ETABS - 14: Ketidakberaturan Horizontal

Summary

This video explains the process of checking horizontal irregularities in a structure according to the latest earthquake standard SNI 1726:2019. The tutorial covers key points such as torsional irregularities, angle irregularities, diaphragm discontinuities, and other structural inconsistencies. With detailed explanations and visual aids, the video guides viewers through each of the five types of horizontal irregularities, showing how to identify and assess them using software tools. It concludes by addressing the consequences of such irregularities in structural design, offering a detailed analysis for engineers and students of structural engineering.

Takeaways

• 😀 The video explains how to check horizontal irregularities in structures based on the SNI 1726:2019 earthquake standards.
• 😀 The SNI 1726:2019 standard introduces some updates compared to the previous 2012 version, but the general content remains similar.
• 😀 The five types of horizontal irregularities to be checked are: Torsional Irregularity (1A), Excessive Torsional Irregularity (1B), Out-of-Plane Corner Irregularity (2), Discontinuity of Diaphragm Irregularity (3), and Non-parallel System Irregularity (5).
• 😀 Irregularity 1A occurs if the maximum displacement between floors is greater than 1.2 times the average displacement.
• 😀 Irregularity 1B occurs if the maximum displacement between floors exceeds 1.4 times the average displacement, indicating excessive torsional irregularity.
• 😀 The software tool helps to analyze displacement ratios for each floor, determining whether a structure meets the criteria for Irregularity 1A or 1B.
• 😀 Irregularity 2, Out-of-Plane Corner Irregularity, occurs if the dimensions of the structure at the corners exceed 15% of the total structural dimensions.
• 😀 For Irregularity 3 (Discontinuity of Diaphragm), a structure with openings or discontinuities greater than 50% of diaphragm area should be checked. The video shows that the structure in question doesn't meet this condition.
• 😀 Irregularity 4 (Vertical Shift in Plane) occurs if vertical elements like columns or shear walls are not continuous from top to bottom, but this structure doesn't exhibit such an issue.
• 😀 Irregularity 5 (Non-parallel System) refers to vertical elements not being parallel with the X and Y axes. The structure shown in the video does not meet this irregularity either.
• 😀 In conclusion, the structure has Irregularities 1B and 2, but no other irregularities, indicating that it requires design modifications to meet the seismic standards.

Q & A

What is the main focus of the video?

The main focus of the video is to explain the process of checking horizontal irregularities in a structure according to the new earthquake standard SNI 1726:2019 using a program.

What is the significance of the new SNI 1726:2019 compared to the older version?

The new SNI 1726:2019 introduces additional visual illustrations and clarifications regarding horizontal irregularities, making it easier to understand compared to the older version from 2012.

What is horizontal irregularity 1A?

Horizontal irregularity 1A occurs if the maximum inter-story displacement or displacement between floors is more than 1.2 times the average displacement between floors at both ends of the structure.

How is horizontal irregularity 1B different from 1A?

Horizontal irregularity 1B is a more severe condition where the maximum inter-story displacement is greater than 1.4 times the average displacement between floors.

How is the displacement ratio used to check for horizontal irregularities?

The displacement ratio is calculated by comparing the maximum displacement (Delta A) and the minimum displacement (Delta B). If Delta A divided by the average displacement (Delta A + Delta B / 2) exceeds certain thresholds (1.2 or 1.4), it indicates a horizontal irregularity.

What is the criterion for checking angular irregularities (horizontal irregularity 2)?

Angular irregularities occur if the dimensions of the structural layout at an internal corner are more than 15% larger than the dimensions in the direction being considered. This is checked by comparing the texture Lex and Kyle values.

How does the video suggest checking for diaphragm discontinuity (horizontal irregularity 3)?

To check for diaphragm discontinuity, the video suggests verifying if a diaphragm or level has an opening or area greater than 50% of its total area, or if there is a change in diaphragm stiffness greater than 50% between levels.

What structure type typically experiences horizontal irregularity 3?

Horizontal irregularity 3 is typically found in structures like malls with large openings in the middle of the building.

What does horizontal irregularity 4 refer to?

Horizontal irregularity 4 occurs when vertical elements, like columns or shear walls, do not extend continuously from top to bottom in the horizontal direction (front-back or side-side), but instead, they are discontinuous along the structure's horizontal plane.

How does the video conclude about the horizontal irregularities in the structure being discussed?

The video concludes that the structure in question exhibits horizontal irregularities 1B and 2, meaning it has significant torsional irregularities and angular irregularities. These findings are crucial for understanding how the structure may perform during an earthquake and for determining appropriate structural adjustments.