Test Programs for Degraded Core Shroud and PLR System Piping: Seismic Test Results and Discussion on JSME Rules Application

2008 ◽  
Author(s):  
Kenichi Suzuki ◽  
Hidefumi Kawauchi
Keyword(s):  
Seismic Design ◽  
Vibration Characteristics ◽  
Shaking Table ◽  
Load Control ◽  
Load Testing ◽  
Test Results ◽  
Static Displacement ◽  
Seismic Safety ◽  
Age Related ◽  
Core Shroud

Since the age-related degradation of structures and components in NPPs has been a key issue regarding assessments of seismic safety, JNES initiated seismic test programs in fiscal 2004 for the degraded core shroud and PLR system piping used in old BWR plants. The objectives were to: i) obtain a better understanding of the vibration characteristics and seismic strength of degraded structures and components having cracks due to aging; ii) ensure a margin of seismic design safety by considering age-related cracking; and iii) verify the JSME Rules on Fitness-for-Service for NPPs in Japan. The quasi-static displacement or load control testing of the components of the core shroud and PLR system piping were conducted. The dynamic load testing of combined components were also performed on a shaking table by using an approximately 1/3 scale PLR system piping specimen and a 1/2.5 scale core shroud specimen. All test specimens were designed to contain simulated cracking due to aging, involving cracks assumed to have the maximum allowable size according to the JSME Rules. These test results were discussed by focusing on the effects of cracking on vibration characteristics and seismic strength, and the margin of seismic safety under the JSME Rules.

Test Programs for Degraded Core Shroud and PLR Piping: Simulated Crack Models and Input Seismic Waves for Shaking Test

2006 ◽  
Author(s):  
Kenichi Suzuki ◽  
Hidefumi Kawauchi ◽  
Hiroshi Abe
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Seismic Waves ◽  
Response Spectra ◽  
Shaking Table ◽  
Seismic Safety ◽  
Age Related ◽  
Test Models ◽  
Core Shroud

Since the age-related degradation of structures and components in nuclear power plants has been a key issue regarding assessments of seismic safety, the Japan Nuclear Energy Safety Organization (JNES) initiated seismic test programs in fiscal 2004 for the degraded core shroud and primary loop recirculation (PLR) system piping used in old BWR plants. The objectives were to: i) obtain a better understanding of the vibration characteristics and seismic strength of degraded structures and components having cracks due to aging, ii) ensure a margin of seismic design safety by considering age-related cracking, and iii) verify the JSME Code Rules on Fitness-for-Service for Nuclear Power Plants in Japan. Plans were made to test the components of the core shroud and PLR system piping under quasi-static displacement control of monotonous and cyclic load conditions. Plans were also made to test combined components on a shaking table by using a 1/2.5-scale core shroud model and an approximately 1/3-scale PLR piping model. All test models were designed to contain simulated cracking due to aging, involving cracks assumed to have the maximum allowable size according to the JSME Code Rules. The input seismic waves were prepared for the combined component tests of the scaled models based on a modified envelope of broadened response spectra of all S2 design seismic waves in Japan. Final evaluation of the simulated crack models and input seismic waves used for the tests will be conducted in fiscal 2005.

scholarly journals Analysis of the Effects of Soil on the Seismic Energy Responses of an Equipment-Structure System via Substructure Shaking Table Testing

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Lanfang Luo ◽  
Nan Jiang ◽  
Jihong Bi
Keyword(s):  
Seismic Design ◽  
Seismic Energy ◽  
Shaking Table ◽  
Input Energy ◽  
Test Results ◽  
Element Analysis ◽  
Testing Method ◽  
Shaking Table Testing ◽  
Soil Effects ◽  
Substructure Approach

This study investigated the real-time substructure shaking table testing (RTSSTT) of an equipment-structure-soil (ESS) system and the effects of soil on the seismic energy responses of the equipment-structure (ES) subsystem. First, the branch modal substructure approach was employed to derive the formulas needed for the RTSSTT of the ESS system. Then, individual equations for calculating the energy responses of the equipment and the structure were provided. The ES subsystem was adopted as the experimental substructure, whereas the reduced soil model was treated as the numerical substructure when the RTSSTT was performed on the ESS system. The effectiveness of the proposed testing method was demonstrated by comparing the test results with those of the integrated finite element analysis. The energy responses of the ES subsystem in the case of rigid ground (i.e., the ES system) were compared with those considering the effects of soil (i.e., the ESS system). The input energy responses of the ES subsystem were found to decrease significantly after taking the effects of soil into account. Differences due to the soil effects should be considered in the seismic design for the ES system.

