Search

Recent seismic events showed the high vulnerability of the existing buildings and the need to improve their seismic performances. Nowadays different techniques for the seismic retrofit of reinforced concrete buildings are available. One of the most effective technique is the base isolation because it aims at reducing the seismic actions transmitted to the super-structure. In the framework of the seismic risk classification it aims at improving the seismic safety index and at reducing the expected annual losses containing the damage to structural and non-structural components. An efficient design of a base isolation system for existing buildings should aim at minimizing the retrofit interventions on the superstructure in order to reduce the level of disruption. This paper deals with the seismic retrofit of a case study reinforced concrete building by means of base isolation. A refined numerical models including the contribution of hollow clay brick infill wall is developed. Nonlinear dynamic analyses are carried out to assess the performance of the building in the asbuilt and base isolated configuration with and without infill walls. A direct comparison between the seismic performance is performed and the results are discussed with the reference to the reduction of the expected economic losses and needs for the intervention on the superstructure

Recent seismic events showed the high vulnerability of existing buildings and the relevant economic and social losses. Nowadays, the modern seismic engineering necessarily needs to account for expected economic losses in order to plan effective mitigation strategy at building and regional level. Different methodologies are available in literature and they are implemented in useful tools suitable for the application in the design practice. Recent seismic events have been a unique occasion for monitoring and collecting the actual reconstruction costs at a large scale. These data can be used to calibrate and validate the loss-assessment procedures. This research work focuses on the actual repair costs of a database of reinforced concrete existing buildings damaged by the 2009 L’Aquila earthquake and then repaired and strengthened. The actual repair costs derived by the quotes submitted for funding applications are analyzed and a focus on the repair cost of infills and partitions (IPs), which is majority of the total repair cost, is presented. The variability of the repair costs of these components and a correlation with observed damage is investigated. High dispersions is found when correlating the repair cost of IPs to the damage state and damage extent derived from empirical data. An in-depth analysis is performed to quantify the real extent of the damage experienced by these components. This results in a significant improvement of the correlations with actual repair costs.