Building sturdy and safe concrete stairs is an important aspect of building construction. Strong and safe stairs not only support aesthetics but also ensure smooth mobility and prevent accidents. For construction workers, especially builders, understanding how to build concrete stairs is the key to quality construction assurance and one of the tips for effective concrete casting.
This article will discuss the formula for concrete stairs that construction workers need to know. We will discuss everything from getting to know the parts of a concrete staircase to basic formulas, such as calculating the length and width of the steps, the height of the landing, and material requirements. Read more below.
Getting to Know Concrete Stair Parts
Before going into the discussion about the formula for concrete stairs, you need to understand the parts of a staircase first. Take notes on the following explanation:
1. Tread
Treads are horizontal parts that people step on when going up or down the stairs. Each tread must have dimensions that comply with the standards of safety and comfort, allowing users to climb easily and safely.
2. Bordes
Bordes are flat parts that connect two or more rows of stairs. The landing serves as an area for rest and helps change the direction of travel.
3. Railing
The next part of the stairs is the railing. Railings are handrails along the sides of stairs that help users maintain balance. To ensure users' safety, the railing must have an appropriate height and be sturdy.
4. Sloof
The last part of the concrete stairs is the sloof. It's a reinforced concrete foundation that supports the entire cast-iron staircase structure. For this reason, the sloof must have sufficient strength to withstand the weight of the stairs and the user.
Read also: Knowing the Importance of Concrete Treatment
How to Build Safe and Sturdy Concrete Stairs
Learn how to build concrete stairs before understanding the formula. Here are several steps to make safe and sturdy concrete stairs:
1. Set Up a Solid Foundation
Building stairs starts with a solid foundation. It serves as a support so that the stairs remain stable. There are several types of foundations that you can use, such as river stone or reinforced concrete foundations. Note that the combination of these two foundations can make a sturdier construction.
2. Make Formwork
For those unfamiliar with the term, stair formwork is a temporary construction that functions as a mold to hold the concrete when it is poured and shaped. It helps ensure the shape and structure of the standard safety stairs.
3. Install the Treads and Main Reinforcing Bars
Once done with the formwork, the next step is to install the treads and main reinforcing bars or rebars. There are several ways to install the main reinforcing bars and treads, as follows:
- Install the main reinforcing bars, then continue by installing the stirrup. Note that the thickness of the decking concrete under the rebar is around 2 cm.
- Connect the reinforcing from the steps with the main rebar using wire to ensure strength and sturdiness.
- Install the rebar lengthwise to ensure the strength of the treads.
- Parallel to the formwork, install concrete decking to complete the construction of the concrete staircase details.
- Finally, tie the formwork from the stair wall to the formwork for the stair body.
4. Casting the Concrete
The final step in making safe and sturdy concrete stairs is casting. Here are several casting stages that you can follow:
- Cast concrete thoroughly on all parts of the stairs.
- Let the cast concrete dry for 12 hours. Check the sturdiness level.
- Once the cast has hardened, separate the mold and stair body to check the strength of the concrete.
- Wait a week to make sure the stairs are safe enough to use.
Read also: Knowing 4 Building Material Types for House Fence
Concrete Stairs Formula
After understanding the parts and steps of building sturdy stairs, it's necessary to understand the formula. Here are some formulas for concrete stairs that you need to pay attention to:
1. How to Calculate the Length of Treads
The first formula for concrete stairs is to calculate the length of the treads. Here's how to do it:
L = (H - T) / n
Information:
L = Length of treads (cm)
H = Floor height (cm)
T = Thickness of treads (cm)
n = Number of treads
Example:
Calculate the length of the treads with a floor height of 240 cm, a tread thickness of 20 cm, and 10 treads.
To answer this, use the formula for making concrete stairs above. Here are the details:
L = (240 cm - 20 cm) / 10
L = 22 cm
2. How to Calculate the Width of Treads
After calculating the length of the treads, the next step is to calculate the width. You can calculate the treads using the following formula:
W = 2 x a + b
Information:
W = Width of treads (cm)
a = Average adult foot length (cm)—generally around 25 cm
b = Distance between heel and toe when stepping (cm)—generally around 5 cm
Example:
Calculate the width of the treads with a standard footrest of 25 cm and a heel-toe distance of 5 cm.
Answer:
W = 2 x 25 cm + 5 cm
W = 55 cm
3. How to Calculate the Height of the Bordes
Calculating bordes includes measuring their thickness. The height of the bordes (Hb) can be calculated using the following formula:
Hb = (2 x w) + 0.15 m
Information:
Hb = Height of bordes (cm)
w = Thickness anak tangga (cm)
Example:
Calculate the height of the bordes with a step thickness of 20 cm.
Answer:
Hb = 2 x 20 cm + 0.15 m
Hb = 55 cm
4. How to Calculate Material Requirements
Material requirements for concrete stairs can be calculated using different formulas, depending on the design and dimensions of the stairs. The following is an example of a material requirements formula.
Concrete volume (V) can be calculated using the following formula:
V = W x L x T
Information:
V = Volume of concrete (m³)
W = Width of treads (m)
L = Length of treads (m)
T = Thickness of treads (m)
Rebar Requirements:
The amount of reinforcing bar (N) can be calculated using the following formula:
N = (L x W x A_s) / f_s
Keterangan:
N = Number of reinforcing bars
L = Stair length (m)
W = Width of stairs (m)
A_s = Cross-sectional area of ​​reinforcing bars (cm²)
f_s = Tensile stress of reinforcing bars (kg/cm²)
That was the discussion about how to calculate concrete stairs. Understanding the formula for concrete stairs can help construction workers build sturdy, safe, and equally aesthetic stairs. By understanding the formula and applying it correctly, construction workers can contribute to creating high-quality and long-lasting buildings.
Apart from introducing the formula, construction workers need to pay attention to the materials used for the project. Therefore, you can use Semen Merah Putih as the main material for concrete stair creation.
Semen Merah Putih is a premium cement product that can be used for various building construction needs, including concrete stairs. Contact us for further information about our products. We'll help you meet your concrete stair construction needs.
