Seismic Evaluation Method of Geometrically Eccentric Reinforced Concrete Structure with Torsional Plastic Hinge

Seismic Evaluation Method of Geometrically Eccentric Reinforced Concrete Structure with Torsional Plastic Hinge

The methods of pushover analyses are still not suitable for the seismic evaluation of eccentric structures. In this, such structures need to consider their members’ torque effect. Thus, this study was tasked to develop torsional plastic hinges of structural members in simulating their torque behavior. The cracking torque and the nominal torsional moment strength were computed according to ACI 318-08 and reasonable reduction in torque strengths has been proposed under combined loadings. Cracking and ultimate torsional rigidities originated by Hsu(1984) was adopted. These rigidities are reasonable and conservative when compared with experimental results. Torsional plastic hinge was established according to the torque-twist relationship. In pushover analysis of a pure frame specimen, torsional effect becomes more obvious when the eccentricity increases. The initial stiffness increases with the eccentricity. The displacement corresponding to the 0.8 maximum base force decreases with the increasing eccentricity.