SOM two additional patents for seismic structural inventions

left to right: link-fuse joint™, pin-fuse frame™ , pin-fuse joint™ 
image © SOM jungmoo lee


link-fuse joint™ and  pin-fuse frame™ are two new high-performance seismic structural
mechanisms developed by SOM. the two structural devices join the series that began with
the pin-fuse joint®, designed to protect buildings in areas of high seismicity.

link-fuse joint™
image © SOM jungmoo lee

the joints and frame operate mechanically during a seismic event, allowing the building structure
to respond flexibly when subjected to extreme ground movement to thereby maintain structural elasticity.
during moderate earthquakes they remain fixed, but during a severe earthquake, they slide or rotate
to dissipate energy and reduce potential damage. following an earthquake, the devices return to their
original positions. these new structural mechanisms provide a safer and more cost-effective solution
than conventional assemblies as they minimize permanent structural deformation during a seismic event,
thereby reducing subsequent repairs to the building structure as well as the associated cost and carbon
emissions of repairs.

movement of link-fuse joint™
image © SOM jungmoo lee

the link-fuse joint™ is composed of two plate assemblies, each featuring a diagonal slot at the center.
the slots of each plate are arranged diagonally perpendicular to each other and are positioned to allow
at least a portion of one slot to align with a portion of the other. a pin is inserted through these openings
such that the joint connection accommodates the movement of at least one of the plate assemblies relative
to the other when the joint is subjected to a high seismic load. the joint is generally utilized in a link
beam assembly, connecting interior walls within a structure. the joint may be incorporated into the reinforced
concrete shear walls or steel braced frames of a structure subject to seismic activity and improves the structure’s
dynamic characteristics by allowing the joint to slip under extreme loads. this slippage allows the structure
to exhibit elastic properties during seismic events.
see the animation

specification of link-fuse joint™
image © SOM



the full-scale testing program of all three mechanisms has commenced with results expected by
fall of 2010. following successful completion of the testing program, these devices may be
manufactured and installed in both new and existing occupied structures.

specification of link-fuse joint™
image © SOM

drawing of link-fuse joint™ in action
image © SOM

pin-fuse frame™ the pin-fuse frame™ incorporates joints that 'fuse', or slide, during earthquakes
in order to protect the structure from damage. by sliding, these joints protect frame members
from buckling and yielding, thereby protecting the integrity of the entire structure
and minimizing costly post-earthquake repair. the system comprises a pre-fabricated
structural steel beam-column frame assembly with diagonal braces within frame bays.
diagonal braces are divided into two halves connected across a middle gap that allows each
half to slip toward or away from the other during a seismic event. rotational joints at each end
of the horizontal beam elements in the frame are also designed to slip when subjected to a
high rotational load.

the friction joints developed use arrays of pre-tensioned bolts that either clamp two halves
of a brace together or clamp a beam and column together until a seismic event causes the force
in the joint to exceed the resistance threshold created by friction. at this threshold, the two
connected members are allowed to slip relative to one another within carefully designed slots.
if the lateral load imposed on the structure continues to increase representing a rare seismic event,
the bolts pass through the full length of the slots and re-engage with the connected members.
at this point only do the elements continue to attract additional force and eventually create
inelastic behavior of the frame members.
see the animation




SOM was founded in 1936 by louis skidmore & nathaniel a. owings. john o. merrill joined them in 1939.
since 1936, SOM has completed more than 10,000 architecture, interior design and planning projects
in over 50 countries. currently, SOM employees represent over 70 countries and speak over
40 different languages.