Building monitoring during the partial implosion stage J. Garcés 1 , J.C. Botero 1 , D. Murià-Vila 2 (1) Universidad EAFIT - Colombia, (2) Instituto de Ingeniería- UNAM – México Abstract The partial collapse of a building in Colombia caused severe damage to its structural components. An implosion was realized to induce the collapse of 50% of the deteriorated building. To evaluate the influence of the implosion on the remaining structure, a monitoring survey was realized using triaxial accelerometers. Time signals associated with ambient, seismic and forced vibration were obtained. A study of the records in the time and the frequency domain was made. The analysis of the information allowed determining some structural properties that were useful to calibrate the analytical model of the structure. 1. Introduction On October 12, 2013 the SPACE building located in Medellin city, Colombia, suffered a partial collapse of the VI stage that caused damages in the rest of the building (Figure 1). Those damages affected notably the stage V; therefore its demolition was necessary and was done on Thursday February 27 2014 at 13:52 UTC hours, through an implosion process. EAFIT University performed the monitoring survey of the remaining four (4) towers in order to register their behavior and to obtain the dynamic properties of the structure through a period of thirty (30) days after the implosion. Figure 1. SPACE building after collapse of VI stage During the monitoring survey, tests of ambient vibration were done before and after the V stage implosion process. Furthermore, the signals produced during the implosion of V stage were registered as well as a seismic event of low intensity that occurred during the monitoring of the previous implosion. Collapse of VI Stage (24 floors) Demolition by implosion of V Stage (21floors) I Stage 11 floors II Stage 12 floors III Stage 15 floors IV Stage 18 floors