1. Masonry Bearing Walls

2. Masonry walls may either be
Load-bearing wall or
Non-load-bearing walls.

3. Masonry infill occupies the space between the frame members.
It used to resist the racking of the frame that is, to serve as a shear wall.

4. Advantages of a Masonry Bearing Wall Building
A load-bearing wall is a wall that supports gravity loads in addition to its self-load. It may also act as shear walls. Major advantages of a load-bearing masonry structure are:
The walls that are required for load-bearing purposes
Function as shear walls
To enclosing and dividing spaces.

5. Traditional Masonry Bearing Wall Construction
The masonry bearing wall design was based on arbitrary rules formulated on an intuitive rather than a scientific basis. The rules required the thickness of exterior masonry walls to increase progressively toward the lower floors. The increase in wall thickness was necessary
To accommodate greater gravity loads at the lower floors.
Another important reason for progressively increasing wall thickness at the base was to ensure stability against overturning by wind loads.
The code-required thickness was based on the assumption that all wind loads on the building were resisted by exterior walls only. In providing this resistance, each exterior wall functioned as a freestanding wall, behaving as a vertical cantilever fixed in the ground like a flagpole

7. Importance of Vertical Reinforcement in Masonry Walls
Masonry walls without vertical reinforcement are referred to as plain- masonry walls, and those with vertical reinforcement are called reinforced-masonry walls.
The benefits of reinforced masonry over plain masonry are as follows:
• Reinforcement increases the strength of a wall against bending caused by (a) eccentric gravity loads on the wall and (b) lateral loads perpendicular to the wall, Figure 4.

9. Reinforcement increases the sliding resistance of the wall to in-plane lateral loads reducing horizontal displacement between floors. Additionally, it provides positive anchorage between the wall and the foundation.
• Reinforcement helps to resist the tension caused by overturning of the wall, Figure 6.

11. Bond Beams in a Masonry Bearing Wall Building
In masonry structures, the floors consist of precast concrete hollow-core slabs, metal deck, or wood deck. Being individual elements, they do not have the continuity to resist diaphragm tension. Therefore, they are anchored to masonry beams called bond beams.

12. Some architects and engineers prefer to use site-cast reinforced-concrete bond beams, Figure 9, which are more robust than masonry bond beams.

13. Wall Layout in a Bearing Wall Building
For a multifloor bearing wall structure, a wall layout in structure is best achieved when the walls at an upper floor are at the same location as the ones on a lower floor, resulting in repetitive floor plans

14. The discontinuity of walls at foundations, referred to as a soft story, is structurally feasible but requires a heavy transfer structure. The transfer structure carries the superimposed gravity loads and provides the required lateral load resistance. A soft story is particularly problematic in seismic zones.

15. Floor and Roof Decks— Connections to Walls
The structural integrity of a bearing wall building depends on the connections between the walls and the floor or roof decks. Gravity load from the floor or roof deck to the wall
Out-of-plane shear between the wall and the floor or roof deck
In-plane shear between the wall and the floor or roof deck

19. Water -Resistive Exterior Finish Required
Bearing walls require some form of weather-resistive exterior coating (clear coating or paint), plaster, or some form of cladding to prevent water from entering the interior. Exterior walls in traditional masonry structures did not require such cladding because their thickness made them inherently water resistive.

20. Bearing Wall and Column-Beam System
Although masonry bearing wall construction is most suited for mid-to high-rise residential occupancies, it is also well suited to low-rise building types. Chief among them are school and college buildings, offices, shopping centers, and religious buildings. However, such buildings generally consist of a hybrid construction system, in which all exterior walls are masonry bearing walls and the interior structure is a combination of masonry bearing walls, drywall partitions, and a column-beam frame. The lateral load resistance is generally designed into the masonry walls.

21. The column-beam frame may consist of cast-in-place concrete or steel
The column-beam frame may consist of cast-in-place concrete or steel. Concrete is better suited because both concrete and concrete masonry have similar properties, causing few differential-movement problems. However, a steel frame is generally more economical and is, therefore, widely used. Differential-movement problems between steel columns and masonry walls must be considered; they are generally more easily managed in low-rise buildings.

22. Figure shows a typical building that combines load-bearing masonry with a steel frame.

23. Thank u