Nonlinear Behavior of Single Piles in Jacket Type Offshore Platforms Using Incremental Dynamic Analysis

2008 ◽  
Author(s):  
Behrouz Asgarian ◽  
Mohammad Amin Assareh ◽  
Pejman Alanjari
Keyword(s):  
Dynamic Analysis ◽  
Site Response ◽  
Free Field ◽  
Nonlinear Behavior ◽  
Incremental Dynamic Analysis ◽  
Offshore Platforms ◽  
Limit States ◽  
Intensity Measures ◽  
Oil Exploitation ◽  
Single Piles

Offshore platforms are some of those structures which are built to withstand environmental and accidental loads during oil exploitation operation. One of the most usual types of these platforms is the Jacket Type Offshore Platform (JTOP) which can be divided into three important parts, which are Deck, Jacket, and piles. In order to increase the safety, particular attention should be paid to earthquake excitations which are directly applied to the piles of these structures. Nonlinearity in piles and buckling of the struts are important issues which have to be considered by the designers of offshore platforms. Incremental Dynamic Analysis (IDA) is a powerful tool to assess the capacity of a structure upon seismic loads. In this paper incremental dynamic analysis has been implemented on single piles considering soil-pile interactions and free field site response. The use of nonlinear materials and lateral load resisting elements in the incremental dynamic analysis done in this paper has made it possible to get promising insights for incorporation of appropriate limit states and applications of performance based engineering. Special Engineering Demand Parameters (EDP) and Intensity Measures (IM) have been introduced for the single pile dynamic analysis in jacket type offshore platforms.

Incremental Dynamic Analysis Considering Pile-Soil-Structure Interaction for the Jacket Type Offshore Platforms

2008 ◽  
Author(s):  
Behrouz Asgarian ◽  
Alireza Fiouz ◽  
Ali Shakeri Talarposhti
Keyword(s):  
Dynamic Analysis ◽  
Nonlinear Response ◽  
Limit State ◽  
Nonlinear Behavior ◽  
Incremental Dynamic Analysis ◽  
Layered Soil ◽  
Winkler Foundation ◽  
Offshore Platforms ◽  
Structure Interaction ◽  
Soil Deposits

Nonlinear response of piles is the most important source of potentially nonlinear behavior of offshore platforms due to earthquake excitations. It is often necessary to perform dynamic analysis of offshore platforms that accounts for soil nonlinearity, discontinuity condition at pile soil interfaces, energy dissipation through soil radiation damping and structural nonlinear behaviors of the piles. Incremental dynamic analysis is an analysis method that has recently emerged as a promising tool for thoroughly evaluating the seismic performance of structures. It involves subjecting a structural model to a suite of ground motion records, each scaled to several intensities and recording the responses at each level to form IDA curves of response versus intensity. In this paper, jacket and soil-pile system is modeled and the effects of Soil-Pile-Structure Interaction (SPSI) are considered, and the Incremental Dynamic Analysis (IDA) is used to investigate nonlinear behavior of offshore platforms. An attempt is made to introduce a practical BNWF (Beam on Nonlinear Winkler Foundation) model for estimating the lateral response of flexible piles embedded in layered soil deposits subjected to seismic loading. This model was incorporated into a Finite Element program (OpenSees). All the analyses are performed in two directions and the results are compared with each others. A computer program for Nonlinear Earthquake site Response Analyses of layered soil deposits (NERA) is used for analysis nonlinear response of soil layers. Limit state of the jacket is calculated from incremental dynamic analysis of the jacket using fiber elements for the nonlinear modeling of the system.

