The document discusses planning considerations for constructing earthquake-resistant buildings, highlighting vital aspects such as lightness, symmetry, regularity, block separation, simplicity, continuity, and building size. It emphasizes the importance of proper staircase design, water tank placement, and overall construction practices by qualified engineers to mitigate earthquake damage. Key structural features, material proportions, and safety measures are suggested to enhance the resilience of buildings against seismic activity.

1. Shantilal shah Engineering College,
Bhavnagar
Civil Engineering Department

2. Building & town planning
Topic:
planning of earthquake resistant building

3. Contents
 Introduction
 General Planning and Design Aspects
 Location of Staircase
 Water Tank
 Sensitivity of building

4. Introduction
 Today the world is facing the problem of natural calamities like
earthquakes, landslides and many other which harm the construction done
by us.
 Most of the loss of life in past earthquakes has occurred due to the collapse
of buildings constructed in traditional materials like stone, brick, adobe and
wood, which were not initially engineered to be earthquake resistant.
 Earthquake:
 A sudden movement of the earth’s crust causes by the release of stress
accumulated along geologic fault or by volcanic activity is called
earthquake.
 Earthquake damage depends on many parameters, including earthquake
ground motion characteristics (intensity, duration and frequency content of
ground motion), soil characteristics (topography, geologic and soil
conditions), building characteristics, and quality of construction, etc.
 Let us understand the concepts of reducing the effect of earthquake.

5. General Planning and Design
Aspects
1)Lightness:
Since the earthquake force is a function of mass, the building shall
be as light as possible. Heavier structure means large inertia force and
collapse of these structure result in heavier damage and and loss of lives.
Thus, roof and upper storeys of building, in particular, should be designed
as light as possible.

6. 2)Symmetry:
The building as a whole or its various blocks should be kept
symmetrical about both X and Y axes. Asymmetry leads to torsion during
earthquakes and is dangerous (see Fig). Symmetry, as far as possible, is
also desirable in the placing and sizing of door and window openings.

7. 3) Regularity:
Simple rectangular shapes (see Fig. 3.2 a) behave better in an earthquake than shapes with
projections (see Fig. 3.2b). Torsional effects of ground motion are pronounced in long narrow
rectangular blocks. Therefore, it is desirable to restrict the length of a block to three times its width. If
longer lengths are required two separate blocks with sufficient separation between should be provided
(see Fig. 3.2 c).
4) Separation of Blocks:
Separation of a large building into several blocks may be required so as to obtain
symmetry and regularity of each block. For preventing hammering or pounding damage
between blocks a physical separation of 30 to 40 mm throughout the height above the plinth
level will be adequate as well as practical for up to 3 storey buildings (see Fig. 3.2 c). The
separation section can be treated just like expansion joint or it may be filled or covered
with a weak material which would easily crush and crumble during earthquake shaking. Such
separation is more practical in larger buildings since it is less convenient in small buildings.

9. 5) Simplicity:
Ornamentation involving large cornices, vertical or horizontal cantilever projections, facia
stones and the like are dangerous and undesirable from a seismic viewpoint. Simplicity is the best
approach.
Where ornamentation is insisted upon, it must be reinforced with steel, which should be properly
embedded or tied into the main structure of the building.
6)Continuity:
The earthquake forces developed at different floor levels in a building need to be brought
down along the height to the ground by the shortest path; any deviation or discontinuity in this load
transfer path results in poor performance of the building.
Some buildings have reinforced concrete walls to carry the earthquake load to the foundation.
Building, in which these walls do not go all the way to the ground but stop at an upper level, are
liable to get severely damaged during the earthquakes.

11. 7)Size of the building:
Buildings of great length or plan area may not respond to
earthquakes in the way calculated. Buildings that are too long in plan may be
subjected to different earthquake movements simultaneously at the two ends,
leading to disastrous results. As an alternate such building can be broken into a
number of separate square buildings .
In tall buildings with large height –to-base size ratio (slenderness ratio > 4),
the horizontal movement of the floors during ground shaking is large, The more
taller a building, the worse the overturning effects of a an earthquake.
In buildings with large plan area like warehouses, the horizontal seismic
forces can be excessive to be carried by columns and walls.

13. Location of Staircase
 The staircases in structure may be vulnerable if not detailed properly.
When attached rigidity to the floors, the flights of the staircase act
like braces and cause damage.
 There are three types of stair construction:
 1)Separated staircase
 2) Built-in staircase
 3)Staircase with sliding joints

14. Separated Staircase:
 One end of the staircase rests on a wall and the other end is carried by columns
and beams which have no connection with the floors. The opening at the vertical
joints between the floor and the staircase may be either covered with a tread
plate attached to one sided of the joint and sliding on the other side, or covered
with some appropriate material which could crumble or fracture during an
earthquake without causing structural damage.
 The supporting members, columns, or walls are isolated from the surrounding
floors by means of separation or crumble sections. A typical example is shown in
figure.

15. Separated staircase

16. Built-in Staircase:
 When stairs are built monolithically with floors they can be protected
against damage by providing rigid walls at their stair opening. An
arrangement in which the staircase is enclosed by two walls, is given figure.

17. Built-in Staircase

18. Staircase with sliding joints:
 In case it is not possible to provide rigid walls around stair openings
for built in staircase or to construct separated staircases, the
staircase should have sliding joints so that they will not act as
diagonal bracing.

19. Water Tank
 Elevated water tank contain huge mass at height supported on columns or
circular RCC shaft. It is an example of single degree of freedom.
 As large mass is supported at height, centroid of mass will be higher. During
earthquake inertia force produced due to mass of water and earthquake
acceleration may cause overturning of the tank.
 Inertia force = mass * acceleration
∴ 𝐹 = 𝑚. 𝑎
 Higher the mass, more will be the inertia force acting on the water tank.
Attempts should be made to reduce the capacity of tank, i.e. mass of water.
 The columns or RCC shaft acts as stiffening member, providing stiffness
resistance during earthquakes.

20. Water Tank
 The location of water tank on roof slab should be carefully decide. It should be
centrally located on the building. Water tank on edge or corner of a building may
cause imbalance of mass, resulting in overturning of tank. For small residential
buildings, light weight PVC tanks are preferred to reduce mass of the building.

21. Sensitivity of building
 Construction work should be carried out by qualified civil engineer.
 Plan of building should be square or rectangle.
 Flat concrete roof is preferred.
 The thickness of wall should not be less than 230mm.
 The proportion of cement : sand mortar should not be weaker than
1:4.
 The total height of the building should not be exceed 15 m.
 Vertical reinforcement must be provided at corners of wall and at
door jambs.
 Site investigation must be carried out. Bearing capacity of soil should
be more than the required safe bearing capacity.
 Proper R>C>C bands should be provided at plinth level, lintel level,
caves level.

22. THANK YOU FOR BEARING
Presented By,
Roll No.1061-1070