scholarly journals Influence of Optimal Intensity Measures Selection in Engineering Demand Parameter of Fixed Jacket Offshore Platform

2021 ◽  
Vol 11 (22) ◽  
pp. 10745
Author(s):  
Sajib Sarker ◽  
Dookie Kim ◽  
Md Samdani Azad ◽  
Chana Sinsabvarodom ◽  
Seongoh Guk
Keyword(s):  
Seismic Performance ◽  
Oil And Gas ◽  
Time History ◽  
Coefficient Of Determination ◽  
Statistical Parameters ◽  
Ground Acceleration ◽  
Jacket Platform ◽  
Intensity Measures ◽  
Optimal Intensity ◽  
Nonlinear Time History

This research identifies the significant optimal intensity measures (IM) for seismic performance assessments of the fixed offshore jacket platforms. A four-legged jacket platform for the oil and gas operation is deployed to investigate the seismic performance. The jacket platform is applied with nonlinearly modeled using finite element (FE) software OpenSees. A total of 80 ground motions and 21 different IMs are incorporated for numerical analyses. Nonlinear time-history analyses are performed to obtain the jacket structure’s engineering demand parameters (EDP): peak acceleration and displacement at the top of the structure. Four important statistical parameters: practicality, efficiency, proficiency, and coefficient of determination, are then calculated to find the significant IMs for seismic performance of the jacket structure. The results show that acceleration-related IMs: effective design acceleration (EDA), A95 parameter, and peak ground acceleration (PGA) are optimal IMs, and the acceleration-related IMs have good agreements with the acceleration-related EDP.

scholarly journals Performance of an Existing Reinforced Concrete Building Designed in Accordance to Older Indonesian Seismic Code: A Case Study for a Hotel in Kupang, Indonesia

2018 ◽  
Vol 20 (1) ◽  
pp. 35
Author(s):  
Pamuda Pudjisuryadi ◽  
Benjamin Lumantarna ◽  
Ryan Setiawan ◽  
Christian Handoko
Keyword(s):  
Plastic Hinge ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Ground Acceleration ◽  
Seismic Code ◽  
Damage Level ◽  
History Analysis ◽  
Nonlinear Time History ◽  
Seismic Hazard Map

The recent seismic code SNI 1726-2012 is significantly different compared to the older code SNI 1726-2002. The seismic hazard map was significantly changed and the level of maximum considered earthquake was significantly increased. Therefore, buildings designed according to outdated code may not resist the higher demand required by newer code. In this study, seismic performance of Hotel X in Kupang, Indonesia which was designed based on SNI-1726-2002 is investigated. The structure was analyzed using Nonlinear Time History Analysis. The seismic load used was a spectrum consistent ground acceleration generated from El-Centro 18 May 1940 North-South component in accordance to SNI 1726-2012. The results show that Hotel X can resist maximum considered earthquake required by SNI 1726-2012. The maximum drift ratio is 0.81% which is lower than the limit set by FEMA 356-2000 (2%). Plastic hinge damage level is also lower than the allowance in ACMC 2001.

Effect of bidirectional excitation on seismic performance of regular RC frame buildings designed for modern codes

2021 ◽  
pp. 875529302110478
Author(s):  
Payal Gwalani ◽  
Yogendra Singh ◽  
Humberto Varum
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Inelastic Behavior ◽  
Moment Frame ◽  
Frame Buildings ◽  
Bidirectional Excitation ◽  
Rc Frame Buildings ◽  
Nonlinear Time History ◽  
Hinge Model

