Strength of Short Concrete Filled Steel Tube columns of Annular Cross Section

Reserves and exposure assessment of reinforced concrete structures safety while reducing its power resistance

“…Thus (36) As noted above, such destruction of the reinforced concrete element is accompanied by a change in the static structure of the element [30][31][32][33][34][35][36].…”

“…The damage effect to the support nodes of beams and columns on the power resistance. The effect of node damage (changes in boundary conditions) is illustrated on the main elements of building frames -beams and columns [17][18][19][20][21][22][23][24][25].…”

“…Two identical single-span beams are compared with a span of l m, but with different boundary conditions; in particular, the B-1 beam, pinched on the supports and loaded with a uniform q = const, and the B-2 beam, pivotally supported on the supports and loaded with the same uniform load q = const. The beam B-1 bending moments in pinching equal: (19) mid-span (20) and the angle of the reference section rotation is zero. The beam B-2 bending moments are described by the equation 21which leads to the calculation of the reference moments (22) and mid-span moments (23) wherein the angle of the reference section free rotation (24) It follows that the beam B-1 without destruction can perceive as a uniform load (25) and beam B-2, respectively (26) that is half as much.…”

“…The structural safety of buildings interests requires ensuring: geometric invariability of the structural scheme at all the stages of their existence (and during reconstruction and dismantling -with the additional connections help), a stable stress-strain state and position in space and time of all supporting structures of the building, and survivability of statically indefinite systems. And yet, the common thing is to ensure the strength and stability of individual load-bearing elements of the system and the so-called «redundant ties» despite the different purpose of these conditions [1][2][3][4][5][6][7][8][9]. At the same time, the assessment of structural safety is an obligatory stage of the decision-making procedure on the issues of continued operation or technological reorganization of production, reconstruction, etc.…”

Residual resource of power resistance during building structures deformation

“…The strength resistance of reinforced concrete is collectively determined by the properties of its components and the specifics of their joint work, including the adhesion of reinforcement to concrete. At the same time, the strength resistance of concrete, reinforcement, and adhesion between them are distinguished by the nonlinearity of the relationship between stresses and strains, creep, a certain irreversibility of strains, age wear; concrete responds to changes in the physicochemical and pyrometric characteristics of the medium, on the history and time conditions of loading and impacts [1][2][3][4][5][6][7][8][9].…”