Note: Descriptions are shown in the official language in which they were submitted.
2~%89~
Traffic Control Barriers
Technical Field
The present invention relates to traffic control and in
particular to a barrier whlch may be used in controlling vehicle
traffic, especially as a temporary highway median barrier for use in
construction zones and the like.
BacX~round Art
Highway traffic is often divided into two or more one way
lanes to control incidents of head-on and side-swipe collision.
Highway median barr~ers are commonly used for this purpose. Such
median barriers are generally construrted from concrete which is
poured in place or pre-cast off site and set in a mortar bed or the
like. These barriers generally conform to one of two styles which
include the New Jersey profile mPdian barrier and the General Motors
profile median barrier. Such barriers are extremely effective in
controlling head-on collision and in reducing ln~uries due to loss of
control of a fast moving motor vehicle.
There is an abundance of prior art relating to highway median
barriers. Those patents known to the ~lpplicant and considered most
relevant to the present invention include:
United States Patent 3,540,699 l:o Guzzardella relates to a
hydraulic barrier structure for roadways intended for use in
preventing or hindering motor vehicles from going off a roadway by
providing a con~inuous line of bag-type containers at least partially
filled with liguid ballast or the like. The problem with such
barriers is that they occupy a great deal of space and tend to catch
rather than repel a vehicle which contacts them.
United States Patent 3,678,815 to Yo~nker di3closes a concrete
structural member and method for forming cast-in-place median
barriers and the like. Such members are only effective for
constructing permanent highway median barriers.
United States Patent 4,113,400 to Smith discloses an impact
resistant tongue-and-groove coupling for use with either permanently
or temporarily placed pre-cast concrete highway median barrlers.
~8~
~ ritish Patent 1,497,860 to Morrlson describes an open-ended
hollow shell constructed from wear-resistant material. The shell has
an integral base, side and top walls arranged to connec~ in an
end-to-end relationship. The shell i8 filled with concrete to form a
ca~t-in-place hig~way median barrier.
Canadian Patent 1,141,574 to Trent, e~. al. teaches a polymer
concrete shell having a top wall and sidewalls. These shells are
placed in an end-to-end relationship on a roadway where a permanent
highway median barrier is desiredO The shells serve as concrete
forms which are pumped full of concrete after they are positioned on
a roadway. The polymer concrete shells are left in place to provide
weathPr resistant protective shells over the concrete barriers.
Because of ~heir effectiveness in controlling traffic, the use
of highway median barriers has also been widely accepted as a method
of traffic control in construction zones where all traffic on a
roadway is routed to one side of the roadway while repairs are being
effected to another side of the roadway. The accepted standard in
median barriers used for this purpose are the pre-cast concrete units
which are formed with a profile similar to the New Jersey or General
Motors shape. Such barriers units may or may not have interlocking
end ~oints. While such barriers are effective and widely used, they
have certain disadvantages which detra~lt from their appeal.
Pre-ca~t highway barrier units are extremely heavY and can
only be maneuvered with heavy equipmen~ such as fork lifts or cranes
and flat bed trailers. A typical 12 foot (4 meter) length of
pre-cast highway median barrier weighs approximately 2 1~2 tons
(2,30~ kg). Placing such barriers is therefore a labor and equipment
intensive activity which requires considerable concentration, time
and energy. Removal of the barriers also requires the availability
of the same equipment. Naturally traffic is completely disrupted
~hrough the area where the barriers are being installed or removed.
Handling such barriers is also a hazardous activity because of their
mass and extreme caution must be exercised in order to avoid physical
in~ury. In addition, cast concrete, being a very inflexible
material, is prone to chlpping and/or breaking when handled so that
the barriers have a l~mited lifespan. Blemishes in their surfAces
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also tend to detract from the effectiveness of their purpose.
Fur~hermore, the barriers mus~ be seored when not in use. Because
the barriers occupy considerable space and weigh thousands of pounds
each, storsge can be a problem. Finally, the barriers are extremely
difficult to recycle and once they are damaged beyond usefulness they
are usually dumped in landfill sites where they continue to occupy
space for an indefinite period of time.
