Horizon_Waves
25-01-2004, 01:21 PM
Steel distributions
This section concentrates on the manner of how the steel is distributed in the reinforced concrete in terms of compression and tension forces the structural element can have in the structural frame as a part. In addition, some times the steel diameter will be as notation of #8 or #9ect, in this case to get the diameter in mm divide that notation by “8”or use the table of ACI – Code.
Spacing
The term spacing means the distance between the steel bars in the concrete is specified by the designer according to the spacing equation or based on the code used.
The main equation for spacing is the following:
Spacing = (net distance) / (#of bars – 1)
#of bars = distance (m). Given number per meter
Net distance = entire distance – [ (2* cover) + ( 2*H. Steel dia.) + (donut dia.)]
Example:
Entire distance = 1000 mm
Concrete cov. = 20 mm
Horizontal Steel (diameter) = 08 mm
Donut diameter = 10 mm
# bars /m = 06
Find the spacing for such situation?
# of bars = (1000/1000) * ( 06) = 6 steel bars per meter
Spacing = (1000 – 40 – 16 – 10) / ( 6 – 1) =186.8 mm
Notice that some time the number of bars will be with fraction like 22.12; however, you take always to the higher integer (ex. 22.01 = 23 )
Concrete Cover
The concrete cover is analogous to the safety factor in the mechanical design, but here its main task is to protect the steel from rusting or corrosion. In general, the following table shows the min concrete cover for such structural element:
Structural element Concrete Cover range(mm)
Foundation 40 – 50
Column 20 – 30
Beam 20 – 30
Slap 15 – 25
Stairs 20 – 30
Moreover, the concrete cover can also protect the steel to be exposed to sudden impacts that can happen.
Ties
This term is used to describe the bended steel that will hold the main steel in column which will be fixed around. In addition, the concrete cover will start from the heads of the ties. In the drawing these details should be clear and in exact dimensions.
Furthermore, ties task is to maintain the main reinforcement steel together and to prevent the buckling of the column due to extra load that can be exist in accident case like earthquake.
Notice that the ties is used only in the column separated by specific distances based on the design of used code either American code or British one.
Main Steel
The main steel reinforcement means the main steel that will have the main loads of other structural elements. The main steel task is based on where the main steel is support the concrete; in other words, in which structural element.
Generally, the main task or the shared one for reinforcing the concrete by the steel is to hold and give more strength for the structural element to stand the loads and forces (shear force, moment, tension, compression, torsion).
Bottom and Top
This is also the main steels bars but with some special tasks for each existing in the beams, slaps, and stairs. Moreover, the top steel reinforces the concrete in order to oppose the compression forces. On the other hand, the bottom steel takes the tension forces in the beam or slap or in the retaining wall. However, sometimes this type of steel (just as matter or speech because they are main sometimes not different type) in stairs is just to support the structural element.
Stirrups or shear hungers
The stirrups hungers or shear are analogous to the ties in column but they have another task, because they are used in the simple and continuous beams to oppose the shear forces and moments. In addition, there is no
difference between them in the drawing, even in the reality except the direction of buckling is now in vertical direction not horizontal direction. Moreover, they can have another task in order to connect the beam with the slap. In addition, in continuous beam the hungers will be extend with specific spacing based on the design (see section of Continuous Beam).
Dowels
Dowels are used to connect the foundation with the column or to connect two column differ in dimensions. In addition, the length of foundations dowel differs from the ones for column based on the code used also.
However, the common length of foundations dowels about 500 mm, noticing that the steel of dowels is the same as the foundation steel. In addition, the dowels of columns have its low which is used once the length of dowel is not given which is the following:
Id = (dia. Main Steel). (50)
Notice one more difference between Id of foundations and the ones for columns, the first one is formed in L – shape extended on the bottom of the foundation and in the column; on the other hand, for columns, it is just to connect both columns only not more.
Extensions in beam and slap
For this part it needs to review the ACI – Standard (American of reinforced Concrete Institute) because they have changed the codes regularly.
In the beginning, the term clear span means the internal distance between two columns which is named as “L” in the ACI – Code. Moreover, the upper extensions for steel in the one way or two way slap is ( L / 4 ) starts from the centre of the main bended steel.
By contrast, in the continuous beam there is no extension like the one in the slap but the extension of the shear hungers (distance) from the column is about ( L / 3 ). And for the bended steels they will start from the end of that distance in 45 degree.
