engleski

Parameters affecting on the reduction factor in pedestrian load models based on pulsating stationary force

Single pedestrian load model is defined, in general, in two ways: as a pulsating force moving over the bridge deck with a certain constant speed, or as a pulsating stationary force acting at the most adverse position of the bridge deck. Although it is easier to obtain the maximum acceleration due to pulsating stationary force it is necessary to establish the stationary load model which produces the same dynamic response of a structure as the moving load model. In this paper, the reduction factor is determined as the ratio of maximum accelerations due to the same model of moving pulsating force and stationary pulsating force. The reduction factors are calculated for bridge structural system of simple supported and fixed beam, span length of 15 m and 20 m, structural natural vertical frequency form 1 Hz to 5 Hz (in steps of 0.4 Hz), structural damping of 0, 5%, 1%, 1, 5%, 2%. From conducted analyses it can be concluded that changes in structural frequency does not affect the reduction factor, while changes in structural damping, structural system and span length affect the reduction factor as follows: the reduction factor increases with increasing in structural damping, the reduction factor is greater for longer spans, the reduction factors for fixed beam are smaller than the corresponding values for simply supported beam. Also, it can be seen that constant value of the reduction factor which can be found in some codes or guides can greatly overestimate of underestimate the maximum deck acceleration due to single pedestrian load model.

pedestrian bridge; pedestrian dynamic load model

Rad je dio znanstvenog projekta "Procjena oštećenja i ojačanje građevinskih konstrukcija" financiranog iz sredstava potpore Sveučilišta u Rijeci (broj potpore: 13.05.1.1.01).