Adjustable barrier wall assembly

A system for producing asymmetrical barrier wall section assemblies from a combination of standardized precast concrete components of complex cross section and custom dimensioned precast components of simple cross section includes first and second half-sections having symmetrical inclined outer face portions, at least one filler block for supporting the second half-section so that its inclined outer face portion is vertically displaced above the inclined outer face portion of the first half-section, and a filler panel for filling a gap between the top of the first half-section and a top portion of the second half-panel. The at least one filler block and the filler panel are essentially rectangular in cross section, so that they can be cast with any desired height dimensions within a predetermined range in simple open-top box molds having one adjustable side. Various arrangements for securing the precast concrete components together include lateral volts and vertical undercut channels containing slidably positionable nuts, cement grout filled vertical roughened recesses on vertical interfaces of the components, and longitudinal interengaging extensions and depressions on horizontal interfaces of the components. With appropriately selected dimensions of the first and second half-sections, symmetrical assemblies can be produced with the first and second half-sections alone or optionally including a filler panel.

BACKGROUND OF THE INVENTION 
1. Technical Field 
This invention relates to precast concrete roadway-dividing wall sections 
and particularly to asymmetrical wall sections for dividing roadways 
having different grade levels and different slopes from one end of the 
section to the other end. 
2. Background Art 
The superior effectiveness of contoured concrete roadway dividing walls of 
the so-called New Jersey type in preventing accidents and mitigating the 
damage when accidents do occur has led to increasing use of these walls as 
replacements for metal guard rails or median strips in highway 
modernization programs as well as in new highway construction. The New 
Jersey type barrier wall has a scientifically developed contour consisting 
of a low vertical base segment (about three inches high), an intermediate 
inwardly sloping segment, and an upper segment of less inward slope than 
the intermediate segment. The latter two segments have specified angles 
and heights that function with the low base segment to effectively 
redirect a vehicle coming into contact with the wall back into the 
roadway, minimizing the tendency to climb the wall, overturn, or ricochet 
into another lane. 
Although mobile adjustable form equipment is available for on-site pouring 
of such walls in a continuous line, most dividers are made up of precast 
concrete sections, which are typically twenty feet long. When the roadways 
on both sides of a dividing wall are at the same grade, symmetrical 
precast sections of standard dimensions can be used. Often, however, the 
roadways are at substantially different levels, particularly on curves, 
and the difference in level can change along the twenty foot length of a 
section. Since the profile on each side of the wall must follow the 
roadway on that side, an asymmetrical barrier is required in such a 
situation. Each section must be custom designed to have vertical 
differences as specified in the construction plans at each end between 
corresponding segments of the opposite contoured profiles. 
U.S. Pat. No. Re. 32,936 of the present inventor discloses an adjustable 
mold for asymmetrical barrier sections. This mold is quickly adjustable to 
specified differences in height and slope of the contoured faces on each 
side to enable pouring of a monolithic asymmetrical barrier section and 
has pivoted sides and hinged ends so that the section can be removed from 
the mold easily after it has cured. The mold is very large and expensive, 
however, compared with a standard symmetrical barrier mold, and the 
resulting custom cast sections are necessarily more expensive than 
standard symmetrical sections. 
The prior art practice of providing monolithic precast asymmetrical wall 
sections has other inherent drawbacks. Because of the vertical offset 
between the two sides, precast asymmetrical wall sections are 
significantly higher and heavier than standard symmetrical sections. This 
means fewer sections per truckload. Because of their individual differing 
dimensions, they cannot be cross-stacked like standard symmetrical 
sections, so they require more storage area at the precasting plant and at 
the job site. 
In some instances where there is sufficient median space, New Jersey type 
barriers have been installed using precast half-sections facing lanes of 
oppositely moving traffic. The half-sections are spaced apart by a 
substantial distance (e.g., several feet), with the intervening space 
backfilled and covered with blacktop or concrete to protect against water 
washing away the backfill material. In these installations, the opposed 
half-sections are essentially independent retaining walls, so each line of 
half-sections can follow the grade of the respective adjacent roadway. 
Because the half-sections are identical, there can result a vertical 
difference between the tops of the sections that creates an uneven top 
surface of the barrier. Settling of the backfill can also cause the 
protective blacktop or concrete layer to crack, allowing water to enter 
the backfilled space. The backfilled space also reduces the area available 
for shoulders or possible additional traffic lanes. 
