D.S. Brown’s Swivel Expansion Joint Systems are one of the most intriguing features of the new Gerald Desmond Bridge in Long Beach, California. The Swivel Expansion Joint Systems are located where the east and west approaches connect to the main span of the bridge. At these “end bents,” the column-supported approaches meet the cable-supported main span. These two types of structures will react differently in an earthquake, and flexible connections are a must.
These special joints, designed by Maurer SE of Germany, and built by D.S. Brown, will enable controlled-swivel movements in three directions (vertical, longitudinal, and lateral) at these junctures to compensate for movements between adjacent structures. This was the first application of this sophisticated joint for a bridge in California. What makes these swivel expansion joints unique is that they are the first joints in the U.S. to utilize Maurer’s fuse box technology. For closing movements beyond the service capacity, the Maurer Fuse Box System will be activated. These fuse boxes will yield allowing the joints to move horizontally in a designated, defined space. In case of seismic opening movements, the extended support bars protect the expansion joint from falling into the structural gap. After the earthquake, fast and simple repair at predetermined locations of the Fuse Box System and the road surface is easily and quickly possible.
These advanced seismic features and design help ensure the new bridge withstands stronger quakes and returns to operation within days rather than weeks.
Between each section of bridge road deck are expansion joints and hinges, allowing each section to move without damaging its adjoining sections during an earthquake. Within the hinges are shear keys. Similar to an electrical fuse, shear keys are a sacrificial, replaceable element to absorb the bulk of seismic forces. At certain energy levels, they are designed to “trip” to release the force of the quake. Atop each column are spherical bearings to enable a sliding movement between the superstructure (the bridge deck) and the substructure (the columns).
The Gerald Desmond Bridge in the Port of Long Beach carries traffic on Ocean Boulevard from Interstate 710 in Long Beach, California, west across the Back Channel to Terminal Island. The bridge is a vital link in the nation’s trade system and will allow passage of the world’s largest cargo ships under the new bridge. It also will have better capacity for trucks, while also serving bicyclists and pedestrians.
The new bridge, expected to be completed in 2020, will be a cable-stayed design with 205 feet of clearance over the Cerritos Channel. With three lanes in each direction plus safety lanes, it will be wider and better able to serve the current 68,000 vehicles traveling over the current bridge each day, which equals about 18 million trips per year.
Conventional large movement expansion joint devices are limited to primarily longitudinal movements and/or less than +/- 0.79 inches (20mm) transverse displacement. For joint locations which produce more demanding structural movements, like the Gerald Desmond Bridge, the Maurer System™ Swivel Expansion Joint Assembly by The D.S. Brown Company is provided in the United States through an exclusive license agreement with Maurer SE in Munich, Germany.
By utilizing a common-to-all centerbeam swiveling support bar, the Maurer System™ Swivel Expansion Joint Assembly is able to accommodate large longitudinal displacements (X), extensive transverse displacements (Y), and vertical displacements (Z), as well as vertical rotations of up to 10 degrees. The centerbeams are free to slide on swiveling support bars, which provide equidistant control for centerbeams without the limitations of typical mechanical control devices.
Dynamic tests conducted at the University of California at Berkeley subjected the Maurer System™ Swivel Expansion Joint Assembly by The D.S. Brown Company to high-velocity seismic displacements (see video of the tests). This first-of-its-kind test program included velocities of more than 40 inches per second (1015mm/sec) in both longitudinal and transverse directions. The successful test results proved the unique capabilities of this patented device in seismic applications.
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The D.S. Brown Company, founded in 1890, designs, supplies and manufactures engineered rubber, steel and concrete products for the transportation and infrastructure sector. D.S. Brown’s proprietary product line includes expansion joints, structural bearings, and waterproofing systems for constructing and rehabilitating highways and bridges. D.S. Brown’s home office and manufacturing facilities are in North Baltimore, Ohio.
D.S. Brown is fully integrated, performing and controlling all manufacturing processes internally:
D.S. Brown has the most comprehensive product line serving the transportation industry. We manufacture solutions for the most challenging infrastructure applications. Our high-quality engineered products are available worldwide for new construction and rehabilitation of bridges, highways, airfields, pavements, and parking structures.
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