U.S. patent application number 10/829876 was filed with the patent office on 2005-11-03 for seismic joint seal.
This patent application is currently assigned to State of California, Department of Transportation. Invention is credited to Delis, Efthymios Tim.
Application Number | 20050241084 10/829876 |
Document ID | / |
Family ID | 35185539 |
Filed Date | 2005-11-03 |
United States Patent
Application |
20050241084 |
Kind Code |
A1 |
Delis, Efthymios Tim |
November 3, 2005 |
Seismic joint seal
Abstract
The present invention is a seismic joint seal comprising a
support plate, a channel assembly, and a deck plate. It is used to
join bridge segments to each other or to an abutment. The invention
has a curved deck plate that rides along a complementarily-curved
support plate to accommodate movements that result from seismic
events.
Inventors: |
Delis, Efthymios Tim;
(Rocklin, CA) |
Correspondence
Address: |
MAGUIRE LAW OFFICE
423 E ST.
DAVIS
CA
95616
US
|
Assignee: |
State of California, Department of
Transportation
|
Family ID: |
35185539 |
Appl. No.: |
10/829876 |
Filed: |
April 21, 2004 |
Current U.S.
Class: |
14/73.5 |
Current CPC
Class: |
E01D 19/065
20130101 |
Class at
Publication: |
014/073.5 |
International
Class: |
E01D 019/04 |
Claims
1.) A seismic joint seal for joining a bridge segment to another
bridge segment or to an abutment, comprising: a support plate
having a curved top surface and a substantially planar bottom
surface, said support plate fixedly attached to a first bridge
segment; and a deck plate having a curved bottom surface, said deck
plate attached to a second bridge segment, and said curved bottom
surface of said deck plate slidably resting on said curved top
surface of said support plate.
2.) The seismic joint seal according to claim 1, wherein said
curved top surface is convex, and said curved bottom surface is
concave.
3.) The seismic joint according to claim 1, additionally comprising
a channel assembly for attaching said deck plate to a bridge
segment.
4.) The seismic joint according to claim 3, wherein said channel
assembly comprises a spring assembly with elastomeric washers.
5.) The seismic joint according to claim 4, wherein said channel
assembly comprises a spring assembly with alternating elastomeric
washers and steel washers.
6.) The seismic joint according to claim 5, additionally comprising
a support sheet between the channel assembly and the deck
plate.
7.) The seismic joint according to claim 6, wherein the support
sheet is made of neoprene.
8.) A method of seismically sealing a bridge joint, comprising:
attaching a support plate with a curved top surface to a first
bridge segment; and attaching a deck plate with a curved bottom
surface to a second bridge segment, so that said curved bottom
surface slidably rests on said curved top surface.
9.) The method according to claim 2, wherein said curved top
surface is convex and said curved bottom surface is concave.
10.) A seismically protected bridge, comprising a first bridge
segment joined to a second bridge segment or to an abutment by a
joint seal according to claim 1, 2, 3, 4, 5, 6, or 7.
11.) A seismic joint seal for joining a bridge segment to another
bridge segment or to an abutment, comprising: a support plate
having a top surface, said support plate fixedly attached to a
first bridge segment; a deck plate having a bottom surface, said
deck plate attached to a second bridge segment, and said bottom
surface of said deck plate slidably resting on said top surface of
said support plate to form an interface; and means for ensuring
that as said deck plate moves longitudinally relative to said
support place the interface remains substantially constant.
12.) The seismic joint according to claim 11, wherein said means
for ensuring that as said deck plate moves longitudinally relative
to said support place the interface remains substantially constant
comprises a curved bottom surface and a curved top surface.
13.) The seismic joint according to claim 12, wherein said top
surface is convex and said bottom surface is concave.
14.) A kit for creating a seismic bridge joint, comprising a deck
plate with a curved bottom surface and a support plate with a
curved top surface.
15.) The kit according to claim 14, wherein said bottom surface is
convex and said top surface is concave.
16.) A seismically-protected bridge, comprising at least one
support plate and a plurality of modular channel assemblies and
deck plates, wherein the support plate has a curved upper surface,
and the deck plates have a curved lower surface.
17.) The bridge according to claim 16, wherein the upper surface is
concave and the lower surface is convex.
18.) A seismic joint seal for joining a bridge segment to another
bridge segment or to an abutment, comprising: a support plate
having a support plate top surface and a support plate bottom
surface, said support plate fixedly attached to a first bridge
segment; a deck plate having a deck plate top surface and a deck
plate bottom surface, said deck plate attached to a second bridge
segment; wherein said support plate top surface is not parallel to
said support plate bottom surface, and wherein said deck plate top
surface is not parallel to said deck plate bottom surface.
19.) The seismic joint according to claim 4, wherein said channel
assembly is protected from liquid by a deck seal.