Disclosure of Invention
It i9 an ob~ect of ~he present invention to provide a
temporary traffic control barrier which overcomes the problems
associated with such barriers taught ~n the known prior art.
It ls a further ob~ect of the invention ~o provide a traffic
control barrier which is light in weight and readily handled without
the use of hea~y equipment.
It i8 a further ob~ect of the lnvention to provide a traffic
control barrier which is stackable in order to conserve ~tora~e space
when the barrier i9 not in u~e and during transporsatlon to and from
a construction site, which reduces the cost of transportation and
thereby reduces the cost o~ the construction.
It is a further ob~ect of the invention to provide a temporary
traffic control barrier whlch may be readily recycled if it i9
damaged to a point t~at it may not be repaired or reused.
In accordance with the present invention there is provided a
llghtweight shell~ made from metal, thermoplastic or the li~e, having
an exterior profile shaped to conform with an accepted highway median
barrier standard and adapted to receive and retain a liquid balla~t
means after being positioned in a location for use, the shell
including means for discharging the liquid ballast when the barrier
ls to be relocated or stored.
The present invention, in accordance with a first preferred
embodiment, provides a traffic control barrier which comprises a
hollow stackable shell having sidewalls are preferably contoured in
accordance with a New Jersey or General Motors profile ~pecification
or the like, and includes a collapsible ballast bag which may be
removable and independent of the she~l or permanently attached to the
2~ ? ~
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shell and collapsible into a top of an overturned barrier when the
bag i8 empty. The ballast bag subAtantially fills the barrier when
the bag is filled with liquid balla~ introduced through a filler
hole in the top of the barrier. This embodiment provides a temporary
barrier which is readily handled and stored yet very effectlve as a
traffic control barrier. This barrier is also preferably provided
wi~h a locking ~olnt on each end to permit the interconnection by
overlapping or interloc~ing two or more units to form an
uninterrupted barrier.
The present invention fur~her provides, in a second preferred
embodiment, a light weight ~hell constructed in the shape of a
highway median barrier. The shell is either made from a waterproof
material or lined with a waterproof material and includes an opening
in its top surface for filling the shell with a llquid ballast and a
drain near a bottom of at least one end or side for draining the
liquid ballast when the barrier is to be moved or placed in qtorage.
The barrier may be additionally provided with means on one or more
ends for interlocking with ad~acent barriers to provide a continuous
barrier which, when filled with a liquid ballast such as ordinary
fresh water, provides a heavy semi-resilient barrier to traffic which
can effectively control vehicles in low speed narrow traffic lanes.
A Concrete Median Barrier Re~eareh study conducted by the
Southwest ~esearch Institute, San An~onio, Texas for the Federal
~ighway Administration, Washington, D.C. concluded that minimal
reinforcement and foundation restraint are required to susta~n heavy
vehicle impacts and effect redirection based on a 53 mph. (85.3 km~h)
16 degree angle impact with a 40,000 lb. (18,000 kg.) bus. It is
therefore apparent that a properly shaped, smooth highway median
barrier ballasted to the same approximate mass of a temporary
concrete barrier of the same shape can effectively sustain and
redirect impacts from traffic in low speed narrow roadway
environments.
The advantage of the traffic control barriers in accordance
with the invention is that they provide a temporary highway median
barrier which is readily handled, transported and stored with a
maximum of efficiency and a minimum of danger while effectively
2~$J~$~
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inhibiting the inridence of head-on and ~ide-swipe collision in
reduced speed areas on narrow highways such as construction zones and
the like. The advantage of using a liquid ballast, fresh water for
instance, is that the ballast ls generally readily available at
little or no cost and may be diæcharged directly onto the roadway
with negligible loss and no environmental hazard.
A further advantage of highway median barriers in accordance
with the invention is tha~ since the barrier units are constructed
with metals and/or thermoplastic~ or the like, broken or damaged
units are readily recycled and therefore do not occupy valuable space
in landfill sites.
