This document discusses earthquake resistant design of masonry buildings. It provides general principles for earthquake resistant structures, including using materials that are not brittle and will resist sudden collapse. It describes various construction systems for masonry, such as unreinforced, reinforced, and confined masonry. Key elements like walls, lintels, floors, and roofs are discussed. Design considerations include using uniformly distributed walls, adequate foundations, reinforced partitions, and limiting spans of cantilever slabs. Overall, masonry buildings can perform well in earthquakes if built with good quality materials and construction according to these design principles.

1. EARTHQUAKE RESISTANT BUILDINGS
(MASONRY)
Prepared by:
Raghwinder
2nd Year (Civil)
150107082

2. Introduction
Earthquake Resistant Structures
• Designed to withstand earthquake
• Can’t be entirely immune to damage
• Prevents collapsing
• Limited loss of functionality
Masonry
• Most important construction method
• Can resist loads and environmental impact
• Fire resistant, Durable, Thermal capacity

3. General Principles
• Shouldn’t be brittle or collapse suddenly
• Resisting Elements
• Tied together
• Good foundation
• Good quality material
• Suitably reinforced

4. Cause of Earthquake
Seismic waves
When pieces of crustal rock suddenly slip and move, they release enormous
amounts of energy, which then propagates through the crust as seismic waves.
• P waves
• S waves

5. Design Philosophy
• Under minor but frequent shaking, the main members of
the buildings that carry vertical and horizontal forces
should not be damaged; however buildings parts that do
not carry load may sustain repairable damage.
• Under moderate but occasional shaking, the main
members may sustain repairable damage, while the other
parts that do not carry load may sustain repairable
damage.
• Under strong but rare shaking, the main members may
sustain severe damage, but the building should not
collapse.

6. Methods of Earthquake Resistant Design
Base Isolation
Energy Dissipation Devices

7. Designing Masonry Buildings
Masonry has been popular through the ages for its fire
resistance, its thermal capacity and its durability.
Use of strong mortars, high strength masonry, added
reinforcement, improved detailing and the
introduction of good anchorage between masonry
walls and floors and roofs have enhanced the
resistance of masonry to seismic stress.

8. Masonry Materials
Masonry Units
Mortar
Concrete Infill
Reinforcing Steel
Figure: Typical bed joint reinforcement

9. Construction Systems
Unreinforced Masonry
Reinforced Masonry
1. Reinforced hollow units masonry.
2. Reinforced cavity masonry.

10. Confined Masonry
This is a construction system where masonry structural walls are
surrounded on all four sides with reinforced concrete.
Figure: Methods of confining masonry

11. Walls
• Walls are to be uniformly distributed along each principal axis of
the plan.
• The minimum thickness of structural walls should be 240 mm. The
total cross-sectional area of structural walls along each of the two
axes should not be less than 3% of the gross floor area.
• Adequate foundations and good anchorage between walls and
floors are essential.
• Distances between structural walls of reinforced masonry should
not be more than 6m; distances in confined masonry should not
be more than 8m.
• Partitions should be reinforced with 6 mm ø bars placed at the bed
joints with vertical spacing of 600 mm in order to prevent their
out-of-plane instability.
General Principles

12. Lintels
Lintels should have a minimum of 250 mm bearing length at both ends to
prevent local collapse due to crushing of supports during an earthquake. The
width of a lintel should not be less than150 mm.
In the case of openings larger in
area than 2.5 m2, the lintel
should be anchored to the tie
columns as shown in Figure (a)
If the distance between top of lintel
and underside of beam above is less
than 60 cm, the two should be
united as shown in Figure (b).

13. Floors and Roofs
During earthquakes, floors and roofs should act as rigid horizontal
diaphragms, which distribute the seismic forces among structural walls
in proportion to their stiffness.
Tie Beams
The function of tie beams is to transfer horizontal shear induced by the
earthquakes from the floor and roof to the structural walls. They
connect the structural walls with each other and improve the rigidity of
the horizontal diaphragms.

14. Cantilever Slabs and Overhangs
These elements can cause harmful vertical vibration during heavy
earthquakes. To reduce this, spans should not exceed those shown on
Figure below.

15. Concluding Remarks
Masonry buildings have performed well in several earthquakes worldwide. This
construction practice is widely used in many countries and regions for the
following reasons:
 It is based on traditional construction practice;
 It does not require highly qualified labour (as is the case with RC frame
construction);
 It has a broad range of applications - it can be used for single-family
houses as well as for medium-rise apartment buildings.
Good earthquake performance is based on the following premises:
 Use of good quality materials,
 Good quality concrete and masonry construction, and
• Simple architectural design.

16. Thank
You