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Top: Kobe Quake, Japan, Jan. 17,1995. Lower left : San Salvador
Quake, EI Salvador, Oct. 10,1986. Lower right: Michoacan Quake,
Mexico, Sept. 19,1985
Pin -Fuse Jointus Pa tent No. 6,681,538 81Date of Patent:
January 27, 2004
Ensuring life safety in structures during and after a seismic
event is an architect's and engineer's primary goal.How ever, the
economic viability of structures followingthe eve nt is crucial to
initial business investment decisions and long-term business
successes. If structureswere capable of resisting potentially
destructive earthquake forces while altering their characteristics
withoutpermanent deformation, the structure would not only besafe
but also economically superior.Structures designed and built in
regions of high seismicity are conceived with juxtaposing criteria.
They must bedesigned for strength, providing enough resistance
toprotect life safety and avoid collapse. However, theymus t be
designed economically, using inherent ductilityto dissipate energy
by means of reasonably sized structural members. Traditionally,
structural steel buildingfram es have utilized beam-to-column
moment connection s that are welded with the frame beams
perpendicular to the columns. Beams connected to the face ofcolumns
rotate when subjected to racking of the buildingframe. These beams
are designed to protect the columnintegrity and prevent potential
collapse by plasticallydeforming during frame motion. This
deformation, however, likely decreases post-earthquake integrity
and economic viability in the process.Following the 1994 Northridge
earthquake in California,designers, academicians, and building
owners found theconventionally designed steel beam-to-columns
momentconnections protected life safety but in many casesresulted
in unsuccessful investment because of failedjoints (cracked welds,
cracked steel sections, etc.) andpermanent building deformations.
With future performance questionable and repairs difficult, the
design andcon struction industry searched for more reliable
solutions. Many solutions were proposed and developed.Some patents
were awarded. These solutions variedfrom strongly reinforcing the
beam-to-column joint withwelded plates to creating slots in the
moment-resisting
beam webs to reducing the flange sections oat the joint (The
"Dogbane"). However, nosolutions addressed the fundamental
behaveliminating plastic (permanent yielding) defoaddition, none
addressed the natural rotatments of the joints that must provide
resistaas must provide a controlled release of enforces are
excessive.The Pin-Fuse JoinPMallows building movemby a seismic
event while maintaining structuafter strong ground motion. The
joint introdular-plated end connection for the steel beainto the
steel or composite columns within resisting frame. Slip-critical
friction-type bothe curved steel end plates. A steel pin orpipe in
the center of the moment-frame beamwell-defined rotation point.
Under typical setions including wind and moderate seismic joint
remains fixed where applied forces dcome the friction resistance
provided becurved end plates. However, during an extrthe joint is
designed to rotate around the pithe slip-critical bolts sliding in
long-slotted hcurved end plates. With this slip, rotationenergy
dissipated, and "fusing" occurs.The rotation of the Pin-Fuse Joint
durinseismic events occurs sequentially in desigtions within the
frame. As the slip occurs,frame is softened. The dynamic
characteriframe are altered with a lengthening of tperiod, less
forces are attracted by the frame; inelastic deformation is
realized. After the sethe elastic frame finds its pre-earthquake,
tered position. The brass shim located bcurved steel plates
provides a predictable cfriction required to determine the onset of
slipthe bolts to maintain their tension and cthe clamping force
after the earthquake has s
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Conventional structural steel momentresisting frame
Conventional Beam-to-Column Joint(Pre-Northridge Connection)-
Beam flanges fully welded and beam web boltedto column at
joint;
- limited ductility;- plastic (permanent) deformations
expected
after medium-level earthquake.
70
Dogbone or Reduced Beam Section( Post Northridge Connection)-
Beam fully welded to column at joint with
partial removal of beam flanges;- good ductility;- plastic
(permanent) deformations expected
after medium-level earthquake.
..... '-',--.-',... '.-. -.- .- .... I - -1 '.'.....-F ------,
t. . ;; ., .\ 1' . . - - . . -\ t _
t -..:-..I \- -Ioil __... I _ -,' .- --.:.--..... lbo&: ..
... . ....I
Structural steel moment-resisting frameillustrating locations of
the Pin-Fuse Joint '"
Pin-Fuse Join!'"
- Curved structural steel end plates bolted togetherwith
friction connection;
- pin placed in beam web to created center of rotation;- no
plastic (permanent) deformations even after
extreme seismic event.
First concept sketch, Feb . 12,2002
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78
(12) United States PatentSarkisian(54) SEISMIC STRUCTURAL
DEVICE(75) Invenlor: Mark I'. Sa rkisian, San Anselmo, CA(US)(73)
Assignee: Skidmo re, Owings & Merrill LLP ,New York, NY (US)(.
) NOlice: Subject to any disclaimer, the term of thispatent is
extended or adjusted under 35U.S.c. 154(b) by 1 day.(21) App!. No.:
10/200,679(22)(51)(52)(58)
(56)
Filed: Jul . 22, 2002Int. CI.7U.S. Cl.
