| PaperNO | Paper / Abstract |
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SE12-017
16:10
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16:25
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FAILURE ESTIMATION OF PRESSURIZED STEEL PIPE FITTINGS UNDER IN-PLANE CYCLIC LOADING : ELBOW AND TEE CASES
For a nuclear power plant, safety is the most important factor as it is a facility handling hazardous materials. Nuclear power plant consists of many kinds of pipes transporting fluid and gas. Thus, piping wholesomeness is a very important element for safety of a nuclear power plant. The piping system of a nuclear power plant is connected of pipe fittings of different forms. When an external load like an earthquake could be applied to a pipe, stress is concentrated in the elbow or tee junction of pipe fittings that are connections of a pipe. In this case, a pipe fittings may be damaged. Therefore, there is a need to understand behavior characteristics of loading for safety of pipe fittings. In this study, a damage index was obtained from the load-displacement relationship of the pipe elbow and tee junctions by the in-plane cyclic loading tests.
Bub-Gyu Jeon, Sung-Wan Kim, Da-Woon Yun, Jae-Bong Kim, Sung-Jin Chang
failure criteria, failure estimation, pipe elbow, pipe fittings, pipe tee
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SE12-014
16:25
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16:40
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Experimental study on the mechanical properties of pipes joints under axial load
In recent years, with the improvement of code for seismic design of buildings, the phenomenon of serious earthquake damage in the structures has gradually decreased, but the earthquake damage in the non-structural components are still significant. The earthquake damage in the non-structural components has caused serious secondary disaster. The pipeline system is an important non-structural components in buildings, the earthquake damage in the pipeline system will disable the buildings’ functions even though the main structures are still intact after earthquake, cause more significant economic losses, even casualties. At present, the researchers have studied the bending and shear capacities of pipe joints in the fire-fighting pipeline system, however, there are still some gaps in the mechanical properties of pipe joints under different axial loads. A series of pipe joints have been experimentally investigated to study the mechanical properties of pipe joint under axial tensile, compression and hysteretic load in this paper, analysed the mechanical properties of different kinds of pipe joints with different pipe diameters, obtained two kinds of failure modes of pipe joints under axial load, the regulations that the ultimate tensile load of pipe joints tend to increase as the pipe diameter increase are also analysed.
Zhi Xudong, Li Wenliang, Zhang Ting, Wang Duozhi
axial load, hysteretic load, mechanical properties, pipe diameters, pipe joint
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SE12-026
16:55
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17:10
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Numerical Analysis of Fire Sprinkler Piping According to the Restraint Method of Branch Lnes
The large relative displacement of sprinkler piping under earthquake can cause a damage to the other nonstructural component near the piping like ceiling, air conditioning, electric lines, water supplying lines and so on. In this study, nonlinear FE models for the branch lines of sprinkler piping system in concrete building were developed to estimate the dynamic behavior of branch lines according to the restraint method under seismic loading. The target piping size is 2 inches(65mm) or less which requires no lateral brace but restraint shall be installed at the end of the sprinkler according to NFPA 13. The FE model is developed using ABAQUS code for the piping without restraint or support. The numerical model is validated using the test results of experiment that is a series of large scale shaking table tests on 10-story reinforced concrete building models conducted by E-Defense of NIED (National Research Institute for Earth Science and Disaster Resilience). As a part of these tests, fire sprinkler piping specimens were installed on the 9th and 10th floors of the building model. Numerical analysis using general FEM code, model updating by free vibration test results and nonlinear material model relatively well predict the dynamic displacement of the sprinkler piping with a diameter of 65mm or less. However, further studies are needed in cases where large displacement occurs at the end of the piping.
Takuya Nagae, Jae-Do Kang, Koichi Kajiwara, Hyoung-Suk CHOI
branch line, numerical analysis, Shaking table test, sprinkler
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SE12-030
17:10
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17:25
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SEISMIC EVALUATION AND STRENGTHENING METHOD FOR FIRE PROTECTION SPRINKLER-PIPING SYSTEM IN BUILDING
In recent years, due to the vigorous development of performance design concepts, the seismic capacity of critical building structures (such as hospitals and high-tech factories) has been improved, and the major disasters and economic losses caused by the earthquake have changed from structural to non-structural systems, which include piping systems.This study takes the medium-scale hospital in Southern Taiwan as an example to discuss the effects of installing strengthened elements on sprinkler piping systems which recommended by NFPA13[1]. First, this research uses detailed analysis results to construct the fragility curves, and compare the fragility curves between before- and after-strengthened systems. The simplified numerical models of the fire protection sprinkler systems in the sample hospital were established for fragility analysis with SAP2000 v.20 software. Second, according to the dynamic characteristics of the sprinkler piping system, the simplified assessment method of original system and strengthened system are proposed in this study. It provides engineers with an alternative, rapid and approximate judgment in the seismic performances of piping systems based on in-situ observations and generic floor response spectrum.
TSAI YUNGAN
Failure mode, fragility analysis, Simplified evaluation method, Sprinkler-piping
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E2-011
17:25
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17:40
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STEEL PIPELINE NONLINEARITY EFFECT ON THE FORCE-DISPLACEMENT ANALYSIS OF BURIED PIPELINES CROSSING STRIKE-SLIP FAULT
The performance of buried pipelines crossing strike-slip fault with nonlinear pipe material and nonlinear soil-pipe interaction is investigated by FEM-based simulations. Wherein mainly focused on the evaluation of steel pipeline nonlinearity effects on pipeline performance. Additionally, FEM-based cases were created by applying various faulting angles (ψ) to investigate deeply the steel pipeline material nonlinearity effect on different cases by compared plastic cases with elastic steel pipeline material cases. Finally, it has been found that yielding of the pipeline has significant effect on the bending moment, shear force, bending stress and maximum tensile stress responses of the pipeline. However, it’s effect on the axial force and axial stress responses of the pipeline is negligible. Besides increasing in the faulting angle (ψ) has a considerable effect on the performance of the buried pipeline which has a direct relationship with axial pipe-soil interaction of pipeline. Consequently, an inappropriate definition of pipeline material and axial pipe-soil interaction could make uneconomical design and even an environmental or human loss disaster at the coming earthquakes.
Junji Kiyono, Farzad Talebi
Buried pipeline, FEM, nonlinear soil-pipe interaction, nonlinear steel material, pipe-soil interaction, strike-slip fault
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