Masonry Magazine August 1992 Page. 23
45A
April
1992
BIA Technical Notes
on Brick Construction
Brick Institute of America 11490 Commerce Park Drive, Reston, Virginia 22091
BRICK MASONRY NOISE BARRIER WALLS
STRUCTURAL DESIGN
Abstract: Rationally designed brick masonry noise barrier walls provide an attractive wall form with reliable structural function. This Technical Notes addresses the structural design of pier and panel, pilaster and panel, and cantilever brick noise barrier walls. Suggested design methodology and design examples are provided. The information presented in this Technical Notes can be applied with slight modifications to the many design schemes and loading demands of noise barrier walls. The result is an attractive noise barrier wall with the durability and versatility inherent in brick masonry structures.
Key Words: brick, cantilever, noise barrier, pier, pilaster, structural design, wall system.
April 1992
40 BRICK
INTRODUCTION
Technical Notes 45 presented an introduction to acoustical, visual, structural, and construction considerations for brick masonry noise barrier walls. In continuation of the series, this Technical Notes addresses structural design considerations in greater detail and provides design examples. Recommended procedures are presented on the structural design of the wall system assuming acoustic and visual considerations are previously addressed. Design recommendations for noise barrier wall footings and caissons have not been addressed in this Technical Notes.
A design approach is presented which follows criteria contained in the Building Code Requirements for Masonry Structures (ACI 530/ASCE 5/TMS 402-92) and, where applicable, the Load and Resistance Factor Design Manual of Steel Construction-First Edition (AISC LRFD). Refer to Technical Notes 3 series for a discussion of the ACI/ASCE/TMS document.
NOTATION
As Area of steel, in.
b Width of section, in.
c Distance from extreme compression fiber to the neutral axis of the cross section, in.
d Distance from extreme compression fiber to the centroid of tension reinforcement, in.
Em Modulus of elasticity of masonry in compression, psi
Es Modulus of elasticity of steel, psi
fa Calculated compressive stress in masonry due to axial load only, psi
fer Modulus of rupture, psi
fs Calculated compressive stress in masonry due to flexure only, psi
Fb Allowable compressive stress in masonry due to flexure only, psi
fm Compressive stress in masonry, psi
f'm Specified compressive strength of masonry, psi
f. Calculated tensile or compressive stress in reinforcement, psi
F. Allowable tensile or compressive stress in reinforcement, psi
f₁ Calculated tensile stress in masonry, psi
F. Allowable flexural tensile stress in masonry, psi
f₁ Calculated shear stress in masonry, psi
F. Allowable shear stress in masonry, psi
fy Specified yield stress for reinforcement, psi
h Height of wall or panel, ft
Ier Moment of inertia of cracked masonry cross section, in.4
I. Effective moment of inertia, in.4
I. Moment of inertia of uncracked masonry cross section, in.4
Ix Moment of inertia of steel pier about the strong axis, in.4
j Ratio of distance between centroid of flexural compressive forces and centroid of tensile forces to depth
k Ratio of distance between compression face and neutral axis to distance between compression face and centroid of tensile forces
M Design moment, ft-lb
M. Nominal moment strength, ft-lb
Overturning moment, ft-lb
Moment due to spanning between piers, ft-lb
Moment induced by Mpx due to plate effects, ft-lb
Resisting moment, ft-lb
Ultimate moment strength, ft-lb
Moment due to spanning between caissons, ft-lb
Elastic moduli ratio, Ex/Em