Scenario-based approach for the determination of the advantages of the combined carbon and seismic retrofitting strategy

Abstract

This Master Thesis focuses on the comparison of different scenarios for the renovation of existing buildings and the demonstration of the environmental benefits of a combined energy and seismic retrofitting strategy. This scenariobased approach comprised the investigation of seven different scenarios for a case-study, existing unreinforced masonry building located in the city of St. Gallen in Switzerland: the preservation of the building as it is, the demolition and reconstruction of the building, the energy renovation of the building, the carbon renovation of the building, the seismic retrofit of the building, the combined seismic and energy retrofit of the building using conventional materials and the combined seismic and energy retrofit of the building using bio-based materials, comprising timber beams and straw infill panels. A parametric LCA analysis led to the determination of the bio-based combined seismic and energy retrofitting solution comprising timber beams and straw infill panels as the solution corresponding to the highest environmental performance for the building, followed by the the carbon renovation of the building. A simplified, nonlinear static analysis procedure was followed to assess the seismic performance of the existing, case-study building. This simplified, force-based, in-plane seismic analysis indicates a high seismic performance for the unretrofitted, case-study building. This is attributed to the low seismicity of St. Gallen, the low seismic mass of the building, comprising light timber floor diaphragms, and the thick, high-strength brick masonry walls of the building. However, only the in-plane seismic behavior of the building was investigated in this Master Thesis. Moreover, this Master Thesis focused on the force-based seismic assessment of the building and did not include any displacement-based analysis. Therefore, a more detailed seismic analysis should be performed to reveal potential seismic deficiencies of the building, particularly related to its seismic out of plane behavior and its displacement capacity.