Comparison of Incremental Dynamic and Pushover Analysis of Jacket Type Offshore Platforms

2007 ◽  
Author(s):  
B. Asgarian ◽  
A. Raziei
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Nonlinear Dynamic ◽  
Interaction Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Nonlinear Static Analysis ◽  
Offshore Platforms ◽  
Nonlinear Static ◽  
Nonlinear Behaviors ◽  
Strong Ground

Jacket Type Offshore Platforms show nonlinear behaviors under strong ground motions result from nonlinear behaviors of soil, pile and jacket members. Nonlinear behavior study isn’t carried out accurately unless an accurate and suitable analytical method is selected. The main focus of this paper is the soil-pile-structure interaction analysis of the jacket type offshore platforms subjected to strong ground motion. A nonlinear dynamic analysis shows a true response if a logical model and an accurate theory are selected. In addition to nonlinear dynamic analysis, nonlinear static analysis is also carried out in this paper and results of the static nonlinear and dynamic nonlinear analyses have been compared. It was concluded that nonlinear static analysis can be used under some conditions instead of nonlinear dynamic analysis.

Bedrock Depth Effect Investigation in Seismic Response of Offshore Platforms Considering Soil-Pile-Structure Interaction

2007 ◽  
Author(s):  
B. Asgarian ◽  
M. A. Roshandel Tavana ◽  
R. H. Soltani
Keyword(s):  
Dynamic Analysis ◽  
Seismic Response ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Offshore Platform ◽  
Offshore Platforms ◽  
Structure Interaction ◽  
Strong Ground

Offshore platforms in seismically active areas should be designed to survive severe earthquake excitations with no global structural failure. In seismic design of offshore platforms, it is often necessary to perform a dynamic analysis that accounts for nonlinear soil-pile-structures interaction effects. Nonlinear dynamic analysis for offshore structures has been a major challenge in marine structural and earthquake engineering. In this paper, nonlinear dynamic analysis of jacket type offshore platforms considering soil-pile-structure interaction subjected to strong ground motion have been studied. A jacket type offshore platform is included of piles, jacket and topside with different behaviors in seismic loading. Both jacket and pile elements have been modeled using fiber cross-sections. In this paper, free field ground motion analysis with respect to bedrock excitations has been done using nonlinear stress-strain relations for soil. This model has been developed using Open System for Earthquake Engineering Simulation (OpenSEES) software. In this paper, nonlinear seismic response analysis of an existing sample offshore platform in Persian Gulf subjected to strong ground motions in different bedrock depths has been performed and the results in terms of lateral deflections of platform, soil layers displacement-time history and acceleration response spectra of pile head, top of jacket and deck have been presented.

A Comparison Between Modal Push-Over and Nonlinear Dynamic Response of Jacket Type Offshore Platforms Subjected to Strong Ground Motions

2008 ◽  
Author(s):  
M. A. Roshandel Tavana ◽  
B. Asgarian
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Nonlinear Dynamic ◽  
Strong Ground Motion ◽  
Ground Motions ◽  
Nonlinear Dynamic Analysis ◽  
Offshore Platforms ◽  
Modes Of Vibration ◽  
Strong Ground

Nonlinear dynamic analysis for offshore structures has been a major challenge in marine structures and earthquake engineering. Nonlinear Dynamic Analysis of the structures subjected to strong ground motions is the most reliable prediction method. This method is very complex and expensive. An alternative procedure that has found to be much applicable in recent years is the nonlinear static analysis called push-over analysis method. Many attempts have been made to improve the predictive capabilities of the push-over analysis, particularly by employing adaptive load patterns and accounting for higher modes of vibration effects through modal push-over. In this paper, modal push-over analysis (MPA) of jacket type offshore platforms considering soil-pile-structure interaction subjected to strong ground motion has been studied and the results have been compared with “exact” nonlinear response history analysis (NLRHA). A jacket type offshore platform includes of piles, jacket and deck with different behaviors during strong ground motion. In this paper, three-dimensional model of jacket and pile has been considered using a combination of finite element method (FEM) and beam on nonlinear winkler foundation (BNWF) approach in an integrated model. Both jacket and pile elements have been modeled using fiber sections. The model has been developed using Open System for Earthquake Engineering Simulation (OpenSEES) software. In this paper, nonlinear seismic analysis of a new designed jacket type offshore platform located in Persian Gulf subjected to different levels of earthquake has been performed and the results have been compared with MPA ones. It can be concluded that the error percentage in MPA procedure is negligible when more modes of vibration are participated in the evaluation of the structure behavior.