E04B 7/00.... 52/289; 521702; 52/167.1;52/283; 403/335;
403/337
Field of Scarch .........................
52/167.1,283,52/289,702,736 .2;
403/335,336,337,338,257,258,83,84,87; 248/250References Cited
U.S. PATENT DOCUMENTS3,938,294 A 2/19763,974,614 A
8/19764,041,659 A 8/ 19774,054,392 A 10/ 19774,091 ,594 A
5/19784,344,716 A 8/19824,348,129 A 9/ 19824,615,157 A 10/
19864,658,556 A 4119874,779,484 A 10119884,781,003 A
11119884,922,667 A 5119904,928,930 A 5119905,319,907 A
6/19945,408,798 A 4119955,491 ,941 A 2/19965,537,790 A 711996
32
12
GaburriStrong.McElhoc.
52/7435215 7352/93.1...... 403/175.....
52/737.2.................... 403/13.............. . 403/218
OppenheimYamashitaSigal ..Confort iMurray.Jenkins.Poe.Rizza
.. 52/167.452/3 1774/60852/396Kobori et al. ................
52/167Chung. 256/67Nicholas et al. .........
52/396.05HohmannL,ncelot, III .Jackson.
Ii.I
52/562....... 52/223.952/393
26 - -11=2132
111111111111111111111111111111111111111111111111111111111111111111111111111US006681538Bl(10)
Patent No.: US 6,681,538 BlJan. 27, 200445) Date of Patent:
,I .\ ,5,797,227 A 811998 ' Garla-Ta mez ............. 521167.
15,875,598 A 311999 Balten el al. 52/396.Ql6,10 1 780 A 8/2000
Kreidl ....................... '52/7126,102 ,627 A 8/2000 Veda el
al ................. 40512556,115,972 A 9/2000 Tamez
....................... 52/167.46,185,897 Hl 2/2001 Jollllson el
al. ......... 52/583.16,237 ,292 III 5/2001 Ilegcmier el al. ..
5212736,289,640 Bl 912001 Veda el al. ................
521167.96,324,795 Bl 12/2001 Sliles el al. ................ 52/
167.4200110045069 Al 1112001 Conslanlinou .............
521167.32002/0184836 Al 1212002 '[;,kclichi el al.
* cited by examinerPrhnmy Examiner-Ca rl D. rricdmanAssislallf
Examhler---NahidAmiri(74) A f l O r l l e ) AgellfJ or
Firm-Sonnenschcin, Nalb &Rosenlhal LLP(57) ABSTRACTThe present
invention is a pin-fuse joint generally utili zed ina
beam-to-columnjoint assembly subject to extreme seismicloading. The
pin-fuse joint resists bending moments andshears generated by these
loads. The joint is comp rised ofstandard structural stee l
building materials, but may beapplied to structure s comprisedof s
tructural steel, reinforcedconcrete, and or composite materials,
e.g., a combination ofs tructura l steel and reinforced concrete.
The bcam-tocolumn assembly is comprised of a column and a beam anda
plate assembly that extends betwcen the column and thebeam. TIle
platc assembly is we lded to the co lumn and isattached to the beam
via the pio-fuse oin t. The pin fuse jointis created by a pin
connection througb the beam and theconnec tion plates of the pla le
as.o;;ern bly at the web of thebeam. Addilionally, bOlh Ihe plale
assembly and Ihe beamhave cu rved flange end connectors that sit
flu sh against oneanother sepa rated only by a brass shim when th e
beam andplate assembly arc joined. The curved flange end
connectorsof the beam and plate assembly arc then secured against
oneanolher by torqued high-slrenglh bolts.
13 Claims, 7 DJ'3wing Sheets
24
------I.
FIG.
26
FIG. 8
/ '032
36 - ' ~ l
FIG. 10
24
-
2
\616 14I: I ;V I ;V I I;V30I8 _ :1!22 'i 25-=- 1!!t -36 ~ H ~ =
IFIG, 4 FIG. 5
i12
32
FIG,FIG. 1 Perspective view of oneembodiment of a beam-to-co
lumnjoint assemblyFIG. 2 Exploded front view ofbeam-to-column joint
assemblyFIG. 2a Front view of a pipe/pinassembly and web stiffener
usedto connect the moment-resistingbeam to the plate assemblyFIG. 3
Exploded top view ofbeam-to-column joint assemblyFIG. 4 Cross
sectional view ofplate assembly (Fig. 2) takenalong line A-AFIG. 5
Cross sectional view ofplate assembly (Fig. 2) takenalong line
B-B
66
FIG . 6
Ii.
I 26
9FIG. 6 Cross sectionmoment-resisting beataken along line
C-CFIG. 7 Cross sectionmoment-resisting beataken along line 0-0FIG
. 8 Front view of embodiment of beamjoint assemblyFIG . 9 Top view
of oment of beam-to-coluassemblyFIG . 10 Perspective beam-to-column
jointit would appear withrotated when subjectloading cond
itions