The existing practice to estimate seismic performance of a regular building is to carry out nonlinear time history analysis using two-dimensional models subjected to unidirectional excitations, even though the multiple components of ground motion can affect the seismic response, significantly. During seismic shaking, columns are invariably subjected to bending in two orthogonal vertical planes, which leads to a complex interaction of axial force with the biaxial bending moments. This article compares the seismic performance of regular and symmetric RC moment frame buildings for unidirectional and bidirectional ground motions. The buildings are designed and detailed according to the Indian codes, which are at par with the other modern seismic codes. A fiber-hinge model, duly calibrated with the biaxial experimental results, is utilized to simulate the inelastic behavior of columns under bidirectional bending. A comparison of the estimated seismic collapse capacity is presented, illustrating the importance of considering the bidirectional effects. The results from fragility analysis indicate that the failure probabilities of buildings under the bidirectional excitation are significantly higher as compared to those obtained under the unidirectional excitation.

scholarly journals The Effect of Long Duration Earthquakes on the Overall Seismic Behavior of Steel Structures Designed According to Eurocode 8 Provisions

Vibration ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 464-477
Author(s):  
Panagiota Katsimpini ◽  
Foteini Konstandakopoulou ◽  
George A. Papagiannopoulos ◽  
Nikos Pnevmatikos ◽  
George D. Hatzigeorgiou
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Steel Structures ◽  
Eurocode 8 ◽  
Steel Buildings ◽  
Long Duration ◽  
Base Steel ◽  
Fixed Base ◽  
Permanent Settlement ◽  
Nonlinear Time History

Premature and simultaneous buckling of several steel braces in steel structures due to the prolonged duration of a seismic motion is one of the issues that must be addressed in the next version of Eurocode 8. In an effort to contribute towards the improvement of the seismic design provisions of Eurocode 8, an evaluation of the overall behavior of some steel building-foundation systems under the action of long duration seismic motions is performed herein by means of nonlinear time-history seismic analyses, taking into account soil–structure interaction (SSI) effects. In particular, the maximum seismic response results—in terms of permanent interstorey drifts, overturning moments and base shears of the steel buildings as well as of the permanent settlement and tilting of their foundations—are computed. It is found that the seismic performance of steel buildings when subjected to long duration seismic motions is: (i) acceptable for the two and five-storey fixed base steel buildings and for the two-storey steel buildings with SSI effects included; (ii) unacceptable for the eight-storey fixed base steel buildings and for the five and eight-storey steel buildings with SSI effects included. In all cases of steel buildings with SSI effects included, the seismic performance of the mat foundation, as expressed by the computed values of residual settlement and tilting, is always acceptable.

Strengthening Research in the Longitudinal Frames of Prefabricated Structures with Viscous Dampers

2013 ◽  
Vol 671-674 ◽  
pp. 782-785
Author(s):  
Bin He ◽  
Jin Lai Pang ◽  
Cheng Qing Liu
Keyword(s):  
Seismic Performance ◽  
Pushover Analysis ◽  
Vertical Direction ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Viscous Dampers ◽  
Existing Building ◽  
Concrete Frame ◽  
Uniform Drift ◽  
Nonlinear Time History

For the lack of research in the longitudinal frame of prefabricated structure for its weak lateral stiffness, pushover analysis is conducted to evaluate the seismic performance of a fabricated concrete frame. Based on case study, the strengthening strategies with viscous dampers are analyzed. In view of the undesirable drift distribution and failure mode in the existing building, it is believed that arrangement of dampers should be designed to attain a uniform drift distribution. Based on the nonlinear time history analysis method, the strategy of damper allocation in vertical direction of the structure is investigated .Results indicate that a proper design might be attained based on the property of existing system, leading to a uniform drift distribution and better seismic performance.

scholarly journals Efficient Earthquake Intensity Measure for Seismic Vulnerability of Integral Abutment Bridges

2020 ◽  
Vol 20 (6) ◽  
pp. 251-260
Author(s):  
Duy-Duan Nguyen ◽  
Md Samdani Azad ◽  
Byung H. Choi ◽  
Tae-Hyung Lee
Keyword(s):  
Seismic Vulnerability ◽  
Lateral Displacement ◽  
Fragility Curves ◽  
Time History ◽  
Coefficient Of Determination ◽  
Integral Abutment ◽  
Earthquake Intensity ◽  
Ground Acceleration ◽  
Integral Abutment Bridges ◽  
Abutment Bridges

