Structural Engineering and Mechanics, Oct 20, 2007
Theoretical foundation for the buckling load determination in reinforced concrete columns is desc... more Theoretical foundation for the buckling load determination in reinforced concrete columns is described and analytical solutions for buckling loads of the Euler-type straight reinforced concrete columns given. The buckling analysis of the limited set of restrained reinforced concrete columns is also included, and some conclusions regarding effects of material non-linearity and restrain stiffhesses on the buckling loads and the buckling lengths are presented. It is shown that the material non-linearity has a substantial effect on the buckling load of the restrained reinforced concrete columns. By contrast, the steel/concrete area ratio and the layout of reinforcing bars are less important. The influence on the effective buckling length is small.
Fixed-pole approach in the non-linear analysis of beam structures offers a different and promisin... more Fixed-pole approach in the non-linear analysis of beam structures offers a different and promising framework for development of new element types with particular potential in the area of conservative time integrators. The finite elements formulated using this approach, however, utilise non-standard degrees of freedom which makes them difficult to combine with standard finite elements in existing codes. A modified approach which combines the benefits of the fixed-pole approach with the use of standard kinematic unknowns from the existing (moving-pole) approaches is presented in this work along with a family of solution procedures for static analysis of geometrically non-linear spatial beam structures. Such a hybrid formulation opens a number of questions which are specifically addressed.
The C-shaped spring is a planar, very flexible elastic beam, the center axis of which is, in an u... more The C-shaped spring is a planar, very flexible elastic beam, the center axis of which is, in an undeformed configuration, ie, a part of a circle. Its free ends are subjected to point loads of constant direction. This note presents essentials of a deformation and stability study of the ...
Theoretical foundation for the buckling load determination in reinforced concrete columns is desc... more Theoretical foundation for the buckling load determination in reinforced concrete columns is described and analytical solutions for buckling loads of the Euler-type straight reinforced concrete columns given. The buckling analysis of the limited set of restrained reinforced concrete columns is also included, and some conclusions regarding effects of material non-linearity and restrain stiffhesses on the buckling loads and the buckling lengths are presented. It is shown that the material non-linearity has a substantial effect on the buckling load of the restrained reinforced concrete columns. By contrast, the steel/concrete area ratio and the layout of reinforcing bars are less important. The influence on the effective buckling length is small.
Proceedings of the Tenth International Conference on Civil, Structural and Environmental Engineering Computing
Abstract This paper shows the influence of the manner the non-linear constitutive equations in th... more Abstract This paper shows the influence of the manner the non-linear constitutive equations in the non-linear spatial beam formulations are solved. Two different approaches are compared:(i) the global approach where the constitutive equations are taken to be the part ...
Zeitschrift für angewandte Mathematik und Mechanik, 1998
Résumé/Abstract The paper presents a quadratically convergent algorithm for the computation of st... more Résumé/Abstract The paper presents a quadratically convergent algorithm for the computation of stability points, ie limit and bifurcation points, in the finite element formulation of the problems of the nonlinear structural mechanics. One such approach was given by ...
ABSTRACT A new mathematical model and its analytical solution for the analysis of the stress-stra... more ABSTRACT A new mathematical model and its analytical solution for the analysis of the stress-strain state of a linear elastic beam cracked in flexure and strengthened with plates on its lateral sides is presented. Both the longitudinal and the transversal interactions at the side plate/beam interface are considered. Linear behaviour of the contact connection is assumed. The method is based upon the linearised planar beam theory of Reissner. The weakening of the beam induced by the flexural crack is modelled conventionally as a rotational spring. The suitability of the theory is demonstrated in a case presentation involving the comparison between analytical results of the present beam (one-dimensional) model, the experiments and the numerical results of a full three-dimensional solid model created in the LUSAS finite element analysis software. An excellent agreement between the results is observed and the proposed formulation is found to be accurate and reliable. Finally, the solution is employed in an engineering analysis, discussing the effects of the material and the geometric properties of selected characteristic cases of the observed beams on the static and kinematic quantities, including the boundary conditions of the side plates, the longitudinal and the transversal stiffness of the connection, the size of the cracks, the span of the beam, and the length and the stiffness of the side plates. For the cracked cantilever beam, a substantial effect of any of these parameters is found. In contrast, for the cracked two-span continuous beam, only the effect of the stiffness of the side plates and the effect of the length of the beam spans are noticeable.
