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Fuse-Element system
FUSE-ELEMENT for modular joints
Seismic devices
Characteristics
Seismic safety feature for modular expansion joints
Extreme closing movements can be accommodated
Avoids or limits damage to bridge and joint
Enables emergency traffic crossing with little or no repair
Principle
The mageba Fuse-Element system protects the TENSA®MODULAR expansion joint and the connecting structure from earthquake damage. Should a regular expansion joint, during an earthquake, close by more than is allowed by its design, severe damage can be caused to the joint and to the bridge. Such damage can be avoided by the use of a Fuse-Element which, in case of an earthquake, is forced upwards and out of the joint’s surface to the extent required for the joint to accommodate extreme closing movements.
Once the Fuse-Element has been released, it can either fall back into its original position automatically or, in some cases, simply be reinserted manually. This is an important factor for emergency vehicles to be able to use the bridge after a seismic event.
Applications
The use of the mageba Fuse-Element is recommended for bridges in seismic regions and can even lead to an optimization of the design of the expansion joint, with fewer gaps than would otherwise be required.
Positioning the Fuse-Element near the middle of the joint enables it to considerably improve the expansion joint’s overall durability by effectively splitting it into two smaller joints, since the impact of cumulative friction across the joint in distributing deck movements is now reduced.
TENSA®MODULAR expansion joint with Fuse-Element seismic protection feature during installation
The same 13-gap joint in service featuring a Fuse-Element alongside a smaller 4-gap joint
Site section view of the Fuse-Element prior installation on the bridge
Fuse-Element is lifted upwards by exceeding closing movements
