This document summarizes Indian Standard IS 4326:1993, which provides guidelines for earthquake-resistant design and construction of buildings. It covers terminology, general principles, special construction features, types of construction, categories of buildings, and masonry, timber, and precast construction. For masonry, it specifies use of strong materials and mortar, wall thickness, reinforcement, and strengthening with horizontal bands and vertical dowels. Vertical reinforcement is also required at wall corners and junctions.

1. PRESENTED BY:-
ER. DIVYA
VISHNOI
IS 4326:1993 (SECOND REVISION)
EARTHQUAKE RESISTANT
DESIGN AND
CONSTRUCTION OF
BUILDINGS- CODE OF PRACTICE

2. SCOPE:-
 This standards deals with the selection of
materials, special features of design and
construction for earthquake resistant buildings
including masonry units timber construction and
buildings with prefabricated flooring/roofing
elements.
 Guidelines for earthquake resistant building
constructed using masonry of low strength and
earthen buildings are covered in separate.

3. DESCRIPTION OF CODE:-
 TERMINOLOGY
 GENERAL PRINCIPLES
 SPECIAL CONSTRUCTION FEATURES
 TYPES OF CONSTRUCTION
 CATEGORIES OF BUILDINGS
 MASONRY CONSTRUCTION WITH
RECTANGULAR MASONRY UNITS
 FLOORS/ROOFS WITH SMALL PRECAST
COMPONENTS
 TIMBER CONSTRUCTION

4. TERMINOLOGY:-
 SEPERATION SECTION
 CENTRE OF RIGIDITY
 SHEAR WALL
 SPECIAL FRAME
 BOX ACTION
 BAND
 SEISMIC ZONE& SEISMIC COEFFICIENT
 DESIGN SEISMIC COEFFICIENT
 CONCRETE GRADE

5. GENERAL PRINCIPLES(CLAUSE 4.0)
 LIGHTNESS
 CONTINUITY OF CONSTRUCTION
 PROJECTING & SUSPENDED PARTS
 BUILDING CONFIGURATION
 STRENGTH IN VARIOUS DIRECTION
 FOUNDATION
 DUCTILITY
 FIRE RESISTANCE

6. SPECIAL CONSTRUCTION FEATURES
(CLAUSE 5.0)
 SEPERATION OF ADJOINING STRUCTURES
 SEPERATION OR CRUMPLE SECTION
 FOUNDATION
 ROOF & FLOORS
 STAIR CASE

7. TYPE OF CONSTRUCTION(CLAUSE 6.0)
 FRAMED CONSTRUCTION
 BOX TYPE CONSTRUCTION

8. CATEGORIES OF BUILDINGS(CLAUSE
7.0)

9. MASONRY CONSTRUCTION WITH RECTANGULAR
MASONRY UNITS(CLAUSE 8.0)
 1. MASONRY UNIT:-
 i) For earthquake resistant buildings, well burnt bricks and
solid concrete blocks having crushing strength not less than
3.5 MPA should be used.
 ii) Squared stone masonry, stone block masonry as per
is:1597(part-2):1992 may also be used

10. MASONRY CONSTRUCTION WITH RECTANGULAR
MASONRY UNITS(CLAUSE 8.0)
 2. MORTARS:-
 i) Since tensile and shear strength are important for earthquake
resistance, use of mud or very weak mortar is not suitable. A mortar
mix of Cement: Sand (1:6) by volume at least should be used.
 Ii) Where steel reinforcing bars are provided in masonry the bars shall
be embedded with adequate cover in cement sand mortar not leaner
than 1 : 3 (minimum clear cover 10 mm) or in cement concrete of grade
M15 (minimum clear cover 15 mm or bar diameter whichever more).

