FAQs

Which design codes does spSlab support?

For information on supported codes please visit spSlab features.

What is the difference between spSlab and pcaSlab?

pcaSlab, also formerly known as ADOSS, was renamed spSlab to better relate and support the registered trade name of the publisher, StructurePoint, formerly the PCA's Engineering Software Group.

Does spSlab calculate long-term deflections?

Yes, a rigorous treatment of instantaneous (short-term) and time dependent (long-term) deflections is offered in spSlab. More information about long-term deflections calculations can be found in Section 2.19.3 in spSlab Manual.

What is the difference between spSlab and spBeam?

spSlab has integrated all of the functions of spBeam although spBeam is still a standalone software. Users who do only one-way slab/continuous beam design may choose spBeam. spSlab can design both one-way slab/continuous beam and two-way slab systems.

I already have spSlab. Do I need spBeam?

No. spSlab has integrated all of the functions of spBeam although spBeam is still a standalone software. Users who do only one-way slab/continuous beam design may choose spBeam. spSlab can design both one-way slab/continuous beam and two-way slab systems.

Why does spSlab require two cantilevers?

Cantilevers are optional and are not required. The use of cantilevers that extend to the face of the exterior supports is recommended to capture the exact geometry of the critical two-way shear section and the exact punching shear strength.

Does spSlab take into account crack control requirements for maximum bar spacing?

Yes, for one-way slab and continuous beam systems. More information about maximum bar spacing can be found in Section 2.15 in spSlab Manual.

Does spSlab design corner reinforcement for two-way slabs?

Yes. spSlab performs calculation of the amount of reinforcement in exterior corners of slabs with stiff edge beams. More information about corner reinforcement can be found in Section 2.18 in spSlab Manual.

Does spSlab support moment redistribution?

Yes, for one-way slab and continuous beam systems. The program allows for redistribution of negative moments at supports. Only reduction in negative moments is considered. More information about moment redistribution can be found in Section 2.10 in spSlab Manual.

Can I open spBeam and ADOSS data files in spSlab?

Yes.

Does spSlab consider torsion?

Yes. Torsion analysis can be engaged for beam and one-way systems using the Torsion Analysis and Design check box located on the Solve Options tab in the Input | General Information dialog box. More information about torsion can be found in Section 2.13 in spSlab Manual.

In spSlab, where do I find the additional longitudinal torsional reinforcement?

The additional longitudinal torsional reinforcement is located in Design Results | Long. Beam Shear and Torsion Reinf. Required | Longitudinal Torsional Reinf. Details. Note that the "Reinforcement" view graphical result does not show the additional longitudinal torsional reinforcement.

What analysis method does spSlab use?

Equivalent Frame Method. More information about this method can be found in Section 2.6 in spSlab Manual. A detailed comparison between Equivalent Frame Method used in spSlab and other commonly used methods can be found in "Comparison of Concrete Two-Way Slab Analysis and Design Methods" technical article.

What is the Equivalent Frame Method (EFM)?

EFM is the most comprehensive and detailed procedure provided by the ACI 318 for the analysis and design of two-way slab systems where the structure is modeled by a series of equivalent frames (interior and exterior) on column lines taken longitudinally and transversely through the building. The equivalent frame consists of three parts: 1) Horizontal slab-beam strip, including any beams spanning in the direction of the frame, 2) columns or other vertical supporting members, extending above and below the slab, and 3) elements of the structure (Torsional members) that provide moment transfer between the horizontal and vertical members.

More information about this method can be found in "StructurePoint - Introduction to Equivalent Frame Method" and "StructurePoint - Equivalent Frame Method a Detailed Description" video tutorials, "Comparison of Concrete Two-Way Slab Analysis and Design Methods" technical article, and Section 2.6 in spSlab Manual.

Can I use spSlab to investigate and design waffle slabs?

Yes. More information about this topic can be found in "Two-Way Joist (Waffle) Slab Design Approach and Methodology" technical article, "Two-Way Joist Concrete Slab Floor (Waffle Slab) System Analysis and Design" design example, and Section 2.4.3 in spSlab Manual.

Can I use spSlab to investigate and design a continuous beam?

Yes. More information about this topic can be found in "Reinforced Concrete Continuous Beam Analysis and Design" design example.

Can I use spSlab to investigate and design standard and wide module joist systems?

Yes. More information about this topic can be found in "One-Way Wide Module (Skip) Joist Concrete Floor System Design" design example.

I don't see any reinforcement in the results in spSlab output, why?

If the calculated reinforcement exceeds the maximum allowed or violates spacing requirements (minimum or maximum), a message will appear in the output and no longitudinal reinforcement will be shown in the "Reinforcement" view graphical result. In such cases, it is recommended that the engineer review the slab thickness and/or reinforcement criteria to ensure a more satisfactory design. More information about this topic can be found in Section 2.14 in spSlab Manual.

Where can I define and/or adjust bars lengths in spSlab?

To adjust bars lengths, Select Reinforcing Bars from the Input menu. The reinforcing bar size, number of bars, bar length, etc. can be defined and adjusted by users if the Run Mode of Investigation is selected in the General Information dialog box. If Run Mode of Design is selected, spSlab calculates the minimum bar lengths required.

Does spSlab consider discontinuous bars in cracked moment of inertia (I_cr) and deflection calculations?

When Compression Reinforcement solve option is not checked, spSlab does not consider discontinuous bars in I_cr and deflection calculations. When Compression Reinforcement solve option is checked, spSlab considers discontinuous bars in I_cr and deflection calculations. More information about this topic can be found in "spSlab/spBeam Reinforcing Bar Arrangement Impact on Deflections" technical article.