In this study, the ultimate bending moment of circular concrete-filled double skin steel tubes (CFDSTs) was investigated. A CFDSTs made of two concentric circular steel tubes with concrete infill and M16 shear connector system was fabricated. The four-point bending test of the 10 m long CFDST consisting of outer and inner steel tubes with 914.4 mm and 514.4 mm in diameter, respectively, was carried out and the ultimate bending moment of the CFDST was investigated. A finite element (FE) simulation of the CFDSTs subjected to bending was developed using the commercial software ABAQUS and the accuracy of the developed FE model was verified by comparing to the experimental result. The ultimate bending moment of CFDSTs was then evaluated with respect to different concrete infill compressive strengths and yield strengths of the steel tubes. The corresponding design ultimate bending moments of the CFDST with regard to the design codes AISC and EC4 were also computed. The results revealed that EC4 and AISC can accurately predict the ultimate moment capacities of the CFDST with shear connector. Keywords: ultimate bending moment; concrete-filled double skin tube; shear connector system; finite element analysis. Received 19 November 2018, Revised 04 January 2019, Accepted 04 January 2019

As a direct/indirect capping material and a dentine replacement material, tricalcium silicate-based endodontic materials such as Biodentine ™ can be used as a lining or as a base material under a final restoration [1]. The use of these materials results in a final structure consisting of multiple layers of different materials. One side of the lining/base material should have the ability to effectively bond (chemically or by microretention) to the overlaid material, and the other side of the lining should adhere properly to the tooth structure (dentine). The physico-mechanical properties of the base material should

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Using the assumption that the load is evenly distributed in the horizontal direction, the article has given the cable deflection equation as a function that depends only on the horizontal coordinates, the length of the cable and horizontal distance between two supports. This result leads to the construction of a general system of equations to calculate the deflection, tension, and elongation of an elastic single cable resting on two supports with or without high difference, bearing uniformly distributed loads (or evenly distributed at intervals) and load is concentrated at many points. Calculations of examples to compare with results have been performed by other methods.