LOAD EFFECTS ON AN ARCH'S FREQUENCY RESPONSE FUNCTION: AN AID TO SERVICEABILITY ASSESSMENT

This paper reports results studying the effect of loading on a brickwork arch bridge's modal characteristics. The arch consisted of a half brick thick ring with spandrel walls and Type 1 granular backfill. Transient dynamic tests were carried out as the load on the arch increased. Loading took place at the 1/2- and 1/4-span points of the arch. Four mass concrete blocks were used as kentledge to study their effect on the arch's dynamic response. The shape and the amplitude of the signal response of the arch was extensively used in this study. The method is offered for further exploration as an aid to either condition based maintenance or assessment. Salient results indicated the effect of compressive stress in the arch ring upon the frequency response function (FRF) in even nominally defect-free states. As such the method may also have potential for analysis of the effects of abnormal vehicle loading upon full scale structures. For the covering abstract see ITRD E111699.