Brief Descrlption of Drawin~s
The invention will now be explained by way of example only and
with reference to the following drawings wherein:
FIG. lA is a profile of a "General Motors" configuration for a
highway median barrier;
FIG. lB is a profile of a "New Jersey" configuration for a
highway median barrier;
FIG. lC i9 a profile of a highway median barrier designated as
"Configuration F" in a study conducted for the Federal Highway
Administration, Washington, D.C. in 1976 and entitled Concrete Median
Barrier Research. Vol. 1, Executive S~mmarv;
FIG. 2 is a perspective view of a first preferred embodiment
of a highway ~edian barrier in accordance with the invention;
FIG. 3 is a side ele~ational view of three highway median
barriér unlt~ interconnected to form a temporary highway divider;
FIG. 4 is cross-sectional view taken along lines 7-7 of the
highway median barrier unit shown in FIG. 2, and an exploded view of
a typical arrangement for preventing lateral spread of the bottom
edges of the unit due to hydraulic pressure exerted by liquid ballast
in the barrier unit;
FIG. 5 is an end elevational view of one arrangement for
stacking highway median barrier units shown in FIG. 2;
FIG. 6 is an end elevational view of an alternate method of
stacking highway median barrier units shown in FIG. 2;
2~2$~
FIG. 7 i~ a cro~s-section along lines 7-7 of a drain cap shown
in FIG. 2;
FIG. 8 is a cross-section along line~ 8-8 of the drain cap
arrangement shown in phantom line3 in FIG. ~;
FIG. 9 i9 a perspective end view of a second preferred
embodiment of a highway median barrier in accordance with ~he
invention;
FIG. 10 is a perspective end view of an opposite end of the
highway median barrier unit shown in FIG. 9;
FIG. 11 is a side elevational view of three of the highway
median barrier unies shown in FIGS. 9 and 10, the highway median
barrier units being interconnected to form a continuous highway
median barrier;
FIG. 12 is a side elevational view of the highway median
barrier unit shown in FIGS. 9 and 10;
FIG. 13 is an isometric view of a cross-section taken along
lines 13-13 of FIG. 12, showing a typlcal bulkhead construction for
the highway median barricr shown in FIGS. 9-12; and
FIG. 14 i9 a cross-sectional view along lines 4-4 of FIG. 9,
showing a typical drain arrangement for a highway median barrier unit
in accordance with the invention.
Detailed DescrlDtion of Preferred Embodiments
FIGS lA through lC show thrae widely used profiles for highway
median barriers. FIG. lA shows a highway median barrier of the
General Motors profile, FIG. lB shows a highway median barrier of the
New Jersey profile and FIG. lC shows a highway median barrier of the
Configuration F profile tested during a study prepared for the
Federal Highway Administration, Washington, D.C. in June of 1976. A
highway median barrier unit in accordance with the invention may be
constructed in accordance with any of the profiles shown above or any
other profile which has proved or may yet prove to be more
efective. The New Jersey profile is the more accepted standard but
the General Motors profile permits better stackability, as will be
discussed later in more detail.
2 ~
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FIG. 2 shows a perspec~ive view of a first preferred
embodiment of a highway median barrier unit, generally referred to by
reference 20, in accordance with the invention. The highway median
barrier uni~, hereinafter referred to as barrier u~it 20, includes
substantially identical sides having an initial step 22 which i~
substantially vertical with respect to a plane of a base of the unit,
a Pirst 310ped plane 24 above the ini~ial step and a second sloped
plane 26 which ~oins a flat top surface 28. It is therefore apparent
that the barrier unit 20 in accordance with the invention is a hollow
shell having an open end generally lndicated by reference 30. The
shell preferably also includes a closed end 32 ~see FIGS. 5 and 6).
A plurality of barrier units 20 are connected in an end to end
fa~hion to provide a continuous barrier unit for temporarily di~iding
a highway lnto two or more lanes which accommodate traffic moving in
opposite direction~.
