TY  - THES
A1  - Udrea, Mihai-Andrei
T1  - Assessment of Data from Dynamic Bridge Monitoring
N2  - The focus of the thesis is to process measurements acquired from a continuous
monitoring system at a railway bridge. Temperature, strain and ambient vibration
records are analysed and two main directions of investigation are pursued.

The first and the most demanding task is to develop processing routines able to extract modal parameters from ambient vibration measurements. For this purpose, reliable experimental models are achieved on the basis of a stochastic system identification(SSI) procedure. A fully automated algorithm based on a three-stage clustering is implemented to perform a modal parameter estimation for every single measurement. After selecting a baseline of modal parameters, the evolution of eigenfrequencies is
studied and correlated to environmental and operational factors.

The second aspect deals with the structural response to passing trains. Corresponding
triggered records of strain and temperature are processed and their assessment is
accomplished using the average strains induced by each train as the reference parameter.
Three influences due to speed, temperature and loads are distinguished and treated individually. An attempt to estimate the maximum response variation due to each factor is also carried out.
KW  - automatic modal analysis
KW  - stochastic subspace identification
KW  - modal tracking
KW  - modal parameter estimation
KW  - clustering
KW  - Messtechnik
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20140429-21742
ER  - 
TY  - THES
A1  - Habtemariam, Abinet Kifle
T1  - Numerical Demolition Analysis of a Slender Guyed Antenna Mast
N2  - The main purpose of the thesis is to ensure the safe demolition of old guyed antenna masts that are located in different parts of Germany. The major problem in demolition of this masts is the falling down of the masts in unexpected direction because of buckling problem. The objective of this thesis is development of a numerical models using finite element method (FEM) and assuring a controlled collapse by coming up with different time setups for the detonation of explosives which are responsible for cutting down the cables. The result of this thesis will avoid unexpected outcomes during the demolition processes and prevent risk of collapsing of the mast over near by structures.
KW  - Abbruch
KW  - Finite-Elemente-Methode
KW  - Optimierung
KW  - Demolition
KW  - Guyed antenna masts
KW  - Explicit finite element method
KW  - Optimization
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20210723-44609
ER  -