Under current economic conditions, it is often necessary to rebuild or 
rehabilitate a highway system in stages, as funds become available. The 
need for safe, effective, and often asymmetric, barriers may exist for 
each construction stage, even though short lived. To provide space-saving, 
monolithic site-specific asymmetrical barrier sections for one stage that 
may need to be changed for the next stage is cost prohibitive. There is a 
need, therefore, to provide asymmetric barrier sections which may be 
easily and economically adjusted and made site-specific for each stage. 
The present invention provides such a system. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide an asymmetrical barrier wall 
section assembly that is as close to being a standardized unit as 
possible. 
Another object of the invention is to provide an asymmetrical wall section 
assembly that combines precast standardized major elements of 
predetermined fixed dimensions with relatively small filler elements that 
can have different dimensions for each section assembly. 
Another object of the invention is to provide such a wall section assembly 
of which the filler elements can be formed in inexpensive easily 
adjustable molds. 
Another object of the invention is to provide a barrier system which can be 
economically and easily adjusted and made site-specific for a different 
configuration. 
These and other objects are achieved by a precast concrete modular 
roadway-dividing barrier wall section assembly comprising: 
a first elongated barrier half-section having a bottom, a vertical inner 
face, an outer face having an inclined portion, and a top portion located 
at a predetermined first height above the bottom, the first half-section 
having a constant cross section from a first end to an opposite second 
end, with the width at the top being substantially less than the width at 
the bottom; 
a second elongated barrier half-section having a bottom, a vertical inner 
face, an outer face having an inclined portion, and a top portion located 
at a predetermined second height above the bottom, the second half-section 
also having a constant cross section from a first end to an opposite 
second end, with the width at the top being substantially less than the 
width at the bottom; 
at least one filler block having a bottom, a top, an inner face, and an 
outer face, the filler block being disposed alongside the first barrier 
half-section with the inner face of the filler block abutting the inner 
face of the first half-section, and the second half-section being disposed 
alongside the first half-section with the bottom of the second 
half-section on the top of the filler block and the inner face of the 
second half-section abutting the inner face of the first half-section, the 
second height being preselected relative to the first height so that there 
is a vertical distance between the top portion of the first half-section 
and the top portion of the second half-section; 
an elongated filler panel having a bottom, a top, an inner face, and an 
outer face, the filler panel being disposed to fill the vertical distance 
between the top portion of the first half-section and the top portion of 
the second half-section with the inner face of the filler panel abutting 
the inner face of the higher of the first and second half-sections; and 
means for securing the filler block, the first and second half-sections, 
and the filler panel together to form an integral barrier section. 
The first and second half-sections are standardized elements of constant 
dimensions. The same two half-sections can be used for asymmetrical 
section assemblies that are custom fabricated for any differences in level 
and slope, within predetermined ranges, between the roadways to be divided 
by the barrier wall section. The at least one filler block can be a single 
elongated block that extends for the length of the section assembly, or it 
can be a plurality of relatively short blocks that are spaced 
longitudinally apart. Normally, a single elongated filler block will be 
preferred, to increase the weight and decrease the center of gravity of 
the assembly, for maximum stability. The filler block or blocks and the 
filler panel are variable elements that can be different for each section 
assembly. If, for example, the two roadways have a grade difference, each 
filler block has a height dimension selected to create the same difference 
between the heights of corresponding segments of the profiled outer faces 
of the two half-sections. 
The filler panel has a height dimension selected to at least fill the 
resulting gap between the top portion of the first half-section and the 
top portion of the second half-section. If the roadway grade difference is 
constant from one end of the section to the other, then the filler block 
or blocks and the filler panel will have constant height dimensions. If 
the difference in level of the roadways changes from one end of the 
section to the other, the height dimensions of the filler block or blocks 
and the filler panel will have the same change. 
Typically, the filler block and filler panels will be precast in accordance 
with a chart or table of site-specific barrier section dimensions. Because 
of the simplicity of the molds required for these elements, they could 
also be cast on the job site. Particularly in the case of the filler 
panels, it is also possible to use simple forms to cast them in place 
after the other section components have been assembled. Thus, the 
invention is not limited to any fabrication method or assembly sequence. 
The first and second half-sections may be identical, resulting in minimum 
mold and inventory requirements and permitting two half-sections to be 
assembled as a symmetrical barrier for use at locations where the roadway 
levels are the same. The height of the second section may be different 
from the height of the first section, however, depending on the range of 
the differences in roadway levels or other design criteria, and usually 
the height of the second section will be greater than the height of the 
first section. One criterion that should be considered when selecting the 
height dimensions of the non-inclined portions of the first and second 
sections is that the intended range of adjustment should not require any 
filler blocks having a height less than some minimum value, such as four 
inches, needed for strength. 
