Page 433 - Design of Reinforced Masonry Structures

WALLS UNDER AXIAL AND TRANSVERSE LOADS 6.83

TABLE 6.10 Transmission Loss for Various Barrier Materials [6.35]

Thickness TL a Thickness
Material (in.) (dBA) Material (in.) TL (dBA)
a
Woods b Concrete, Masonry, etc.
Fir 1 / 2 17 Light concrete 4 36
1 20 6 39
2 24
Dense concrete 4 40
Pine 1 / 2 18
1 19 Concrete block 4 32
2 23 6 36
Composites
Redwood 1 / 2 16
1 19 Aluminum-faced 3 / 4 21–23
2 23 plywood e
Aluminum-faced 3 / 4 21–23
Cedar 1 / 2 15 particle board e
1 18 Plastic lamina on 3 / 4 21–23
2 22 plywood
Plastic lamina on 3 / 4 21–23
Plywood 1 / 2 20 particle board
1 23
Particle board c 1 / 2 20
Metals d Miscellaneous
Aluminum 1 / 16 23
1 25 Glass (safety glass) 1 22
/ 8 / 4
1 27 Plexiglass (shatterproof) —
/ 4
Masonite 1 / 2 22–25
Steel 24 ga 18 Fiberglass/Resin 1 / 4 20
20 ga 22 Stucco on metal lath 1 32
16 ga 25 Polyester with aggregate 3 20–30
Surface f
Lead 1 / 16 28
a
A weighted TL is based on generalized truck spectrum.
b
Tongue-and-groove boards recommended to avoid leaks (for fir, pine, redwood, and cedar).
c
Should be treated for water resistance.
d
May require treatment to reduce glare (for aluminum and steel).
e
Aluminum is 0.01 in. thick. Special care is necessary to avoid delamination (for all composites).
f
TL depends on surface density of the aggregate.

latter type is easy to build and economical due to the reduced thickness of the wall and
intermittent pier foundations. The panel is designed to span horizontally between the
piers. In both cases, design lateral loads on the wall can be determined as discussed also
in the previous section. A discussion on pier and panel highway sound barrier walls can
be found in NCMA TEK Notes [6.36, 6.37]. Reference 6.36 also provides design tables
(based on allowable stress design method) for 6-, 8-, and 12-in.-thick concrete masonry
cantilever highway noise barrier walls spanning 10 to 20 ft in 2-ft increments. Likewise,
Ref. [6.37] provides allowable stress design (ASD) tables concrete masonry pier and
panel sound barrier walls.