TO STUDY AND IMPROVE THE BEHAVIOR OF FLAT PLATE AND FLAT SLAB UNDER SEISMIC EXCITATION

Abstract

Pakistan is still striving for improvements in construction industry. Major construction in private sector is carried out as non-engineered; there are very few projects that are properly designed for gravity and lateral loads, which is main cause behind deaths in major earthquakes. For example, Kashmir-Hazara (2005) earthquake caused deaths of 85,000 people. Nevertheless, after the Kashmir-Hazara (2005) earthquake, the government and engineering commission stressed on execution of a seismic code. Flat-plate and Flat-slab structures possess major advantages over conventional beamcolumn supported frame structures because of absence of deep beams these structures have freedom in building layout, lesser construction time, architectural, efficient and economical parameters. These structural systems are significantly more flexible and have less stiffness. Two-storey representative commercial building was selected for analysis, which is common practice in Rawalpindi-Islamabad region. Frame (having both columns and beams) structure was taken as a baseline and Flat plate and slab were compared with it. After doing Push-over analysis of these structures results showed weak behavior of flat plate and slab which was quantified using the backbone curves of these structures. CFRP (Carbon fiber reinforced Polymers) fabric was wrapped on concrete cylinders casted in lab and compression test (ASTM C39) along with strain monitoring mechanism was done to achieve stress-strain curve of wrapped and unwrapped specimens. In order to model CFRP fabric being applied in potential plastic-hinge zone of the columns of flat plate and flat slab structures plastic hinge properties of columns were modified according to moment curvature curve of the column section and these retrofitted structures were again analyzed and results were quantified to compared these retrofitted structures with non-retrofitted structures and with frame structure.