Applied Incremental Dynamic Analysis

2004 ◽  
Vol 20 (2) ◽  
pp. 523-553 ◽  
Author(s):  
Dimitrios Vamvatsikos ◽  
C. Allin Cornell
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Hazard Analysis ◽  
Limit State ◽  
Incremental Dynamic Analysis ◽  
Test Bed ◽  
Limit States ◽  
Intensity Measures ◽  
Structural Demand

We are presenting a practical and detailed example of how to perform incremental dynamic analysis (IDA), interpret the results and apply them to performance-based earthquake engineering. IDA is an emerging analysis method that offers thorough seismic demand and capacity prediction capability by using a series of nonlinear dynamic analyses under a multiply scaled suite of ground motion records. Realization of its opportunities requires several steps and the use of innovative techniques at each one of them. Using a nine-story steel moment-resisting frame with fracturing connections as a test bed, the reader is guided through each step of IDA: (1) choosing suitable ground motion intensity measures and representative damage measures, (2) using appropriate algorithms to select the record scaling, (3) employing proper interpolation and (4) summarization techniques for multiple records to estimate the probability distribution of the structural demand given the seismic intensity, and (5) defining limit-states, such as the dynamic global system instability, to calculate the corresponding capacities. Finally, (6) the results can be used to gain intuition for the structural behavior, highlighting the connection between the static pushover (SPO) and the dynamic response, or (7) they can be integrated with conventional probabilistic seismic hazard analysis (PSHA) to estimate mean annual frequencies of limit-state exceedance. Building upon this detailed example based on the nine-story structure, a complete commentary is provided, discussing the choices that are available to the user, and showing their implications for each step of the IDA.

Seismic Performance of Jacket Type Offshore Platforms Through Incremental Dynamic Analysis

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Behrouz Asgarian ◽  
Azadeh Ajamy
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Earthquake Engineering ◽  
Dynamic Instability ◽  
Ground Motions ◽  
Nonlinear Behavior ◽  
Incremental Dynamic Analysis ◽  
Offshore Platforms ◽  
Strong Ground Motions ◽  
Strong Ground

Fixed offshore platforms in seismic active areas may be subjected to strong ground motions, causing the platform to undergo deformation well into the inelastic range. In this paper, incremental dynamic analysis (IDA) of jacket type offshore platforms subjected to earthquake was performed in order to study the linear and nonlinear dynamic behavior of this type of structures. IDA is a parametric analysis method that has been recently presented to estimate structural performance under seismic loads. By using incremental dynamic analysis of jacket type offshore platforms, the assessment of demand and capacity can be carried out. The method was used to predict nonlinear behavior of three newly designed jacket type offshore platforms subjected to strong ground motions. The engineering demand parameters of the platforms in terms of story drifts and intermediate elevation maximum displacement for different records were compared. This method was used for the performance calculations (immediate occupancy, collapse prevention, and global dynamic instability) needed for performance-based earthquake engineering of the above mentioned platforms. Two different behaviors were observed for the third platform in the X and Y directions. Particular attention has to be paid for the seismic design of this kind of platform. The results of jacket type offshore platforms incremental dynamic analysis shows that the method is a valuable tool for studying dynamic behavior in a nonlinear range of deformation. Because of high uncertainty in the nonlinear behavior of this type of structures, it is recommended to use this method for the assessment and requalification of existing jacket type offshore platforms subjected to earthquake.

Vector-valued intensity measures for incremental dynamic analysis

2017 ◽  
Vol 100 ◽  
pp. 380-388 ◽  
Author(s):  
Ying Zhou ◽  
Pinglan Ge ◽  
Jianping Han ◽  
Zheng Lu
Keyword(s):  
Dynamic Analysis ◽  
Incremental Dynamic Analysis ◽  
Intensity Measures ◽  
Vector Valued

scholarly journals Incremental Dynamic Analysis for Estimating Seismic Performance of Multi-Story Buildings with Butterfly-Shaped Structural Dampers

Buildings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 78 ◽  
Author(s):  
Alireza Farzampour ◽  
Iman Mansouri ◽  
Hamzeh Dehghani
Keyword(s):  
Dynamic Analysis ◽  
Seismic Performance ◽  
Structural Integrity ◽  
Specific Area ◽  
Load Resistance ◽  
Incremental Dynamic Analysis ◽  
Seismic Loads ◽  
Limit States ◽  
Braced Frame ◽  
Collapse Behavior