Zeitschrift für angewandte Mathematik und Mechanik, 2001
Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable ... more Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable or unstable sections and critical points, and may bifurcate. A number of procedures has been devised to follow the nonlinear response curve and to determine the critical ...
Zeitschrift für angewandte Mathematik und Mechanik, 2001
Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable ... more Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable or unstable sections and critical points, and may bifurcate. A number of procedures has been devised to follow the nonlinear response curve and to determine the critical ...
The article contains contributions from four authors: Gaberc,A refers to a computer program for t... more The article contains contributions from four authors: Gaberc,A refers to a computer program for the analysis of the consolidation of non-linear and viscous layered soils in linear strain conditions and presents the results of an application of this program. Saje,M presents the fundamentals of numerical stress and strain computation by the finite element method in plane strain conditions for cases when the stress-strain relations can be expressed in terms of octahedral values; the experimentally obtained families of stress versus strain charts are approximated by spline functions. Majes,B presents the results of the application of such a computer program to the computation of stresses and displacements in a layer of limited thickness subjected to a surface load. Vidmar,S presents the results of a similar program which facilitates the analysis of the increase of passive earth pressures with increasing movements of a rigid retaining plate. The resulting earth pressures have been compar...
The article contains contributions from four authors: Gaberc,A refers to a computer program for t... more The article contains contributions from four authors: Gaberc,A refers to a computer program for the analysis of the consolidation of non-linear and viscous layered soils in linear strain conditions and presents the results of an application of this program. Saje,M presents the fundamentals of numerical stress and strain computation by the finite element method in plane strain conditions for cases when the stress-strain relations can be expressed in terms of octahedral values; the experimentally obtained families of stress versus strain charts are approximated by spline functions. Majes,B presents the results of the application of such a computer program to the computation of stresses and displacements in a layer of limited thickness subjected to a surface load. Vidmar,S presents the results of a similar program which facilitates the analysis of the increase of passive earth pressures with increasing movements of a rigid retaining plate. The resulting earth pressures have been compar...
Structural Engineering and Mechanics, Oct 20, 2007
Theoretical foundation for the buckling load determination in reinforced concrete columns is desc... more Theoretical foundation for the buckling load determination in reinforced concrete columns is described and analytical solutions for buckling loads of the Euler-type straight reinforced concrete columns given. The buckling analysis of the limited set of restrained reinforced concrete columns is also included, and some conclusions regarding effects of material non-linearity and restrain stiffhesses on the buckling loads and the buckling lengths are presented. It is shown that the material non-linearity has a substantial effect on the buckling load of the restrained reinforced concrete columns. By contrast, the steel/concrete area ratio and the layout of reinforcing bars are less important. The influence on the effective buckling length is small.
Fixed-pole approach in the non-linear analysis of beam structures offers a different and promisin... more Fixed-pole approach in the non-linear analysis of beam structures offers a different and promising framework for development of new element types with particular potential in the area of conservative time integrators. The finite elements formulated using this approach, however, utilise non-standard degrees of freedom which makes them difficult to combine with standard finite elements in existing codes. A modified approach which combines the benefits of the fixed-pole approach with the use of standard kinematic unknowns from the existing (moving-pole) approaches is presented in this work along with a family of solution procedures for static analysis of geometrically non-linear spatial beam structures. Such a hybrid formulation opens a number of questions which are specifically addressed.
The C-shaped spring is a planar, very flexible elastic beam, the center axis of which is, in an u... more The C-shaped spring is a planar, very flexible elastic beam, the center axis of which is, in an undeformed configuration, ie, a part of a circle. Its free ends are subjected to point loads of constant direction. This note presents essentials of a deformation and stability study of the ...
Theoretical foundation for the buckling load determination in reinforced concrete columns is desc... more Theoretical foundation for the buckling load determination in reinforced concrete columns is described and analytical solutions for buckling loads of the Euler-type straight reinforced concrete columns given. The buckling analysis of the limited set of restrained reinforced concrete columns is also included, and some conclusions regarding effects of material non-linearity and restrain stiffhesses on the buckling loads and the buckling lengths are presented. It is shown that the material non-linearity has a substantial effect on the buckling load of the restrained reinforced concrete columns. By contrast, the steel/concrete area ratio and the layout of reinforcing bars are less important. The influence on the effective buckling length is small.
