國立虎尾科技大學 |

Failure mode analysis of a post-tension anchored dam using linear finite element analysis.

紀錄類型:	書目-語言資料,手稿 : Monograph/item
正題名/作者:	Failure mode analysis of a post-tension anchored dam using linear finite element analysis./
作者:	Corn, Aimee.
面頁冊數:	1 online resource (80 pages)
附註:	Source: Masters Abstracts International, Volume: 76-08.
Contained By:	Masters Abstracts International76-08.
標題:	Geophysics. -
電子資源:	click for full text (PQDT)
ISBN:	9781321490909

Failure mode analysis of a post-tension anchored dam using linear finite element analysis.
Corn, Aimee.

Failure mode analysis of a post-tension anchored dam using linear finite element analysis. - 1 online resource (80 pages)

Source: Masters Abstracts International, Volume: 76-08.

Thesis (M.S.)--Colorado State University, 2014.

Includes bibliographical references

There are currently over 84,000 dams in the United States, and the average age of those dams is 52 years. Concrete gravity dams are the second most common dam type, with more than 3,000 in the United States. Current engineering technology and technical understanding of hydrologic and seismic events has resulted in significant increases to the required design loads for most dams; therefore, many older dams do not have adequate safety for extreme loading events. Concrete gravity dams designed and constructed in the early 20th century did not consider uplift pressures beneath the dam, which reduces the effective weight of the structure. One method that has been used to enhance the stability of older concrete gravity dams includes the post-tension anchor (PTA) system. Post-tensioning infers modifying cured concrete and using self-equilibrating elements to increase the weight of the section, which provides added stability. There is a lack of historical evidence regarding the potential failure mechanisms for PTA concrete gravity dams. Of particular interest, is how these systems behave during large seismic events. The objective of this thesis is to develop a method by which the potential failure modes during a seismic event for a PTA dam can be evaluated using the linear elastic finite element method of analysis. The most likely potential failure modes (PFM) for PTA designs are due to tensile failure and shear failure. A numerical model of a hypothetical project was developed to simulate PTAs in the dam. The model was subjected to acceleration time-history motions that simulated the seismic loads. The results were used to evaluate the likelihood of tendon failure due to both tension and shear. The results from the analysis indicated that the PTA load increased during the seismic event; however, the peak load in the tendons was less than the gross ultimate tensile strength (GUTS) and would not be expected to result in tensile failure at the assumed project. The analysis also indicated there was a potential for permanent horizontal displacement along the dam/foundation interface. The horizontal movement was not considered large enough to develop a shear failure of the tendons at the project. The results from this study indicate demand to capacity ratios (DCR) of 0.79 for the anchor head, 0.75 for the tendon, and 0.63 for the foundation cone failure, and a potential displacement of 0.33 inches, which is not large enough to shear the tendon. The methods developed are appropriate for the evaluation of the tensile and shear failure modes for the PTA tendons. Based on the results, it would appear that shear failure of the tendon is a more likely failure mechanism. Thus, shear failure of the tendon should be a focus of seismic evaluations.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9781321490909Subjects--Topical Terms:

686174
Geophysics.
Subjects--Index Terms:

Concrete gravity damIndex Terms--Genre/Form:

554714
Electronic books.

Failure mode analysis of a post-tension anchored dam using linear finite element analysis.
LDR:04262ntm a22004337 4500 001 1151956
005 20241125080152.5
006 m o d
007 cr mn ---uuuuu
008 250605s2014 xx obm 000 0 eng d
020 $a 9781321490909
035 $a (MiAaPQ)AAI1573039
035 $a (MiAaPQ)colostate:12797
035 $a AAI1573039
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Corn, Aimee. $3 1478806
245 1 0 $a Failure mode analysis of a post-tension anchored dam using linear finite element analysis.
264 0 $c 2014
300 $a 1 online resource (80 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Masters Abstracts International, Volume: 76-08.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Heyliger, Paul.
502 $a Thesis (M.S.)--Colorado State University, 2014.
504 $a Includes bibliographical references
520 $a There are currently over 84,000 dams in the United States, and the average age of those dams is 52 years. Concrete gravity dams are the second most common dam type, with more than 3,000 in the United States. Current engineering technology and technical understanding of hydrologic and seismic events has resulted in significant increases to the required design loads for most dams; therefore, many older dams do not have adequate safety for extreme loading events. Concrete gravity dams designed and constructed in the early 20th century did not consider uplift pressures beneath the dam, which reduces the effective weight of the structure. One method that has been used to enhance the stability of older concrete gravity dams includes the post-tension anchor (PTA) system. Post-tensioning infers modifying cured concrete and using self-equilibrating elements to increase the weight of the section, which provides added stability. There is a lack of historical evidence regarding the potential failure mechanisms for PTA concrete gravity dams. Of particular interest, is how these systems behave during large seismic events. The objective of this thesis is to develop a method by which the potential failure modes during a seismic event for a PTA dam can be evaluated using the linear elastic finite element method of analysis. The most likely potential failure modes (PFM) for PTA designs are due to tensile failure and shear failure. A numerical model of a hypothetical project was developed to simulate PTAs in the dam. The model was subjected to acceleration time-history motions that simulated the seismic loads. The results were used to evaluate the likelihood of tendon failure due to both tension and shear. The results from the analysis indicated that the PTA load increased during the seismic event; however, the peak load in the tendons was less than the gross ultimate tensile strength (GUTS) and would not be expected to result in tensile failure at the assumed project. The analysis also indicated there was a potential for permanent horizontal displacement along the dam/foundation interface. The horizontal movement was not considered large enough to develop a shear failure of the tendons at the project. The results from this study indicate demand to capacity ratios (DCR) of 0.79 for the anchor head, 0.75 for the tendon, and 0.63 for the foundation cone failure, and a potential displacement of 0.33 inches, which is not large enough to shear the tendon. The methods developed are appropriate for the evaluation of the tensile and shear failure modes for the PTA tendons. Based on the results, it would appear that shear failure of the tendon is a more likely failure mechanism. Thus, shear failure of the tendon should be a focus of seismic evaluations.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2024
538 $a Mode of access: World Wide Web
650 4 $a Geophysics. $3 686174
650 4 $a Hydrologic sciences. $3 1179176
650 4 $a Civil engineering. $3 561339
653 $a Concrete gravity dam
653 $a Finite element analysis
653 $a Post-tension anchor
653 $a Potential failure mode
653 $a Seismic
655 7 $a Electronic books. $2 local $3 554714
690 $a 0373
690 $a 0388
690 $a 0543
690 $a 0467
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Colorado State University. $b Civil and Environmental Engineering. $3 1178865
773 0 $t Masters Abstracts International $g 76-08.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1573039 $z click for full text (PQDT)