Desain Pelat 2 Arah Beton Bertulang - Part 2 - Pehitungan dengan Metode Koefisien Momen

Summary

This video provides a comprehensive guide on designing a two-way slab, focusing on key aspects such as thickness calculation, moment design, and reinforcement details. The process includes evaluating the minimum thickness requirements according to SNI 2847:2019, determining the slab’s inertia and moment capacity, and calculating the necessary reinforcement. Detailed steps are given for calculating the design moment, selecting appropriate reinforcement bars, and ensuring the design meets structural requirements. The video also demonstrates various reinforcement placement techniques, including standard and bent-bar methods, ensuring effective load distribution and structural integrity.

Takeaways

• 😀 The design project involves creating a 6m x 4m interior slab with an initial assumed thickness of 120mm, supported by concrete beams around the slab.
• 😀 The first step in the design is to verify if the assumed thickness of 120mm meets the minimum requirements of SNI 2847 2019.
• 😀 To verify the thickness, the inertia of both the slab and the beam is compared, calculating their effective spans and moments.
• 😀 The calculation process starts with determining the effective span of the slab, which is reduced by the beam dimensions to 5.7m and 3.7m.
• 😀 Inertia calculations are crucial for ensuring the slab and beam meet the necessary structural requirements, including comparing the beam's and slab's inertia values.
• 😀 The assumed slab thickness of 120mm is found to be insufficient according to the SNI 2847 2019 standards, requiring an adjustment to 125mm.
• 😀 Moment capacity is calculated for the slab based on its boundary conditions and loading factors, using appropriate coefficients for each side of the slab.
• 😀 Reinforcement design begins by calculating the required area of reinforcement, ensuring that the tensile forces and compressive forces balance each other.
• 😀 The required reinforcement is found to be D10 bars with a spacing of 175mm, which is checked against the minimum reinforcement area specified by the SNI standard.
• 😀 The final reinforcement design includes specific bar arrangements for various sections of the slab, ensuring both positive and negative moments are adequately reinforced.
• 😀 The reinforcement is visualized with clear diagrams showing the placement of bars, including top and bottom reinforcement, and bent reinforcement for different slab regions.

Q & A

What is the primary goal of the design described in the transcript?

The primary goal is to design a reinforced concrete slab with specified dimensions and ensure that its thickness and reinforcement meet the minimum standards outlined in the SNI 2847:2019 code.

How is the slab thickness determined in the design process?

The initial assumed thickness of the slab is 120 mm, but calculations involving the inertia of both the beam and slab reveal that the minimum required thickness is 125 mm, as per the standard SNI 2847:2019.

What are the dimensions of the slab and beam in the design?

The slab dimensions are 6 meters by 4 meters, and it is supported by concrete beams that are 300 mm wide and 500 mm high.

Why is the ratio of inertia between the beam and slab important in this design?

The ratio of inertia is crucial because it helps determine whether the slab's thickness is sufficient to resist bending under the applied loads. If the ratio exceeds a certain value, the thickness must be adjusted accordingly.

What is the significance of the coefficient values in the moment calculation?

The coefficient values represent factors that account for different support conditions (such as fixed or simply supported). These values are used to adjust the calculation of bending moments and ensure the slab's design is accurate for each support type.

What role does the modulus of elasticity play in the calculation?

The modulus of elasticity is used to compare the stiffness of the beam and slab. Since both materials are assumed to have the same modulus, the calculation simplifies by focusing on the inertia values of the beam and slab.

How is the reinforcement area calculated for the slab?

The reinforcement area is calculated based on the bending moment and the required stress in the reinforcement. The formula involves factors such as the steel yield strength (F), the effective depth of the slab, and the dimensions of the slab and beam.

What is the minimum required steel area for reinforcement in the slab, and how is it determined?

The minimum required steel area is calculated according to the SNI 2847:2019 standard, which is based on the dimensions of the slab and beam. In the design, the minimum steel area is found to be 250 mm², but the calculated steel area exceeds this, ensuring the design is compliant.

How are the bar spacing and diameter determined for the reinforcement?

The bar spacing is calculated to ensure that the slab can resist the bending moments. The bars used are D10 with varying spacing, such as 175 mm for the main reinforcement and 250 mm for secondary reinforcement.

What is the significance of the 3D visualization in the design process?

The 3D visualization helps to clearly depict the placement and arrangement of the reinforcement bars in the slab, ensuring that the bars are positioned correctly for both positive and negative moments, which is crucial for the structural integrity of the slab.