Effect of P-Delta analysis for tall slender building structures (original) (raw)

P DELTA (P-∆) EFFECT ON MULTISTORIED REINFORCED CONCRETE FRAMED BUILDING WITH VERTICAL ERRIGULARITIES

1st International Conference on Research and Innovation in Civil Engineering (ICRICE 2018), 2018

The demand of high rise building is increasing day by day to accommodate more people in less space. Generally, P-Delta analysis is not performed during design and analysis of Reinforced Concrete framed structure. High rise structure may collapse under severe perimeters if 'P-Delta' analysis is not considered in the analysis and design phase. Due to defective construction practices and ignorance for earthquake resistant design of buildings in our country, most of the existing buildings are vulnerable to future earthquakes. This study deals with the analysis of RC framed regular and irregular buildings in Zone-IIΙ using inelastic method (P-Delta Analysis). The objective of this study is to find out the effect on response quantities (Story Drift, Displacement & Stiffness) due to 'P-Delta' effect on the RC framed structure and also find out the effect of asymmetry on this analysis. 'P-Delta' analysis is nonlinear static analysis, so the structural responses are included the additional response produced due to the simultaneously action of lateral and gravity load on un-deformed as well as deformed geometry. After analysis, it is found that the response quantities are higher if 'P-Delta' effect is considered and in the case of irregular structure the response quantities are higher in compare to the regular structure.

GEOMETRIC NON-LINEAR ANALYSIS OF HIGHRISE BUILDINGS UNDER SEISMIC LOADING

P-delta effect is a secondary effect on structure, also known as ‘ Geometric nonlinearity effect ’ . With increase in number of stories, P-Delta effect becomes more important. If the variation within bending moments and displacements is more than 10%, P-delta effect should be considered in design. In this study, high rise building is studied and both, linear static analysis (without P-delta effect) and second order analysis (with P-delta effect) on high rise building having different number of stories have been carried out. Building models with different storey heights have been analyzed to investigate the maximum response in the building in terms of displacement, drift ratio, moment and shear forces. The analysis of multistoried RC building have been done using ETABS 2015 Ver. 15.2.0 structural analysis software.

BEHAVIOUR OF STEEL STRUCTURES IN SEISMIC AREAS

Rapid growth of urbanization world over indicates that there is growing movement of population which result in high concentration of building construction activities in urban areas. The high rise buildings require high frame structure stability for safety and design purposes. Structures subjected to lateral loads often experience secondary forces due to the movement of the point of application of vertical loads. This secondary effect, commonly known as P-Delta effect plays an important role in the analysis of the structure. In the above context, this thesis work describes Seismic analysis of a multi-storey R.C.C building and STEEL building by using STAAD structural analysis Software. Usually the multi-storey buildings are analyzed using general one step linear static analysis assuming the full loads to be applied on the structure. But there may be lot of differences in the outcomes obtained from the analysis against practical aspect. Therefore, to briefly understand and to overcome this problem a P-Delta analysis is performed for the structure.

STABILITY ANALYSIS OF STEEL FRAME STRUCTURES: P-DELTA ANALYSIS

The high rise buildings require high frame structure stability for safety and design purposes. This research focused on P-delta analysis to be compared with linear static analysis. In this study, a 18 storey steel frame structure with 68.9 m has been selected to be idealized as multi storey steel building model. The model is analyzed by using STAAD.Pro 2007 structural analysis software with the consideration of P-delta effect. At the same time the influence of different bracing patterns has been investigated. For this reason five types of bracing systems including X, V, Single Diagonal, Double X, K bracing with unbraced model of same configuration are modeled and analyzed. The framed structure is analyzed for Wind load as per IS 875 (part 3)-1987. After analysis, the comparative study is presented with respective to Maximum storey displacement and Axial Force. The present work showed that the 'X'bracing in continuous bracing pattern is proved to be more effective with respect to both Static and P-delta analysis.

Evaluation of p-delta effect in structural seismic response

Numerous recent studies have assessed the effect of P-Delta on the structures. This paper investigates the effect of P-Delta in seismic response of structures with different heights. For indicating the effect of P-Delta, nonlinear static analysis (pushover analysis) and nonlinear dynamic analysis (Time history analysis) were conducted by using finite element software. The results showing that the P-Delta has a significant impact on the structural behavior mainly on the peak amplitude of building when the height of the structures increased. In addition, comparison has been made between concrete and steel structure.

