Project Information
Input | Description |
---|---|
Project | Project name |
Location | Location of the project |
Date | Date printed on the report (defaults to current date) |
Client | Name of the client |
Designer | Name of the designer |
Job Number | Job number for the project |
Design Number | Design number for the design |
Spec | Let the user select the given specification. Options are ACI 318-14 and ACI 318-11. |
Description | Long form description for the project. Shift+Enter adds a new line. |
Material Properties
Concrete
Input | Description |
---|---|
f’c | Final compressive strength of the wall concrete (often referred to as the 28-day strength). |
f’ci | Concrete compressive strength at time of release of the prestress in the casting yard, or at time of stripping of members without prestressing. The release strength cannot exceed the final compressive strength. This is used for all stripping and handling analysis. It may also be used for erection (user input). |
wc | Density of the concrete used in the wall. |
Ec | Modulus of elasticity of the wall concrete at final. This value will be calculated and updated when f’c or the unit weight of the beam are changed. |
Eci | Modulus of elasticity at time of release of the prestress in the casting yard, or at time of stripping of members without prestressing. This value will be calculated and updated when f’ci or unit weight are changed. |
Type | Wall concrete type can be designated as normalweight, sand-lightweight, or all lightweight. |
Stress Stain Curve
The concrete stress strain curve comes from Collins, Michael P. and Mitchell, Denis, Prestressed Concrete Structures. This curve is used anytime the stress strain curve needs to be evaluated for the concrete, which can happen for flexure capacity.
Rebar / Mesh
Input | Description |
---|---|
fy | Yield strength of the rebar / wire. Note that rebar can (and usually does) have a different yield than wires. |
Es | Modulus of elasticity of the rebar / wire. |
Stress Strain Curve
The mild stress strain curve assumes linear elastic behavior up until yield. At that point the stress always returns the yield stress. Strain hardening is not accounted for and rupture strain is not checked.
Strand
Input | Description |
---|---|
fpu | Ultimate tensile strength of prestressing steel. |
Ep | Modulus of elasticity of prestressed reinforcement. |
Stress Strain Curve
The prestress stress strain curve uses the equations found in the PCI Design Handbook 8th Edition Design Aid 15.2.3. Note that in these equations, the coefficients found in the equation are solved for to account for the user defined material properties. The yield stress in the strand is assumed to be 90% of the ultimate stress.
Prestress Losses
Input | Description |
---|---|
Method | Losses can be user defined, calculated using the lump sum method present in the PCI Design Handbook, or calculated using the time dependent method in the PCI Journal. |
Humidity | Relative humidity (percent). |
Include LL Regain | Indicate whether to include the effects of live load in your losses. |
Time at… | Release: Time when release happens. Used in the loss calculation for transfer. Erection: Time when erection happens. Used in the loss calculation for erection and construction. |
For more information on how prestress losses are calculated, see Prestress Losses .
Load Combinations
Load combinations can be enabled and disabled by using the include check box. Auto select load combinations will turn on only the combinations which match your load input’s load types.
Strength Combinations
Import default strength and service combinations from the currently selected specification. You need at least one strength combination to run the analysis.
Service Combinations
Import default strength and service combinations from the currently selected specification. You need at least one strength combination to run the analysis.
Settings
Deflection Limits
Header | Description |
---|---|
Add initial bow to reported deflections | If checked, the initial deflections will be included in the reported total deflections. The initial deflections (defined by the additional bow the user input and bow due to prestressing camber) always affects the P-Delta analysis. |
Additional bow | If this number is non-zero then the nodes of the panel are adjusted to create a deflection of this magnitude at the mid-height of the panel. The rest of the nodes in the panel are then arranged to fit a 4th order equation of the deflection for a uniformly simply supported beam under a uniform load. For sign convention, a negative initial bow moves the panel toward the interior, while a positive bow moves the panel toward the exterior. |
Total deflection limit: L / | Sets the limit for deflection multipliers for both total and live load deflections. The deflection limit is always L, as defined above, divided by the inputted value. |
Elastic Analysis
Header | Description |
---|---|
2nd order effects | The user can select from P-Delta, Moment Magnification, or None. See the Engineering Theory for a discussion of these analysis procedures. |
Analysis beta d | When P-Delta has been selected, the user can then select the type of Beta d value used, non-sway or sway (see ACI 318 for a discussion of these two factors). The user can also select to input their own Beta d factor used in the analysis. |
R-Value Calculation
For information on the thermal analysis, see the PCI Design Handbook 11.1.
