International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 11 | Nov 2024
p-ISSN: 2395-0072
www.irjet.net
A REVIEW ON IMPACT OF P-DELTA EFFECTS ON THE SEISMIC PERFORMANCE OF HIGH-RISE RC BUILDINGS WITH VERTICAL GEOMETRIC IRREGULARITIES Dipesh D. Sambare1, Trupti Narkhede2, P. J. Salunke3 1PG Student, Dept. of Civil Engineering, Mahatma Gandhi Mission's College of Engineering and Technology
(MGMCET), Kamothe, Navi Mumbai, Maharashtra, India
2Assistant Professor, Dept. of Civil Engineering, Mahatma Gandhi Mission's College of Engineering and Technology
(MGMCET), Kamothe, Navi Mumbai, Maharashtra, India
3Head of Department, Dept. of Civil Engineering, Mahatma Gandhi Mission's College of Engineering and
Technology (MGMCET), Kamothe, Navi Mumbai, Maharashtra, India ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - The seismic performance of high-rise reinforced
phenomenon refers to the secondary effects that arise when the building undergoes lateral displacement. The lateral drift causes vertical loads (axial forces) to create additional moments in structural elements like columns, leading to increased deformation and potentially significant damage. As the building’s height increases, these P-Delta effects become more pronounced, particularly in buildings with vertical geometric irregularities. Such irregularities can lead to an uneven distribution of forces, exacerbating the impact of seismic events on the structure’s overall performance.
concrete (RC) buildings with vertical geometric irregularities is a critical consideration for structural engineers, especially in regions prone to seismic activity. One of the primary concerns is the influence of P-Delta effects, which arise due to the interaction between lateral displacements and the axial loads on structural elements. This study investigates the impact of PDelta effects on the seismic response of high-rise RC buildings with vertical geometric irregularities, including setbacks, changes in floor heights, and varying column sizes. A series of nonlinear dynamic analyses were conducted using various building configurations subjected to different seismic scenarios, considering both elastic and inelastic behavior. The results highlight the exacerbating influence of vertical irregularities on the seismic performance, with a significant increase in lateral displacements and internal forces due to the P-Delta effects. It was found that these effects can lead to increased inter-story drifts, potential non-uniform damage distribution, and overall system instability.
1.1 The Role of P-Delta Effects in Seismic Performance The P-Delta effect refers to the additional internal forces and moments that arise in a structure as it undergoes lateral displacement. These effects are most prominent in tall structures, as the lateral sway increases with height. As the building moves laterally under earthquake loading, the weight of the structure (P) acts on the displaced mass, creating additional forces that further amplify the lateral sway. This leads to increased axial forces in the columns and moment magnification at the joints and beams, which can significantly affect the building’s stability.
Key Words: P-Delta, Time History Analysis, Shear Wall, Seismic Performance, Vertical Geometric Irregularities, highrise RC Buildings.
1.INTRODUCTION
Key aspects of the P-Delta effect include:
High-rise reinforced concrete (RC) buildings are particularly susceptible to seismic forces due to their height and mass, which lead to significant lateral displacements during an earthquake. While structural systems are typically designed to resist lateral forces through a combination of shear walls, bracing, and moment-resisting frames, high-rise buildings often face additional challenges due to their vertical geometric irregularities. These irregularities can take various forms, such as abrupt changes in floor height (stepbacks), varying column spacing, or floor plans that reduce stiffness or mass distribution in certain sections of the building.
Increased Deformation: The displacement-induced moments in structural elements can increase overall drift and cause excessive deformations, potentially resulting in the failure of load-bearing components. For buildings with vertical irregularities, the P-Delta effect can exacerbate these deformations, especially in regions where the stiffness and strength may already be compromised. Moment Magnification: The moment induced by the PDelta effect can be especially severe in the upper floors of tall buildings. When combined with the vertical irregularities (e.g., reduced stiffness or mass at higher floors), the moment magnification becomes critical, potentially leading to the buckling of columns or failure of beams.
In seismic engineering, the P-Delta effect plays a crucial role in how buildings respond under lateral loading. This
© 2024, IRJET
|
Impact Factor value: 8.315
|
ISO 9001:2008 Certified Journal
|
Page 518