Reinforcement of Sections
Enter the longitudinal (element local axis direction) reinforcement, shear reinforcement and torsion reinforcement data of PSC section. The longitudinal reinforcement data entered here will be reflected in section stiffness calculation and PSC design. In addition, the restraining effect of reinforcement on creep and shrinkage will be considered.
Longitudinal reinforcement in reinforced concrete beams restrains deformations due to creep and shrinkage. The restraining effect is calculated on the basis of the compatibility condition of strains in the reinforcement and the concrete beam section.
The strain of reinforcement due to the strains of creep and shrinkage can be calculated as follows based on the compatibility condition of strain.
The restraining forces of reinforcement acting in the opposite direction to creep and shrinkage are calculated from the strain of reinforcement. The restraining forces at the centroid of the section are as shown below.
where, the properties of the beam section and reinforcement are:
Es: Modulus of elasticity of reinforcement
As: Total area of steel reinforcement
ys: Distance from the center of reinforcement to the neutral axis of the section in the direction of element local-y axis.
zs: Distance from the center of reinforcement to the neutral axis of the section in the direction of element local-z axis.
E: Modulus of elasticity of concrete beam
A: Cross sectional area of concrete beam
Iy: Moment of Inertia of the concrete beam section about the element local y-axis
Iz: Moment of Inertia of the concrete beam section about the element local z-axis
: Axial strain due to creep and shrinkage
: Curvature about the element local y-axis
: Curvature about the element local z-axis
P: Axial force due to the axial strains of creep and shrinkage
My: Moment due to the curvature of creep and shrinkage about the element local y-axis
Mz : Moment due to the curvature of creep and shrinkage about the element local z-axis
Even though reinforcement has been inputted here, if Consider Reinforcement for Section Stiffness Calculation option from Analysis>Main Control Data is not checked, then the reinforcement will not be included when section stiffness property is calculated.
From the Main Menu select Model > Properties > Reinforcement of Sections
Select Geometry > Properties > Reinforcement of Sections in the Menu tab of the Tree Menu.
Reinforcement of PSC Section dialog box (Longitudinal Reinforcement tab)
Select a Section ID for which reinforcement data will be entered from the List. Reinforcement data can be entered for PSC Section only, and as such, Sections other than PSC Sections do not appear in the List.
Copy Reinforcement to
Select a PSC section of any inputted reinforcement and copy the reinforcement to any other PSC section.
Section List: List of PSC sections
Selected Section List: Select the sections to which the previously inputted reinforcement data will be copied.
Longitudinal Reinforcement: Copy the longitudinal reinforcement of the selected i-end or j-end.
Shear Reinforcement: Copy the shear reinforcement of the selected i-end or j-end.
Longitudinal Reinforcement tab
Enter the longitudinal (element's local axis direction) reinforcement data.
Both end parts (I & j) have the same reinforcement.
Dia.: Select the diameter of bar.
Number: Number of bars
Ref.Y: Select a reference point to locate the longitudinal rebars in the transverse direction within the section. When Centroid is selected, the centroid of reinforcement will be located at the neutral axis of the section. When Left is selected, the reinforcement will be located from the far left.
Y: Enter the distance from Ref.Y (specified reference) to the centroid of reinforcement in the transverse direction.
Ref.Z: Select a reference point to locate the longitudinal rebars in the vertical direction within the section. Select either Top (from the upper end of a section) or Bottom (from the lower end of a section).
Z: Enter the vertical distance from Ref.Z (specified reference) to the reinforcement.
Spacing: Enter the transverse spacing of longitudinal reinforcement.
Reinforcement of PSC Section dialog box (Shear Reinforcement tab)
Shear Reinforcement tab
Enter the data for shear reinforcing bars and steel bars within the PSC Section webs.
Both end parts (I & j) have the same reinforcement.
Pitch: Enter the interval of inclined shear reinforcement.
Angle: Enter the angle of inclination for the shear reinforcement. The positive (+) angle is measured clockwise as illustrated in the figure below.
Sign convention of inclined shear reinforcement
Aw: Enter the total area of inclined shear reinforcing steel.
Steel Bar for Web
Pitch: Enter the interval of shear steel bars.
Angle: Enter the angle of inclination of shear steel bars.
Ap: Enter the total area of shear steel bars in webs, per unit length of section.
Pe: Enter the effective prestress of the total shear steel bars in webs.
Shear Reduction Factor: Enter the reduction factor for effective prestress (Pe).
Pitch: Enter the interval of transverse torsional reinforcement.
Awt: Enter the total area of transverse torsional reinforcing steel.
Alt: Enter the total area of longitudinal torsional reinforcing steel.
Enclosing Stirrup for Enclosed Section Area
Cover Thickness: Input the cover thickness of the enclosed stirrup.
Include Flange/Cantilever: I-type section flange and cantilever part of Box type section is included in the enclosed section.
Select a Section ID for which reinforcement data will be entered from the List. Steel - I and Steel Box type Composite Sections appear in the List.
By clicking on , we can check the section properties calculated using Part 2 section and reinforcement. If Cracked Section is checked on, Part 2 section is ignored and the section properties are calculated using the reinforcement only.
: Copy the previously inputted reinforcement data to other composite sections.
: Check this option to ignore the concrete deck section, which exhibits tensile stress, and consider only the longitudinal reinforcement of deck for the section property calculation. After entering the reinforcement data while checking on "Cracked Section" and clicking on the [Add/Replace] button, 'O' will appear under 'Crack' of the Section List. If the section is defined as Cracked Section, Part 2 section will be ignored and only the inputted reinforcement will be considered for the section property calculation.