Saddle connections are semi-rigid connections that are widely used in Iran. Many existing buildings contain this type of connection. The present study conducted fullscale experiments and used extensive numerical modeling to study the mechanical characteristics of saddle connections. The mechanical characteristics examined were the moment-transfer mechanism, initial stiffness, yield moment, maximum moment, and fracture rotation. The configuration and dimensions of the experimental and numerical specimens were chosen to be similar to those of saddle connections in existing buildings. A parametric study was conducted to determine the factors affecting the mechanical characteristics of these connections. It was shown that the conventional method used to design saddle connections failed to predict the correct stress distribution. Empirical formulas were provided for predicting these mechanical characteristics and it was shown that the proposed expressions could predict the pertinent parameters accurately.
Due to the many advantages of FRP decks, such as lightweight and high strength, recently, using FRP decks as building deck panels is considered an alternative choice to traditional decks. Accordingly, there is an increasing need for an analysis tool for engineering and academic applications. Finite element is an accurate and reliable method for analyzing FRP decks. However, high computational cost and modeling difficulty somewhat limit its application. To overcome this shortcoming, this study presents an integrated, easy-to-use, computationally-efficient, and yet rather accurate analysis method for FRP decks. This integrated method was implemented in a computer code and can be easily used to analyze building FRP deck panels. To evaluate the deck's applicability as a building floor panel system, some requirements are needed to be met, including maximum allowable elastic deflection, local stability of components, vibration frequency, and ductility of the flooring system. The proposed method uses the Rayleigh-Ritz method to calculate these requirements. Using three different FRP deck examples, it was shown that the proposed method is generic and capable of analyzing various forms of the FRP deck panels, including all-FRP and hybrid decks made of two or more different materials.
The Newmark design spectra are commonly adopted in seismic codes to calculate design spectra, while these spectra generally differ from the statistically driven ones. This study aims to re-construct the Iranian design spectra by implementing a modified Newmark method on an extensive database of previous earthquakes in Iran. To this end, three sets of earthquakes recorded at three different sites are considered. The effects of parameters such as source-to-site distance, the magnitude of ground motion, and the shear wave velocity are evaluated. Subsequently, the amplification factors are obtained through a statistical approach, and the spectral bounds are calculated for three site categories and two types of earthquake magnitudes. As a result, for the first time, the coefficients of the site design spectrum of Iran are presented as a function of ground motion’s magnitude for the aforementioned site categories. The calculated coefficients can be used to modify the Newmark spectral values in displacement, velocity, and acceleration-sensitive regions to obtain suitable design spectra. Finally, a comprehensive statistical study is conducted on earthquake parameters to assess the characteristics of the earthquakes in Iran from statistical perspective. The proposed design spectra can address most shortcomings of 4th edition of the Iranian seismic design code, and it is recommended to include them in the next revision.
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