The top portion of the second section may be simply a flat surface 
extending between the inner and outer faces of the half-section. 
Alternatively, the top portion of the second half-section may have a lip 
that extends laterally from the inner face to provide a protective top cap 
over the filler panel, or vice-versa, for preventing water seepage between 
the half-sections. 
Other features and advantages of the invention are described below in 
connection with the drawings of preferred embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the following description of the drawings, identical or substantially 
identical components shown in different drawings will be identified by the 
same reference numeral. 
With reference to FIGS. 1-3a, an asymmetric barrier wall section assembly 1 
according to the invention includes four precast concrete elements: an 
elongated first half-section 2, an elongated second half-section 3, a 
filler block 4 at each end, and an elongated filler panel 5. The first 
half-section 2 has a bottom 6, a flat vertical inner face 7, an outer face 
8 having an inclined portion 9, and a top portion 10 located at a 
predetermined height h.sub.1 above the bottom 6. The second half-section 3 
also has a bottom 11, a flat vertical inner face 12, an outer face 13 
having an inclined portion 14, and a top portion 15 located at a 
predetermined height h.sub.2 above the bottom 11. Each filler block 4 is 
of substantially rectangular cross section and has a bottom 16, a top 17, 
an inner face 18, and an outer face 19. The filler panel also is of 
substantially rectangular cross section, with a bottom 20, a top 21, an 
inner face 22, and an outer face 23. 
As best shown by FIG. 3a, the inclined portion 9 of the first half-section 
2 includes a lower inwardly sloping segment 24 that is intermediate 
between a vertical base segment 25 and an upper inclined segment 26 of 
less inward slope than the lower segment. The inclined portion 14 of the 
second half-section 3 has an identical profile, with a lower inwardly 
sloping segment 27 intermediate between a lower vertical base segment 28 
and an upper inclined segment 29 of less inward slope than the 
intermediate segment. In the embodiment of FIGS. 1-3a, the top portion 10 
of the first half-section is at the upper edge of the upper inclined 
segment 26, but the second half-section has an upper vertical segment 
extending from the upper edge of the upper inclined segment to the top 
portion 15. 
The angles and heights of the lower and upper inclined segments on both the 
first and second half-sections are identical and correspond to the optimum 
values determined by the research leading to the New Jersey type barrier 
profile. The heights of the lower vertical base segments 25 and 28 of the 
first and second half-sections, and the overall heights h.sub.1 and 
h.sub.2 of the two half-sections are not critical, but they should be 
selected after considering the expected range of differences in grade 
between the divided roadways (the levels of which are indicated by lines 
31 and 32 on FIG. 3a) and the desired minimum barrier height in relation 
to the higher of the two roadways. In the embodiment of FIGS. 1-3a, the 
heights of the lower vertical base segments 25 and 28 of both the first 
and second half-sections are the same. This is not necessary, but it 
provides an advantage that the two half-sections can be used without a 
filler block or blocks to produce a symmetrical barrier section. Whatever 
values are selected for these dimensions, the cross sections of both the 
first and second half-sections are constant from one end to the other, and 
the cross-sectional dimensions of successive first and second 
half-sections are respectively the same, as illustrated in FIG. 1. 
Typically, the section assemblies will be set on foundation blocks, such as 
sleeper blocks 33 in FIG. 1, which are placed on twenty foot centers, for 
example, along the line of the barrier wall at a preselected distance 
below the grade of the lower roadway. The height of the lower vertical 
base segment 25 of the first half-section 2 should be predetermined so 
that the lower edge of the lower inward sloping segment 24 of the first 
half-section will be approximately three inches above the level 31 (FIG. 
3) of the finished adjacent roadway. 
Each filler block 4 provides the desired vertical separation of the 
inclined portion 14 of the second half-section 3 above the inclined 
portion 9 of the first half-section 2 such that the lower edge of the 
lower inclined segment 27 of the second half-section will be approximately 
three inches above the level 32 of the finished roadway adjacent to the 
second half-section. Since each filler block has an essentially 
rectangular cross section, it can be cast on its side in a simple open 
mold having one side that is adjustably movable toward and away from an 
opposite side to match the grade difference between the two roadways at 
the intended location of the barrier wall section assembly. In the 
embodiment of FIGS. 1-3a, there are two longitudinally spaced short filler 
blocks 4 for each section assembly 1, the lengths and spacing of the 
filler blocks being approximately the same as the lengths of the 
respective sleeper blocks 33. 