Evaluation of Nonlinear Static Procedures in the Assessment of Building Frames

2013 ◽  
Vol 29 (4) ◽  
pp. 1459-1476 ◽  
Author(s):  
Rui Pinho ◽  
Mário Marques ◽  
Ricardo Monteiro ◽  
Chiara Casarotti ◽  
Raimundo Delgado
Keyword(s):  
Dynamic Analysis ◽  
Adaptive Capacity ◽  
Nonlinear Dynamic ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Capacity Spectrum Method ◽  
Modal Pushover Analysis ◽  
Spectrum Method ◽  
Capacity Spectrum ◽  
Nonlinear Static

In recent years a number of nonlinear static procedures (NSPs) have been developed and proposed. Such pushover-based seismic assessment procedures are relatively straightforward to employ and are generally chosen over nonlinear dynamic analysis, especially within the realm of design office application. Parametric comparisons between the different NSPs available, however, are still somewhat sparse. In this work, five commonly employed NSPs (the N2 method, capacity spectrum method, modal pushover analysis, adaptive modal combination procedure, and the adaptive capacity spectrum method) are applied in the assessment of 16 frames subjected to a large number of input motions with a view to assess the accuracy level of such approaches through comparison with nonlinear dynamic analysis results. The evaluation shows that all the NSPs are able to accurately predict displacements and to produce reasonable estimates for other response parameters, with limited dispersion. Even though no single NSP tested led to consistently superior results, modal pushover analysis and the adaptive capacity spectrum method seemed to perform slightly better.

Applications of Capacity Spectrum Method for Buildings With Metallic Yielding Dampers

2005 ◽  
Author(s):  
Bo-Jen Chen ◽  
C. S. Tsai ◽  
L. L. Chung ◽  
Tsu-Cheng Chiang
Keyword(s):  
Static Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Iteration Procedure ◽  
Nonlinear Static Analysis ◽  
Severe Damage ◽  
Capacity Spectrum Method ◽  
Spectrum Method ◽  
Capacity Spectrum ◽  
Earthquake Resistant ◽  
Nonlinear Static

The 921 Chi-Chi Earthquake was one of the most destructive earthquakes in Taiwan in the twentieth century. The earthquake caused severe damage or collapse to the residential and public structures. It is a sensible choice to utilize the metallic yielding dampers for retrofitting damaged structures and to enhance earthquake-resistant capacity of new structures. In this paper, in order to facilitate the designs of the metallic yielding dampers, an improved nonlinear static analysis iteration procedure based on the capacity spectrum method for buildings with metallic yielding dampers has been proposed. The numerical results of the buildings with the metallic yielding dampers through the nonlinear static analysis iteration procedure and the nonlinear dynamic analysis have been obtained, compared and verified in this study. Moreover, it is also illustrated that the proposed nonlinear static analysis iteration procedure based on the capacity spectrum method for structures with metallic yielding dampers can fairly predict the seismic responses of the buildings with metallic yielding dampers during the earthquakes.

The Use of a Simplified Model for the Nonlinear Dynamic Analysis of Fixed Offshore Structures

1993 ◽  
Author(s):  
Marco A. Souza ◽  
Osvaldo C. Pinto
Keyword(s):  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Ocean Waves ◽  
Offshore Structures ◽  
Simplified Model ◽  
Brazilian Coast ◽  
Offshore Platforms ◽  
Exact Form ◽  
Linear Dynamic

Abstract A simplified model is used in the nonlinear dynamic analysis of fixed offshore platforms. The characteristics of the model are presented and its adequacy for the study is discussed. The action of ocean waves on the model is obtained using typical waves of the Brazilian coast. The nonlinear equation of motion is obtained in its exact form and is expanded up to the cubic term. A comparison between the nonlinear analysis and the linear dynamic analysis is presented. A comparison between experimental results and those obtained with the model is also presented.

scholarly journals Progressive Collapse Analysis of Reinforced Concrete Structures: A Simplified Procedure

