Generation of Slab Reinforcement Rectangles [BDS]

In the Building Design Suite of AEC|BOLT, the reinforcement of slabs is accomplished through the generation of three design rectangles:

Reinforcement Intensity Rectangle (yellow)
Rebar Distribution Rectangle (white)
Rebar Length Rectangle (dark blue)

1.Reinforcement Intensity Rectangle on Columns

The calculation of reinforcement demand is determined based on the reinforcement intensity rectangle. To determine the width of the yellow intensity rectangle in a specific direction,

Measure the linear center-to-center distance between the columns connected with stress lines in the desired direction.

Measure the linear center-to-center distance between the columns connected with stress lines in the adjacent directions.
The distance between the center of the column and the yellow rectangle in the desired direction is 25% of the shortest distance measured.

For example ;

Min (166.125”,281”,315.50”) = 166.125”
0.25*(166.125”) = 41.53125”

The distance between the face of column and yellow rectangle can not be less than 1.5 times the thickness of slab.

The average intensity of reinforcement is calculated according to this rectangle.

SAFE top slab reinforcement results are exported as XREF file to calculate the average reinforcement intensity.

Average intensity is calculated by dividing the sum of all maximum strip line values inside the yellow rectangle to the width(feet) of the yellow rectangle. However there are some exceptions for this calculation.

→ If design strip width extends beyond the yellow rectangle but strip line is still inside the rectangle, design strip value is multiplied by a factor which is a ratio of width in yellow rectangle to total strip width. To calculate the factor;

Measure the strip width remaining in the intensity rectangle
Divide it to total design strip width

For example ;

The strip line (red) is still in yellow rectangle but design strip width drawn by magenta color extends beyond the intensity rectangle.

Strip width remaining in the intensity rectangle = 6.75”
Total design strip width = 12”
Factor = 6.75/12=0.5625
Modified strip value = 0.3075*0.5625=0.17297

→ If design strip line is not inside the intensity rectangle, the strip value is ignored even if design strip width extends to the intensity rectangle.

→ If design strip line is not inside the intensity rectangle but the design width extends to the intensity rectangle, the sum of maximum strip values are divided by a modified rectangle width.

Modified rectangle width is calculated as follows ;

Measure the width of strip remaining within the intensity rectangle
Substract it from rectangle width

Average intensity of C53 column at 1st layer is calculated as follows;

→ The sum of maximum strip values : (0.3075*0.5625+0.4344+0.6622+1.1984+1.1007+0.5222+0.3456)=4.4365

→ Modified rectangle width in feet : 78.8750”/12=6.5729'

→ Average intensity = 4.4365/6.5729=0.67496

Rebar decision

Column Strip Top Rebar Decision

Rebar diameter and spacing is being decided from table according to the determined intensity.

Note : Column top rebar diameter can not be less than #5 .

Note : Column top rebar can not be less than minimum required rebar.

Middle Strip Top Rebar Decision

Reinforcement intensity for the span between two columns is the maximum strip value between the intensity rectangles of two columns.

Rebar diameter and spacing is being decided from the table according to the determined intensity.

Note : Middle strip top rebar can not be less than minimum required rebar.

Note : Minimum required rebar = 0.0018*Slab Thickness*12

Note : Maximum rebar = 0.01*(Slab Thickness-Clear cover)*12

Note : Maximum Rebar Spacing = min(2*Slab Thickness , 18”)

2) Rebar Distribution Rectangle

Top slab reinforcement is being distributed in certain areas. Distribution rectangle indicates in which area the reinforcement will be distributed. And the number of rebar is calculated according to this rectangle.

Distribution rectangle is drawn as follows;

Measure the linear center to center distance of columns connected with stress lines.
For direction1, positive direction width is 0.25*max(positive direction length, negative direction length)
For direction1, negative direction width is 0.25*max(positive direction length, negative direction length)

For direction2, positive direction width is 0.25*max(positive direction length, negative direction length)
For direction2, negative direction width is 0.25*max(positive direction length, negative direction length)

Distribution rectangle must be symmetrical.

Note : The distance between the face of column and distribution rectangle can not be less than 1.5*SlabThickness.

→ Number of column top rebar is calculated as follows;

Divide the distribution rectangle width in desired direction to rebar spacing
Add 1
Round the number to upper integer

Note : If slab edge is rotated, number of rebar is calculated according to longer distance.

→ Number of column bottom rebar is calculated as follows;

Generally bottom rebar is #4@14 for both directions for columns unless otherwise noted.

Note : Column bottom rebar can not be less than minimem required rebar.

→ Number of rebar is not specified for middle strip.

Reinforcement Condition of Columns Linked by Beams

In cases where beam and column are connected, the aim is to meet the reinforcement needs in the direction parellel to the beam from the beam reinforcement. The method we set is as follows;

→ If the beam and column connected to the beam are both continuous, there is no need for reinforcement.

→ If the beam is discontinuous reinforcement parallel to beam is required.

→ Reinforcement perpendicular to beam direction is required in both conditions.

Kalan kısmı eklenecek

3) Rebar Length Rectangle

Rebar length is equal to navy blue rectangle width of desired direction.

Column Top Rebar Length

Navy blue rectangle is drawn as follows ;

Measure the linear face to face distance of columns connected with stress lines in each directions
Distance between column face and length rectangle is equal to 0.3*measured maximum distance at selected direction
If column is located at corner or edge rebar must be extended to slab edge

Note : If slab edge is rotated, 0.3*measured maximum distance must be equal or greater than the distance from column face to slab edge.

Middle Strip Reinforcement Length

Middle strip reinforcements are generated between columns connected with stresslines.For example, determining the reinforcement length of the middle strip region indicated with white circle is as follows;

Determine the columns that are associated in parallel to middle strip reinforcement with the two end columns of stress line.

→ C9-C54 columns are associated with C53 column and C10-C56 columns are associated with C55.

Measure the linear clear distance from end columns of stress line to associated columns
Measure the maximum column width parallel to reinforcement of two end columns.
Sum the half of maximum width with 0.22*maximum distance
Draw lines at calculated distance perpendicular to the reinforcement direction and parallel to stress line.
The lines must extend to the column distribution rectangles at both ends.

The middle strip rebars are placed in this region.

For example;

→ Maximum clear distance = 291.50”

→ Maximum end column width parallel to rebar direction = 24”

→ Half width of middle strip rectangle = 24/2+0.22*291.50=76.1234”

If middle strip rectangle is near to slab edge;

→ Inner half of rectangle( distance from stress line) will be calculated as explained above

→ Outer half will end at slab edge

→ Reinforcement length will be shorter than two times of calculated value.

Merge Column Reinforcements

2 Columns Combine

If navy blue (length) rectangles of two columns intersect, column rebars must be merged.

3 Columns Combine

If three navy blue (length) rectangles of columns intersect, determine the critical rebar. Then measure the longest width of length rectangles and place the reinforcement. The number of reinforcement is not specified but the direction of the reinforcement must be specified in the drawing.

Merge Middle Strip Reinforcements

If two or more middle strip rectangles intersect, user must merge reinforcements manually.

Merge middle strip reinforcement kısmı yeni konsept üzerinde uygunluğu belirlendikten sonra güncellenecek.

Building Design Suite