If the grade difference between the roadways is constant over the length of 
a section, the heights of the filler blocks at each end of the section 
will be the same. If the grade difference between the roadways changes 
over the length of a section, the heights of the filler blocks at each end 
of the section will be different. This situation is illustrated in FIG. 1, 
where the height of the filler block at the left end of the left hand 
section assembly 1 is .DELTA., the height of the filler blocks at the 
interface between the two section assemblies is .DELTA.+.delta., and the 
height of the filler block at the right end of the right hand section 
assembly is .DELTA.+.delta.'. Since the adjacent ends of successive 
section assemblies are set to the same difference in grade level between 
the two roadways, it may be advantageous to provide a single filler block 
to support both adjacent ends. 
The height of the second half-section in the embodiment of FIGS. 1-3a is 
greater than the height of the first half-section. The height difference 
is selected to provide a suitable minimum height dimension for the filler 
panel 5 when the difference between the grade levels of the two roadways 
is zero. FIG. 3b illustrates an assembly for this situation. Since the 
vertical offset is zero, the filler block may be eliminated, and the 
assembly becomes symmetric. The height dimension of the filler panel 5 in 
FIG. 3b is less than that of the filler panel in FIG. 3a due to the 
elimination of the filler block 4 of FIG. 3a. The filler panel can be 
eliminated also if the assembly is made of two first half-sections or two 
second half-sections (i.e., the two half-sections of the assembly have 
identical cross sections), with the sections being secured together. 
As mentioned earlier, the filler panel fills the gap between the top 
portion of the first half-section and the top portion of the second 
half-section, as best seen in FIGS. 2, 3a, and 3b. Because the filler 
panel comprises a visible portion of the installed barrier wall section 
assembly, it is made as a single element having a length the same as the 
lengths of the first and second half-panels. As with the filler block or 
blocks, the filler panel can be precast on its side in a simple open box 
mold having one adjustable side to provide any desired constant or 
variable height dimension. 
Although the arrangements of FIGS. 1-3a and FIG. 3b have the simplest cross 
sections for each element of the barrier wall section assembly, a drawback 
is that the junction between the inner faces of the filler panel 5 and the 
second half-section 3 extends to the top surface of the assembly. This 
joint provides a path for moisture to enter between the elements, possibly 
corroding fasteners that secure the elements together and damaging the 
concrete interface surfaces by freezing and expanding. The embodiments of 
FIG. 3c and of FIGS. 4-6 overcome this drawback at the cost of a slight 
increase in complexity in the cross section of the filler panel and the 
second half-section, respectively. 
In the modification of FIG. 3c, the filler panel 5 extends above the top 
portion of the second half-section 3 and is provided with a lip 5a that 
extends over the top of the second half-section to cover the vertical 
interface between the filler panel and the second half-section. 
In the alternative embodiment of FIGS. 4-6, the top portion of the second 
half-section includes a lip 34 that extends beyond the inner face 12 of 
the second half-section, the lip having a lower face 35 and a 
strengthening fillet 36. The filler panel 5 in this embodiment has a 
height that is reduced by the vertical dimension of the lip 34, relative 
to the filler panel of the first embodiment, so that it fits in the gap 
between the top portion of the first half-section 2 and the lower face 35 
of the lip. FIG. 6 shows that the lip extends to be coplanar with the 
outer face 23 of the filler panel 5, providing a protective unitary cap 
for the top of the barrier wall section assembly. 
FIGS. 7-9 show arrangements for securing the elements of a barrier wall 
section assembly together to provide the necessary strength to resist 
design impact loads. The assembly in these figures represents a 
modification of the embodiment of FIGS. 3-6 to incorporate a single 
elongated filler block 4 that extends the length of the section. 
Several different securing systems combine to provide a high degree of 
interconnection between the four precast concrete elements. One system 
uses lateral tension members such as bolts and vertical nut-retaining 
channels for tying the filler block and second half section to the first 
half-section and the filler panel to the second half-section. A second 
system provides roughened vertically-extending recesses in the opposing 
inner faces of the precast concrete elements. After assembly, the recesses 
are filled with concrete grout to produce keys that resist longitudinal 
and vertical shear forces at the vertical interface. A third system 
provides longitudinal keys for resisting lateral shear forces at the 
horizontal interfaces. Still another system ties the second half-section 
and the filler blocks or blocks together with gusset plates. 