In the preferred embodiment 3hown in FIG. 2, the ~oint
includes a male portion 34 and a female portion 36. The male portion
further includes a protruding rib 38 along a top edge of its free
end, which rib is complementary with a ~,roove 40 ~n the female
portion. When two units are connected together~ the protruding rib
38 cooperates with the groove 40 to provide a locking connection
between the units.
In order to lend weight and stabLlity to the barrier unit 20,
the unit includes at least one collapsible balla~t bag 42 constructed
of a heavy, durable plastic such as polyurethane, or the like which
is preferably treated with an ultraviolet light inhibitor. The
ballast bag 42 is recessed from the female end of the barrier unit 20
to permit the insertion of the male end of an ad~oining barrier
unit. The ballast bag 42 preferably includes a reinforced bottom
wall 43 to prevent puncture or tear damage from incidental contact
with rough road surfaces or extraneous debris. The bottom wall 43
may be reinforced by increasing ~he thickness or toughness of plastic
used in that area or by the incorporation of a synthetic fabric webJ
such as a rip rYsistant nylon or the like, as an integral part of
that region of the bag 42.
- 8 - 2~ 8~
The ballast bag 42 is pr~ferably filled with liquid ballast, water
for example, by means of a flller opening 44 which may b~ located in
the male end of the barrier unit 90 that a subsequent unit ad~oined
will cover the openlng and obviate any requirement for a cap.
Alternatively, one or more filler openings can be located along the
length of each barrler unlt so that a barrier may be filled with
liquid ballast af~er i~ has been connected to other unlts. In order
to provide a means for discharging ballast from the barrier unit 20,
at least one drain plug 46 must be provided. A preferred structure
for this plug will be explained in more detail in relation to FIGS. 7
and 8. Since each barrier unit 20 preferably includes only one end
wall 32, and since each unit accommoda~es considerable volume of
liquid ballast, it is advisable to provide a reinforcement for the
bottom edges of the sidewalls to prevent lateral spread due to the
hydra~lic pressure of the liquid ballast in the ballast bag 42. One
preferred method of the accomplishing this purpose i8 the use of a
metal retainer bar A8 will explained below in relation to FIG. 4.
Opposite ends of the retainer bars are received in sockets 48 90 that
in an assembled condition of the highway med~an barrier, the initial
step 22 is a smooth flat surface that provides no hazard to the tires
of a vehlcle which may contact the barrier.
FIG. 3 shows three barrier unit~ 20 ~oined together to form a
short section of a temporary highway median barrier. As i~ apparent,
the barrier unit 20 on ths right end of the bsrrier is shaped with a
sloped end, a common shape for starter units for such constructions.
FIG. 4 shows a cross-sectional end view of barrler unit 20
taken along lines 7-7 of FIG. 2. FIG. 4 also shows, in exploded
view, a sidewall retainer bar 50 which fits in sockets 48 (see FIG.
2) and serves the purpose of preventing a lateral spread of the
sidewalls of the barrier unit 20. As may be seen in FIG. 3, each
barrier unit 20 iQ preferably provided with at least a pair of
sidewall retainer bars 50, one of which reinforces the sidewalls near
a middle of the unit and one which reinforces the ~cint between two
ad~acent units. The number of sidewall retainer bars fitted to each
unit depends on the unit length as well as the material from which
the unit is construrted. Alternatively, the sidewalls may be
2~$2~
g
retained by retainer straps 53 which may be affixed to or integral
with the bottom of the ballast bag 42 ~see FIG. 5), or the retainer
strap~ 53 may be lndependent units as shown in phantom lines in FIG.
5. The retainer straps, if provided, are connected to retainer clips
51, which are affixed to or integral with an interior bottom edge of
the sidewall3 22. Retalner hook-~ 55 are provided on opposite ends of
retainer s~rapq 53 and hook oYer retainer clips 51. For long unit3,
it i8 advisable to have retainer hook~ 53 attached to at lea~t the
four corner~ of a ballast bag 42 so that the corners of the bag may
be clipped to appropriately positioned clips 51 to ensure that the
bag is properly positioned to receive ballast before ballast is
introduced into the ballast bag 42.
