSINGS ON THE ICE KW ice passage KW ice thickness KW freezing KW structure of ice KW bearing capacity of ice cover JO NATURAL AND MAN-MADE RISKS (PHYSICO-MATHEMATICAL AND APPLIED ASPECTS) AU Grashchenko, E.A. AU Ivanov, A.N. PY 2016 IS 2016 PB Saint-Petersburg University of State Fire Service of Emercom of Russia