This study deals with the seismic behavior of old- type reinforced concrete (RC) beam-column jointand the effectiveness of an innovative application of Fiber Reinforced Concrete (FRC) as seismicstrengthening solution. Two real joint subassemblies were extracted from an existing buildingdamaged and demolished after the L’Aquila 2009 earthquake and tested in laboratory. The jointsexhibited poor quality concrete and reinforcement details typical of old design practice, which arevery difficult to reproduce in laboratory simulations. The joint tested in the as-built configurationshowed a brittle failure with joint diagonal cracking, as commonly observed in the aftermath of recentdevastating earthquakes. The FRC thin jacketing avoided the joint panel shear failure promoting amore favorable beam yielding. This resulted in a significant increase of the shear strength (until 50%)and energy dissipation (85%). The strengthening phases and the details of the proposed strengtheninglayout are described. A direct comparison between as-built and strengthened specimen in terms ofglobal and local behavior is reported. Strain measurements on the FRC jacketing are also discussedas an effective design parameter.
Seismic retrofit of real beam-column joints using Fiber Reinforced Cement (FRC) composites
DEL VECCHIO, CIRO
;BALSAMO, ALBERTO;
2018-01-01
Abstract
This study deals with the seismic behavior of old- type reinforced concrete (RC) beam-column jointand the effectiveness of an innovative application of Fiber Reinforced Concrete (FRC) as seismicstrengthening solution. Two real joint subassemblies were extracted from an existing buildingdamaged and demolished after the L’Aquila 2009 earthquake and tested in laboratory. The jointsexhibited poor quality concrete and reinforcement details typical of old design practice, which arevery difficult to reproduce in laboratory simulations. The joint tested in the as-built configurationshowed a brittle failure with joint diagonal cracking, as commonly observed in the aftermath of recentdevastating earthquakes. The FRC thin jacketing avoided the joint panel shear failure promoting amore favorable beam yielding. This resulted in a significant increase of the shear strength (until 50%)and energy dissipation (85%). The strengthening phases and the details of the proposed strengtheninglayout are described. A direct comparison between as-built and strengthened specimen in terms ofglobal and local behavior is reported. Strain measurements on the FRC jacketing are also discussedas an effective design parameter.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