Satisfactory materials for the construction of a barrier unit
20 include corrosion ~reated or corrosion resistant steel, aluminum,
and lmpact resistant thermoplastics including but not restricted to
ABS, polyvinyl chloride, polyethylene, polypro W lene, or a
polyethylene) polypropylene co-polymer. Many other materials may
also be used. Preferably, each barrier unit 20 is light enough in
construction that it may be handled by two to four persons. Weight
is therefore a factor in determining the length of a barrier unit
20. Another factor which must be considered in determining the
length of a barrier unit 20 is the quality and topography of a road
surface to be temporarily divlded. Shorter barrier unlt~ 20 are
prefexred for road surfaces which include hillq, hummocks and/or
sharp curves. Longer units may be used on ~traight level roadways.
In general, a barrier unit 20 which is 8 to 12 feet in length is
preferred. Shorter units of 4 to 8 feet as well as units of 20 feet
or more may, however, be used if appropriate.
Referring again to FIG. 4, it can be seen that the top corners
of the barrier unit 20 are preferably reinforced by reinforcement
members 52. The reinforcement members 52 may be steel or aluminum
angles welded to the barrier unit 20 or plastic moldings or
e~trusionA which are heat welded to or integral with the sidewalls,
in an instance where the barrier unit 20 is constructed from a
thermoplastic material. If the barrier is constructed from
thermoplastlcJ the sidewalls 22, 24 and 26 as well as top wall 28 may
2 ~
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also be reinforced by incorporating ridges or corrugations into their
inner surface.
The ballast bag 42 maybe glued or heat welded to the sides of
the unit beneath or on the reinforcement members 52 and to the
underside of the top surface 2~ of the unit to provide a liquid proof
seal between the ballast bag 42 and the top 28 of the barrier unit.
Alternatively, the ballast bag 42 ma~ be a removable bag ha~ing a
neck 45 which is attached directly to the filler opening 44 in a
manner well known in the art.
FIG. 5 shows a stacking arrangement for barrier units 20 when
not in use. When the ballast bag~ are drained of liquid ballast by
removing drain plugs 46 tsee FIG. 4) from drain orifices 54, the
uni~s maybe inverted so that the ballast bag 42 collapses into the
in~erted top of the barrier unit 20. Two or more units may then be
stac~ed in an inverted condition. This i5 one distinct advantage of
the barrier units 20 since several units maybe stacked together in
order to save storage space. On the interior of eac~ sidewall 26
there are preferably provided ridges or bosses 56 which act as a stop
to provide a support surface for the top ed~es of one barrier unit 20
stacked inside another unit. The ridges or bosses 56 thus preven~
two units from sticking together when they are stacked one inside
another.
The posltion of the ridges or bo~3ses 56 is dictated by the
slope of the sidewalls 26. Of the three profiles shown in FIG. 1,
the General Notors profile is best su~ted for stacking and permits
the greatest nesting of the barrier units 20. Each profile
accommodates stacking nonethele~s and minimal experimentation is
required to determine the best location for ridges or bosses 56.
If the barrier units 20 are to be stored outdoors, it is
preferable that the units be s~acked in an upright condition. As
~hown in FIG. 6, the units may be stacked in an upright condition if
means are provided for retaining the ballast bags 42 in a top of the
unit when the ballast bag is not filled with liquid ballast. The
units may therefore be provided with straps 58 attached at regular
intervals to the interior sidewalls 26 by gluing, heat weldin~ or the
like. Median barriers stacked in this fashion out of doors shed the
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rain, snow and the like and may therefore be stored in a minim~m of
space in any climate. The barrier unit5 may also be stacked in this
fashion if the ballast bags 42 are independent bags which are removed
from the barrier units 20 when it is not in use.
