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Horizontal loads such as earthquake and wind are considered dominant loads for the design of tall buildings. One of the most efficient structural systems in this regard is the tube structural system. Even though such systems have a high resistance when it comes to horizontal loads, the shear lag effect that is characterized by an incomplete and uneven activation of vertical elements may cause a series of problems such as the deformation of internal panels and secondary structural elements, which cumulatively grow with the height of the building. In this paper, the shear lag effect in a typical tube structure will be observed and analyzed on a series of different numerical models. A parametric analysis will be conducted with a great number of variations in the structural elements and building layout, for the purpose of giving recommendations for an optimal design of a tube structural system.
Ivan Hafner; Anđelko Vlašić; Tomislav Kišiček; Tvrtko Renić. Parametric Analysis of the Shear Lag Effect in Tube Structural Systems of Tall Buildings. Applied Sciences 2020, 11, 278 .
AMA StyleIvan Hafner, Anđelko Vlašić, Tomislav Kišiček, Tvrtko Renić. Parametric Analysis of the Shear Lag Effect in Tube Structural Systems of Tall Buildings. Applied Sciences. 2020; 11 (1):278.
Chicago/Turabian StyleIvan Hafner; Anđelko Vlašić; Tomislav Kišiček; Tvrtko Renić. 2020. "Parametric Analysis of the Shear Lag Effect in Tube Structural Systems of Tall Buildings." Applied Sciences 11, no. 1: 278.
The amount of energy dissipated during an earthquake depends on the type of failure of the concrete element. Shear failure should be avoided because less energy is spent than that due to bending failure. Compression controlled failure is usually avoided by increasing the thickness of a wall. Considering that the current code largely decreases this strength, this becomes hard to achieve in practice. Because of that, the analysis described in this paper is made to determine the reason for a large strength reduction at high curvatures. Mechanisms contributing to compression controlled shear strength are analysed. Using Rankine’s strength theorem, section equilibrium, arch mechanism and bending moment-curvature diagrams, the influence of different parameters are observed and charted. The findings are compared to the existing procedures and a new, simple and safe analytical equation is derived. Compression controlled shear strength is mainly influenced by axial force, followed by the amount of longitudinal reinforcement and the achieved confinement. Results show that the value of strength reduces significantly with the increase of ductility and that some reduction exists even for lower levels of curvature. Current code provisions may lead to unsafe design, so designers should be careful when dealing with potentially critical walls.
Tomislav Kišiček; Tvrtko Renić; Damir Lazarević; Ivan Hafner. Compressive Shear Strength of Reinforced Concrete Walls at High Ductility Levels. Sustainability 2020, 12, 4434 .
AMA StyleTomislav Kišiček, Tvrtko Renić, Damir Lazarević, Ivan Hafner. Compressive Shear Strength of Reinforced Concrete Walls at High Ductility Levels. Sustainability. 2020; 12 (11):4434.
Chicago/Turabian StyleTomislav Kišiček; Tvrtko Renić; Damir Lazarević; Ivan Hafner. 2020. "Compressive Shear Strength of Reinforced Concrete Walls at High Ductility Levels." Sustainability 12, no. 11: 4434.
Masonry structures are notoriously vulnerable to horizontal actions caused by earthquakes. Given the high seismicity of the European region, and that the European building stock comprises a lot of masonry buildings, knowledge about their structural response to seismic excitation is particularly important, but at the same time difficult to determine, due to the heterogenous nature of materials and/or constructional techniques in use. An additional issue is represented by the current methods for mechanical properties assessment, that do not provide a reliable framework for accurate structural estimations of existing buildings characterized by different typological properties. Every structure, in other words, should be separately inspected in regard to its mechanical behaviour, based on dedicated approaches able to capture potential critical issues. In this review paper, an insight on the Croatian ARES project is presented (Assessment and Rehabilitation of Existing Structures), including a state-of-the-art of the actual building stock and giving evidence of major difficulties concerning the assessment of existing structures. The most commonly used techniques and tools are compared, with a focus on their basic features and field of application. A brief overview of prevailing structural behaviours and Finite Element numerical modelling issues are also mentioned. As shown, the general tendency is to ensure “sustainable” and energy-efficient building systems. The latter, however, seem in disagreement with basic principles of structural maintenance and renovation. The aim of the ongoing ARES project, in this context, is to improve the current knowledge regarding the assessment and strengthening of structures, with a focus on a more reliable design and maintenance process for existing masonry buildings.
Mislav Stepinac; Tomislav Kisicek; Tvrtko Renić; Ivan Hafner; Chiara Bedon. Methods for the Assessment of Critical Properties in Existing Masonry Structures under Seismic Loads—The ARES Project. Applied Sciences 2020, 10, 1576 .
AMA StyleMislav Stepinac, Tomislav Kisicek, Tvrtko Renić, Ivan Hafner, Chiara Bedon. Methods for the Assessment of Critical Properties in Existing Masonry Structures under Seismic Loads—The ARES Project. Applied Sciences. 2020; 10 (5):1576.
Chicago/Turabian StyleMislav Stepinac; Tomislav Kisicek; Tvrtko Renić; Ivan Hafner; Chiara Bedon. 2020. "Methods for the Assessment of Critical Properties in Existing Masonry Structures under Seismic Loads—The ARES Project." Applied Sciences 10, no. 5: 1576.
The behaviour of concrete structures is greatly influenced by the tensile strength and fracture energy of concrete. Tensile strength is usually determined by indirect, splitting, or bending test methods. However, tensile behaviour of concrete can not accurately be estimated using indirect test methods. It is explained why these methods are inappropriate, and an overview of more accurate direct tensile test methods is presented. Advantages and disadvantages of all the methods are discussed, and technical problems that may arise during testing are presented. The biggest issue with the direct tensile test method is the fact that it is still not standardized.
Tvrtko Renić; Tomislav Kišiček. Direct tensile strength test of concrete. 4th Symposium on Doctoral Studies in Civil Engineering 2018, 1 .
AMA StyleTvrtko Renić, Tomislav Kišiček. Direct tensile strength test of concrete. 4th Symposium on Doctoral Studies in Civil Engineering. 2018; ():1.
Chicago/Turabian StyleTvrtko Renić; Tomislav Kišiček. 2018. "Direct tensile strength test of concrete." 4th Symposium on Doctoral Studies in Civil Engineering , no. : 1.