Influence Study of Different Site Type on Seismic Performance of Pipeline with Defects

2013 ◽  
Vol 357-360 ◽  
pp. 1551-1554
Author(s):  
Li Li Wang ◽  
Liang Liang Xu ◽  
Xiao Qing Zhang
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Oil Fields ◽  
Geological Condition ◽  
Oil Pipeline ◽  
Site Type ◽  
Time History Response ◽  
Site Category ◽  
Corrosion Defects ◽  
Site Types

With the further study on the exploration and development of oil fields,some oil fields have gone into the later period for developing gradually. The problems of oil pipeline are more and more prominent. Earthquakes have occurred frequently in recent years. So it is particularly important to study on the seismic performance of corrosive pipeline. Due to the length of pipeline, the geological condition is more complicated, the same pipeline across the site category may have a big distinction. The software of ANSYS was used in this paper to study pipelines with corrosion defects in different site types. The seismic response were calculated, thus various types of site conditions of the velocity, displacement and acceleration time-history response were obtained, and the results were compared and analyzed.

Seismic Response Research on Oil Pipeline with Corrosion Defects

2012 ◽  
Vol 166-169 ◽  
pp. 2124-2127
Author(s):  
Han Bing Qi ◽  
Qiu Shi Wang ◽  
Li Li Wang ◽  
Xiao Dan Wu
Keyword(s):  
Seismic Response ◽  
Maximum Stress ◽  
Great Influence ◽  
Time History ◽  
Element Analysis ◽  
Oil Pipeline ◽  
The Finite Element Analysis ◽  
Oil Pipelines ◽  
History Of ◽  
Corrosion Defects

The finite element analysis method was used to analyze the seismic response of two oil pipelines, which have corrosion defects and no defects correspondingly. The velocity, displacement and acceleration time history of the two pipelines and the contrastive analysis of the maximum stress of two pipelines were obtained. The results show that the displacement, velocity and acceleration of the pipeline with corrosion defects are larger than those of the pipeline without corrosion defects, the corrosion has great influence on the bottom of the pipeline, and the influence also has certain wide, the farther away from the corrosion, the smaller the influence is.

Seismic Performance Analysis of Oil Pipeline with Crack Defects

2013 ◽  
Vol 721 ◽  
pp. 710-713
Author(s):  
Li Li Wang ◽  
Xiao Qing Zhang ◽  
Liang Liang Xu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Concentration ◽  
Performance Analysis ◽  
Fracture Mechanics ◽  
Seismic Performance ◽  
Time History ◽  
The Finite Element Method ◽  
Seismic Responses ◽  
Oil Pipeline

The pipelines distribute extensively in China, but pipelines cracks caused pipeline damaged frequently. Once the pipeline’s cracks are considered in the seismic condition, the performance of pipelines will face many problems. The finite element method was used to analyze the seismic responses of pipeline’s cracks. According to fracture mechanics [1], the time-history responses of displacement, acceleration and stress of pipeline with crack defects and seamless pipeline were obtained, and the results were also compared and analyzed. The results indicate that cracks will cause the stress concentration of the pipeline, the pipeline cracks should be considered in seismic responses of pipelines to make the pipelines in safety and economy, and more attention should be paid to the design and study of pipelines with crack defects.

Study on Rational Ratios of Lateral Stiffness for Masonry Building with Frame Structure at First Two Stories

2012 ◽  
Vol 174-177 ◽  
pp. 2012-2015
Author(s):  
Xiao Long Zhou ◽  
Ying Min Li ◽  
Lin Bo Song ◽  
Qian Tan
Keyword(s):  
Seismic Performance ◽  
Time History ◽  
Shear Wall ◽  
Calculation Model ◽  
Frame Structure ◽  
Wall Structure ◽  
Masonry Building ◽  
Lateral Stiffness ◽  
Stiffness Ratio ◽  
Lateral Stiffness Ratio

There are two typical seismic damage characteristics to the masonry building with frame shear wall structure at first two stories, and the lateral stiffness ratio of the third storey to the second storey is one of the key factors mostly affecting the seismic performance of this kind of building. However, some factors are not considered sufficiently in current Chinese seismic codes. According to the theory of performance-based seismic design, the seismic performance of this kind of structure is analyzed in this paper by taking time-history analysis on models which with different storey stiffness ratios. The results show that when the lateral stiffness ratio controlled in a reasonable range, the upper masonry deformation can be ensured in a range of elastic roughly, and the bottom frame can be guaranteed to have sufficient deformation and energy dissipation capacity. Finally, according to the seismic performance characteristics of masonry building with frame shear wall structure at first two stories, especially the characteristics under strong earthquakes, a method of simplified calculation model for the upper masonry is discussed in this paper.

