Premature brittle failures because of seismic actions strongly affect the behavior of existing reinforced concrete (RC) structural systems. They commonly involve exterior beam-column joints of structures designed without transverse reinforcement. This paper investigates the behavior of unconfined joints that do not conform to current seismic codes and the effectiveness of externally bonded fiber-reinforced polymers (FRPs) as a strengthening technique. It presents an experimental program carried out on six full-scale RC corner joints under constant axial load and transverse cyclic loading in the as-built and FRP-strengthened configuration. After describing the specimen design strategy and test setup, seismic performance is compared. Particular attention is paid to comparing the experimental capacity of as-built joints and the capacity, which can be predicted on the basis of models available in the literature. Finally, a discussion on the effectiveness of different FRP-strengthening layouts is reported.

Recent seismic events are a unique opportunity to monitor and collect details of direct repair costs and the downtimes associated with massive reconstruction processes. This paper focuses on the actual repair costs of five RC buildings damaged by the 2009 L'Aquila earthquake. The repair costs for structural and nonstructural components that experienced different types of earthquake damage are discussed and then used as a benchmark for the predictions. The comparison at both the building and component levels revealed that the FEMA P‐58 methodology is suitable, in general, for application to different types of building stock. Ad hoc upgrades to the FEMA fragility database for components that are typical of the Mediterranean area are required. When implementing the proposed modifications, a reasonable level of consistency is achieved in terms of actual and predicted repair costs (differences in the range of 30–48%). A discussion on the actual repair costs and the main differences with the predicted costs for infills and partitions, structural subassemblies, floor finishes, and other acceleration‐sensitive nonstructural components is provided, along with suggestions for further improving.

This paper studies the seismic behavior of old-style reinforced concrete beam-column joints and the effectiveness of an innovative application of fiber-reinforced concrete (FRC) as a seismic strengthening solution. Two real joint subassemblies were extracted from an existing building damaged and demolished after the L’Aquila 2009 earthquake and tested in the laboratory. The joints exhibited poor-quality concrete and reinforcement details typical of old design practice, which are very difficult to reproduce in laboratory simulations. The joint tested in the as-built configuration shows brittle failure with joint diagonal cracking, as commonly observed in the aftermath of recent devastating earthquakes. The FRC thin jacketing prevents the joint panel shear failure, promoting a more favorable beam yielding. This results in a significant increase of the shear strength (until 50%) and energy dissipation (85%). The strengthening phases and the details of the proposed strengthening layout are described. The as-built and strengthened specimens are compared in terms of global and local behavior. Strain measurements on the FRC jacketing are also discussed as an effective design parameter.

Modern seismic design and the retrofitting of buildings necessarily need to account for expected economic losses. Available refined and simplified procedures implemented in automatic computer tools allow for probabilistic loss assessments. These mostly rely on consequence functions derived by simulating the repair actions needed to restore a component to its pre‐earthquake condition. However, due to the lack of data, only a few studies have benchmarked theoretical loss assessments with actual repair costs monitored in the aftermath of earthquake events. This paper analyses the actual repair costs of a database of 120 reinforced concrete residential buildings damaged by the 2009 earthquake in L’Aquila, Italy. The repair cost distributions and the correlation with observed earthquake damage are provided at the building and component levels. The repair costs of drift‐ and acceleration‐sensitive components are also reported. This study outlines that repairing hollow clay brick infills and partitions that are typical of the Mediterranean construction standard constitutes the majority of total repair costs. Reliable consequence functions calibrated on actual cost data are proposed for different damage states.