Uncertainty in determination of neutral axis of a steel stringer bridge

2014 ◽  
pp. 2429-2436
Author(s):  
D Sigurdardottir ◽  
B Glisic
Keyword(s):  
Neutral Axis

scholarly journals Calculation of steel-reinforced concrete beam for instant loading taking into account the non-linearity of the concrete diagram ε-σ

2020 ◽  
Vol 17 (2) ◽  
pp. 85-94
Author(s):  
S. O. Chepilko ◽  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
System Of Equations ◽  
Nonlinear System Of Equations ◽  
Steel Reinforced Concrete

Issues of calculating steel-reinforced concrete beams are considered taking into account a nonlinear concrete diagram based on the Sargin formula. The nonlinear system of equations for determination of curvature and neutral axis, which is solved numerically, is written in explicit form. Explicit expressions for determination of other calculated quantities needed for design of steel-reinforced concrete beams are derived. Numerical examples are given. The analysis of accounting nonlinearity in comparison with the linear calculation is carried out.

scholarly journals A derivation of the generalized model of strains during bending of metal tubes at bending machines

2014 ◽  
Vol 19 (1) ◽  
pp. 145-163
Author(s):  
Z. Śloderbach
Keyword(s):  
Analytic Form ◽  
Neutral Axis ◽  
Point Of View ◽  
Process Conditions ◽  
Tube Bending ◽  
Generalized Model ◽  
Bending Process ◽  
Analytic Expressions ◽  
Kinematic Point

Abstract According to the postulate concerning a local change of the “actual active radius” with a bending angle in the bend zone, a generalized model of strain during metal tube bending was derived. The tubes should be subjected to bending at tube bending machines by the method of wrapping at the rotating template and with the use of a lubricated steel mandrel. The model is represented by three components of strain in the analytic form, including displacement of the neutral axis. Generalization of the model during bending metal tubes at the tube bending machines as compared with the existing papers (Śloderbach, 1999; Śloderbach and Rechul, 2000) consists in including the neutral axis displacement and possibility of determination of strains at each point along the thickness of the wall of the bent tube in the bending and bend zone. The derived scheme of strain satisfies initial and boundary kinematic conditions of the bending process, conditions of continuity and inseparability of strains. The obtained analytic expressions can be classified as acceptable from the kinematic point of view

scholarly journals Ultimate Moment Capacities of Round Prestressed Concrete Poles

2000 ◽  
Vol 16 (3) ◽  
pp. 127-132
Author(s):  
Ine-Wei Liu ◽  
Jun-Kai Lu
Keyword(s):  
Prestressed Concrete ◽  
Reduction Factor ◽  
Neutral Axis ◽  
Iterative Design ◽  
Area Reduction ◽  
Equilibrium Approach ◽  
Ultimate Moment ◽  
Compression Area ◽  
Satisfactory Manner

ABSTRACTAn alternative technique for the determination of ultimate moment capacities of round prestressed concrete poles is presented in this paper. The traditional concrete compression area of poles is determined using the conventional iterative design process, the compatibility and equilibrium approach. Moreover, the area of annulus defined by the neutral axis is multiplied by an area reduction factor. It is possible to use numerical methods to calculate the centroid of the reduced annulus. However, the concrete compression zone and strain variation in the longitudinal reinforcement makes the calculation awkward. This paper addresses the problem from a different perspective. No reference to area reduction factor is required in the course of locating the neutral axis. The results are compared in a very satisfactory manner with that obtained using PCI approach. The purpose is to provide formulations that can be easily computerized and implemented on relevant software for the design of round prestressed concrete poles.

scholarly journals IX.—On the Measurement of Stress by Thermal Methods, with an Account of some Experiments on the Influence of Stress on the Thermal Expansion of Metals

1906 ◽  
Vol 41 (2) ◽  
pp. 229-250 ◽  
Author(s):  
E. G. Coker
Keyword(s):  
Thermal Expansion ◽  
Great Majority ◽  
Neutral Axis ◽  
Thermal Methods ◽  
Experimental Knowledge ◽  
Many Instruments ◽  
Polarised Light ◽  
Full Knowledge ◽  
Glass Beam

In the determination of the effects of stress upon different materials, the investigator has several methods of attack open to him, each of which has its own particular advantages. In the great majority of cases the material under investigation obeys the generalised Hooke's law, and the effects of a stress are therefore most easily followed and measured by observations of the strains produced. The strains being usually exceedingly minute, it is necessary to magnify them sufficiently to allow of accurate measurement. To this end many instruments have been devised for measuring the strains obtained by the action of different stresses, and in fact the great majority of our experimental knowledge has been obtained in this way. The application of polarised light to the determination of stress was first suggested by Brewster, and he applied it to many problems, particularly the determination of the neutral axis of a glass beam. Neumann, with a full knowledge of the work of Brewster, developed a theory of the analysis of strain by polarised light, and Maxwell also independently developed a theory. A third method, which has assumed great prominence in recent years, is the microscopic examination of metals under stress, as developed by Ewing, and Rosenhain, and others.

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