Seismic Isolation Bearings are the most technologically advanced means of protecting a structure against earthquake forces. They are one of the most powerful tools in earthquake engineering for isolating a structure and helping to protect them from the most devastating consequences of a seismic event. Simply stated, they are a collection of structural elements which should substantially decouple or isolate a superstructure from its substructure resting on a shaking ground thus protecting a bridge or building’s structural integrity.
UNASUR Building, Quito Ecuador
The basic components of the EQS consist of a sliding multirotational bearing assembly with damping and a maintenance free device called the mass energy regulator (MER)
The EradiQuake System (EQS)
The EradiQuake System (EQS) is a state of the art Isolation Bearing System designed to minimize forces and displacements experienced by structures during an earthquake. The basic components of the EQS consist of a sliding multirotational bearing assembly with damping and a maintenance free device called the mass energy regulator (MER). This innovative system was developed based on extensive research conducted at the Multidisciplinary Center for Earthquake Engineering Research (MCEER) at the State University of New York at Buffalo. Shake table testing confirmed that the EQS is an extremely effective system for significantly reducing forces and displacements caused by strong ground motion accelerations.
How EQS Works
The EQS transfers the energy of a moving mass (kinetic energy), such as a bridge deck during an earthquake, into heat and spring (potential energy). This is done through the MER which connects the superstructure to the substructure. The EQS structural bearing devices can be adjusted at the direction of the design engineer to achieve a wide variety of energy dissipation levels. This is because the EQS is designed to dissipate energy through friction. By adjusting the friction levels the amount of damping can be controlled. This extraordinary feature gives the engineer the ability to optimize the structural design. Unlike an elastomeric isolation bearing, the lateral effective stiffness of an EQS bearing can be varied in different directions to optimize the response of a structure.
The simplicity of the EQS and the use of readily available engineering materials results in a low cost isolation system. In addition the use of the EQS in a structure design can actually reduce the overall cost by reducing forces and displacements.
The EQS has been used on over 100 structures around the world.
Performance is unaffected by long term cycling. EQS does not need to be replaced after seismic events.
The EQS is designed to restore the structure to its original pre-quake position. No costly jacking of the structure or replacement of fuses is required.
COMPACT IN SIZE – LOW PROFILE
Since the bearing plates, sliding surfaces and MER’s are all integral, the EQS is compact bearing design. EQS will maintain a low profile for all design displacements.
LOW TEMPERATURE PERFORMANCE
Unlike rubber isolators the EQS is not significantly affected by low temperature extremes.
EASE OF RETROFIT
Because of the compactness of the EQS bearing, existing structures can be retrofitted with these devices to improve their overall seismic performance.
The total EradiQuake System can be confined within the sole and masonry plates. This means that during installation of the bearings, no additional component connections are required.
Because the EQS is so effective in reducing forces and displacements, column/footing costs can be reduced, bearing seats can become more compact and joint details can be made simpler and smaller. Secondary systems such as utility lines and drainage systems can be designed for much smaller displacements.
The EQS can be adjusted to the desired level of stiffness and damping. This means that the system can be fine-tuned for an ideal response to any design excitation.
Because the EQS employs the use of multirotational and multidirectional bearings, protection from earthquakes is provided regardless of the direction or orientation of seismic forces.
MER Compression Testing
Performance & Testing
The EradiQuake System (EQS) has undergone extensive prototype and shake table testing at MCEER located at the State University of New York at Buffalo. Tests include individual component testing as well as full scale cycle testing in accordance with AASHTO Guide Specifications for Seismic Isolation Design. In addition the EQS has been subjected to the HITEC Technical Evaluation Testing Program.