Shake Table Test of a 1/6 Scale Two-Story Lightly Reinforced Concrete Building
A.G. El-Attar, R.N. White and P. Gergely
A 1/6 scale, 2-story, one-bay by one-bay, lightly reinforced concrete building was tested on the Cornell University shake table. The model structure was designed solely for gravity loads and had no walls or partitions. Reinforcement was based on reinforced concrete frame structures constructed in the Central and Eastern United States since the mid 1900's, and characterized by a) low reinforcement ratio in the columns; b) discontinuous positive moment beam reinforcement at the columns; c) little or no joint confinement; and d) lap splices located immediately above the floor level. The model was tested using the time-compressed Taft 1952 S69E at different amplitudes. Auxiliary tests (static loading and free-vibration) were performed before and after each seismic test to study the changes in the model building properties. Results indicated that this type of reinforced concrete frame will experience very large deformations and considerable stiffness degradation during a moderate earthquake. Non-seismic reinforcement details may form a potential source of damage for lightly reinforced concrete buildings, though they did not lead to collapse or complete failure. The model failures occurred outside the joint regions, indicating that the lack of joint confinement was not a potential source of damage. The column lap splices did not cause a serious problem. Finally, both experimental and analytical results indicated that the inclusion of the slab contribution to the beam flexural strength is a vital step in the assessment of the performance of lightly reinforced concrete structures during earthquakes.
Lightly Reinforced Concrete Buildings, Shaking Table Tests, Detailing, Reinforcement, Eastern United States, Column Reinforcement Ratio, Joint Confinement, Lap Splices, and Earthquake Engineering.