As shown particularly in FIG. 8, the first-mentioned system comprises at 
least one vertically extending channel 37 in the inner faces of both the 
filler block 4 and the second half-section 3. Each channel 37 is embedded 
in the concrete and has an opening 38 that is narrower than a laterally 
inward portion 39 of the channel. The first half-section 2 has a lower row 
of holes 40 opposite the filler block and at least one upper row of holes 
41 opposite the second half-section. The filler panel 5 also has at least 
one row of holes 42. Each hole in each row is located opposite to the 
opening in a respective channel. Each hole receives a bolt 43 of 
appropriate length, which engages a nut 44 that is slidably captured in 
the channel 37. Preferably, each hole has a counterbore 45 on the outer 
end for recessing a bolt head 46 and washer 47 and has an expanding 
tapered portion 48 extending to an enlarged opening on the inner end. The 
tapered portion 48 compensates for some degree of misalignment between the 
centerline of the respective holes and the centerline of the channel 
opening 38. Channels designed for this purpose and having spring-loaded 
nuts that can be positioned at selected locations long the length of the 
channel are sold commercially under the trademark "UNISTRUT." 
The components of a barrier wall section assembly can be secured together 
with this system by first setting the second half-section on the filler 
block so that the channels 37 are aligned. Next, the bolts 43 are inserted 
through the holes 40 and 41 in the first half-section, and nuts 44 are 
started on the ends of the bolts. The first half-section is lifted above 
the second half section so that their inner faces are substantially 
coplanar. The first half-section then is gently lowered while guiding the 
bolts into the openings of the corresponding channels, with the nuts on 
the ends of the bolts entering the undercut portions of the channels. 
After the first half-section is set in place, the same procedure is 
followed with the filler panel. Finally, the bolts are tightened by 
applying a wrench to the exposed bolt heads. 
The second of the above mentioned systems comprises at least one vertically 
extending recess 49 in the inner face of the filler block 4 and at least 
one corresponding recess 50 in the inner face of the second half-section 
3, each recess in the second half-section being vertically aligned with a 
recess in the filler block. The inner faces of the first half-section 2 
and the filler panel 5 have respective similar recesses 51 and 52 (see 
FIG. 9) that are located directly opposite the recesses in the filler 
block and second half-section. At least the bottom walls of the opposing 
recesses are roughened, preferably with horizontal extensions 53 and 
depressions 54 having a sawtooth cross section. A grouting port 55 
extending through the top portion of the second half-section in line with 
each set of opposed recesses permits grout to be poured into the recess 
cavity after the barrier wall section has been assembled. When hardened, 
the grout plug acts as a shear key to oppose forces acting parallel to the 
interface in the longitudinal direction and also as a shear key in 
opposition to vertical forces, due to its interengagement with the 
sawtooth profiles of the opposed recesses. 
Also shown in FIG. 9, the third of the above mentioned securing systems 
comprises mating extensions and depressions, such as axially extending 
tongue 56 and groove 57, in the opposed top of the first half-section and 
the bottom of the filler panel and mating extensions and depressions such 
as axially extending tongue 58 and groove 59 in the respective opposed 
lower surface of the lip of the second half-section and top of the filler 
panel. Similar extensions and depressions, such as axially extending 
tongue 60 and groove 61, are provided in the top of the filler block and 
bottom of the second half-section. FIG. 9 also illustrates the use of 
gusset plates 62 secured by bolts 63 threaded into embedded inserts 64 to 
tie the second half-section to the filler block as another system for 
securing the components of the barrier wall section assembly together. 
It should be appreciated that the illustrated systems are exemplary of the 
best mode known to the applicant at this time, but other securing systems 
can be used to achieve the object of providing an assembly that is 
comparable in strength to a monolithic concrete casting economically and 
with minimum installation time. 
FIGS. 10-13 provide perspective assembled and exploded views of barrier 
wall section assemblies that are similar to the embodiment of FIGS. 7-9. 
Each of the three consecutive section assemblies shown in FIGS. 11 and 13 
has a different filler panel and a different filler block. The filler 
panel 5 of the right hand section in FIG. 10 and the corresponding filler 
block 4 in FIG. 13 have constant cross sections from one end to the other. 
The height dimensions of the filler panels of the middle and left hand 
sections in FIG. 10 and the corresponding filler blocks in FIG. 13 
increase in the direction from right to left in FIG. 10. The first and 
second half-sections of each unit are identical to the respective first 
and second sections of the other units. The exploded views of FIGS. 11 and 
13 make especially clear the advantage of the present invention in 
providing the major components of the assembly as standardized elements 
and minimizing the size and complexity of the variable components. 
