Antanas Šapalas

Research and practice of concrete-filled steel tubes in Lithuania

Abstract The research and practice of concrete-filled steel tubular members in Lithuania are described. Attention is especially paid to more effective super-thin and thin-walled concrete-filled steel tubes incorporating hollow concrete cores formed by centrifugal force. The fundamentals of behaviour and structural analysis with substantiation of principles of the design methods for such members as tubular columns, beam-columns, beams and trusses, as well as for their connections are presented. It is shown that, because of loading, an interaction occurs between these two traditional materials—steel and concrete—located in the external shell and internal core, and that this also significantly increases the resistance of hollow structural members. Attention is paid to projects that utilize hollow concrete-filled steel tubular structures, incorporated in various buildings, which prove their great technical and economical efficiency, safety and reliability.

Application of the non‐linear Fe models to estimate effect of soft defects on thin walls of steel cylindrical tanks

Abstract Steel storage tanks and other structures of such kind of buildings have been extensively designed following the requirements of continuous cyclic operations. Because of many economically based reasons any engineering inspections of a huge volume are very expensive, so numerical investigations of the local defects are practically important. Natural inspection of tank dents (volumes of tanks were from 1 000 to 50 000 m3, diameter of dents from 0,40 to 4,50 m, a depth up to 120 mm) has shown that analytical approach of their investigation by using existing design standards is rather complicated. The main objectives of the presented investigations are: to determine an appropriate size of the finite element for geometrical defect modelling on thin wall of the steel cylindrical tank; to identify stress/strain state by using finite element method in the place of the defect; to define the appropriate results of the proposed analytical solutions and requirements of the codes with FEM results. The results,...

Composite and interaction effects in steel‐concrete structures for higher fire resistance

Abstract Wide application of steel structures for office and industrial buildings is one of the main features of Lithuanian and world building industry. This fact is related to an essentially wider use of new structural solutions, new structural members and materials. Usage of different types of materials in one structural system for better utilisation of positive properties of each component is very popular in current building industry. Composite beams, columns, beams‐columns and composite floors can be mentioned. Structures that were designed and erected twenty or more years ago are mostly a collection of different types of structural elements. In general, interaction or composite effect is not taken into account, when designing such structures. Though a considerable number of roofs and ceilings made up of reinforced concrete slabs and steel beams or steel trusses are still in maintenance. Structural solution of the slabs, welding of embedded steel parts of slabs to steel structures, filling with concre...

Bearing Capacity of Axially Loaded Timber Members – Estimation Under Uneven Fire Action

Abstract The article deals with the peculiarities of calculating bearing capacity for axially loaded timber members under uneven fire action. According to LST EN 1995-1-2 and finite element modelling for determining temperature fields and variations in timber strength under elevated temperature, the method of simple calculations was applied. Calculations are based on the data and results of experimental investigations into the resistance of axially loaded members to fire. Data on variations in timber strength were obtained conducting laboratory tests using the specimens of Lithuanian pine under elevated temperature.

Plastic capacity of bolted RHS flange-plate joints under axial tension

AbstractThis article considers the calculation of load-bearing capacity of flange-plate joints with bolts along two sides of rectangular hollow sections (RHS) under axial tension. It provides a review and comparison of various calculation methodologies for establishing the load-bearing capacity of RHS flange-plate joints, such as suggested in EN 1993-1-8:2005 and STR 2.05.08:2005 as well as those proposed in different countries and by other authors. Common design principles and derived results for load-bearing capacity of flange-plate joints have been analysed and compared. Following the numerical modelling, which has been done using ANSYS Workbench finite element program, the derived results for load-bearing capacity have been compared with analytical load-bearing capacity results for flange-plate joints of the same structure. The analysis has focused on one type of flange-plate joints with bolts – both preloaded and non-preloaded – along two opposite sides of the tube, with the flange thickness of 15 mm...