Segmental concrete box girder bridge thermal analysis based on new Turkish solar zone map developed to assess temperature gradient loading

Yılmaz, Arzu İpek
Solar radiation and daily temperature fluctuation originated non-linear temperature distribution through the depth of the box girder bridge structures cause significant stress development in addition to the ones caused by other load effects such as dead, live and uniform temperature loading on concrete superstructure. Unfortunately, the significance of hourly temperature gradient changes on segmental bridge design had not been addressed in detail for Turkish bridge design mainly due to the lack of a Turkish solar zone map and limited awareness of engineers on computation methods. The aim of this study is to construct a new solar zone map for Turkey to assess the magnitude of non-linear temperature gradient to be used in thermal analysis of segmental concrete bridges and outline a comprehensive analysis method. In this scope, temperature and solar radiation changes at sixteen Turkish cities representing different geographies are evaluated to form the boundaries of solar zone regions on Turkish country map and obtain corresponding temperature gradient loading. It has been found out that the solar zones defined for the bridges of United States of America and Turkey results in slightly different thermal gradient loading. The new findings on region based temperature gradient loading have been used in analysis of a selected segmental concrete box girder bridge. The nonlinear temperature distribution developed through the depth of the sample box girder type bridge caused stresses as high as the ones generated by dead and live loads; that, especially for negative gradient condition, the high tensile stresses imposes the requirement of additional prestressing, in order to satisfy tensile stress limitation requirements and avoid cracking of the section.


Current transport mechanisms in low resistive CdS thin films
Günal, İbrahim; Parlak, Mehmet (Springer Science and Business Media LLC, 1997-02-01)
The current transport mechanisms in polycrystalline CdS thin films have been studied as a function of temperature over the temperature range 20-230 K. Conductivity data for the high temperature region has been analysed using Seto's model of thermionic emission. At intermediate temperatures it was found that thermionic emission and tunnelling of carriers through the potential barrier both contribute to the conductivity. Below 100 K Mott's hopping process appears to be the predominant conduction mechanism.
Parametric Study and Seasonal Simulations of a Solar Powered Adsorption Cooling System
Taylan, Onur; Baker, Derek Keıth; Kaftanoglu, Bilgin (2009-09-03)
Models of solar-thermal powered adsorption cooling systems with and without heat recovery developed in TRNSYS and results from steady-periodic and seasonal simulations are presented. A normalized model is presented and used to process the seasonal TRNSYS results to investigate the coincidence between the solar-supplied cooling power and cooling load as the relative sizes of the cooling system and storage are varied. The normalized model yields a seasonal solar fraction and seasonal loss fraction (the excess...
Spinodal instabilities in symmetric nuclear matter within a nonlinear relativistic mean-field approach
Acar, Fatma; Yılmaz, Osman; Department of Physics (2011)
Spinodal instability mechanism and early development of density fluctuations for symmetric nuclear matter at finite temperature are studied. A stochastic extension of Walecka-type relativistic mean-field model including non-linear self-interactions of scalar mesons with NL3 parameter set is employed in the semi-classical approximation. The growth rates of unstable collective modes are investigated below the normal density and at low temperatures. The system exhibits most unstable behavior in longer wave len...
Dynamics of extended objects in general relativity
İlhan, İbrahim Burak; Tekin, Bayram; Department of Physics (2009)
In this thesis, multipole expansions of mass, momentum and stress density will be made for a body in Newtonian mechanics. Using these definitions; momentum, angular momentum, center of mass, force and torque are defined for N gravitationally interacting isolated bodies. Equations of motions of such a system are derived. Definitions of momentum, angular momentum, center of mass, force and torque are made in a relativistic theory. Dynamical (gravitational) skeleton is defined and the multipole moments of the ...
Thermal stress problems ın FGMS
Akdoğan, Esra Nur; Kadıoğlu, Fevzi Suat; Department of Mechanical Engineering (2019)
In this thesis transient temperature distribution, thermal stresses and thermal stress intensity factors (TSIFs) of an infinitely long functionally graded material (FGM) strip containing periodic cracks under thermal shock are studied. Thermal shock is applied by imposing a sudden change in the boundary temperatures. Solution of the present thermoelasticity problem is considered in three successive steps. First the thermal (conduction) problem is solved and the transient temperature distribution is determin...
Citation Formats
A. İ. Yılmaz, “Segmental concrete box girder bridge thermal analysis based on new Turkish solar zone map developed to assess temperature gradient loading,” M.S. - Master of Science, Middle East Technical University, 2015.