Aside from a different number of recesses, lateral bolt holes, and 
nut-retaining channels than in the embodiment of FIGS. 7-9, the only other 
difference in the section assemblies of FIGS. 10-13 is the optional 
provision of vertically oriented bolts 65 to secure the filler panel 5 to 
threaded inserts 66 embedded in the top of the first half-section 2 
instead of the lateral bolts 43 of the previous embodiment. This option 
may be desirable when the filler panel has a low height dimension relative 
to its width dimension. 
FIGS. 14 and 15 illustrate further modifications that are useful when the 
vertical separation between the roadways exceeds a predetermined value. In 
such a situation, the barrier wall must also serve as a retaining wall and 
requires some type of stabilization to resist the lateral pressure and 
overturning moment exerted by the backfill on the high roadway side. A 
footing slab 67 is a simple way to provide such stabilization. In FIG. 14, 
the first half-section is secured to one edge of the footing slab 67 by 
angle brackets 68 secured by bolts 69, and a tie rod 70 having a lower end 
71 retained in a threaded socket 72 embedded in the footing slab and an 
upper end 73 carrying a nut 74 secures the filler block and the second 
half-section to the footing slab. In FIG. 15, a large angle bracket 75 
secured by bolts 76 performs the function of the tie rod of FIG. 14. 
FIGS. 16-18 illustrate an alternative to the system of lateral bolts and 
nut-retaining channels for securing the components of the barrier wall 
section assembly together. This alternative comprises vertical steel 
angles 77 welded to internal reinforcing bars 78 at each end of the inner 
face of each of the first and second half-sections, the filler block, and 
the filler panel. The molds are modified to create corner recesses 79 to 
permit access to the angles 77 for bolting them together. As shown in FIG. 
17, at least one of each pair of facing angles is provided with vertically 
elongated slots 80 that register with corresponding holes or slots in the 
other angle of the pair over the full design range of vertical 
displacement between the first and second half-sections. A bolt 81 
inserted through each hole or slot in one angle and the registering slot 
or hole in the opposing angle is provided with a nut 82 to fasten the 
angles together. This arrangement leaves the outer faces of the assembly 
smooth, but requires that the section be assembled before it is put in 
place at the job site. After the barrier wall is installed, the angles and 
bolts are not accessible for inspection. The potential for loosening or 
corrosion can be minimized, however, by filling the corner recesses with 
cement grout after the barrier wall is in place. 
FIGS. 19 and 20 show still another alternative for securing the components 
together. This system includes at least one pair of opposed vertical 
channels or slotted rectangular pipes 83 embedded in the inner faces of 
each pair of opposed components, such as the filler panel 5 and second 
half-section 3, so that the channel openings or slots face each other. A 
clamping assembly comprises two angle bars 84 loosely secured to opposite 
sides of the web 85 of a T-bar 86 by at least one rivet or bolt 87. As 
shown in FIG. 20, the stem 88 of each rivet 87 passes through a camming 
slot 89 in the web 85 of the T-bar, permitting relative movement between 
the T-bar and the angles as shown by the arrow A. 
In use, after the components of the barrier wall section assembly are 
placed together so that their inner faces abut and the channel openings 
are in alignment, the T-bar 86 is shifted longitudinally with respect to 
the angle bars 84 in the upward direction of arrow A to increase the space 
between the head 90 of the T-bar and the opposite legs 91 of the angle 
bars. The clamping assembly is then inserted into the channels 83 so that 
the head 90 of the T-bar is in one channel and the angle bars 84 are in 
the opposite channel. Finally, the clamping assembly is tightened by 
forcing the T-bar in the downward direction of arrow A relative to the 
angles, so that the rivet stem moves in the camming slot to the position 
shown in FIG. 20. 
It will be appreciated that other equivalent devices and arrangements can 
be used for securing the components of the barrier wall section assembly 
together without departing from the scope of the invention as defined by 
the following claims. It also is clear that the relation between 
interengaging means shown in the drawings, such as tongues and grooves, 
lateral bolts and nut-retaining channels, can be reversed without changing 
their function or result. 
Finally, although the full range of features and advantages of the 
invention is realized in an asymmetric barrier wall assembly including all 
four of the described components, at least some of the same advantages are 
obtained with an assembly of only a first and second half-section, with or 
without a filler panel, to provide a symmetrical barrier wall section.