20.) The seismic joint according to claim 19, wherein said deck
seal is placed between said first bridge segment and said deck
plate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to joints for connecting segments of
a bridge.
[0003] 2. General Background
[0004] Joints of various types have been developed to connect
roadway bridge segments to each other and to abutments. In the
past, these joints were only designed to accommodate the
differential displacement and rotation that occur during ordinary
service conditions, and were not designed to withstand the effects
of significant seismic events. Instead, the joints were simply
repaired or replaced after an earthquake, with the bridge typically
inoperable until the repairs could be made.
[0005] But many bridges are so important that they must remain
passable even after a significant seismic event. Thus, seismic
joints have been developed to accommodate the great displacement
(both longitudinal and transverse) and rotation that results from
an earthquake.
[0006] The present invention is an improved seismic joint that has
robust performance and that does not cause significant discomfort
to drivers.
SUMMARY OF THE INVENTION
[0007] The present invention is a seismic joint seal comprising a
support plate, a channel assembly, and a deck plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is side cross-sectional view of a seismic joint seal
according to an embodiment of the present invention.
[0009] FIG. 2 is a top view of a channel assembly for a seismic
joint seal according to an embodiment of the present invention.
[0010] FIG. 3 is a cross-sectional view of a channel assembly for a
seismic joint seal according to an embodiment of the present
invention.
[0011] FIG. 4 is a side view of a channel assembly for a seismic
joint seal according to an embodiment of the present invention.
[0012] FIG. 5 is a close-up of the indicated area of FIG. 4.
[0013] FIG. 6 is a top view of a series of seismic joint seals
according to an embodiment of the present invention.
[0014] FIGS. 7a-7g show an exemplary construction sequence for a
seismic joint seal according to an embodiment of the present
invention.
[0015] FIGS. 8a-8b depict the movement of a seismic joint seal
according to an embodiment of the present invention during a
seismic event.
DETAILED DESCRIPTION
[0016] The present invention is a seismic joint seal comprising a
support plate, a channel assembly, and a deck plate. It is used to
join bridge segments to each other or to an abutment.
[0017] As shown in FIGS. 1, 7a-7g, and 8a-8b, the present invention
can be used on a bridge deck 10 to join a first bridge segment 20
with a second bridge segment 30. It can also can be used to join a
bridge segment to an abutment.
[0018] The bridge segments 20, 30 are modified by creating a
blockout area 22, 32 in each, as shown best in FIGS. 7a-7g. Mild
steel reinforcement 24, 34 is then placed in the blockout area. See
FIG. 7a. Concrete 26, 36 is poured in the blockout areas 22, 32
after placement of the steel frames 24, 34. Preferably
self-consolidating concrete is used, although standard concrete may
be used as well. Also, a gutter 28 may be placed on one of the
bridge segments to catch water that leaks between the support plate
40 and the deck plate 80. See FIG. 1. A gap 38 of varying width
lies between the bridge segments 20, 30.
[0019] The support plate 40 is secured by means of shear studs 42.
See FIGS. 1, 7b, 7c, 7f, 7g, 8a, and 8b. The support plate 40 also
may have ventilation holes to prevent the formation of air cavities
during construction.
[0020] The support plate 40 is curved in a convex manner so as to
mate with the concave sliding deck plate 80. As explained further
below, the complementary curvature of the support plate 40 and the
deck plate 80 offers a number of advantages over the prior art. Of
course, the curvature of the support plate 40 and deck plate 80 may
vary without departing from the scope of this patent.
[0021] The purpose of the support plate 40 is to provide a
structure upon which the deck plate 80 may slide and move. In one
embodiment, it is made of steel or equivalent material, with an
approximate thickness of at least 25 mm.
[0022] The channel assembly 50 is built into the second blockout
area 32 and is used to secure one end of the deck plate 80. See
FIGS. 1, 2, 3, 4, It is formed by steel plates, namely structural
steel plates 56 and stiffener steel plates 54, which are placed
along in parallel to the roadway along the channel assembly 50. See
FIGS. 1, 2, 3, and 4. The channel assembly is secured to the
blockout area 32 by anchor studs 52.
[0023] The spring assembly 60 is fitted within the channel assembly
50. See FIGS. 1, 2, 3, and 4. The spring assembly 60 rotatably
secures one end of the deck plate 80, with the other end free to
slide along the support plate 40. See FIG. 1. The spring assembly
60 comprises two high strength bolts 62, 63 that are fitted through
the deck plate 80 and into the channel assembly 50, two slotted
nuts 64, 65 that secure the bolts 62, 63, and an alternating series
of elastomeric washers 66 and steel washers 68. See FIGS. 1, 2, 3,
4, and 5. The spring assembly 60 is pre-tensioned so that the deck
plate 80 maintains its proper position. The elastomeric washers 66
are essential elements of the joint since they secure the deck
plate in case of a bridge settlement, bearing failure, or seismic
event.
