Title: SP-339-13: Seismic Performance of Full-Scale Reinforced Concrete Beam-Column Connections Extracted From Earthquake-Damaged Buildings
Author(s): Giulio Leon Flores, Reza V. Farahani, Hussien Abdel Baky, and Paul C. Rizzo
Publication: Symposium Paper
Appears on pages(s): 217-238
Keywords: seismic performance, full-scale seismic test, measured lateral stiffness, beam-column connections, precast concrete frames
This paper presents the structural testing of four full-scale reinforced concrete beam-column connections, extracted from reinforced concrete buildings that suffered minor damage from the Canterbury Earthquakes in New Zealand. Two connections are extracted from a moment frame comprising the secondary seismic-resisting system of a concrete building; two are extracted from moment frames of the primary seismic-resisting systems of a precast concrete building. The seismic performance of the connections is evaluated from the test results and compared to recommendations in ASCE 41 (2013) for the evaluation of existing buildings. Due to the size of the specimens, the tests were stopped when the actuator reached its maximum stroke, at interstory drifts between 2.5% and 3. The cast-in-place connections showed moderate damage after the tests, at ductility levels above 2.9, and their initial lateral stiffness was approximately 80% of the lateral stiffness of numerical models representing the undamaged state. The precast connections exhibited extensive damage along the construction joint between the precast beams and the cast-in-place beam-column joint, at ductility levels above 3.4. The plastic mechanism was governed by sliding shear of the precast beams, which caused severe stiffness deterioration at the end of the tests. The measured stiffness in this case was approximately half of the stiffness predicted by numerical models in which nonlinearity is considered in the form of flexural plastic hinges only. This unexpected behavior is attributed to the low quantity of reinforcing steel crossing the construction joint, and presumably earthquake damage.