scholarly journals Performance Criteria for Liquid Storage Tanks and Piping Systems Subjected to Seismic Loading

Author(s):  
Maria Vathi ◽  
Spyros A. Karamanos ◽  
Ioannis A. Kapogiannis ◽  
Konstantinos V. Spiliopoulos

In this paper, performance criteria for the seismic design of industrial liquid storage tanks and piping systems are proposed, aimed at defining a performance-based design framework towards reliable development of fragility curves and assessment of seismic risk. Considering “loss of containment” as the ultimate damage state, the proposed performance limits are quantified in terms of local quantities obtained from a simple and efficient earthquake analysis. Liquid storage tanks and the corresponding principal failure modes (elephant’s foot buckling, roof damage, base plate failure, anchorage failure and nozzle damage) are examined first. Subsequently, performance limits for piping systems are presented in terms of local strain at specific piping components (elbows, Tees and nozzles), against ultimate strain capacity (tensile and compressive) and low-cycle fatigue. Modeling issues for liquid storage tanks and piping systems are also discussed, for an efficient analysis that provides reliable estimates of local strain demand. These models are compared successfully with available experimental data. Using those reliable numerical models, the proposed performance limits are applied in two case studies: (a) a liquid storage tank and (b) a piping system, both located in areas of high seismicity.

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Maria Vathi ◽  
Spyros A. Karamanos ◽  
Ioannis A. Kapogiannis ◽  
Konstantinos V. Spiliopoulos

In this paper, performance criteria for the seismic design of industrial liquid storage tanks and piping systems are proposed, aimed at introducing those industrial components into a performance-based design (PBD) framework. Considering “loss of containment” as the ultimate damage state, the proposed limit states are quantified in terms of local quantities obtained from a simple and efficient earthquake analysis. Liquid storage tanks and the corresponding principal failure modes (elephant's foot buckling, roof damage, base plate failure, anchorage failure, and nozzle damage) are examined first. Subsequently, limit states for piping systems are presented in terms of local strain at specific piping components (elbows, Tees, and nozzles) against ultimate strain capacity (tensile and compressive) and low-cycle fatigue. Modeling issues for liquid storage tanks and piping systems are also discussed, compared successfully with available experimental data, and simple and efficient analysis tools are proposed, toward reliable estimates of local strain demand. Using the above reliable numerical models, the proposed damage states are examined in two case studies: (a) a liquid storage tank and (b) a piping system, both located in areas of high seismicity.


Author(s):  
Matthias Wieschollek ◽  
Benno Hoffmeister ◽  
Markus Feldmann

Pipes and nozzles attached to large liquid storage tanks can be susceptible to earthquake induced damages. Adequate design and detailing of shell nozzle reinforcements significantly improves their seismic performance. Damages to nozzles, often combined with elephant-foot-buckling, belong to the most frequent failure modes of large liquid storage tanks caused by earthquakes. The failure consequences depend very much on the liquid contents which may be hazardous; prevention of leakage is a crucial design and verification criteria. European and American standards provide detailed recommendations for structural dimensioning and detailing of shell nozzle reinforcements, however no reliable statements can be made to their seismic behaviour. This paper describes the results of six experimental tests on three typical types of shell nozzle reinforcements. These full scale tests were carried out in the range of ultra-low cycle fatigue for longitudinal and transverse load directions as they can be expected under seismic actions. Based on the evaluation of the test results appropriate FE-models were derived by which parametrical numerical investigations were conducted. Through these studies the influence of different parameters (e.g. thickness of shell plate, reinforcing plate, bottom plate etc.) on the seismic behaviour has been investigated. Finally recommendations for the dimensioning of nozzles reinforcements with particular attention to seismic resistance were developed.


2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.


Author(s):  
Satoshi Tsunoi ◽  
Akira Mikami ◽  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori

The authors have proposed an analytical model by which they can simulate the dynamic and failure behaviors of piping systems with local wall thinning against seismic loadings. In the previous paper [13], the authors have carried out a series of experimental investigations about dynamic and failure behaviors of the piping system with fully circumferential 50% wall thinning at an elbow or two elbows. In this paper these experiments have been simulated by using the above proposed analytical model and investigated to what extent they can catch the experimental behaviors by simulations.


Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori

In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3-D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned wall elbow, because the life of piping models with wall thinning subjected to out-of-plane bending may reduce significantly.