Study of P-Delta Effect on Tall Steel Structure

The high rise buildings require high frame structure stability for safety and design purposes. This research focused on Pdelta effect on the Tall Steel Structures and compared with linear static analysis. In this study, a 40 storey steel frame structure with m has been modelled by using SAP2000 structural analysis software with the consideration of P-delta effect. At the same time the influence of different bracing patterns has been investigated. For this reason five types of bracing systems including X, V, Single Diagonal, Inverted V , with unbraced model of same configuration are modelled and analysed. The framed structure is analysed for Earthquake load . After analysis, results showed that displacement due to P-Delta effect is 40% more compared to linear analysis and increase in the Axial force is about 8% for bare frame. The X bracing proved to be more stiff and effective with respect to linear analysis and P-Delta analysis. The decrease in the displacement is about 47.5% and 47.9% for linear and second order analysis.

A NOVEL APPROACH FOR SEISMIC ANALYSIS OF RESIDENTIAL REINFORCED CEMENT CONCRETE STRUCTURE AND TO SHOW IT'S P-DELTA EFFECT A Novel Approach for Seismic Analysis of Residential Reinforced Cement Concrete Structure and to Show It's P-Delta Effect

In present scenario, constructing multi-storied buildings such as regular type of buildings are gradually increasing, because due to the cost of site, foundation and architectural aesthetic view. These types of buildings are extremely dangerous if the buildings are built in seismically active regions. When the structures are exposed to critical loads the behavior of the structure is a difficult phenomenon, and is generally dependent on the kind of forces acting on the structure, magnitude of force, and direction on which it is acting. The design of these regular buildings should be proper, otherwise it leads to abrupt damage of the structures, and hence special consideration in analysis is to be given. The P-Delta effect is defined as an extra action by the loads in the structure, because of the structural deformation. In this paper, the effect of P-Delta on multi storey building is studied by using linear static analysis and P-Delta analysis in ETABS v15.2.2. The results obtained from the analysis are compared for Shear force, bending moment and displacement .P-Delta analysis shows 22% more than the Linear Static Analysis .Therefore the effect of P-Delta is important and it should be included in the analysis of multi storey buildings.

Analytical Study on Seismic Response of Reinforced Concrete Buildings Considering P-Δ Effect

Journal of Structural and Construction Engineering (Transactions of AIJ), 2019

When the building responses by earthquakes, the additional overturning moment the gravity load of the building produces as horizontal displacement increases. This influence called P-Δ effect is generally remarkable when the base shear coefficient is small. The purpose of this paper is to investigate the P-Δ effect on the horizontal deformation of ordinary high-rise buildings by earthquake response analysis using three types of input seismic motions (sweep wave, earthquakes specified in the notification and recorded seismic waves), and to derive response evaluation formula considering the P-Δ effect. The induced evaluation formula induced theoretically showed excellent compatibility with analytical response results.

INVESTIGATION OF THE EFFECTS OF P-DELTA ON TUBULAR TALL BUILDINGS

Due to rapid urbanization availability of land for buildings has become scarce, especially in urban landscape and the only way to overcome the same is go for vertical expansion resulting in tall buildings. Tubular tall buildings offer a viable solution for building heights greater than 120 m. However designing tall skyscrapers poses unique structural challenges which have to be overcome. There are several factors to be considered in the design of tall buildings out of which p-delta effect is an important one. Tall tubular buildings are designed not only to satisfy strength requirements but also serviceability considerations in the form of drift and deflections. P-delta effect is expected to cause additional deflections as well as moments. The configuration of the structure like its plan dimensions, height to least lateral plan dimension ratio and lateral stiffness play a significant role accentuating p-delta effect. This paper is an attempt to study systematically the effects of p-delta in tall tubular buildings. In this paper 9 models are analyzed and designed to understand the effect of p-delta. The models considered are of tubular rigid frame structures of total height of 126 m consisting of 42stories each. The models are analyzed for vertical as well as lateral earthquake loads using STAAD-Pro software.

Comparative Study of Seismic Performance of a Building with and without P-Delta Effect Using Response Spectrum Analysis

— The G+20 multi storey regular building is taken for present study. This building is modeled and analyzed by using ETABS V9.7.4. Assuming the material property as linear and non linear. The performance of the building is studied by comparing the base shear, displacement, storey drift in response spectrum analysis. Multi-storey buildings with open (soft) ground floor are inherently vulnerable to collapse due to earthquake load, even then their construction is still widespread in the developing nations. An investigation has been performed to study the behavior of the columns at ground level of multi-storey buildings with soft ground floor as satellite bus stop and moment transfer beams in all storey subjected to earthquake loading. The structural action of masonry infill panels of upper floors has also been taken into account by modeling them as diagonal struts. Shear wall is one of the most commonly used lateral load resisting in high rise building. In this study building is modeled with different shapes of shear wall with top and bottom soft storey.