Seismic rehabilitation of steel framed buildings

Due to the increasing pressure for leaner construction and reduced carbon footprint structures, the contribution of “non-structural” elements to the structural response of steel frame structures, is once more under the spotlight. This paper identifies the effects of infill wall existence and arrangement in the seismic response of steel frame structures. Despite their non-structural nature quantifiable differences have been recorded in the overall seismic behaviour, with different infill wall arrangements, highlighting their potential seismic design significance. This paper advocates the use of infill walls as a light method of seismic rehabilitation intervention that can provide considerable structural benefit without the traditional difficulties associated with seismic upgrade. To demonstrate the above, a methodology based on the utilisation of overall seismic response indicators was followed. This post processing enables a straightforward comparative statistical distillation of the complex structural response. The overall structure damage index after Park/Ang (OSDIPA) and the maximum inter-story drift ratio (MISDR) have been selected as widely utilized structural seismic response parameters. A set of 225 spectrum compatible accelerograms, based on EC8 and the Greek national compendium provisions, have been created and a series of non-linear dynamic analyses have been executed on an indicative steel frame structure with 5 different infill wall topologies. Results indicate the significant overall contribution of infill walls. Response reduction in the range 35-47% of the maximum and 74-81% of the average recorded OSDIPA values followed by an overall reduction of 64-67% and 58-61% for the respective maximum and average recorded MISDR values, demonstrates the relative benefits of infill wall presence. Similar reductions were also observed in 1st level damage indicators.