Beam Section Design Contents

Beam Section Design Contents

The Storey Beam Section Design and Detailing form can be accessed by clicking the “Storey Beam Section Design and Detailing” option under the “Design” pulldown menu and then selecting one of the “Storey Beams”, “Ribs Beams” or “Foundation Beams” sub-options. 

General

Settings to be used in the beam designs are assigned using the  Beam Design Settings option in the “Options” tab.


Concrete and steel grades to be used in the beam designs are assigned using the  Materials button on the “Pre-Analysis” page of the “Building Analysis” dialog.


Analysis results for the beams are automatically transferred to the “Beam Section Design and Detailing” module. Beams can be designed either according to the original results from the building analysis or for member forces defined by the user.

Beam Types

The Beam Section Design and Detailing menu options are explained below.

Storey Beams 

Following the completion of the structural analysis without any errors, a Beam Summary File consisting of the maximum effects in the beams is created. This file will be used as the input data for the Beam Reinforcement Design.

Rib Beams 

The analysis results of the rib beams are generated using the “Ribbed Slab Analysis” menu option in the “Design” pulldown. These results will then be automatically transferred to the Beam Section Design and Detailing module.

Foundation Beams 

If strip footings are used in the building, the “Strip Footing Calculations” should be completed first. The strip foundation axis information will be transferred to the Beam Section Design and Detailing module automatically. 

How The Beam Design Forces are Generated

The "Storey Beam Section Design and Detailing" module requires six “Design Moments” and two “Design Shear Forces” for each beam to calculate the reinforcement.
These bending moments moments are creating the most critical tension values at:
  1. Left support top
  2. Right support top
  3. Span top of the beam
  4. Left support bottom
  5. Right support bottom
  6. Span bottom of the beam.
Bending moment is checked for the top edge in three regions:
  1. Left (worst case forces in end region ‐ 25% clear span)
  2. Middle (worst case forces in mid region ‐ 50% clear span)
  3. Right (worst case forces in end region ‐ 25% clear span)
                        

Similarly, bending moment is checked for the bottom edge in three regions:

      4. Left (worst case forces in end region ‐ 15% clear span)
      5. Middle (worst case forces in mid region ‐ 70% clear span)
      6. Right (worst case forces in end region ‐ 15% clear span))


The design moments for each of the six regions can be displayed by from the "Beams" tab by firstly highlighting the beam required in the table and then clicking the "Interactive Design" button as shown below:



Values for K, K’, x, As, and As’ are then all calculated for each region and are also shown in the same table.

Where the ratio of K/K’ is less than 1.0 no compression steel is required.

The effective depth " h’ " to the centre of the bars is worked out separately at each location. This is automatically reduced if the steel doesn’t fit in a single layer.

You can control this calculation via the Design tab of "Beam Design Settings" as shown below:



The design shear forces that will be used in design are the most critical support shear values developed.
All the effects chosen for design will also be listed in the beam design output reports.

Storey Beams

ProtaStructure Structural Analysis Module transfers the analysis results obtained using all the loading combinations to the “Storey Beam Section Design and Detailing” module automatically.

After the structural analysis the most critical of the six design moments and two design shear forces are selected for each beam, among all the effects obtained from all loading combinations.

Rib Beams

The analysis of the Rib beams can be accomplished using the “Ribbed Slab Analysis” menu option   in the “Design” pulldown.

As a result of the “Ribbed Slab Analysis” all the ribbed slab strips defined in the Graphic Editor are analysed and transferred to the “Beam Section Design and Detailing” module automatically. Similar to the storey beams, the most critical effects in the support and span of the ribs are used.

Foundation Beams

After performing the analysis of the all of the strip footings in the Graphic Editor, the “Foundation Beams Section Design and Detailing” module is loaded with the “Foundation Beams” option; all effects will be transferred automatically.
Beam Reinforcement Design Modes
After clicking the “Storey Beam Section Design and Detailing” option in the “Run” pulldown, and selecting the type of the beam (Storey, Rib or Foundation Beams) you will see all the beam axes in the current project listed for all storeys.

Beam Design can be performed in two modes:

Interactive Mode


The design can be performed for individual axes one storey at a time using the “Reinforcement Data Editor”. Consideration should certainly be given for designing axes containing critical beams by this method to obtain the best results.

More information about this method can be found under the titleInteractive Beam Reinforcement Design”.

Batch Mode


Using this mode, reinforcement of all beams can be calculated and selected by the program automatically. More information about this method can be found under the title “Beam Reinforcement Design (Batch Mode)”.


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