INFLUENCE OF CORE ECCENTRICITY ON THE P-DELTA SENSITIVITY OF TALL REINFORCED CONCRETE BUILDINGS

Abstract

In this thesis, we deal with the effects of P-delta on tall buildings which have core eccentricities and load irregularity in them. Seismic performance of buildings can also be greatly affected by this phenomenon. A regular planed high-rise building is taken in this project and with help of shear walls eccentricity is introduced in the structure. To study the isolated effect of eccentricity and P-delta, all the other parameters such as size of members, grid spacing, loading and material properties were kept constant. Multiple models were created with P-delta effect on and off so as to get a better understanding of second order effects on high-rise buildings. Building was created over 50m so as to meet the criteria of tall buildings according to IS CODE 16700: 2023. Grid spacing was kept at a constant of 8m with secondary beams provided to lessen the slab length. Material was kept M30 in all the members and models throughout the length and height of the building. This study compares responses like Maximum storey displacement, Storey drift, Torsional moment about Z-axis, Overturning moment and time period of different models. The results indicate that as the eccentricity is increased in the structure and load irregularity increases, the torsional moment and displacement of top storey is considerably increased under P-delta effect. Buildings with more centrally located cores show much more balanced response to the lateral forces such as Earthquake. We have used Response spectrum method to monitor the seismic performance of the building/ models.