SNI - 1: SNI 1726:2012 vs SNI 1726:2019

Summary

This video compares the key differences between SNI 1726:2012 and SNI 1726:2019, focusing on structural seismic design guidelines. Notable changes include a revised load combination method, an expanded design response spectrum with new formulas for long-period structures, and stricter modal analysis participation requirements. The 2019 version also emphasizes a 100% mass participation in the modal analysis, compared to the 90% in the 2012 version. Furthermore, shear force calculations now require that the modal shear forces meet or exceed the static equivalent by 100%. These updates aim to enhance earthquake resilience and precision in Indonesian construction standards.

Takeaways

• 😀 The first major difference between SNI 1726:2012 and SNI 1726:2019b is in the load combination for the Ultimate Method in Article 4.2.2, where the changes are mainly in the numbering and reorganization of the points.
• 😀 In SNI 1726:2012, the load combination points 5-7 are restructured in the 2019 version, with some points renumbered, for example, point 6 from 2012 becoming point 5 in 2019.
• 😀 A new consideration in the 2019 version is the inclusion of horizontal and cortical load combinations for earthquake analysis, which was highlighted in the updated guidelines.
• 😀 In the design response spectrum section (Article 6.4), SNI 2012 uses only three equations to represent response spectra, but SNI 2019 introduces a fourth equation for long-period structures, particularly when the period exceeds 8 seconds.
• 😀 The 2019 standard provides a more detailed response spectrum that accounts for long-period structures by including additional equations to reflect greater seismic activity for these longer periods.
• 😀 For locations with specific seismic characteristics, the updated standard in 2019 offers a more granular approach by incorporating the long-period response spectrum when the structure period exceeds 8 seconds.
• 😀 A significant change in the 2019 SNI is in the number of modes required for structural analysis. The 2012 version required participation of at least 90% of the total structure mass in horizontal directions, while the 2019 version raises this to 100%.
• 😀 In cases where 100% participation is difficult to achieve, the 2019 standard allows for a 90% participation threshold as an exception, in line with the older 2012 guidelines.
• 😀 SNI 2019 places stricter requirements on the calculation of base shear forces. The base shear forces derived from the combination of vibration modes must now match or exceed 100% of the static equivalent forces, compared to the 85% requirement in the 2012 version.
• 😀 The 2019 revision emphasizes that the forces from the modal analysis must be sufficiently high to ensure the safety and structural integrity of buildings in earthquake-prone areas, removing the 85% threshold and making 100% mandatory.

Q & A

What is the main difference between SNI 1726:2012 and SNI 1726:2019 regarding load combination for the Ultimate Method?

The main difference lies in the combination of loads in the Ultimate Method. In SNI 2019, minor adjustments were made to the numbering of certain points in the load combinations, with a particular focus on combinations involving FW (vertical) and horizontal forces.

How does the response spectrum design change between the 2012 and 2019 versions of SNI 1726?

In SNI 2012, the design response spectrum is divided into three parts. However, SNI 2019 divides it into four parts, adding a new formula for long-period acceleration and updating the earthquake hazard map to account for longer periods in some locations.

What change was made regarding the number of vibration modes in structure analysis between the 2012 and 2019 versions?

In SNI 2012, the structure analysis required sufficient modes to achieve at least 90% of the actual mass participation. In SNI 2019, this requirement increased to 100% mass participation, with a provision for exceptions allowing the use of the 2012 standard with a 90% threshold.

How does the treatment of shear forces change between SNI 2012 and SNI 2019?

In SNI 2012, shear forces from modal analysis must be at least 85% of those calculated using static methods. SNI 2019 increases this threshold to 100%, meaning the shear forces derived from modal analysis must match or exceed those from static analysis.

What is the significance of the new formula introduced in SNI 2019 for long-period acceleration?

The new formula introduced in SNI 2019 for long-period acceleration is designed to account for structures with longer periods, improving the accuracy of earthquake response predictions, especially in areas with higher seismic hazard.

How do the changes in response spectrum affect structures with long periods in SNI 2019?

For structures in areas with long-period acceleration (e.g., periods of 8 seconds or more), SNI 2019 provides a new formula for the response spectrum, making it applicable for structures with longer periods, unlike the 2012 version which only used a three-part equation.

What does the 100% mass participation requirement in SNI 2019 mean for structural analysis?

The 100% mass participation requirement in SNI 2019 ensures that the vibration modes considered in structural analysis account for the entire mass of the structure, leading to a more accurate representation of its seismic response.

Why was there a change from 90% to 100% mass participation in SNI 2019?

The increase from 90% to 100% mass participation was made to improve the accuracy of seismic analysis and ensure that all significant vibration modes contribute to the structure's response during an earthquake.

What is the impact of the updated seismic hazard map in SNI 2019?

The updated seismic hazard map in SNI 2019 provides more detailed information about long-period accelerations, helping to refine earthquake resistance design for structures in areas with longer periods, such as certain regions in Indonesia.

How does the 2019 version of SNI 1726 ensure that seismic forces are accurately accounted for in structural design?

The 2019 version ensures seismic forces are accurately accounted for by requiring 100% mass participation in vibration mode analysis, revising load combinations, and introducing new response spectrum formulas that better reflect seismic conditions, including longer periods.