spSlab/spBeam Reinforcing Bar Arrangement Impact on Deflections
The solve options in spSlab/spBeam offer users the flexibility to customize design options, punching shear options, and deflection calculations options. However, it is crucial to exercise sound engineering judgment and remain aware of how these options are implemented within the software to ensure the most accurate representation of the physical model and its conversion to an analytical model. It is also important to understand the consequences of each solve option and how it impacts the analysis and design results.
This technical article investigates the implications of activating the compression reinforcement solve option in spSlab/spBeam, with a particular focus on how it influences bar arrangement and its subsequent impact on deflection calculations. By shedding light on this aspect, engineers and designers can gain valuable insights to make informed decisions for optimal structural analysis and design outcomes.
References
• “spSlab/spBeam” Engineering Software Program Manual v5.50, STRUCTUREPOINT, 2015
• “Doubly Reinforced Concrete Beam Design (ACI 318-14)” Design Example, STRUCTUREPOINT, 2020
• “Doubly Reinforced Concrete Beam Design (CSA A23.3-14)” Design Example, STRUCTUREPOINT, 2021
• Contact “Support@StructurePoint.org” to obtain supplementary materials (spBeam models: A1, A2, B1, and B2)
Condition A: Compression Reinforcement option IS NOT checked to be considered.
Reinforcing Bar Arrangement | Deflection Notes |
All bottom reinforcement IS “Bottom Continuous” Type. Bottom reinforcement DOES NOT contain “Bottom Discontinuous” Type. | Model A1: Program considers “Bottom Continuous” Type (4 - #15) in the calculation of cracked moment of inertia, Icr. No “Bottom Discontinuous” Type. |
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Bottom reinforcement DOES contain BOTH “Bottom Continuous” AND “Bottom Discontinuous” Types. | Model A2: When Compression Reinforcement option IS NOT checked, Program considers “Bottom Continuous” Type (3 - #15) in the calculation of cracked moment of inertia, Icr. However, “Bottom Discontinuous” Type (1 - #15) IS NOT considered in Icr calculation. As a result, deflection (14.338 mm) in Model A2 is greater than deflection in Model A1 (12.546 mm). |
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Condition B: Compression Reinforcement option IS checked to be considered.
Reinforcing Bar Arrangement | Deflection Notes |
All bottom reinforcement IS “Bottom Continuous” Type. Bottom reinforcement DOES NOT contain “Bottom Discontinuous” Type. | Model B1: Program considers “Bottom Continuous” Type (4 - #15) in the calculation of cracked moment of inertia, Icr. No “Bottom Discontinuous” Type. |
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Bottom reinforcement DOES contain BOTH “Bottom Continuous” AND “Bottom Discontinuous” Types. | Model B2: When Compression Reinforcement option IS checked, Program considers BOTH “Bottom Continuous” Type (3 - #15) AND “Bottom Discontinuous” Type (1 - #15) in the calculation of cracked moment of inertia, Icr as BOTH ARE considered in Compression Reinforcement algorithm. As a result, deflection in Model B2 (12.546 mm) equals to deflection in Model B1. |
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