Material Properties
- Tim Kostka
This tab covers the material properties of the pile design.
Concrete Properties
In this block, you enter all information that sets the base pile concrete properties. The inputs for this section are:
Header | Description |
|---|---|
Strength at Transfer, fci | 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). |
28-Day Strength, fc | Final compressive strength of the pile concrete. |
Stripping Strength | The strength required for the pile to withstand the stresses it will experience during stripping. This is used in piece ticket generation. To specify concrete strength during stripping use the “Handling” input option “Concrete Strength” here. |
Unit Weight, wc | Density of the concrete used in the pile. |
Ultimate Compressive Strain, εcu | Concrete ultimate compressive strain. |
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.
Strand Properties
Input | Description |
|---|---|
Elastic Modulus, Eps | Modulus of elasticity of prestressed reinforcement. |
Ultimate Strength, fpu | Ultimate tensile strength of prestressing steel. |
Rebar Properties
Input | Description |
|---|---|
Elastic Modulus, Es | Modulus of elasticity of the rebar. |
Yield Strength, fy | Yield strength of the rebar. |
Transverse Steel Properties
Input | Description |
|---|---|
Elastic Modulus, Es | Modulus of elasticity of the transverse rebar / wire. |
Yield Strength, fy | Yield strength of the transverse rebar / wire. Rebar can (and usually does) have a different yield than wire. |
Prestress Loss Computation
Depending on which of the section types are selected, the input content will change.
Input | Description |
|---|---|
Loss | Loss may either be calculated using the equations from AASHTO LRFD Article 5.9.3.3, or may be user defined percentages. |
At Release | Initial loss percentage as a function of the jacking stress of the strands. Only shown if the Loss field is set to “Specify” |
At Final | Total loss percentage as a function of the jacking stress of the strands. |
Strand Type | Specifies if the strand is of type low-relaxation or stress-relieved. |
Humidity | Relative humidity (percent). |