Author(s):  
Zhen-Yu Lin ◽  
Fan-Ru Lin ◽  
Juin-Fu Chai ◽  
Kuo-Chun Chang

Based on the issue of life safety and immediate needs of emergency medical services provided by hospitals after strong earthquakes, this paper aims to introduce a research programme on assessment and improvement strategies for a typical configuration of sprinkler piping systems in hospitals. The study involved component tests and subsystem tests. Cyclic loading tests were conducted to investigate the inelastic behaviour of components including concrete anchorages, screwed fittings of small-bore pipes and couplings. Parts of a horizontal piping system of a seismic damaged sprinkler piping system were tested using shaking table tests. Furthermore, horizontal piping subsystems with seismic resistant devices such as braces, flexible pipes and couplings were also tested. The test results showed that the main cause of damage was the poor capacity of a screwed fitting of the small-bore tee branch. The optimum improvement strategy to achieve a higher nonstructural performance level for the horizontal piping subsystem is to strengthen the main pipe with braces and decrease moment demands on the tee branch by the use of flexible pipes. The hysteresis loops and failure modes of components were further discussed and will be used to conduct numerical analysis of sprinkler piping systems in future studies.


Author(s):  
Jinsuo Nie ◽  
Giuliano DeGrassi ◽  
Charles H. Hofmayer ◽  
Syed A. Ali

The Japan Nuclear Energy Safety Organization/Nuclear Power Engineering Corporation (JNES/NUPEC) large-scale piping test program has provided valuable new test data on high level seismic elasto-plastic behavior and failure modes for typical nuclear power plant piping systems. The component and piping system tests demonstrated the strain ratcheting behavior that is expected to occur when a pressurized pipe is subjected to cyclic seismic loading. Under a collaboration agreement between the U.S. and Japan on seismic issues, the U.S. Nuclear Regulatory Commission (NRC)/ Brookhaven National Laboratory (BNL) performed a correlation analysis of the large-scale piping system tests using detailed state-of-the-art nonlinear finite element models. Techniques are introduced to develop material models that can closely match the test data. The shaking table motions are examined. The analytical results are assessed in terms of the overall system responses and the strain ratcheting behavior at an elbow. The paper concludes with the insights about the accuracy of the analytical methods for use in performance assessments of highly nonlinear piping systems under large seismic motions.


Author(s):  
Izumi Nakamura ◽  
Naoto Kasahara

Abstract To investigate the failure behavior of piping systems under excessive seismic loads, shaking table tests on piping system models made of a simulation material have been executed. The simulation material adopted in the experiment was lead-antimony (Pb-Sb) alloy. The piping system model was composed of two elbows made of Pb-Sb alloy, one additional mass, and two fixed anchors. Input motions were sinusoidal wave. The failure modes of the piping system were examined by varying the additional mass and frequency of the input sinusoidal wave. Through the excitation tests, the failure mode which was named as “ratchet and subsequent collapse” was obtained successfully. The result which was classified as “no failure after 500 cycles” was also obtained. It was found that the occurrence of the failure depended on the ratio of the input frequency to the specimen’s natural frequency, and the ratio of additional mass weight to the limit mass weight. Though the effect of higher modes on the failure behavior was necessary to be more investigated, it seemed that the tendency of dominant failure behavior was similar to that of the single-elbow specimen investigated in the previous study. Moreover, it was confirmed that the experimental approach to use a simulation material was applicable for piping system model with multiple elbows.


1990 ◽  
Vol 43 (11) ◽  
pp. 261-282 ◽  
Author(s):  
Franz G. Rammerstorfer ◽  
Knut Scharf ◽  
Franz D. Fisher

This is a state-of-the-art review of various treatments of earthquake loaded liquid filled shells by the methods of earthquake engineering, fluid dynamics, structural and soil dynamics, as well as the theory of stability and computational mechanics. Different types of tanks and different possibilities of tank failure will be discussed. We will emphasize cylindrical above-ground liquid storage tanks with a vertical axis. But many of the treatments are also valid for other tank configurations. For the calculation of the dynamically activated pressure due to an earthquake a fluid-structure-soil interaction problem must be solved. The review will describe the methods, proposed by different authors, to solve this interaction problem. To study the dynamic behavior of liquid storage tanks, one must distinguish between anchored and unanchored tanks. In the case of an anchored tank, the tank bottom edge is fixed to the foundation. If the tank is unanchored, partial lifting of the tank’s bottom may occur, and a strongly nonlinear problem has to be solved. We will compare the various analytical and numerical models applicable to this problem, in combination with experimental data. An essential aim of this review is to give a summary of methods applicable as tools for an earthquake resistant design, which can be used by an engineer engaged in the construction of liquid storage tanks.


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