Structural strength and stiffness were previously investigated to sufficiently improve the lateral load resistance against major events. Many buildings require appropriate design to effectively withstand the lateral seismic loads and reduce the corresponding damages. Design methodologies and structural elements were recently introduced to improve the energy dissipation capability and limit the high force demands under seismic loadings. The new systems are designed to protect the structural integrity and concentrate the inelasticity in a specific area, while the remaining parts are kept undamaged and intact. This study introduces a new structural system with dampers having strategic cutouts, leaving butterfly-shaped shear dampers for dominating the yielding mechanism over other brittle limit states. The new system is designed for re-establishing the conventional eccentrically braced frame system with simple linking beams. The system with strategic cutouts is subsequently used and compared with the eccentrically braced frames (EBF) system for seismic performance investigation and incremental dynamic analysis (IDA), using the OpenSees program, which is used to indicate the collapse behavior under forty-four selected ground motions. Results show that the butterfly-shaped multi-story buildings, compared to the corresponding conventional systems, are capable of enhancing the system resistance against lateral seismic loads by postponing the collapse state to the larger drift ratio values.

Fragility analysis of a subway station structure by incremental dynamic analysis

2016 ◽  
Vol 20 (7) ◽  
pp. 1111-1124 ◽  
Author(s):  
Tong Liu ◽  
Zhiyi Chen ◽  
Yong Yuan ◽  
Xiaoyun Shao
Keyword(s):  
Dynamic Analysis ◽  
Earthquake Engineering ◽  
Seismic Vulnerability ◽  
Probabilistic Method ◽  
Incremental Dynamic Analysis ◽  
Seismic Intensity ◽  
Fragility Analysis ◽  
Subway Station ◽  
Limit States ◽  
Station Structure

Fragility analysis constitutes the basis in seismic risk assessment and performance-based earthquake engineering during which the probability of a structure response exceeding a certain limit state at a given seismic intensity is sought to relate seismic intensity and structural vulnerability. In this article, the seismic vulnerability assessment of a subway station structure is investigated using a probabilistic method. The Daikai subway station was selected as an example structure and its seismic responses are modeled according to the nonlinear incremental dynamic analysis procedure. The limit states are defined in terms of the deformation and waterproof performance of the subway station structure based on the central column drift angle and the structural tension damage distribution obtained from the incremental dynamic analysis. Fragility curves were developed at those limit states and the probability of exceedance at the limit states of operational, slight damage, life safety, and collapse prevention was determined for the two seismic hazard levels. Results reveal that the proposed fragility analysis implementation procedure to the subway station structure provides an effective and reliable seismic vulnerability analysis method, which is essential for these underground structural systems considering their high potential risk during seismic events.

The Effects of Free Field Ground Motion Analysis on Seismic Response of Offshore Piles

2005 ◽  
Author(s):  
Mehrdad Kimiaei ◽  
Mohsen Ali Shayandar ◽  
M. Hesham El Naggar ◽  
Ali Akbar Aghakouchak
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Free Field ◽  
Nonlinear Behavior ◽  
Winkler Foundation ◽  
Main Concern ◽  
Offshore Platforms ◽  
Seismic Excitations ◽  
Earthquake Design ◽  
Offshore Piles

Nonlinear response of piles is the most important source of potentially nonlinear behavior of pile-supported offshore platforms due to earthquake excitations. Earthquake design of offshore platforms is one of the main parts in offshore platforms design on which seismic soil pile structure interaction could be the main concern. In this paper, seismic response of offshore piles embedded in layered soil deposits is determined using a BNWF model (Beam on Nonlinear Winkler Foundation). Results of the free field ground motion analyses using equivalent-linear or nonlinear approaches are applied as input seismic excitations to the support nodes of BNWF model. Sensitivity of the results to input ground motions are discussed and addressed in this paper. Computed responses are also compared with centrifuge test results.

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