A simplified method in comparison with comprehensive interaction incremental dynamic analysis to assess seismic performance of jacket-type offshore platforms

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.

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Seismic vulnerability assessment of a high-rise molten-salt solar tower based on incremental dynamic analysis

E3S Web of Conferences ◽

10.1051/e3sconf/202019401005 ◽

2020 ◽

Vol 194 ◽

pp. 01005

Author(s):

Weiwei Sun ◽

Dina D’Ayala ◽

Jinxing Fu ◽

Wentao Gu ◽

Jun Feng

Keyword(s):

Dynamic Analysis ◽

Molten Salt ◽

Seismic Performance ◽

Vulnerability Assessment ◽

Seismic Vulnerability ◽

Incremental Dynamic Analysis ◽

Seismic Excitations ◽

Ground Acceleration ◽

Seismic Vulnerability Assessment ◽

High Rise

This paper investigates the seismic performance of a high-rise molten-salt solar tower by finite element modelling. The integrated and separated models for solar tower based on the concrete damage plastic model are validated by matching the behaviour of similar reinforced concrete chimney specimens. The modal analysis demonstrates the first four modes of the solar tower are translational vibration. Seismic simulations are developed through the incremental dynamic analysis. The most disadvantageous position of the tower is all concentrated in the opening section under multidirectional seismic excitations. The top displacement of the tower under bidirectional and three-directional earthquake actions is larger than that under unidirectional earthquake actions. The results of the seismic vulnerability assessment show that when the PGA equals to 0.035g, the tower will be intact; when the PGA equals to 0.1g (design peak ground acceleration), the probability of the moderate damage state is within 1.5%; when the PGA equals to 0.22g (maximum considered earthquake), the probability of the destruction state is below 0.7%. The seismic partitioned fragility analysis of the tower under multidirectional earthquake excitations illustrates that there are two peaks in the vulnerability surfaces. The anti-collapse analysis indicates the tower has a good seismic performance under multidirectional seismic excitations.

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

American Journal of Applied Sciences ◽

10.3844/ajassp.2008.1793.1803 ◽

2008 ◽

Vol 5 (12) ◽

pp. 1793-1803 ◽

Cited By ~ 9

Author(s):

Assareh

Keyword(s):

Dynamic Analysis ◽

Nonlinear Behavior ◽

Incremental Dynamic Analysis ◽

Offshore Platforms ◽

Single Piles

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

Buildings ◽

10.3390/buildings9040078 ◽

2019 ◽

Vol 9 (4) ◽

pp. 78 ◽

Cited By ~ 2

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.

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