Evaluated Results of Seismic Design Approach Using Inelastic Dynamic Analysis for Equipment

2019 ◽  
Author(s):  
Ichiro Tamura ◽  
Atsushi Okubo ◽  
Yusuke Minakawa ◽  
Tadashi Iijima ◽  
Yoshio Namita ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Seismic Design ◽  
Evaluation Method ◽  
Design Approach ◽  
Model Parameters ◽  
Seismic Safety ◽  
Inelastic Analysis ◽  
Safety Margins ◽  
Core Shroud

Abstract Securing adequate seismic safety margins has been important in safety reviews regarding the seismic design of equipment and piping systems in nuclear power plants, and there exists an increasing need for a more exact method for evaluating these margins. To this end, it is reasonable to take into account the reduction of seismic responses resulting from inelastic deformation. The authors studied this approach utilizing an elastic allowable limit in existing standard. The applicability of the proposed evaluation method was investigated by comparison with the conventional evaluation method. The proposed method consists of an inelastic dynamic analysis and an elastic-static analysis. The elastic-static analysis uses a load obtained from the inelastic dynamic analysis. For the investigation, the result obtained from the proposed method was compared with that obtained from the conventional elastic analysis to quantify the reduction in responses leading to seismic safety margins. For the comparison, the authors constructed three models that simulate a cantilever-type beam, four-legged tank, and core shroud and applied them to the analysis herein, and the applicability of our method was discussed for these models. In this paper, we present three topics. First, we present a scheme for developing the design approach of using inelastic analysis. Second, we report a sensitivity study of model parameters, such as yielding stress and second stiffness, done by analyzing the cantilever-type beam for the proposed method. Finally, we report the application of the method to the four-legged tank and core shroud.

scholarly journals Effect of Roof and Diaphragm Connectivity on Dynamic Behaviour of the PP-band Retrofitted Adobe Masonry Structures

2018 ◽  
Author(s):  
Navaratnarajah Sathiparan
Keyword(s):  
Shaking Table Test ◽  
Masonry Wall ◽  
Shaking Table ◽  
Experimental Program ◽  
Masonry Structures ◽  
Test Results ◽  
Structural Components ◽  
Masonry Unit ◽  
Seismic Safety ◽  
Lateral Drift

This paper discusses the shaking table test results of three PP-band (Polypropylene band) retrofitted quarter scale one-story masonry house models with different roof conditions. Better connections between masonry wall and roof connection are one factor to improve the seismic safety of the masonry houses. Past studies show that PP-band retrofitting improves the integrity of structural components and prevent the collapse of masonry structures during an earthquake. Although the effect of masonry unit type, surface plastering, the pitch of the PP-band mesh, PP-band connectivity in mesh and tightness of the mesh attachment to walls were studied by experiment program, the effect of the roof and its diaphragm connectivity on PP-band retrofitted masonry structure is nonexistent. Therefore, an experimental program was designed and executed for an understanding the effect of the roof and its connection on the dynamic behavior of the PP-band retrofitted box-shaped masonry house models. Results reveal that the PP-band retrofitted models with proper roof diaphragm improves the seismic behavior with respect to lateral drift, shear resistance and ductility.

Experimental Study on Steel Frames Infilled with Sandwich Composite Panels

2011 ◽  
Vol 243-249 ◽  
pp. 499-505
Author(s):  
Can Xing Qiu ◽  
He Tao Hou ◽  
Wei Long Liu ◽  
Ming Lei Wu
Keyword(s):  
Seismic Design ◽  
Steel Frames ◽  
Strength Degradation ◽  
Hysteretic Behavior ◽  
Sandwich Composite ◽  
Viscous Damping ◽  
Test Results ◽  
Ductility Index ◽  
Damage Process ◽  
Seismic Behaviors

A model of full scale one-bay, one storey was tested under low cyclic loading in order to study the hysteretic behavior of steel frames with sandwich composite (SC) panels. According to the failure pattern and damage process of test specimen, seismic behaviors were evaluated. Hysterics loops, skeleton curves, curves of strength degradation, and curves of stiffness degradation, ductility index and viscous damping coefficient were analyzed. Test results show that the failures of panels mainly occurred around the embedded parts, but compared with traditional panels and walls, SC panels exhibit a better integration. The connection between panel and steel frame is vital to the mutual work of the two parts. Finally, seismic design recommendations based on the analysis of ductility index and energy dissipation of the structures are presented.

