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The concept of influence surface has been largely used for the determination of the internal forces of bridge decks. Differently from the load that acts on usual building structures in bridge decks, those loads are in movement; therefore, a more careful evaluation must be conducted for the determination of the maximum efforts. Equilibrium, Müller-Breslau and Adjoint methods are alternative methodologies for the construction of influence surfaces. This manuscript addresses the implementation of such methods through the finite element method and the application of influence surfaces for the obtaining of internal forces. Parameters, as mesh density and shape functions of finite elements are explored through a numerical example. The results show the three procedures provided similar influence coefficients for shear and bending moments, in nodes distant from the reference point and very sensitive values to the mesh density and shape functions of finite elements in the reference point. The convergence values found for the internal forces calculated with the distributed load of the wheel did not show a strong dependency on the parameters under analysis. [ABSTRACT FROM AUTHOR]

In this work, the ratio contribution of Ra and U in γ spectra with the latest update nuclear data will be revised. The results showed that in the total count rate of the 186 keV peak consists of 57.2% of Ra (186.2 keV) and 42.8% of U (185.7 keV) with the existence of equilibrium. These calculations were used for determining mass activity of U for the direct and fast measurement using only the 186 keV peak and verifying the U-Ra secular equilibrium. An equilibrium method was measured secular equilibrium of decay chain U (by the product daughter Bi-609.3 keV) that was used for this study. The maximum relative deviation was less than 4.0% between both methods proved the direct method was reliable and can be applied to determine the mass activity of U in the radioactive equilibrium samples. [ABSTRACT FROM AUTHOR]