Everything we make for seismic protection.

Base isolators consist of a laminated rubber and steel bearing with steel flange plates for mounting to the structure. Ninety percent of our isolators have an energy-dissipating lead core.

The rubber acts as a spring, very soft laterally, very stiff vertically. The high vertical stiffness comes from thin layers of rubber reinforced by steel shims. These two characteristics allow the isolator to move laterally with low stiffness while carrying significant axial load. The lead core provides damping by deforming plastically when the isolator moves laterally in an earthquake.

Isolators from 12 to 60 inches in diameter, with capacities up to 4,000 tons, are manufactured. Custom dimensions are available for special applications. Shims are laser-cut to exacting tolerances; steel mounting plates are machined by computer-controlled milling centers. Each bearing's curing phase is continuously monitored to ensure that the rubber is uniformly cured throughout.

A sliding isolator consists of a PTFE (Teflon) disc that slides on a stainless steel plate. The most common slider has the same construction as a base isolator with a Teflon disc substituted for the flange plate.

Sliders support vertical loads with low lateral resistance. They are typically used alongside isolators to optimize an isolation system, placed under lighter parts of the structure such as stairs and lightly-loaded columns. An elastomeric backing accommodates rotations; the sliding contact provides additional damping from friction. Sliding isolators are manufactured from 12 to 41 inches in diameter.

Dynamic Isolation Systems processes over 2,000 tons of steel a year. Steel mounting plates, sole plates, anchor bolts and fasteners are routinely fabricated and supplied alongside DIS isolators.

For the I-40 Bridge over the Mississippi River in Memphis, Tennessee, DIS supplied 112 isolators plus tapered sole plates, masonry plates, and all mounting hardware.

DIS also designs and builds specialty bearings for non-seismic applications such as ship loaders, where the bearings control forces within the structure during the off-loading of oil from tankers. For Caltrans's Richmond–San Rafael Bridge, bearings located six feet above the waterline, DIS developed corrosion-resistant assemblies with low-permeability rubber and stainless steel construction.

The DIS Viscous Wall Damper (VWD) has been used extensively in Japan for more than 20 years in more than 100 projects. DIS is licensed to provide this innovative technology in the United States; the first U.S. wall damper project is a hospital in San Francisco.

Each VWD consists of a narrow steel tank connected to the lower floor, an inner steel plate (vane) connected to the upper floor, and a viscous fluid in the small gap between them. During seismic excitation, the relative floor movement causes the vane to move through the viscous fluid. The damping force from the shearing action is dependent on the displacement and velocity of the relative motion.

Wall dampers reduce seismic accelerations and inter-story drift by over 50% and also reduce wind-induced vibration. Double-vane configurations give twice the damping force with only a small increase in plan size. The viscous fluid is non-toxic, odorless, transparent, with a viscosity of 90,000 poise. Dampers are made to fit typical building openings: widths of 6'–20' and heights of 6'–14'.

The DIS Low Mass Isolation System was developed to isolate computer floors in data centers. The system uses DIS Multidirectional Spring Units and roller supports. Spring stiffnesses range 2 to 50 pounds per inch, far softer than the 5,000 to 30,000 lbs/in typical of building and bridge isolators.

The low spring stiffness allows isolation of lighter structures and equipment in the 0.5- to 50-ton weight range. Accelerations are reduced by more than a factor of three, allowing equipment to remain operational during a major earthquake. Lower forces also reduce foundation costs.

Over 200 shake table tests at DBE and MCE levels were performed at the University of Nevada, Reno and at SUNY Buffalo, including SAC motions with up to 3g input accelerations. These tests conclusively demonstrated superior seismic protection by reducing accelerations while controlling displacements.

The DIS Floor Isolation System consists of multi-directional spring units and a combination of roller and slider bearings. A complete floor is assembled from modules connected by stringers. Standard computer floor tiles make up the top surface.

The floor system is available in heights from 13 to 24 inches. The 24-inch height is a direct substitute for conventional raised computer flooring. Services and wiring run in the space beneath the stringers. Custom stringers accommodate services, columns and geometric constraints.

A full-scale shake table test at the University of Nevada, Reno, more than 100 earthquake tests, including 75 DBE and MCE motions, produced peak accelerations and spectral accelerations reduced by up to a factor of seven, with floor displacements as large as 18 inches relative to the table.