Journal of
Faculty of Civil Engineering

CONFERENCE PROCEEDINGS
4th INTERNATIONAL CONFERENCE
CONTEMPORARY ACHIEVEMENTS IN CIVIL ENGINEERING 2016 , 2016.y., pp. 133-142

	DOI: 10.14415/konferencijaGFS 2016.012
	UDC: 539.3
	CC-BY-SA 4.0 license
	Author : Filipović, Aljoša; Divac, Ljubo; Šumarac, Dragoslav
	Summary:
	Elastic capacity of the cross section is defined with a linear stress and strain relationship and is determined from the condition that no plastic deformation can occur at any point of the cross section. If the cross section is exposed to bending, then the elastic capacity of the section is reached when the stress in the furthest points from the neutral axis is equal to the yield strength of the material. Elastoplastic capacity of the cross section is reached when the stress in every point of section get equal to the yield strength of the material. More conservative design standards are based on the elastic cross section capacity, while newer standards, such as Eurocod 3, allow engineer to determine a cross section capacity by using an elastoplastic analysis, provided that section can develop plastic moment resistance without local buckling preventing it. But even the exhaustion of the elastoplastic capacity of the cross section at some point of the construction does not necessarily mean the collapse of a structure. When we talk about statically indeterminate structures, development of one plastic hinge only reduces the degree of static indeterminacy, so the structure is still able to carry additional loads. In this paper, the basics of the elastic and elastoplastic theories are given, as well as the procedures for determining the limit load for statically indeterminate structures. Also, as a numerical example, the steel frame will be analyzed in three different ways to show the differences between elastic, elastoplastic and limit-load approach when calculating the structures.
	Keywords:
	Elasticity, plasticity, stress, strain, cross section, yield, plastic hinge