The installation spacing of seismic bracing is typically one brace every 12 meters. For all domestic water supply and fire protection piping systems with a diameter of DN65 or larger, lateral seismic bracing is required, and longitudinal seismic bracing should also be installed every 24 meters. The application of seismic bracing is increasingly widespread. Its function is to limit equipment vibration, reduce displacement caused by earthquakes, thereby reducing the damage to building's internal water supply, drainage, fire protection, heating, and other electromechanical engineering facilities during earthquakes, minimizing secondary disasters, and protecting personnel safety.
1. For domestic water supply and fire protection piping systems with a diameter equal to or greater than DN65, it is recommended to install one lateral seismic brace every 12 meters and one longitudinal seismic brace every 24 meters.
2. For all ventilation duct systems with a diameter greater than or equal to 0.7 meters, lateral seismic bracing should be installed at 9 meters, and longitudinal seismic bracing at 18 meters.
3. For electrical system conduits and cable trays with a diameter greater than or equal to 60 mm, and all cable trays, cable ladders, cable boxes, and busbars with a load capacity greater than or equal to 150 N/m, it is recommended to install one transverse seismic brace every 12 meters and one longitudinal seismic brace every 24 meters.
Seismic bracing plays a crucial role in seismic design. The following are the installation requirements for seismic bracing:
- Air conditioning unit fans with a load capacity greater than 1.8 kN and air ducts with a cross-sectional area greater than or equal to 0.38 m² and a diameter greater than or equal to 0.7 m should use seismic bracing.
- Smoke exhaust ducts, emergency ventilation ducts, and related equipment also require seismic bracing.
- Indoor water supply, hot water, and fire protection pipes requiring seismic protection, especially horizontal pipes with a diameter greater than or equal to DN65, should also be equipped with seismic bracing.
- In high-rise buildings located in areas with seismic intensity of 8 or 9 degrees, seismic measures should be implemented if the straight length of water supply and drainage risers exceeds 50m; if the straight length exceeds 100m, seismic measures should be implemented.
- Electrical conduits with an inner diameter of not less than 60mm and cable trays, cable troughs, and busbars with a weight of not less than 150N/m should also be equipped with seismic bracing.
Seismic bracing should be firmly connected to the main building structure. Its design should consider the seismic fortification intensity of the project location, with seismic force as the main load, and consist of anchors, reinforcing hangers, seismic connection components, and seismic bracing diagonal braces. All components should be prefabricated, and the construction of connecting fasteners should facilitate installation. Seismic supports for pipelines should not restrict displacement caused by thermal expansion and contraction, and their installation and design should comply with relevant specifications. All seismic supports should be reliably connected to the main building structure, and when pipelines cross building settlement joints, the effects of uneven settlement should be considered.
For new construction projects, the maximum lateral spacing of seismic bracing for rigid cable ladders, circular cable trays, and cable troughs should be 12 meters, and the maximum longitudinal spacing should be 24 meters.
