This document discusses wind loads on structures. It describes how high velocity winds create low pressure areas that exert lifting and pulling forces on buildings. Wind load is classified as static or dynamic, with static wind causing elastic bending and twisting, while dynamic wind from gusts induces oscillations. Wind load analysis is used for structures over 10-30 meters tall. Design wind speed is calculated per IS code 875 using factors for probability, terrain height/structure size, and topography. The key effects of wind load are uplift, shear, and lateral loads.

1. Presented by:- Presented to :-
Praveen kumar Akash pandey sir

2. 1. INTRODUCTION
2. TYPES OF WIND LOAD
3. EFFECTS OF WIND LOAD
4. SOME BASIC QUESTIONS ON WIND

3.  Wind load is the load placed by the wind speed and it is
air density onto a building, with high velocity winds, low
pressure areas are created on the building which creates
section pressure. Some are so strong that they can pull of
the corner of a roof.
 The effect of wind on the structure as a whole is
determined by combined action of external and internal
pressures acting upon it .
 We can use wind load analysis the structure having more
then 10 to 30 meters.
 It is design as per IS code :875(part 3) -1987

4. 1. UPLIFT LOAD
2. SHEAR LOAD
3. LATERAL LOAD

5. Wind flow pressures that create a strong lifting effect, much
like the effect on airplane wings . Wind flow under a roof
pushes upward ; wind flow over a roof pulls upward.

6.  Horizontal wind pressure that could cause racking of walls
making a house tilt .

7.  Horizontal pushing and pulling pressure on walls that
could make a house slide off the foundation or overturn.

8. “Wind effects on structures can be classified as static and
dynamic .
Static :-
Static wind effect primarily causes elastic bending and
twisting of structure.
Dynamic :-
For tall , long span and slender structures a Dynamic
analysis of the structure is essential wind gusts cause
fluctuating forces on the structure which induces large
dynamic motions , including oscillations .”

9.  In the majority of structures , it is satisfactory to treat wind
as a static load . The factors which determine the proper
equivalent static pressure(p e) are best understood through
the following equation presented by Davenport (1960 ):
Pe = C S .C a .C g . q

10. C a = a coefficient depending upon nearby
topographic features
C g = a gust coefficient dependent upon the
magnitude of gust velocities and size of the structure
q = dynamic-pressure intensity ,given by
q =1/2 𝜌 𝜐h
2

11. 𝜌=air density
𝜐H = design wind velocity at height H

12. Design wind speed as per IS 875-1987
The design wind speed is obtained by multiplying the basic
wind speed(Vb) by the factor k1, k2, k3:
Vz = Vb k1 k2 k3
K1= probability factor
K2=terrain height and structure size factor
K3=topography factor