Seismic Posts-Details for San Francisco



4/7/20231 min read

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Compression posts, also known as struts or seismic separation joints, are used in suspended acoustical ceiling systems to provide additional support and stability during seismic events. They transfer compression loads from the suspended ceiling grid to the building structure, helping to prevent the ceiling from collapsing.

The specific details for compression posts can be found in the industry standard for suspended ceiling systems, ASTM E580 / E580M - Standard Practice for Installation of Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels in Areas Subject to Earthquake Ground Motions.

Here are some key details about compression posts:

  1. Location: Compression posts should be installed along the main runners of the suspension system, spaced no more than 12 feet (3658 mm) apart in both directions. They should be placed near the mid-span of the main runner between hanger wires.

  2. Size and Material: Compression posts should be made of steel and be of adequate size and strength to resist the compressive forces imposed during a seismic event. The size of the posts will depend on the ceiling system's specific design and requirements, which should be determined by a qualified professional.

  3. Connection: The compression posts must be securely connected to both the suspended ceiling system's main runners and the building structure above. The connection details should be designed to accommodate the anticipated seismic forces without causing damage to the ceiling system or the building structure.

  4. Bracing: Compression posts should be used in conjunction with other seismic bracing components, such as sway braces and diagonal splay wires, to provide a comprehensive seismic bracing system for the suspended acoustical ceiling.

  5. Inspection: Compression posts should be inspected periodically to ensure they are properly installed and in good condition. Any signs of damage, corrosion, or loosening connections should be addressed promptly.

Please refer to the most recent version of ASTM E580 / E580M and any local amendments for specific details and requirements for compression posts in suspended acoustical ceiling systems. The building code requirements and industry standards may change over time, so it is essential to stay up-to-date with the latest versions.