Pushover Test, CPRI, Bangalore

Pushover Test

Reactor Safety Division (RSD), BARC along with Central Power Research Institute (CPRI) Bangalore conducted a round robin exercise and theme meeting on pushover test on prototype Reinforced Concrete structure at CPRI Bangalore.

The test was Asia’s largest pushover test and was one of its kind. The structure built was a replica of a substructure of an existing office building at BARC. The structure was tested till failure in the tower testing facility present in CPRI.

This structure was then repaired and retrofitted using Fibre Reinforced Polymer Composites (FRPC). The institutes/organizations who participated in the second phase of the exercise included, BARC, NPCIL, DCS&EM, IIT Bombay, IISc Bangalore, CPRI Bangalore, SERC Chennai, Thapar Institute of Technology Patiyala, UVCE Bangalore, IIIT Hyderabad, SIT Tumkur and PSN College of Engineering Tirunelveli, Sardar Patel College of Engineering, Mumbai. All the Materials used and fibre wrapping on the structure was taken care by R&M International at the site.

N order to evaluate the fundamental frequency of the structure in the two directions, before commencing the pushover test, a free vibration test was conducted for the retrofitted structure. Highly sensitive accelerometers were placed at different floors to pick up the vibration signal generated by the blow of a hammer. Fast Fourier Transform (FFT) of the signal gave the information on the fundamental frequency of the structure.

The conclusions involved the effect of fibre wrapping on the structure. The fundamental frequency determination of the structure after rehabilitation with fibre wrapping and before pushover test in two directions were also carried out. The testing gave a insight about earthquake resistance of rehabilitation with fibre wrap and also it was shown that almost 100% of strength was gained back by fibre wrapping on the damaged structure.