Behavior of Steel Structures in Seismic Areas (STESSA 2006) (original) (raw)
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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.
Effect of P-Delta analysis for tall slender building structures
Behaviour of Steel Structures in Seismic Areas (STESSA), Japan, 2006
High-rise buildings are essential in metro cities of developing countries. One of the important aspect of design of tall buildings / frames is to ensure its lateral stability taking care of maximum drift stipulation. This paper includes guidelines stipulated in various codes [such as UBC–Vol. 3 (1997), IS: 800(2007), IS: 1893 (2002 Part-1), etc.] to restrict the P-Delta effect. According to the recent trends for economic limit state design, it is necessary to carry out the nonlinear dynamic analysis in seismic condition for highly ductile material. This also helps to avail advantage of high strength within elastic range. As steel is more ductile than reinforced concrete, geometric non-linearity including stress softening P-Delta effect is an important factor in the design of tall slender steel structures. This also ensures suitability of steel intensive construction including steel-concrete composite construction over the conventional RCC framed construction. Also it requires high end softwares such as STAAD Pro, SAP, ETABS etc. for computation purpose. In the present case STAAD software has been used.
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.
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.
P-Delta effects on SCWB & WCSB steel frames subject to seismic loading
Routledge (Taylor & Francis group), 2023
With the increase in population worldwide, the demand for modern houses is increasing. Earthquakes take a huge toll on life and property. Since the effect of seismic forces on structures is quite significant, it is important that the design of the structures must be done in the best possible way to take into account these effects and thereby aiming for an adequate structural response. In this discussion we will address in a concise way, two methods in the design of steel structures, which are linear analysis and second order effects (P-Δ). It is known that a nonlinear analysis is more accurate than a linear analysis, but on the other hand is an inefficient analysis in terms of time consuming with calculations and computer memory. So static P-delta analysis is considered here and compared with the linear response spectrum analysis of SCWB and WCSB steel frames.
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.
— 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.
Investigating the P-Delta effects on the seismic collapse capacity of adjacent structures
Pounding between structures during earthquakes has been a subject of research for many years, and researchers have considered a variety of conditions of adjacent structures in their studies. The pounding phenomenon includes some factors such as cracking, plastic deformation, energy dissipation, friction and fracture due to impact. The purpose of this study is to evaluate the P-delta effects on the seismic collapse capacities of pounding structures assuming different values of clear distance among them. For this purpose, 2-, 4-and 6-story structures with different values of clear distance, having linear viscoelastic contact elements in floor levels among them, are assumed. Nonlinear Multi-Degree-of-Freedom (MDOF) stick models are applied to simulate Moderately Ductile (MD) structures representing steel intermediate moment-resisting frames. It is worth mentioning that an algorithm is used to remove the collapsed structure during the Incremental Dynamic Analyses (IDAs) to compute the seismic collapse capacities of both structures using the OpenSees software. Furthermore, in contrast to many studies that investigated pounding without considering the P-delta effect, two types of models with and without considering the P-delta effects are analyzed. The results indicate that considering the P-delta effect in modeling has a significant influence on the seismic collapse capacities of the structures and the impact forces. Also, the results indicate that the existence of the P-delta effect and insufficient clear distance between the structures affect the acceleration and other responses of the structures.
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.
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.