Polygonal Cross-Section Shearwall Web Reinforcement Limits
- oğuzcan hadim
- Zeynep Aladağ
The condition that the total cross- sectional area of the web reinforcements on both sides of the polygon wall will not be less than 0.0025 of the gross cross-section area of the curtain body between the wall end regions for each longitudinal and transverse reinforcement is applied automatically.
If H w / l w ≤ 2.0, the curtain body region is considered as the whole section of the curtain. The condition that longitudinal and transverse reinforcement spacing in the curtain body is not selected more than 250 mm is applied automatically.
It is automatically checked whether the conditions given in 7.6.1.3 with Equation (7.14) are met or not. If provided, the user is asked whether to reduce the longitudinal and transverse total web reinforcement ratios to 0.002 each. The reinforcement range is never less than 250 mm.
ICONS
ΣA g = The sum of the cross-sectional areas of the
structural system elements working as a curtain parallel to the earthquake direction considered at any floor ΣA p = Sum of the plan areas of all floors of the building
f ctd = Design tensile strength of concrete
H cr = Curtain critical height
H w = Above the foundation or Total curtain height measured from the ground floor slab
l w = Plan length of the curtain or tie-beam curtain piece
V t = Section 4According Total seismic load acting on the building (base shear)
φ = Rebar diameter
Polygon Shear Body Reinforcement Conditions
According to Article 7.6.3.1 of TBDY , the total cross section area of the reinforcements on both sides of the polygon wall arms should not be less than 0.0025 of the gross cross section area of the polygon wall arm body for each of the longitudinal and transverse reinforcement . If H w / l w ≤ 2.0, the curtain body is considered as the whole section of the curtain. However, longitudinal and transverse reinforcement spacing in the curtain body should not be more than 250 mm. These conditions are specified in the Preliminary Polygon Curtain Report. A sample Polygon Curtain Preliminary Information report is shown in the picture below. The conditions described above are marked in red.
TBDY Figure 7.11 shows the wall body and minimum reinforcement spacing conditions.
According to Article 7.6.3.2 of TBDY , in buildings where both the conditions given in Equation 7.14 are met, the longitudinal and transverse total body reinforcement ratio can be reduced to 0.002. However, in this case, the reinforcement range should not exceed 300 mm.
If the condition specified in 7.6.3.2 is fulfilled, the user is asked to reduce the screen rate to 0.002 before performing the analysis. In the picture below , the analysis status visual for a building where both of the conditions given by Equation 7.14 are met. After the analysis command is pressed, if the building complies with the article 7.6.3.2 , the question whether the minimum wall reinforcement ratio will be reduced to 0.002 is asked to the user. If the "Yes" option is applied, the curtain body reinforcement ratio is reduced to 0.002. If the "No" option is applied, the minimum wall reinforcement ratio is taken into account as 0.0025, as stated in 7.6.3.1 .
When "Yes" option is selected in the picture above and 7.6.3.2 is applied, since the minimum reinforcement range is 300 mm, if the web reinforcement interval is entered as 300 mm, there will be no inadequacy in the Reinforced Concrete Section. In addition, the minimum body reinforcement ratio is taken into account as 0.002.
However, if the "No" option is selected, since 7.6.3.1 will be applied , if the web reinforcement interval is entered as 300 mm , an insufficiency warning will be given in the Wall Reinforced Concrete section. In addition, the minimum body reinforcement ratio is taken into account as 0.0025.
In accordance with the Article 7.6.3.3 of TBDY, the reinforcement nets on both sides of the curtain bodies are interconnected with at least four special seismic crossties on each square meter curtain face. The diameter of the crossties is chosen at least as the diameter of the horizontal reinforcement.
An example curtain drawing is shown in the picture below. In this drawing, curtain body reinforcements were created automatically in accordance with TBDY Section 7.6.3 .