Change search
ReferencesLink to record
Permanent link

Direct link
Pilot Testing of a Hydraulic Bridge Exciter
KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
2015 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Pilottest av en hydraulisk broexciterare (Swedish)
Abstract [en]

In the design of a railway bridge that is meant for train speeds larger than 200 km/h, the Swedish Traffic Administration requires a dynamic analysis in addition to the conventional static design. The models used for static design may not always be suitable for dynamic analysis, which could lead to inaccurate estimations of the dynamic response. The reason for this is a limited knowledge of the actual structural dynamic behaviour of bridges, which is why a hydraulic bridge exciter has been developed. With this device, smaller bridges can be excited in a load- or displacement-controlled manner under variable frequency and load. By having known inputs, the bridges’ dynamic properties can be evaluated using experimental modal analysis. A finite element model of the double tracked railway bridge Pershagen was created in order to plan a pilot test of the bridge exciter. The influence of the load amplitude and sweep rate was evaluated. A theoretically optimal excitation position was also investigated in order to excite as many eigenmodes as possible from one position during the pilot test. Based on these results, a pilot test was performed on the Pershagen Bridge. The dynamic properties of the bridge were evaluated based on the results from the test. From the pilot test it could be concluded that the load amplitude had a direct influence on the dynamic properties of the bridge, hence the dynamic behaviour is non-linear. The 1st vertical bending mode and its dynamic properties could also be identified.

Abstract [sv]

Då en järnvägsbro som är avsedd för tåghastigheter över 200 km/h ska dimensioneras ställs det krav av Trafikverket att en dynamisk analys av bron skall utföras, utöver konventionell statisk dimensionering. De bromodeller som används för statisk analys är dock inte alltid lämpliga för dynamisk analys, vilket kan leda till felaktiga skattningar gällande den dynamiska inverkan. Anledningen till detta är att kunskapen om broars dynamiska egenskaper är begränsade, och av denna anledning har en lastexciterare utvecklats. Med hjälp av denna anordning kan mindre broar exciteras med kontrollerad last eller förskjutning under variabel frekvens och last. Då dessa input-parametrar är kända kan broars dynamiska egenskaper utvärderas genom experimentell modal analys. En finit element-modell av den tvåspåriga järnvägsbron vid Pershagen har skapats för att kunna planera ett pilottest av lastexciteraren. Svephastigheten och lastamplituden har analyserats. En teoretiskt optimal exciteringsposition har utvärderats för att excitera största möjliga antal moder från en och samma position under pilottestet. Utifrån dessa resultat utfördes ett pilottest på bron vid Pershagen, där brons dynamiska egenskaper utvärderades utifrån resultaten. Från pilottestet kunde en slutsats dras om att lastamplituden hade en direkt inverkan på de dynamiska egenskaperna, vilket betyder att det dynamiska beteendet är olinjärt. Den första vertikala böjmoden och dess dynamiska egenskaper kunde också fastställas.

Place, publisher, year, edition, pages
2015. , 96 p.
TRITA-BKN-Examensarbete, ISSN 1103-4297 ; 460
Keyword [en]
Hydraulic bridge exciter, controlled excitation, modal testing, experimental modal analysis, railway bridges, measurements, load shaker, FEM, FE-modelling, script
Keyword [sv]
Hydraulisk broexciterare, kontrollerad excitering, modala tester, experimentell modal analys, järnvägsbroar, mätningar, lastexciterare, FEM, FE-modellering, script
National Category
Infrastructure Engineering
URN: urn:nbn:se:kth:diva-170113ISRN: KTH/BKN/EX--460--SEOAI: diva2:827298
Subject / course
Structural Design and Bridges
Educational program
Master of Science in Engineering - Urban Management
Available from: 2015-06-26 Created: 2015-06-26 Last updated: 2015-06-26Bibliographically approved

Open Access in DiVA

Pilot Testing of a Hydraulic Bridge Exciter(12743 kB)1224 downloads
File information
File name FULLTEXT01.pdfFile size 12743 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Borg, RichardDymén, Olivier
By organisation
Structural Engineering and Bridges
Infrastructure Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 1224 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 729 hits
ReferencesLink to record
Permanent link

Direct link