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Select which bars you would like epoxied, the options are ‘none’, ‘top steel if fill < 2ft’ and ‘all steel’. If ‘top steel if fill < 2ft’ is selected the program will always assume the top layer of steel in the top slab is epoxy coated for fill depths less than 2 feet. Otherwise, all steel in the culvert is assumed to be uncoated at all fill depths. If ‘all steel’ is selected, the program will assume all steel is epoxy coated at all fill depths.
Maximum As used in Vc Calcs
In LRFD, when the shear capacity of the concrete is calculated using the iterative approach in Appendix B5, a preliminary estimate of the reinforcing steel is based on moment demand. Then the area of steel is used to calculate the shear capacity and checked against the shear demand. If the preliminary estimate of the area of reinforcing steel is unsatisfactory the program enters a loop inside the shear calculations to increase the area of steel until this requirement it met. This area of steel should be limited to around 2.0 in2/foot for practical purposes, and can be adjusted up or down here. If this limit of the reinforcing steel cannot be satisfied then the program increases the member thickness, recalculating the structural steel demand, and re-starts the shear demand loop.
Live Load Deflection Criteria
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If unchecked, the flexural moment capacity is taken from a location (based on the applied P) on a P-M diagram built internally by the analysis routine for AASHTO Codes. If checked, the flexural moment capacity is set to where the P-M diagram crosses the horizontal axis (P = 0), causing Ma (allowable) to be equal to Mu (pure flexure) in the printout. Also if checked, the variable phi will not be calculated under LRFD, and will be set to that which the user has input on the Load and Resistance Factors page.
Shear:
Always Check Iterative Beta
If checked, the program will calculate the shear capacity of the concrete using the iterative beta method in LRFD Appendix B5. This value is then compared to the shear capacity already calculated using the internal decision table (see Section 5.7) and the larger of the two values is used for the current member.
Use LRFD 5.14.5.3
If checked, the program will calculate the shear capacity of the top slab of a 3-sided culvert with more than 2 foot of fill using LRFD 5.14.5.3, which is usually only used in 4-sided culverts. However, some states allow this provision to be used for 3-sided culverts as well.
Maximum As used in Vc Calcs
In LRFD, when the shear capacity of the concrete is calculated using the iterative approach in Appendix B5, a preliminary estimate of the reinforcing steel is based on moment demand. Then the area of steel is used to calculate the shear capacity and checked against the shear demand. If the preliminary estimate of the area of reinforcing steel is unsatisfactory the program enters a loop inside the shear calculations to increase the area of steel until this requirement it met. This area of steel should be limited to around 2.0 in2/foot for practical purposes, and can be adjusted up or down here. If this limit of the reinforcing steel cannot be satisfied then the program increases the member thickness, recalculating the structural steel demand, and re-starts the shear demand loop.
Environmental:
Apply Environmental Durability Factors
If checked, the program will calculate the and apply the environmental durability factors (as defined in ACI-350) to the flexural demand.
Exposure
Select the appropriate exposure option for your design, the options are ‘normal’ and ‘severe’. This is used in computing the environmental durability factors, defined in ACI-350.