Rational Choice of Reinforcement of Reinforced Concrete Frame Corners Subjected to Opening Bending Moment

This paper discusses a choice of the most rational reinforcement details for frame corners subjected to opening bending moment. Frame corners formed from elements of both the same and different cross section heights are considered. The case of corners formed of elements of different cross section is not considered in Eurocode 2 and is very rarely described in handbooks. Several reinforcement details with both the same and different cross section heights are presented. The authors introduce a new reinforcement detail for the different cross section heights. The considered details are comprised of the primary reinforcement in the form of straight bars and loops and the additional reinforcement in the form of diagonal bars or stirrups or a combination of both diagonal stirrups and bars. Two methods of static analysis, strut-and-tie method (S&T) and finite element method (FEM), are used in the research. FEM calculations are performed with Abaqus software using the Concrete Damaged Plasticity model (CDP) for concrete and the classical metal plasticity model for reinforcing steel. The crucial CDP parameters, relaxation time and dilatation angle, were calibrated in numerical tests in Abaqus. The analysis of results from the S&T and FE methods allowed for the determination of the most rational reinforcement details.

TECHNOLOGICAL PARAMETERS OF WELDING DURING THE REINFORCEMENT OF STEEL TRUSSES COVERING INDUSTRIAL BUILDINGS

The main provisions of rational reinforcement technologies are presented by the method of increasing the cross-section of compressed and stretched rods from pairs of rafter trusses covering industrial buildings. The justifi cation of the technology is given from the position of the available thermal eff ect of welding in this case. Criteria are given for the safe conduct of welding operations at any level of load. Theoretically, the advantages of this technology over known technological schemes are substantiated. On a concrete example the issues of the present interrelation of technical, ecological and economic aspects are considered.

Researches on Rational Reinforcement of Equi-Limb +-Shaped Reinforced Concrete Columns

A nonlinear analysis program for the capacity of +-shaped columns with numerical integral method is complied. Using the program, the Date of Mx-My curves under different axial compression ratios is obtained for four different reinforcement of equi-eimb +-shaped reinforced concrete columns. The maximum moments in various loading angles are analyzed, the cross-sections ability to bear load influenced by different reinforcement is discussed, The rational reinforcement of equi-limb +-shaped reinforced concrete columns is derived. The date shows that the theoretical values and experimental results meet closely. Finally, Some suggestions in practice design for equi-limb +-shaped columns are given.

Researches on Rational Reinforcement of Equi-Limb L-Shaped Reinforced Concrete Columns

A nonlinear analysis program for the capacity of L-shaped columns with numerical integral method is complied. Using the program, the Date of Mx-My curves under different axial compression ratios is obtained for five different reinforcement of equi-eimb L-shaped reinforced concrete columns.The maximum moments in various loading angles are analyzed, the cross-section’s ability to bear load influenced by different reinforcement is discussed, The rational reinforcement of equi-limb L-shaped reinforced concrete columns is derived. The date shows that the theoretical values and experimental results meet closely. Finally, Some suggestions in practice design for equi-limb L-shaped columns are given.