This section concentrates on the manner of how the steel is distributed in the reinforced concrete in terms of compression and tension forces the structural element can have in the structural frame as a part. In addition, some times the steel diameter will be as notation of #8 or #9ect, in this case to get the diameter in mm divide that notation by “8”or use the table of ACI – Code.
Spacing
The term spacing means the distance between the steel bars in the concrete is specified by the designer according to the spacing equation or based on the code used.
The main equation for spacing is the following:
Spacing = (net distance) / (#of bars – 1)
#of bars = distance (m). Given number per meter
Net distance = entire distance – [ (2* cover) + ( 2*H. Steel dia.) + (donut dia.)]
Example:
Entire distance = 1000 mm
Concrete cov. = 20 mm
Horizontal Steel (diameter) = 08 mm
Donut diameter = 10 mm
# bars /m = 06
Find the spacing for such situation?
# of bars = (1000/1000) * ( 06) = 6 steel bars per meter
Spacing = (1000 – 40 – 16 – 10) / ( 6 – 1) =186.8 mm
Notice that some time the number of bars will be with fraction like 22.12; however, you take always to the higher integer (ex. 22.01 = 23 )
Concrete Cover
The concrete cover is analogous to the safety factor in the mechanical design, but here its main task is to protect the steel from rusting or corrosion. In general, the following table shows the min concrete cover for such structural element:
Structural element Concrete Cover range(mm)
Foundation 40 – 50
Column 20 – 30
Beam 20 – 30
Slap 15 – 25
Stairs 20 – 30
Moreover, the concrete cover can also protect the steel to be exposed to sudden impacts that can happen.
Ties
This term is used to describe the bended steel that will hold the main steel in column which will be fixed around. In addition, the concrete cover will start from the heads of the ties. In the drawing these details should be clear and in exact dimensions.
Furthermore, ties task is to maintain the main reinforcement steel together and to prevent the buckling of the column due to extra load that can be exist in accident case like earthquake.
Notice that the ties is used only in the column separated by specific distances based on the design of used code either American code or British one.
Main Steel
The main steel reinforcement means the main steel that will have the main loads of other structural elements. The main steel task is based on where the main steel is support the concrete; in other words, in which structural element.
Generally, the main task or the shared one for reinforcing the concrete by the steel is to hold and give more strength for the structural element to stand the loads and forces (shear force, moment, tension, compression, torsion).
Bottom and Top
This is also the main steels bars but with some special tasks for each existing in the beams, slaps, and stairs. Moreover, the top steel reinforces the concrete in order to oppose the compression forces. On the other hand, the bottom steel takes the tension forces in the beam or slap or in the retaining wall. However, sometimes this type of steel (just as matter or speech because they are main sometimes not different type) in stairs is just to support the structural element.
Stirrups or shear hungers
The stirrups hungers or shear are analogous to the ties in column but they have another task, because they are used in the simple and continuous beams to oppose the shear forces and moments. In addition, there is no
difference between them in the drawing, even in the reality except the direction of buckling is now in vertical direction not horizontal direction. Moreover, they can have another task in order to connect the beam with the slap. In addition, in continuous beam the hungers will be extend with specific spacing based on the design (see section of Continuous Beam).
Dowels
Dowels are used to connect the foundation with the column or to connect two column differ in dimensions. In addition, the length of foundations dowel differs from the ones for column based on the code used also.
However, the common length of foundations dowels about 500 mm, noticing that the steel of dowels is the same as the foundation steel. In addition, the dowels of columns have its low which is used once the length of dowel is not given which is the following:
Id = (dia. Main Steel). (50)
Notice one more difference between Id of foundations and the ones for columns, the first one is formed in L – shape extended on the bottom of the foundation and in the column; on the other hand, for columns, it is just to connect both columns only not more.
Extensions in beam and slap
For this part it needs to review the ACI – Standard (American of reinforced Concrete Institute) because they have changed the codes regularly.
In the beginning, the term clear span means the internal distance between two columns which is named as “L” in the ACI – Code. Moreover, the upper extensions for steel in the one way or two way slap is ( L / 4 ) starts from the centre of the main bended steel.
By contrast, in the continuous beam there is no extension like the one in the slap but the extension of the shear hungers (distance) from the column is about ( L / 3 ). And for the bended steels they will start from the end of that distance in 45 degree.