11. MASONRY CONSTRUCTION WITH RECTANGULAR
MASONRY UNITS(CLAUSE 8.0)
 WALL:-
 i) The thickness of load bearing wall should not be less than
190mm and wall length should not be greater than 15m.
 ii) The masonry bearing wall can be built up to a maximum
of four storeys.
 iii) The masonry bearing wall should be properly
reinforced.
 iv) The bearing wall should be straight and symmetrical in
plan in both directions.
 v) The wall panels should be checked for strength in
bending and shearing.

12. MASONRY CONSTRUCTION WITH RECTANGULAR
MASONRY UNITS(CLAUSE 8.0)
 4. Masonry Bond:-
 i) For achieving full strength of masonry, the usual bonds specified for
masonry should be followed.
 ii) the vertical joints are broken properly from course to course.
 iii) For having full bond between perpendicular walls, it is necessary to
make a slopping (stepped) joint by making the corners first to a height
of 600 mm and then building the wall in between them. Otherwise, the
toothed joint should be made in both the walls alternatively in lifts of
about 450 mm.

13. MASONRY CONSTRUCTION WITH RECTANGULAR
MASONRY UNITS(CLAUSE 8.0)
 Openings in Walls:-
 As openings in walls reduce their lateral load resistance and hence,
should preferably be small and more centrally located. The guidelines
on the size and position of opening are given in Table 4 of IS
4326:1993.
 Openings in any storey shall preferably have their top at the same level
so that a continuous band could be provided over them,
 If opening are not provided according to the codal provision, they
should be strengthened by providing reinforced concrete lining with
high strength deformed bar of 8mm diameter as shown in Fig. 8.
 If a window or ventilator is to be projected out, the projection should be
in reinforced masonry or concrete and tied together properly.
 The use of arches to span over the openings is a source of weakness and
shall be avoided.Otherwise, steel ties should be provided.

14. Seismic Strengthening Arrangements
 All masonry buildings shall be strengthened in
horizontal as well as vertical direction for improving
the earthquake resistance. The strengthening
arrangements are discussed in clause 8.4 of IS
4326:1993.
 1. Horizontal Reinforcement
 2. Vertical Reinforcement

15. Horizontal Reinforcement
 The horizontal reinforcing of walls is required for
imparting them horizontal bending strength against
inertia force. It also help in tying the wall together.
In the exterior walls horizontal reinforcement helps
in preventing shrinkage and temperature cracks. The
following arrangements of horizontal reinforcement
are necessary for earthquake resistant buildings.
 A) Horizontal bands or ring beam
 B) Dowel bars

16. Horizontal bands or Ring beams
 A band is reinforced concrete or reinforced brick
runner provided in the walls to tie them together and
to impart horizontal bending strength to them.
 i) Lintel Band
 ii) Plinth Band
 iii) Roof Band
 iv) Gable Band

17. Dowel Bars
 Dowel bars are provided in category D and E
buildings. These are provided to improve the box
action of walls. Steel dowel bars may be used at
corners and T-junctions of walls at the sill level of
windows to length of 900 mm from the inside corner
in each wall. Such dowel may be in the form of U
stirrups 8 mm dia. Where used, such bars must be
laid in 1 : 3 cement-sand-mortar with a minimum
cover of 10 mm on all sides to minimize corrosion.

18. Vertical Reinforcement
 Vertical steel at corners and junctions of walls, which
are up to 340 mm (brick) thick, shall be provided as
specified in Table 7 of IS4326:1993.
 For walls thicker than 340 mm the area of the bars
shall be proportionately increased. The amount of
vertical steel depends upon number of storeys and
category of building. No vertical steel need be
provided in category A buildings.
 The vertical reinforcement should be properly
embedded in the plinth masonry and roof slab or
roof band.

19. Vertical Reinforcement
 The vertical reinforcement should pass through the
lintel bands and floor slabs or floor level bands in all
storeys.
 Vertical reinforcement for window and door
openings should start from foundation of floor and
up to lintel band.
 Typical details of providing vertical steel in
brickwork masonry with rectangular solid units at
corners and T-junctions are shown in Fig. 12 of
IS4326:1993.