Seismic Safety Evaluation for Mountainous Highway Bridge Based on Risk Matrix

2011 ◽  
Vol 255-260 ◽  
pp. 4212-4216
Author(s):  
Gong Yuan Xie ◽  
Zhang Yue
Keyword(s):  
Seismic Design ◽  
Seismic Risk ◽  
Control Method ◽  
Safety Evaluation ◽  
Technical Support ◽  
Highway Bridge ◽  
Risk Matrix ◽  
Seismic Safety ◽  
Seismic Safety Evaluation

Risk matrix is applied to evaluate seismic risk on mountainous bridge. In this article, a continuous bridge is used as example to analyze the seismic risk of key position under a usual earthquake. Related control method is proposed to provide technical support for bridge seismic design and operation maintenance.

Experimental Research on Vibration Characteristics of Laminated Composite Cantilever Beam

2021 ◽  
Author(s):  
Rui Yang ◽  
Xiaobin Li ◽  
Hongxi Li
Keyword(s):  
Cantilever Beam ◽  
Optical Measurement ◽  
Laminated Composite ◽  
Experimental Methods ◽  
Test Methods ◽  
Vibration Characteristics ◽  
Test Method ◽  
Vibration Measurement ◽  
Vibration Test ◽  
Test Results

Abstract In this paper, the vibration characteristics of laminated composite cantilever beam is taken as the research object. Firstly, a vibration formula specific for laminated composite cantilever beam is derived, from which the low order natural frequency of laminated composite cantilever beam is calculated; Secondly, two experimental methods, electrical and optical measurement, are used to study the vibration characteristics of laminated composite cantilever beam, and the influence of different test methods, sensor types, number of measuring points and excitation methods on the test results are analyzed. Through the combination of theory and experiment, a test method that can be applied to the vibration test of composite material laminated structure cantilever beam is obtained. Based on the laser vibration measurement method in the optical method, the results show that the deviation between the experimental data and the theoretical solution is the smallest when the distance between the probe and the specimen is 0.5m and the sampling time is 5s by using the optical fiber vibrometer. The research content of this article can provide a reasonable reference for related vibration test research.

scholarly journals Laboratory Tests for Subgrade Reaction Coefficient in Seismic Design of Underground Engineering Domain

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Kunpeng Xu ◽  
Liping Jing ◽  
Xinjun Cheng ◽  
Haian Liang ◽  
Jia Bin
Keyword(s):  
Seismic Design ◽  
Shaking Table Test ◽  
Free Field ◽  
Deformation Mode ◽  
Shaking Table ◽  
Subgrade Reaction ◽  
Underground Structures ◽  
Testing Methods ◽  
Underground Engineering ◽  
Reaction Coefficient

Subgrade reaction coefficient is commonly considered as the primary challenge in simplified seismic design of underground structures. Carrying out test is the most reliable way to acquire this intrinsic soil property. Owing to the limitations of experimental cost, time consumption, soil deformation mode, size effect, and confined condition, the existing testing methods cannot satisfy the requirements of high-precision subgrade reaction coefficient in seismic design process of underground structures. Accordingly, the present study makes an attempt to provide new laboratory testing methods considering realistic seismic response of soil, based on shaking table test and quasistatic test. Conventional shaking table test for sandy free-field was performed, with the results indicating that the equivalent normal subgrade reaction coefficients derived from the experimental hysteretic curves are reasonable and verifying the deformation mode under seismic excitation. A novel multifunctional quasistatic pushover device was invented, which can simulate the most unfavorable deformation mode of soil during the earthquake. In addition, the first successful application of an innovative quasistatic testing method in evaluating subgrade reaction coefficient was reported. The findings of this study provide preliminary detailed insights into subgrade reaction coefficient evaluation which can benefit seismic design of underground structures.

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