FIG. 7 shows a cross-sectional detail of a suitable drain plug
arrangement, taken along lines 7-7 of FIG. 2. In this particular
arrangement, a drain plug 46 threadedly engages a drain orifice 54
molded onto a side of the ballast bag 42 in a manner well Xnow in the
art. Drain plugs 46 and drain orifices 54 are preferably as large as
practical SQ that a drainage of liquid ballast is effected as quickly
as poRsible. It is important that drain plug 46 fit flush with the
initial step 22 of the barrier unit 20 so that thP drain plug can not
be damaged or displaced by contact with the tire of a vehicle. The
drain plugs are, nonetheless, preferably positioned along at least
one side of leach unit 80 that drainage may be effected before the
units are disassembled. There are many flush-fit drain plug
constructions well known in the art which are su1table for this
purpose. Nany alternate arrangement may therefore be substituted for
the drain plug 46 shown in FIG. 7.
A drain plug may also be placed at the ~oint between two
units, as shown in phantom lines in FIG. 2. FIG. 8 is a
cross-~ectional view taken along lines 8-8 of FIG. 2. In this
arrangement, the drain plug 46 i8 attached to a drain orifice 54
after two ad~acent units are hooked together. A retainer nut 58 may
be screwed on to the threaded drain orifice 54 to hold the ballast
bag 42 ln position with respect to the female portion 30 of the
~oint~. The drain cap 46 is then screwed on~o the outer end of drain
orifice 54. The peripheral edge of the drain cap 46 is preferably
tapered or stepped so that the drain cap 46 exerts some pressure on
the male portion of the ~oint 34 when it is screwed securely onto the
drain orifice 54. This arrangement tends to reinforce the ~oint
between two ad~acent units but the arrangement shown in FIG. 3
wherein sidewall retainer bars 50 reinforce the ~oint is preferable
because the sidewall retainer bar provides a stronger and more secure
reinforcement
2 ~
FIGS. 9 and 10 show isometrlc end views of an alternate
embodiment of the invent~on wherein a highway median barrier unit 20A
in accordance with the invention comprises a hollow ~hell having a
wide base which includes a bottom wall 60 and upwardly eonverglng
sidewalls that preferably include a vertical first step 22, an
inwardly inclined first slopped plane 24, a econd sloped plane 26
and a substantially flat top surface 2~. The hollow shell further
includes opposite end walls 62 so that a completely enclosed
container ha~ing a New Jersey, General Motors or any other suitable
profile. The opposite end walls 62 further preferably include ~oint
means for connecting the opposite ends of ad~acent barriers. A
preferred ~oint includes a wide Male tongue ~ith an arcuate outer
surface 64 and a complementary female socket 6S for recelving the
male tongue 64. The arcuate male tongue and complementary female
socket are preferred although many alternate connectors are not only
pos~ible but also practical. The arcuate element is preferred
because it permits an easily mated but strong ~oint. ~he width of
the arcuate male tongue 64 preferably tapers towards its distal end
and ~he female socket 66 preferably tapers towards its inner end 80
that mating of the two parts is facilitated while the stren8th of the
~oint is not compromised. At least one! end of the barrier unit 20A
i9 provided with a filler opening 44 which accommodates a filler cap
68. Any number of filler cap de.signs, well known in the art~ are
suitable. Threaded caps are pre~erred since they securely engage the
filler opening 44 and thereby inhibit a los9 of ballust due to a
vehicle impacting the barrier. ~iller caps 68 are also recommended
because they prevent a loss of liquid ballast due to evaporation.
Each barrier unit 20A is also pre~erably provlded with at
least two drain plug9 46 for discharging with the ballast from the
units. The drain plugs 46 may be placed on the opposite ends of each
unit bu~ drain plugs are also preferably provided on the sides o~
each unit 90 that drainage may be accomplished while the barriers are
in a Joined condition.