The purpose of this study is to identify efficient earthquake intensity measures (IMs) for evaluating the seismic vulnerability of integral abutment bridges. A total of 90 ground motion records and 20 typical IMs were employed for the numerical analyses. A series of nonlinear time-history analyses was performed on the bridges to observe the lateral displacement of the bridge piers. Statistical parameters such as the coefficient of determination, standard deviation, and correlation coefficient were calculated to identify the strongly correlated IMs with the seismic performance of the bridges. The numerical results show that the efficient IMs are spectral acceleration, spectral velocity, spectral displacement at the fundamental period, acceleration spectrum intensity, effective peak acceleration, peak ground acceleration, and A95. Moreover, a set of fragility curves of the bridges was developed with respect to the efficient IMs.

Study on Methods for HCLPF Value of Nonlinear Supports System of Steam Generator

2018 ◽  
Author(s):  
Feng-chun Cai ◽  
Xian-hui Ye ◽  
Qian Huang ◽  
Wenzheng Zhang
Keyword(s):  
Steam Generator ◽  
Nonlinear Model ◽  
Seismic Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Cost Calculation ◽  
Seismic Capacity ◽  
Ground Acceleration ◽  
Reactor Building ◽  
Nonlinear Time History

High confidence of low probability of failure (HCLPF) values of equipment, representing the seismic capacities of the equipment, are the fundamental ingredient in seismic probability safety assessment (SPSA) and seismic margin analyses (SMA). In this paper, two methods for calculating the HCLPF values of equipment were investigated, fragility analysis, and conservative deterministic failure margin (CDFM). These methods are linear methods. Based on these methods, HCLPF value of equipment can be computed conveniently by scaling the results of the existing seismic analysis. For a nonlinear systems, the HCLPF values based on these linear scaling methods are unrealistic. For a complicated nonlinear equipment or structure, a detail nonlinear model was used to derive the seismic capacity. The results by this method are realistic, but cost calculation time. In this paper, a nonlinear model of reactor coolant system coupled reactor building was built. This model includes the steam generator and considers the nonlinear factors of steam generator such as gap in the supports, plasticity of hot leg and cold leg. Forced motion was applied to the base of reactor building. And seismic response of the steam generator was calculated iteratively by scaling the ground motion level step by step. Based on these calculations, a curve of load on the supports VS peak ground acceleration (PGA) can be obtained. Then based on these curves and allowable load of supports of steam generator, which derived from stress analysis on support of steam generator, seismic capacity of the supports of steam generator was determined. Then the HCLPF Value of the supports of steam generator was obtained by this nonlinear time history analysis and was compared with the results based on the CDFM. The two results were different. Therefore, the HCLPF seismic capacity of equipment with nonlinearity, such as gap nonlinearity, should be calculated by nonlinear time history method.

Seismic Performance and Effects of Different Joint Shapes for Unbonded Precast Segmental Bridge Columns

2016 ◽  
Vol 32 (4) ◽  
pp. 427-433
Author(s):  
H.-L. Wang ◽  
S.-W. Liu ◽  
Z. Zhang
Keyword(s):  
Seismic Performance ◽  
Residual Deformation ◽  
Time History ◽  
Bridge Columns ◽  
Nonlinear Time History Analysis ◽  
Backbone Curve ◽  
Coulomb’S Friction ◽  
Plane Contact ◽  
Nonlinear Time History ◽  
Segmental Bridge

AbstractTo study the seismic performance and the effects of different joint shapes for unbonded precast segmental bridge columns under low-reversed cyclic loading, two 3-D finite element (FE) models respectively using plane-contact joints and shear resistant joints were established. In the FE models, the mechanical behaviors of concrete and tendons were respectively described by the damage-plastic model and the bilinear model, and the contact criteria was based on Coulomb's Friction. The results of nonlinear time history analysis showed that the deformation of the columns was mainly composed of alternately open-closed joints, and the failure of the column was mainly caused by concrete crush on the bottom segment. Compared with two model's hysteresis loop, backbone curve, ductility and residual deformation, it was found that the column with shear resistant joints had longer stable period of strength, better ductility, and smaller residual displacement than the column with plane-contact joints, so it had better seismic performance.