[0024] A bridge deck seal 70 is placed between the deck plate 80
and the second bridge segment 30. See FIG. 1. This deck seal 70
prevents the flow of water into the joint. It includes a silicone
seal 72 or equivalent on top of polyethylene foam 76, with an
underlying neoprene support sheet 76 that runs the length of the
channel assembly 50. This neoprene sheet 76 facilitates stress
distribution and thus improves the bearing of the deck plate
80.
[0025] To protect against corrosion, all metal parts of the
assembly are either painted with inorganic zinc-rich primer or hot
dip galvanized. Also, the channel assembly 50, bolts, 62, 63 and
joints between deck plates may be sealed with a silicon-based
sealant.
[0026] The deck plate 80 is rotatably attached at one end to the
channel assembly 50, but is free to move at the other end, along
the support plate 40. See FIGS. 1, 7a-7g, 8a-8b. The deck plate 80
has freedom of movement in all directions (longitudinal,
transversal, vertical, and rotational), and thus can accommodate
seismic events and remain drivable. The deck plate 80 will move
during both seismic events and ordinary service conditions, but
will obviously is subject to greater movement during seismic
events. FIGS. 8a and 8b depict the longitudinal movement of the
deck plate 80 relative to the support plate 40.
[0027] The deck plate 80 is tapered on its underside, with its free
end thinner than the end that is rotatably secured to the channel
assembly 50. See FIGS. 1, 7a-7g, 8a-8b. In one embodiment, the deck
plate is 12 mm thick at its free end, and has a taper ratio of 30:1
or better from the thicker end to the narrow end. This results in a
12 mm gap or bump between the deck plate 80 and the support plate.
The deck plate may have grooves 82 on its top surface for greater
traction, and traction welds (not shown) may be used for portions
of the deck plate that are too thin for grooves 82. Except for the
grooves 82 or the traction welds, the top of the deck plate 80 is
flat.
[0028] A critical aspect of the invention is the relationship
between the deck plate 80 and the support plate 40. In the present
invention, the underside of the deck plate 80 is concave, and the
top side of the support plate 40 is convex. See FIG. 1. The deck
plate 80 and support plate 40 have complementary curvatures, so
that they mate with each other. As the deck plate 80 moves
longitudinally, it rides along the convex surface of the support
plate. This results in a minor rotation of the deck plate about the
transverse axis, which translates to an approximately 2 mm rise or
fall of the deck plate at its pinned end. This does not pose a
problem to joint performance, since the uneven stress distribution
at the pinned side is very small, and can be absorbed by the
neoprene sheet and the elastomeric springs. Because the top of the
deck plate is flat and the initial 12 mm bump at the tip of the
free end of the deck plate 80 is lower than that of the horizontal
tangent of the support plate 40, the joint of the present invention
does not exhibit the "ramp up" feature of earlier joints. More
particularly, the present invention provides a significantly
smoother driving surface than joints in which the undersurface of
the deck plate and the top surface of the support plate are planar.
This is because the interface at the free end of the deck plate
remains constant in the present invention despite longitudinal
movements, while the interface can change in earlier,
planar-mating-surface joints as a result of longitudinal movement.
For instance, with planar-mating-surface joints, a "v" or
depression is formed and deepened as the deck plate moves away from
the support plate, but with the present invention the interface
remains relatively constant notwithstanding longitudinal
movements.
[0029] An exemplary construction sequence is depicted in FIGS.
7a-7g. In this example, the first step is preparing the blockout
areas 22, 32, and then placing the mild steel reinforcement 24, 34
within the blockout areas 22, 32. See FIG. 7a. Next, the support
plate 40, channel assembly 50, and deck plate 80 are temporarily
installed so that each component be properly positioned relative to
the others. See FIG. 7b. Then the deck plate 80 is removed and
self-consolidating concrete is poured at the free end of the joint.
See FIG. 7c. The deck plate 80 is then reinstalled, see FIG. 7d,
and self-consolidating concrete is poured in the pinned end, as
shown in FIG. 7e. The gutter can then be installed, and the bolts
and pins tightened as necessary. See FIG. 7f. Finally, a deck
overlay 90 is placed adjacent to the pinned end of the joint, and
silicone can be used to seal the joint. See FIG. 7g. This sequence
is exemplary only, and other sequences can be used without
departing from the scope of this patent.
[0030] Typically, each lane or half-lane will have its own channel
assembly 50 containing a plurality of spring assemblies, thereby
creating a modular joint that can be more easily installed and
repaired. See FIGS. 2 and 3. The deck plate 80 will also typically
have the same width as the channel assembly 50, making the entire
unit modular. A number of such modules could be combined to create
a multilane joint. See FIG. 6.
[0031] One skilled in the art will appreciate that the present
invention can be practiced by other than the preferred embodiments,
which are presented for purposes of illustration and not of
limitation.
* * * * *