FIG. 11 shows three barrier units 20A assembled in a short
highway median barrier. The unit on the right hand side of the
barrier is a starter unit with a sloped end. The units are ad~oined
~ ~ $ ,~
by inserting the male element 64 into the female element 66. The
cooperative engagement of these two elements guide3 the barrier units
20A into perfect registry and provides a strong yet flexible joint
between ad~acent units. Drain plugs 46 are preferably positioned SG
that they are readily accessible for dralning liquid ballast from the
barriers while the barriers are in an ad~oined condition. As noted
above, the outer ~urface of drain plugs 46 should be fluRh with the
outer surface of the initial step 22 of the sidewalls of ~he barrier
unit 20A ~o that a plug is not accidentally dislodged by a passing
vehicle which could drain the barrier and therefore render it
vulnerable to failure should it be sub~ected to the impact of a
subsequent colli~ion.
FIG. 12 shows a side view of a barrier unit in accordance wi~h
the invention. The barrier unlt 28 may be construc~ed of any of the
materials suitable for the construction of the first preferred
embodiment of the barrier unit 20 described above. Thus, corros~on
resistant or corroslon treated steel, aluminum plate, or heat welded
thermoplastics are all suitable construction ma~erials. Materials
which are not corrosion resistant or waterproof may also be used if
they have adequate structural strength since they can be lined with a
waterproof material such a~ sheet plastics, or the like. Since water
has about half the density of most concrete mixtures, both of barrier
u~its 20 and 20A are preferably constructed so that they are about
twice the width of ths temporary concrete barriers currently in wide
use throughout North America. Because pre-cast temporary concrete
barriers are generally only about sixteen inches wide at the base, a
temporary barrier of twice that width i9 usually quite acceptable
since no appreciable road surface is sacrificed.
YIG. 13 shows an isometric cross-section of the barrier unit
30 20A taken along lines 13-13 of FIG. 12. As may be seen, the barrier
unit 20A preferably includeY bulkheads 70 spaced at intervals within
the interior of the hollow shell to reinforce the converging
sidewalls of the hollow ~hell and to stabilize liguid ballast in the
shel~ in the event that the barrier unit 20A is impacted by a
vehicle. The bulkheads 70 include a drain path 72 which is
conveniently centered at a bottom edge of each bulkhead. Bul~heads
2~3~
- 14 -
70 need not, of course, be continuous webs in order to adequately
reinforce the sidewalls of the units. A substantially continuous
bulkhead 70, nonetheless, provides fluid stability which is not
provided by other bulkhead arrangements.
FIG. 14 is a detailed cross-sectional view of a typical
construction for a dr~in plug 46, taken along lines 14-14 ~f FIG. 9.
The dra~n plug threadedly engages a threaded drain orifice 54
constructed in a manner well known in ~he art. A drain orifice i9
preferably provided with a gasket 74 which is forced against a bottom
wall 76 of the drain orifiçe 54 to prevent leaXs around the periphery
of the drain plug 46. Many alternate drain plug arrangements known
in the art are equally adapted for use with the median barrier 20A.
In use, either of median barriers 20 or 20A are preferably
filled with a liquid ballast, water or salt water being the liqu~ds
of choice since they are readily available and easily disposed of
without environmental consequence. As noted above, the barriers are
preferably constructed so that they have approximately double t~e per
unit volume of comparable pre-cast concrete barrier. When installed
and ballasted a highway median barrier in accordance with the
invention thereby has approximately the same mass as a temporary
pre-cast concrete barrier and is therefore substantially equivalent
in its ability to re-direct a vehicle back into the lane of traffic
from which it came. After the hlghway median barriers 20 and 20A
have served their purpose, they are drained of liquid ballast and
eollected for transpor~ to a new location of use or to a storage
site. Since the barriers are relatively light in their void
condieion, they are readily handled without danger and a large number
of units can be accommodated on a carrier vehicle because weight i8
not an impediment.
It is therefore readily apparent that a new and useful highway
median barrier construction has been provided which offers distinct
advantage~ over the known prior art since a recyclable highway median
barrier which is readily and easily handled and positioned on a
roadway is provided.
Changes and modifications to the specific embodiments
hereinbefore described may be made without departing from the scope
of the invention which is intended to be limited solely by the scope
of the appended claims.
