The civil structures bearing capacity assessment for 150 m high reinforced concrete ventilation pipe based on the field and numerical surveys

In the paper the results of the building structures bearing capacity assessment are presented for a reinforced concrete ventilation pipe with a height of 150 m under seismic effects and tornado loads, taking into account the results of full-scale dynamic and instrumental building structures surveys, based on the linear and nonlinear spatial design models numerical studies. This goal was achieved by solving the following tasks: the vibrodynamic surveys execution; the concrete structures strength determination by an ultrasonic method; development of linear and nonlinear spatial design models of the pipe; the calculations of class F3 tornado effects and intensities 6 (MDE) and 7 (above MDE) seismic impacts. Based on the results of vibrodynamic surveys, the actual dynamic parameters of the ventilation pipe structures were determined (vibration modes, prevailing periods and frequencies during principal modes vibrations). Based on the results of structures instrumental studies by ultrasonic method, the actual characteristics of concrete structures strength are determined. The obtained field data were used in the development of the facility spatial design models. To determine the bearing capacity of structures, the models calculations were performed using the LIRA CAD software package, which is a computer system for structural analysis and design. The calculations were performed for the class F3 tornado loads, as well as the intensities 6 and 7 seismic effects determined by the spectral method. Additionally, the bearing capacity of facility reinforced concrete structures was assessed under extreme loads (intensity 7 seismic impacts and class F3 tornado) taking into account the concrete and reinforcement plastic properties. The structures non-linear static analysis (Pushover analysis) applied in the standards of Ukraine, the European Union, the USA and other countries for the assessment of the operating structures seismic resistance was used. Based on the results of the research, the reinforced concrete ventilation pipe structures stress-strain state parameters under the considered seismic and tornado loads were obtained and the recommendations were prepared to reduce the possible consequences of an intensity 7 earthquake and a class F3 tornado.