2017 ◽  
Vol 2 (10) ◽  
pp. 7 ◽  
Author(s):  
Arash Naji ◽  
Mohamadreza Rohani
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Static Analysis ◽  
Progressive Collapse ◽  
Concrete Structures ◽  
Nonlinear Static Analysis ◽  
Reinforced Concrete Structures ◽  
Collapse Analysis ◽  
Nonlinear Static ◽  
Progressive Collapse Analysis

In this paper, a simplified analysis procedure to calculate the column removed point displacement at progressive collapse analysis of reinforced concrete structures is proposed. The energy absorption capacity under the column missing event is used for formulations. The approximate method is simple to utilize, user friendly, yet accurate. For progressive collapse analysis of structures, linear static analysis, nonlinear static analysis, linear dynamic analysis and nonlinear dynamic analysis can be performed. In this paper, the nonlinear static analysis from alternate load path method is used and the reason of initial local collapse has not been considered. In fact, an energy-based method by using load-displacement curve of RC frame and considering the effect of floor slab for the progressive collapse analysis is considered. The accuracy of the proposed method is demonstrated by comparing the results to three experimental and analytical results. Finally, the effects of the spans length, sections dimensions, material properties and the beams reinforcements of column removed spans on substructure behavior is studied, as well.

Improvement of progressive collapse resistance potential of semi-rigid jointed steel frames through bracings

2016 ◽  
Vol 7 (4) ◽  
pp. 518-546
Author(s):  
Milan Bandyopadhyay ◽  
Atul Krishna Banik
Keyword(s):  
Static Analysis ◽  
Progressive Collapse ◽  
Steel Frames ◽  
Nonlinear Dynamic Analysis ◽  
Nonlinear Static Analysis ◽  
Braced Frame ◽  
Collapse Resistance ◽  
Column Removal ◽  
Rigid Frames ◽  
Nonlinear Static

Progressive collapse studies of both unbraced and braced semi-rigid jointed steel frames have been carried out to evaluate the contribution of bracings in improving progressive collapse resistance potential. Numerical models of 10-story frames with different types of semi-rigid connections have been developed using SAP2000. Progressive collapse potential of semi-rigid frames is first investigated without bracings. Bracings are then included in a systematic manner, and response of the braced frame is compared with that of unbraced frame to evaluate the contribution of bracings. Two different arrangements of bracings, that is, bay-wise and floor-wise arrangements, are considered to find out a preferred arrangement of bracings. Parametric studies include eight column removal conditions at center and corner locations of different floors. Development of catenary action has also been considered as it gives additional resistance, especially to braced frame. Apart from nonlinear static analysis, effects of bracings are evaluated also through nonlinear dynamic analysis and the responses of the frames in nonlinear dynamic analysis are compared with those of nonlinear static analysis. From the study, it is found that provision of bracings significantly improves the progressive collapse resistance potential of the semi-rigid frames under different column removal conditions. Floor-wise arrangement of bracings is much effective as compared to bay-wise arrangement.

Nonlinear Dynamic Response of Membranes: State of the Art

1991 ◽  
Vol 44 (7) ◽  
pp. 319-328 ◽  
Author(s):  
Chris H. Jenkins ◽  
John W. Leonard
Keyword(s):  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Nonlinear Static Analysis ◽  
Fluid Structure Interactions ◽  
Membrane Structures ◽  
Field Equations ◽  
Surface Geometry ◽  
Large Rotation ◽  
Strain Type

Membrane structures have been used since the earliest of times. Until recently, their analysis has relied chiefly on trial and error; however, modern methods of analysis are evolving. The deformations are nearly always of the large rotation and/or strain type and are thus inherently nonlinear. Static analysis can be considered as a special case of the dynamic analysis. This paper is concerned then with reviewing methods of nonlinear dynamic analysis of membrane structures. Two problems of analysis are associated with membrane structures: (i) shape (or form) finding; (ii) response (deformation and/or stress) analysis. Shape finding (ie, determination of the surface geometry given an initial prestress, generation of cutting patterns, etc) is nontrivial but well documented in the literature and is not considered in this paper. In this review attention is instead focused on formulation of field equations, wrinkling analysis, fluid/structure interactions, material nonlinearities, and computational methods.

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