Masonry Magazine August 1992 Page. 32
Design Example #4: Reinforced Brick Pilaster and 6 Inch Panel Noise Barrier Wall
Type S portland cement/lime mortar, f'm 3000 psi, Em 2.9 x 106 psi
Wall dimensions shown in Fig. 6.
Running bond, face shell bedding, spacing of pilasters shall be 10 ft
Ladder type joint reinforcement: fy 80 ksi, E= 29 x 106 psi, n = 10
Pier reinforcement: fy 40 ksi, E, 29 × 106 psi, n = 10
Loads: wind 15 psf, panel weight = 40 psf, pilaster weight 120 pcf
Step 1: Based on acoustical considerations, the wall height shall be 6 ft minimum.
Step 2: Critical load combinations result in the following design values:
a) For the panel span between piers, assume a two span continuous condition. The critical cross section is at the support or pilaster. Thus, joint reinforcement must be continuous through the pilaster.
Mpx (1/8)(W)(L)2 = (1/8)(15 psf)(10 ft)2 = 188 ft-lb/ft of panel
Vpx (0.625)(W)(L) = (0.625)(15 psf)(10 ft) = 94 lb/ft of panel
b) For the panel span between caissons, consider the panel as entirely supported by the ground.
c) For the pilaster:
M (0.625)(W)(L)(h)2 = (0.625)(15 psf) (10 ft)(6 ft)2 = 3375 ft-lb
V=(1.25)(W)(L)(h) (1.25)(15 psf) (10 ft)(6 ft)= 1125 lb
P(pilaster weight)(b)(t)(h) = (120 pcf)(11.63 in.) (11.63 in.)(6 ft) = 676 lb
Step 3: Calculate required reinforcement for the panel for the design moment, Mpx. Assume the distance from the extreme compression face to the joint reinforcement is 4.9 inches.
As req'd= Mpx (188 ft-lb)(12 in./ft) / Fajd (4/3)(30 ksi)(0.9)(4.9 in.) = 0.013 in.2
Try W1.7 ladder type joint reinforcement in every third course, brick height is 3.63 in.
Noise Barrier Wall Design Example #4
Reinforced Brick Pilaster and 6 Inch Panel
FIG. 6
10