Advanced light-frame timber solutions in architectural top additions

A study on architectural top additions of reinforced concrete buildings made of light-frame timber (LFT) structures is reported in this paper. Initially, the possibilities offered by traditional LFT solutions are examined. Then, a new configuration based on the incorporation of a small-sized supplemental damping system, easily hidden behind the oriented strand board sheathing panels of the light-frame structure, are proposed. A two-storey reinforced concrete residential buildings selected for a demonstrative application of the two structural solutions. The single-storey top addition covers approximately 70% of the flat roof level. The paper reports: a seismic assessment analysis of the building in current conditions; the modelling criteria and the design of the light-frame timber superstructure in the traditional configuration and in the presence of the supplemental damping system, consisting of dissipative braces incorporating small-sized pressurized fluid viscous spring-dampers; and comparisons between the seismic performance of the superstructure and the entire building under the two different design hypotheses.