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Buried pipelines are critical infrastructure components which employed for delivering and distributing vital products such as water, gas and oil. Such energy transmission lines might cross fault lines on their routes, undergo tension and compression strains due to crossing angle under permanent ground deformations and severely damaged. Steel pipe failures are expected to be due to tensile loads in terms of design issues. However, in cases where reverse or some strike-slip faults have to be crossed due to forced routing, premature failures may occur under net axial compressive loads. According to the current code, the design principles for pipelines are specified due to maximum axial tension and compression deformation values correspond to uninterrupted and controlled damage cases. In this study, limit states due to axial deformations under axial compressive and bending load conditions, which mainly cause loss of pressure integrity and pipe damages, are investigated. For this purpose, corresponding D/t ratios and material properties are considered to characterize the existing pipelines in Turkey such as, Kullar water transmission, Trans-Anatolian-Natural Gas (TANAP) and Baku-Tbilisi-Ceyhan Crude Oil (BTC) pipelines by using three-dimensional finite element model under combined loading conditions. In this way, limit states due to displacements and rotation demands are specified. The results of this study are expected to be used in the performance-based design of steel pipes in Turkey. [ABSTRACT FROM AUTHOR]

Reinforced concrete flat slab systems are supported to columns directly without beams. In this analytical study, a structure which has reinforced concrete flat slab with four storey is investigated under earthquake effect. The structure was analyzed by three different methods to compare bending moments in columns and flat slabs. In this study, explanatory information about flat slab systems is presented and different types of solution methods which are adopted our countries specification was compared through a structural example under the horizontal loads. Under the influence of horizontal earthquake forces; selected bearing system have been analyzed by the equivalent frame method, called the moment transfer coefficients method developed by Ünlüoğlu and finite elements method based SAP2000 software. The result of comparing the findings obtained from different solution methods to each other is presented with the help of column top and bottom moments in all floors, flat slab bending moments in inner and edge column strands, tables and graphs. According to this, the method developed by Ünlüoğlu using moment transfer coefficients and the results obtained from finite elements based SAP2000 software are very close to each other. The results obtained from the equivalent frame method are different from those result of the other methods of analysis. Because the equivalent frame method is an approximate method, it does not give as accurate results as the results obtained by the finite element method. However, the method developed by Ünlüoğlu may be an alternative to the finite element method. [ABSTRACT FROM AUTHOR]