The Analysis of Bearing Capacity of Axially Compressed Cold Formed Steel Members

This paper presents a calculation method for axially compressed cold formed stainless, high strength and carbon steel profiles. Results of different authors in this field published in international journals depict current trends in this field. Paper also presents author’s numerical and experimental analysis of cold-formed centrally compressed elements. Numerical analysis was carried out by finite element method and program for the nonlinear static and dynamic structural analysis - PAK. The results obtained by experimental and numerical methods included boundary conditions, maximum force, buckling curve etc. Small difference observed in the values obtained by these different methods. Results werw compared to values predicted by international designing code in order to analyze if they are too conservative for cold formed steel sections

Experimental Research on Reinforced Concrete Columns Strengthened with Steel Jacket and Concrete Infill

Experimental research on axially compressed columns made from reinforced concrete (RC) and RC columns strengthened with a steel jacket and additional fill concrete is presented in this paper. A premade squared cross-section RC column was placed inside a steel tube, and then the space between the column and the tube was filled with additional concrete. A total of fourteen stub axially compressed columns, including nine strengthened specimens and five plain reinforced concrete specimens, were experimentally tested. The main parameter that was varied in the experiment was the compressive strength of the filler concrete. Three different concrete compression strength classes were used. Test results showed that all three cross-section parts (the core column, the fill, and the steel jacket) worked together in the force-carrying process through all load levels, even if only the basic RC column was loaded. The strengthened columns exhibited pronounced ductile behavior compared to the plain RC columns. The influence of the test parameters on the axial compressive strength was investigated. In addition, the specimen failure modes, strain development, and load vs. deformation relations were registered. The applicability of three different design codes to predict the axial bearing capacity of the strengthened columns was also investigated

Analysis of the bearing capacity of the composite column as the function of the base material

The paper presents the results of the experimental-theoretical model research of the composite concrete-steel columns. Columns were formed from steel tubes with concrete core. Ultimate load bearing capacities were determined by applying Euro code 4 guidelines while varying mechanical properties of the basic materials

Analysis and design of 40 m high steel chimney according to Eurocode and SRPS standards

This paper presents structural analysis according to Eurocode and SRPS standards. Analysed construction is 40 m high steel chimney, made of 33 m long upper circular cross-section segment of constant diameter D=1834 mm and bottom variable circular cross-section segment of D=2234 mm on the foundation level. Wind loads are dominant loads for this kind of structures. In analyzing workload basic wind speed is thoroughly treated according to SRPS U.C7.110, and respectively wind speed is treated according to Eurocode 1 for the location of Prahovo. Design of model for the effects of its own weight, a constant load and wind load was conducted according to the second order theory for pre-formed load combinations. The load combinations do not contain partial load safety factors. Design of chimney shaft segments are carried out for different ticknes by height of the pillar, for bearing capacity of cross-section, buckling due normal stress, buckling due tangential stress and buckling control is carried out due shear stress

Calculation and design of steel bearing structure for wind turbine

Wind represents directed movement of the air and is caused by differences in atmospheric pressure which are caused by uneven heating of air masses. Global and local winds can be distinguished. Global winds have high altitude, while local winds occur in the ground layer of the atmosphere. Given that the global wings have high altitude they cannot be used as propellant for wind generators, but they should be known for their effects on the winds in the lower atmosphere. Modern wind turbines are made with a horizontal axle that has a system for the swiveling axis in the horizontal plane for tracking wind direction changes. They can have different number of blades, but for larger forces three blades are commonly used because they provide the greatest efficiency. Rotor diameter of these turbines depends on the strength and it ranges from 30 m for the power of 300 kW to 115 m for the power of 5 MW. Wind turbines are mounted on vertical steel tower which can be high even more than 100 m. Depending on the diameter of the turbine rotor, column is usually built as steel conical and less often as a steel-frame. This study includes analysis and design of steel tower for wind generator made by manufacturer Vestas, type V112 3MW HH 119 (power 3.2 MW) for the construction of wind farm 'Kovačica'

Behavior of Two-Chord Steel–Concrete Composite Columns under Axial Compression

Experimental and numerical research on axially compressed columns made from built-up two-chord concrete-filled steel tubes (TCCFSTs) is presented in this study. The columns were constructed from two parallel circular high-strength steel tubes connected by five batten tubes. The chord tubes were filled with high-strength concrete. The yield stress of the steel used was 600 MPa, while the cylinder compressive strength of the concrete was 95 MPa. Hollow specimens were also tested to serve as a control group. An experimental analysis investigated the influence of the compressive strength of the concrete fill on the load-bearing capacity of the column and the influence of the concrete fill on the slenderness of the column. The behavior under load, stress and strain development, and the failure modes of the specimens were also analyzed. The results of the tests showed that all parts of the built-up column participated in the load-bearing process. The load-bearing capacity of the hollow two-chord columns was improved by around 1.74 times, and the slenderness increased by 16% with the concrete infill. The columns filled with concrete exhibited almost linear behavior with a higher ultimate strength and stiffness than the hollow built-up steel columns. Furthermore, the application of three calculation codes to forecast the capacity of the TCCFST columns was evaluated. Additionally, finite element method (FEM) modeling was used to investigate the stresses, strains, deformations, and ultimate capacity of the TCCFST column models loaded with axial compressive force. The FEM model showed good predictions of strength, stresses, deformations, and buckling