Analytical Study on Seismic Performance of Switchboard with Hybrid Spring Supports

2013 ◽  
Vol 470 ◽  
pp. 966-969
Author(s):  
Kyung Suk Choi ◽  
Sae Mee Jun ◽  
Waon Ho Yi ◽  
Hyung Joon Kim
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Small Deformation ◽  
Electrical Equipment ◽  
Hysteretic Behavior ◽  
Vertical Stiffness ◽  
Electric Power Supply ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Nonlinear Time History

Electrical equipment such as switchboard should be protected from the seismic hazard to enable stable electric power supply even after the earthquake, since its seismic damage results in the severe damage such as social chaos, fire, and explosion. The general method to secure the excellent seismic performance of switchboards is to reduce the inertial forces by introduction of base isolating systems into a switchboard frame. However, the introduction of base isolating systems may cause the increase of installation and manufacturing costs, which is more true for a low-and medium-seismicity zones, such as Korea. In order to solve finance-related problems, this paper evaluates the seismic performance of switchboards supported by the hybrid springs consisting of wire rope elastic mounts with vertical and horizontal direction stiffness and polyurethane that provides additional vertical stiffness and damping. To do this, this study constructs an analytical model that can properly capture the hysteretic behavior of a hybrid spring. Nonlinear time-history analyses were carried out with floor acceleration time-histories taking into account Koreas seismic design quantities. The analysis results show relatively small deformation of switchboard supported by hybrid springs and high resistance against over-turning moments due to additional vertical stiffness of polyurethane.

Research about Influence of Strength Variability on Seismic Performance of Weak Shear Type Concentrically-Braced Steel Frames

2011 ◽  
Vol 243-249 ◽  
pp. 1396-1400
Author(s):  
Yong Sheng Qi ◽  
Feng Hua Zhao ◽  
Jun Wen Zhou
Keyword(s):  
Seismic Performance ◽  
Steel Frames ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Analysis Method ◽  
History Analysis ◽  
Concentrically Braced ◽  
Shear Type ◽  
Nonlinear Time History ◽  
Strength Variability

Influence of strength variability of braces on the weak shear type concentrically-braced steel frames is studied by pushover and nonlinear time history analysis method, which leads to a conclusion that the overstrength of brace has obviously detrimental influence on the seismic performance of the structure, induces stronger seismic reaction and higher seismic risk. Another valuable discovery is that after the area of the braces of weak shear type centrically-braced steel frames are determined according to the requirement of current codes, the designer can intentionally specify the structural steel of comparatively low strength (for example, the 2nd group in the paper taking 70% strength of steel Q235) for the brace, which can provide the structure more excellent seismic performance.

Study on a Roller-Footing Isolated Single-Pier System

2012 ◽  
Vol 204-208 ◽  
pp. 2658-2661 ◽  
Author(s):  
Biao Wei ◽  
Shan Shan Li
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Internal Force ◽  
Nonlinear Time History Analysis ◽  
Isolation System ◽  
History Analysis ◽  
Object Of Study ◽  
Design Earthquake ◽  
Nonlinear Time History ◽  
Rolling Balls

As to improve bridges’ seismic performance, horizontal earthquake was isolated at the bottom of piers. With one pier system as the object of study, adopting nonlinear time history analysis analyzed the un-isolation system, the traditional isolation system and the new isolation system’s seismic performance especially when the actual earthquake was different from the design earthquake, in which the new isolation system was based on rolling balls. Results shows, as for the new isolation system, the internal force is independent of earthquake accelerations and earthquake periods, therefore, sympathetic vibration will not exist, and the internal force is always too small to destroy the system.

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