Proceedings of the Tenth International Conference on Civil, Structural and Environmental Engineering Computing
Abstract This paper shows the influence of the manner the non-linear constitutive equations in th... more Abstract This paper shows the influence of the manner the non-linear constitutive equations in the non-linear spatial beam formulations are solved. Two different approaches are compared:(i) the global approach where the constitutive equations are taken to be the part ...
Zeitschrift für angewandte Mathematik und Mechanik, 1998
Résumé/Abstract The paper presents a quadratically convergent algorithm for the computation of st... more Résumé/Abstract The paper presents a quadratically convergent algorithm for the computation of stability points, ie limit and bifurcation points, in the finite element formulation of the problems of the nonlinear structural mechanics. One such approach was given by ...
ABSTRACT A new mathematical model and its analytical solution for the analysis of the stress-stra... more ABSTRACT A new mathematical model and its analytical solution for the analysis of the stress-strain state of a linear elastic beam cracked in flexure and strengthened with plates on its lateral sides is presented. Both the longitudinal and the transversal interactions at the side plate/beam interface are considered. Linear behaviour of the contact connection is assumed. The method is based upon the linearised planar beam theory of Reissner. The weakening of the beam induced by the flexural crack is modelled conventionally as a rotational spring. The suitability of the theory is demonstrated in a case presentation involving the comparison between analytical results of the present beam (one-dimensional) model, the experiments and the numerical results of a full three-dimensional solid model created in the LUSAS finite element analysis software. An excellent agreement between the results is observed and the proposed formulation is found to be accurate and reliable. Finally, the solution is employed in an engineering analysis, discussing the effects of the material and the geometric properties of selected characteristic cases of the observed beams on the static and kinematic quantities, including the boundary conditions of the side plates, the longitudinal and the transversal stiffness of the connection, the size of the cracks, the span of the beam, and the length and the stiffness of the side plates. For the cracked cantilever beam, a substantial effect of any of these parameters is found. In contrast, for the cracked two-span continuous beam, only the effect of the stiffness of the side plates and the effect of the length of the beam spans are noticeable.
Zeitschrift für angewandte Mathematik und Mechanik, 2001
Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable ... more Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable or unstable sections and critical points, and may bifurcate. A number of procedures has been devised to follow the nonlinear response curve and to determine the critical ...
Zeitschrift für angewandte Mathematik und Mechanik, 2001
Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable ... more Résumé/Abstract The response curve of a structure in the load-displacement space exhibits stable or unstable sections and critical points, and may bifurcate. A number of procedures has been devised to follow the nonlinear response curve and to determine the critical ...
The article contains contributions from four authors: Gaberc,A refers to a computer program for t... more The article contains contributions from four authors: Gaberc,A refers to a computer program for the analysis of the consolidation of non-linear and viscous layered soils in linear strain conditions and presents the results of an application of this program. Saje,M presents the fundamentals of numerical stress and strain computation by the finite element method in plane strain conditions for cases when the stress-strain relations can be expressed in terms of octahedral values; the experimentally obtained families of stress versus strain charts are approximated by spline functions. Majes,B presents the results of the application of such a computer program to the computation of stresses and displacements in a layer of limited thickness subjected to a surface load. Vidmar,S presents the results of a similar program which facilitates the analysis of the increase of passive earth pressures with increasing movements of a rigid retaining plate. The resulting earth pressures have been compar...
The article contains contributions from four authors: Gaberc,A refers to a computer program for t... more The article contains contributions from four authors: Gaberc,A refers to a computer program for the analysis of the consolidation of non-linear and viscous layered soils in linear strain conditions and presents the results of an application of this program. Saje,M presents the fundamentals of numerical stress and strain computation by the finite element method in plane strain conditions for cases when the stress-strain relations can be expressed in terms of octahedral values; the experimentally obtained families of stress versus strain charts are approximated by spline functions. Majes,B presents the results of the application of such a computer program to the computation of stresses and displacements in a layer of limited thickness subjected to a surface load. Vidmar,S presents the results of a similar program which facilitates the analysis of the increase of passive earth pressures with increasing movements of a rigid retaining plate. The resulting earth pressures have been compar...
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