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Abstract

The Dez dam was commissioned in 1963 and since sediments accumulated in the reservoir up to an elevation of approximately 15m below the intake of the power tunnel. One of the possible measures to improve operation of the reservoir is by heightening of the existing dam. This paper describes the conducted procedure for static and thermal calibration of this 203m dam in Iran based on micro geodesies measurements. Also the nonlinear response of existing dam is investigated under maximum credible earthquake ground motions considering joint behavior and mass concrete cracking and safety of dam is evaluated for possible heightening. For thermal calibration of provided numerical model, transient thermal analysis was conducted and results were compared with thermometers records installed in central block. In addition, for static calibration; thermal distribution within dam body, dam self weight, hydrostatic pressure and silt load applied on the 3D fi nite element model of dam-reservoir-foundation were considered. Results show that the distribution of stresses will be critical within dam for heightening case under seismic loads in MCL.

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Authors and Affiliations

M.A. Hariri-Ardebili
H. Mirzabozorg
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Abstract

It is presented in detail how the selection of a structural model describing the behaviour of a steel hall transverse frame when subject to fire exposure in a more or less complex way may affect the fire resistance evaluation for such a frame. In the examples compiled in this paper the same typical one-aisle and single-story steel hall is subjected to simulated fire action, each time following the same fire development scenario.Aresultant fire resistance is identified individually in each case, using various computational models, on an appropriate static equilibrium path obtained numerically. The resulting estimates vary, not only in the quantitative sense, but also in terms of their qualitative interpretation. It is shown that the greater the simplification of the model used, the more overstated the estimated fire resistance is in relation to its real value. Such an overestimation seems to be dangerous to the user, as it gives him an illusory but formally unjustified sense of the guaranteed safety level.
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Authors and Affiliations

Mariusz Maślak
1
ORCID: ORCID
Michał Pazdanowski
1
ORCID: ORCID
Maciej Suchodoła
1
ORCID: ORCID
Piotr Wozniczka
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Civil Engineering, Warszawska 24, 31-155 Cracow, Poland
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Abstract

To evaluate the occupational safety of a high signal operator exposed to the electric field induced by contact wires with a frequency of 50 Hz and a voltage of 27.5 kV, this study established a model of a high signal operator working in the vicinity of singleand double-track railways. The electric field distribution in the operator’s body and his head were calculated and analyzed during the operation using the finite element method (FEM). The calculated results were compared with the international standard occupational exposure limits formulated by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and action levels (ALs), exposure limit values (ELVs) in Directive 2013/35/EU (EU Directive). In the case of a single-track railway exposure, the maximum electric field strength in the worker’s body, in the scalp layer, and inside the brain are 227 mV/m, 2.76 kV/m, and 0.14 mV/m, respectively. For a double-track railway exposure, the maximum internal electric field strength of the operator is 310 mV/m, which is 37.85% of the occupational exposure basic restriction limit. The maximum electric field strength in the head layers is 3.42 kV/m, which is 34.2% of the occupational exposure reference level and 34.2% of the low ALs. The maximum electric field strength of the brain is 0.19 mV/m, which is 0.19% of the occupational basic restriction limit and 0.135% of the sensory effects ELVs. Results show that the electric field exposure of the high signal operator to contact wires in single- and double-track railways is lower than the occupational exposure limits provided by the ICNIRP and EU Directive standards and is thus regarded as safe forworkers.
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Authors and Affiliations

Chang-Qiong Yang
1
ORCID: ORCID
Mai Lu
1
ORCID: ORCID

  1. Lanzhou Jiaotong University, China

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