Dynamic factors in case of damaging continuous beam supports
The article provides the research results of the continuous beam operation in case of the support damage. When the support is damaged, the design model of the beam is changing, the spans are increasing, and the force in the beam is increasing. Moreover, a fast removal of the support at the effect of the unaltering during the destruction of the beam concentrated or distributed force will lead to the evolvement of the vibrations and increase of the beam force. The theoretical jurisdictions are provided for the determination of dynamic factors which might be used for the determination of dynamic force based on the results of the static calculations for the damaged construction. Theoretical dynamic factors are determined for the beams loaded by the concentrated loads. The numerical computations have been performed with the use of finite-element design models. By the example of the continuous beams loaded by the concentrated and distributed forces, the consequence of the dynamic calculations for damaged beams is shown taking to account the time of the support breakdown. It is set that the maximum force values appear in the beams with time for the support damage from 0.01 to 0.1 sec. The comparison of theoretical and numerical dynamic factors is conducted. It showed a good compliance of factor values determined by different methods. The recommendations are provided for practical applications of the dynamic factor at the calculation of continuous beams.