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The study on damage evaluation induced by atmospheric corrosion of engineering structures has attracted more and more international concern over the past three decades. However, the effects of atmospheric corrosion on reticulated shells have not been systematically investigated. In this regard, the performance assessment of a reticulated shell subjected to atmospheric corrosion damage is actively conducted in this study. The atmospheric corrosion model of shell elements is first presented, and a refined exponential model for estimating the corrosion depth of steel materials is developed by using the pattern recognition technique. The sensitivity of stiffness matrix to element thickness is established by using Euler–Bernoulli beam element. The sensitivity of mass matrix to element thickness is developed based on lumped mass assumption. Then, the expression of natural frequency sensitivity to element thickness and mass is derived by considering the section loss induced by both the inner and outer surface corrosion. In addition, the explicit expression of frequency sensitivity to mass of spherical joints is also established in detail. The nonlinear static structural analysis is conducted to evaluate effects of atmospheric corrosion on the stress of structural elements. A real reticulated shell constructed in northern China is taken as the example structure to examine the feasibility of the proposed approach and to assess the potential damage caused by atmospheric corrosion to the structure. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with vertical distributions of mean wind speed and atmospheric turbulence characteristics over a typical urban area. The wind data were measured from more than 30 anemometers installed at 15 different height levels on the 325m high Beijing Meteorological Tower during numerous windstorms. Profiles of mean wind speed are presented based on the field measurements and are compared with empirical models’ predictions. Aerodynamic parameters of atmospheric boundary layer are determined from the measured wind speed profiles. Furthermore, wind velocity data in longitudinal, lateral and vertical directions, which were recorded by ultrasonic anemometers at three height levels during windstorms, are analyzed and discussed. Atmospheric turbulence information such as turbulence intensity, gust factor, turbulence integral length scale and power spectral densities of the three-dimensional fluctuating wind velocity are presented and used to evaluate the adequacy of the existing theoretical and empirical models. A comparative study between the measured profiles of turbulence parameters and those estimated by and is performed. The objective of this study aims to provide useful information on boundary layer wind characteristics for the wind-resistant design of tall buildings and high-rise structures in urban areas. [Copyright &y& Elsevier]