Service Checks
Serviceability Class
The serviceability class is determined by using the stress limits defined in Table 24.5.2.1 - Classification of prestressed flexure members based on ft. The stress multipliers defined in this article are the default values used by Eriksson Beam but may be overridden by the user. Once the serviceability class is determined, Table R24.5.2.1 -Serviceability design requirements, is used to determine which additional checks are required.
Deflection Methodology
To calculate deflections, Eriksson Beam uses the effective moment of inertia method for mildly reinforced members and a bilinear model for prestressed members. Note that if the prestressed member remains uncracked the bilinear model will only use gross, uncracked, section properties. More information on the deflection calculation procedure can be found below in the More Information section.
Cracked Section Properties
Cracked section properties for both prestressed and mildly reinforced member are computed using the procedure given by Robert Mast in his paper “Analysis of Cracked Prestressed Concrete Sections: A Practical Approach.” This procedure is summarized in the PCI Design Handbook Section 5.2.2.2, but for more detailed explanation see the paper above. For Class C prestressed components, Δfps is calculated as part of this procedure as well..
Codes
ACI 318-14
References
PCI Design Handbook 8th Edition
Mast, Robert F. “Analysis of Cracked Prestressed Concrete Sections: A Practical Approach.”