Braceless seismic restraints for suspended nonstructural elements

The seismic performance of nonstructural elements has become a key component of the resilience capacity of modern society. Even if a building does not suffer considerable structural damage during a seismic event, its nonstructural elements can compromise the building’s habitability and functionality. Recent earthquakes have demonstrated the susceptibility of suspended nonstructural elements (e.g., piping, cable trays, etc.) to suffer substantial damage, generating significant economic losses and reducing the overall building’s seismic performance. Current practice aims to protect suspended nonstructural elements through the implementation of seismic restraints incorporating braced supports that increase the lateral strength of the system. However, such approach can still exhibit significant damage, especially at high shaking intensities. This study explores the application of a novel low damage braceless seismic restraint system for suspended nonstructural elements. The system is composed of vertical hangers connected to rotational hysteretic dampers that work as the pivot of the system and provide supplemental damping to control the seismic response. A design example for a suspended piping is presented, comparing the seismic response of a transverse braced channel trapeze with that of the proposed braceless seismic restraint. Numerical results show that for a given design displacement, the braceless seismic restraint can carry a larger tributary seismic mass, allowing a smaller number of anchoring points compared to the conventional restraint