Header | Description |
---|---|
Concrete Resistance | Thermal resistance of the concrete. |
Insulation Resistance | Thermal resistance of the insulation. |
Interior Resistance | Thermal resistance of the interior air space. |
Exterior Resistance | Thermal resistance of the exterior air space. |
Bottom length ignored | Allows the user to ignore the thermal resistance of the parapet. |
Top length ignored | Allows the user to ignore the thermal resistance of the panel below grade. |
Stress Options
Header | Description |
---|---|
Failure if cracked | Cracking is flagged as a failure condition if checked. |
Ignore lateral strand eccentricity | If unchecked, applies a moment about the strong axis if the strand are not symmetrical about the centerline of the cross section. |
Use principal axis | If unchecked, Izy will be set to 0 for stress computations. |
In Place Stress Limits
Header | Description |
---|---|
Tension | Factor multiplied by the square root of the concrete strength and used for calculating final tensile stress limit. |
Compression | Factor multiplied by final concrete strength and used for calculating final compressive stress limit. |
Allowable delta fps | Upper limit on the calculated value of delta fps. |
Handling Stress Limits
Header | Description |
---|---|
Tension | Factor multiplied by the square root of the initial concrete strength and used for calculating initial tensile stress limit. |
Compression | Factor multiplied by initial concrete strength and used for calculating initial compressive stress limit. |
Flexure Options
Header | Description |
---|---|
Method | Whitney Stress Block: Use an approximate volume of the concrete compression zone known as the Whitney stress block to calculate the compression force. Stress-Strain Integration: Integrate the area under a concrete stress strain curve to calculate the compression force. Eriksson Wall uses the concrete stress-strain curve contained in Collins/Mitchell. |
Cracking check | Option to control if an ultimate cracking check is performed for strength combinations. None: No cracking check is performed. Mu < Mcr: Checks that the ultimate moment is less than the cracking moment. phiMn > 1.2Mcr: Checks that the flexure capacity exceeds 1.2 times the cracking moment. Both: Checks both of the above conditions. |
Use plain concrete strength as minimum | If checked, plain concrete strength will be used as a minimum flexure strength for wall panels. |
Resistance Factors
Header | Description |
---|---|
Tension | Strength reduction factor for tension controlled flexure. You can define separate reduction factors for use within the transfer length and past the transfer length. An option exists for fully developed and strand that is transferring. |
Compression | Strength reduction factor for compression controlled flexure. |
Shear | Strength reduction factor for shear. |
Development Multipliers
Header | Description |
---|---|
Strand | Normal: This multiplier is applied to the development length of prestressing strand, except for debonded and cut strand (see below). Debonded: This multiplier is applied to debonded prestressing strand only. Cut: This multiplier is applied to cut prestressing only (at openings). |
Mild | This multiplier is applied to all mild reinforcement. |
Shear Options
Header | Description |
---|---|
Treat as column | When checked, requires minimum shear reinforcement when Vu exceeds 1/2 phi Vc. |
Use ACI 22.5.8.2 | Uses ACI Table 22.5.8.2 instead of 22.5.8.3 to compute shear capacity. |
Axial Options
Header | Description |
---|---|
Ignore tensile strength failures | If checked the program won’t flag any ultimate tensile failures. |
Ignore buckling failures | If checked the program won’t flag any buckling failures. |
Use span’s average properties for buckling load | When computing buckling, the average section properties for the span will be used. |