Field surveys in the aftermath of major seismic events, laboratory tests and numerical studies outlinedthat existing reinforced concrete (RC) structures are likely to exhibit premature shear failures.However, a proper quantification of the shear capacity of existing members with seismic details nonconformingto current seismic code is still a challenging task. Several models based on mechanicalapproaches or experimental observations are available in literature, current standards and guidelines.Nevertheless, the lack of a widely accepted theory often results in the use of old formulations, mainlydeveloped for design purposes, to assess the shear strength of non-conforming RC members. This studyinvestigates the available shear strength formulations. Eight capacity models commonly adopted in thecurrent practice and worldwide standards or guidelines have been assessed comparing the model predictionswith a unique database of 180 experimental tests properly selected to be representative of nonconformingRC members. Members with rectangular or circular cross-section, different aspect ratio(i.e. slender or squat) and shear or flexure-shear failure mode have been investigated. Meaningful statisticshave been used to quantify the accuracy and the level of safety of each formulation. Several criticismsin the use of the available formulations are herein outlined. Suggestions for the model applicability havebeen provided in order to drive the reader to select the most appropriate shear strength formulation forassessment purposes. Finally, corrective factors have been calibrated to allow the use of the selectedmodels with specific levels of safety.
Comparison of available shear strength models for non-conforming reinforced concrete columns
DEL VECCHIO, CIRO;
2017-01-01
Abstract
Field surveys in the aftermath of major seismic events, laboratory tests and numerical studies outlinedthat existing reinforced concrete (RC) structures are likely to exhibit premature shear failures.However, a proper quantification of the shear capacity of existing members with seismic details nonconformingto current seismic code is still a challenging task. Several models based on mechanicalapproaches or experimental observations are available in literature, current standards and guidelines.Nevertheless, the lack of a widely accepted theory often results in the use of old formulations, mainlydeveloped for design purposes, to assess the shear strength of non-conforming RC members. This studyinvestigates the available shear strength formulations. Eight capacity models commonly adopted in thecurrent practice and worldwide standards or guidelines have been assessed comparing the model predictionswith a unique database of 180 experimental tests properly selected to be representative of nonconformingRC members. Members with rectangular or circular cross-section, different aspect ratio(i.e. slender or squat) and shear or flexure-shear failure mode have been investigated. Meaningful statisticshave been used to quantify the accuracy and the level of safety of each formulation. Several criticismsin the use of the available formulations are herein outlined. Suggestions for the model applicability havebeen provided in order to drive the reader to select the most appropriate shear strength formulation forassessment purposes. Finally, corrective factors have been calibrated to allow the use of the selectedmodels with specific levels of safety.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
