Masonry Magazine December 1994 Page. 13
The development of design aids in the form of design tables, manuals and computer programs is also a challenge for load-bearing masonry. Researching the structural properties and performance of masonry is another challenge; however many of the fundamental principles of structural behavior and performance have been documented.
Researching more effective construction methods, including materials handling, and placement of units, mortar, grout and reinforcement, as well as advancements in the materials themselves, are also challenges.
Continuing evaluation of building code criteria and the need to maintain state-of-the-art masonry codes and standards creates another challenge.
Attributes of loadbearing masonry
Structural masonry is ideally suited to loadbearing construction because of its inherent compressive strength, stiffness and shear strength. The masonry shear wall is a multi-functional structural element which supports vertical loads of the building's dead weight as well as live loads due to occupants, furnishings and equipment. The shear wall also provides lateral stability in resisting horizontal forces acting on the building due to wind pressure or horizontal ground movements due to earthquakes.
Frame systems also provide these structural functions, however only shear wall systems combine strength and stiffness to limit deformations which allows other building components, as well as occupants, to function without interruption or distress.
The shear wall may also serve as an exterior envelope enclosing the building and providing a barrier to the elements, including resistance to rain penetration, and a thermal barrier. The shear wall may also serve as an interior wall separating living spaces and providing a barrier to the spread of fire, and noise and providing privacy. In addition to providing a barrier to the spread of fire, masonry is noncombustible so that it does not contribute fuel in the event of a fire.
One Room to Another
■ Exterior Walls Resist Heat Transmission through Insulation and Thermal Mass
■ Exterior Walls Resist Rain Penetration
■ Exterior Walls Maintain Attractive Appearance
■ Exterior Walls Resist Effects of Weathering
GROUT SPACE REQUIREMENTS
| Grout type | Maximum grout pour height, ft. | Minimum width of grout space, in. | Minimum grout space dimensions for grouting cells of hollow units, in. x in. |
| ----------- | ----------- | ----------- | ----------- |
| Fine | 1 | 3/4 | 112x2 |
| Fine | 5 | 2 | 2x3 |
| Fine | 12 | 212 | 212x3 |
| Fine | 24 | 3 | 3x3 |
| Coarse | 1 | 112 | 112x3 |
| Coarse | 5 | 2 | 212x3 |
| Coarse | 12 | 212 | 3x3 |
| Coarse | 24 | 3 | 3x4 |
Loadbearing construction
Construction of loadbearing masonry typically requires a greater commitment to planning, which results in reduced construction time. The fact that structural framing is eliminated means that fewer trades are required and equipment for erection of the frame is eliminated. Through coordination of loadbearing construction, masonry crews can work simultaneously with crews erecting floors and roofs.
Precast plank floors are particularly popular in multi-story construction because they are relatively easy to place and position, and once in place they provide a platform for construction on the next level. Furthermore, multi-story loadbearing construction allows other trades to work simultaneously on lower levels while masonry crews work on upper levels. Working off the floor platform reduces scaffolding cost and increases mason productivity.
These multi-function attributes of shear walls should be considered by each member of the design team when comparing alternative systems. It is not just a comparison of shear wall cost vs. frame cost. The comparison should include these additional non-structural functions of the masonry shear wall system.
Attributes of the masonry shear wall system
■ Vertical Force Resisting System (Gravity Dead and Live Load)
■ Vertical Force Resisting System (Earthquake and Wind Loads)
■ Barrier to the Spread of Fire (Fire Resistive Construction)
■ Non-combustible (Does not contribute fuel to a fire)
■ Stiffness Lateral Force Resisting System (Limits Story Drift)
■ Interior Walls Isolate Noise from
TOLERANCES FOR PLACING REINFORCEMENT
(A) In Walls and Flexural Elements:
± 12 in. when d≤8 in.
± 1 in. when 8 in. ± 114 in. when d° > 24 in.
(B) Location of Vertical Bars Along Length of Walls:
2 in. from location indicated on project drawing
*d distance from centerline of steel to opposite face of masonry
Reinforced masonry construction
Advances in reinforced masonry construction methods have resulted in more viable applications for reinforced.