Seismic evaluation of single-storey steel buildings

1999 ◽  
Vol 26 (4) ◽  
pp. 379-394 ◽  
Author(s):  
M S Medhekar ◽  
DJL Kennedy
Keyword(s):  
Seismic Performance ◽  
Response Spectrum ◽  
Time History ◽  
Analytical Models ◽  
Steel Buildings ◽  
Concentrically Braced Frames ◽  
Braced Frame ◽  
Seismic Zones ◽  
Concentrically Braced Frame ◽  
Concentrically Braced

The seismic performance of single-storey steel buildings, with concentrically braced frames and a roof diaphragm that acts structurally, is evaluated. The buildings are designed in accordance with the National Building Code of Canada 1995 and CSA Standard S16.1-94 for five seismic zones in western Canada with seismicities ranging from low to high. Only frames designed with a force modification factor of 1.5 are considered. Analytical models of the building are developed, which consider the nonlinear seismic behaviour of the concentrically braced frame, the strength and stiffness contributions of the cladding, and the flexibility, strength, and distributed mass of the roof diaphragm. The seismic response of the models is assessed by means of a linear static analysis, a response spectrum analysis, a nonlinear static or "pushover" analysis, and nonlinear dynamic time history analyses. The results indicate that current design procedures provide a reasonable estimate of the drift and brace ductility demand, but do not ensure that yielding is restricted to the braces. Moreover, in moderate and high seismic zones, the roof diaphragm responds inelastically and brace connections are overloaded. Recommendations are made to improve the seismic performance of such buildings.Key words: analyses, concentrically braced frame, dynamic, earthquake, flexible diaphragm, low-rise, nonlinear, seismic design, steel.

Changes in DOC and DON fluxes in response to harvest intensity of black-spruce-dominated forest ecosystems in northwestern Ontario

2009 ◽  
Vol 89 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Dave M Morris
Keyword(s):  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Black Spruce ◽  
Site Type ◽  
Northwestern Ontario ◽  
Clearcut Harvesting ◽  
Second Year ◽  
Forest Floors ◽  
Source Sink ◽  
Site Types

The current study was conducted to quantify and compare dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) fluxes through black-spruce-dominated forests, to compare the source/sink characteristics of sphagnum- versus feathermoss-dominated forest floors, and to identify changes in DOC and DON flow patterns occurring as a result of clearcut harvesting. After 2 yr of pre-harvest monitoring, replicated, experimental harvests of varying intensities of biomass removals were conducted followed by 4 yr of post-harvest sampling. Prior to harvest, the upland site type, dominated by feathermoss, was a significant source of DOC and DON, whereas, the wet-sphagnum-dominated sites exported minor amounts of these solutes. After harvest, DOC and DON fluxes peaked in the second year, but then dropped off significantly to at or below pre-harvest levels. On the upland site type, chipper debris appeared to be a major source of DOC and DON generating fluxes well above the pre-harvest levels. On the wetter site types, it appeared that microclimate differences between harvest treatments had a stronger influence on DOC and DON production than did the amount or type of harvest residue. Full-tree harvesting did not significantly alter the production of DOC and DON when compared with stem-only harvesting on the sites included in this study. Key words: DOC, DON, forest floor leachate, black spruce, harvesting response

A statistical study on artificially generated earthquake records

1976 ◽  
Vol 3 (1) ◽  
pp. 11-19
Author(s):  
W. K. Tso ◽  
B. P. Guru
Keyword(s):  
Statistical Study ◽  
Spectral Response ◽  
Flexible Structures ◽  
Time History ◽  
Maximum Response ◽  
Response Analysis ◽  
Seismic Region ◽  
Natural Period ◽  
Earthquake Records ◽  
Time History Response

A statistical study has been done to investigate (i) the variation of spectral responses of structures due to artificially generated earthquake records with identical statistical properties, (ii) the effect of duration of strong shaking phase of artificial earthquakes on the response of structures, and (iii) the number of earthquake records needed for time-history response analysis of a structure in a seismic region. The results indicate that the flexible structures are more sensitive to the inherent statistical variations among statistically identical earthquake records. Consequently several records must be used for time-history response analysis. A sample of eight or more records appear to provide a good estimate of mean maximum response. The duration of strong shaking can significantly affect the maximum response. Based on the results, it is suggested that for the purpose of estimating peak response, the strong shaking duration of the input earthquake motion should be at least four times the natural period of the structure. The maximum responses due to statistically identical ground motion records are observed to fit approximately the type 1 extreme value distribution. Thus, it is rationally possible to choose a design value based on the mean, standard deviation of the spectral response values and tolerable probability of exceedance.

A Seismic Effective Method for Double-Layer Reticulated Shell Using Buckling-Restrained Braces

2010 ◽  
Vol 163-167 ◽  
pp. 2852-2856
Author(s):  
Chang Wu ◽  
Xiu Li Wang
Keyword(s):  
Double Layer ◽  
Seismic Performance ◽  
Linear Time ◽  
Ground Motions ◽  
Equations Of Motion ◽  
Time History ◽  
Original Structure ◽  
Loading Test ◽  
Strong Earthquakes ◽  
Buckling Restrained Braces

In this study a kind of buckling-restrained braces (BRBs) as energy dissipation dampers is attempted for seismic performance of large span double-layer reticulated shell and the effectiveness of BRBs to protect structures against strong earthquakes is numerically studied. The hysteretic curve of such members is obtained through the simulation of the cyclic-loading test, and the equations of motion of the system under earthquake excitations are established. BRBs are then placed at certain locations on the example reticulated shell to replace some normal members, and the damping effect of the two installation schemes of BRBs is investigated by non-linear time-history analyses under various ground motions representing major earthquake events. Compared with the seismic behavior of the original structure without BRBs, satisfactory seismic performance is seen in the upgraded models, which clarifies the BRBs can reduce the vibration response of spatial reticulated structure effectively and the new system has wide space to develop double layer reticulated shell.

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