An investigation of bridge influence line identification using time-domain and frequency-domain methods

The method to obtain an accurate influence line (IL) from the direct measurement is important research topic for structural condition assessment, model correction and bridge weigh-in-motion (BWIM) system. two most common approaches used identification of IL are time-domain (TD) frequency-domain (FD) method. Despite having a similar mathematical framework, TD FD methods treated as different by researchers working on this field. This paper presents detailed theoretical demonstration show that discussed above nothing but same. were compared experimentally using field data existing steel girder which obtained three calibration trucks (CTs) with axle weights configurations. Although ILs identified apparently different, insight into frameworks revealed basically same seeming difference between due inherent assumptions involved in discrete Fourier transform (DFT) such assumption cyclic nature analysis interval. Finally, has been outlined.