Effect of wind and earthquake on structures.pptx

Effect of wind and earthquake on structures.pptx

1. Effect of wind and earthquake on structures SHUBHANGEE KARMAKAR SEC-A SEM-4 TH YEAR-2 ND SUB- STRUCTURE SUB CODE- ARCH401

2. Effects of wind and earthquake on structures : The effects of wind and earthquakes on structures are significant and must be carefully considered during the design and construction of buildings and other infrastructure. Wind and earthquake forces both act as lateral loads on structures, causing them to sway and potentially experience damage. Buildings vibrate as a consequence of the ground shaking; damage takes place if the building cannot withstand these vibrations. Compressional waves and shear waves mainly cause high-frequency (greater than 1 Hertz) vibrations which are more efficient than low-frequency waves in causing low buildings to vibrate.

3. Vibration effects on Structures are subjected to Two types of Loads:  Static loads  Dynamic Loads Equation of Static Equilibrium F = K Y F - External Force K – Stiffness of Structure Y – Resulting Displacement The restoring Force ( KY) resists the applied force ground responds to P, S, and surface waves by moving in all directions. the motion can't be captured by a single  seismometer in one direction. three signals are received by the three components to reflect N-S, E-W, and up-down motion

4. Earthquake Motions ◦ Three components  Two Horizontal  Longitudinal (X) & Transverse ( Y)  One Vertical (Z) ◦ Vertical component  Add or subtract the gravity effect  Nor critical to structures ◦ Horizontal components  Inertia force & lateral displacement  Critical for structures performance  Need adequate load transfer path

5. The effect of wind load on structures: The effect of wind loads can result in a dynamic response of some structures, especially those which are tall or slender. Some factors which contribute to this action are buffeting, vortex shedding, galloping, and flutter. The term 'Wind Load' is used to refer to any pressures or forces that the wind exerts on a building or structure. There are actually three types of wind forces that would be exerted on a building. Uplift Wind Load : Uplift Wind Load is an upwards force of the wind that would affect roof structures or similar horizontal structures in a building, such as canopies or awnings. The wind flow under a roof structure pushes the roof upwards, the wind flow over the horizontal structure pulls the roof upwards. Shear Wind Load : Shear Wind Load is a horizontal pressure or force that can cause walls or vertical structural elements to tilt or crack, causing a building to tilt. Lateral Wind Load : Lateral Wind Load is another horizontal wind pressure that can make a structure move off its foundations or overturn.

6. Wind can cause various types of damage to the roof, walls, and foundation, as well as to structural components like trusses, beams, and columns. If an earthquake hits a populated area, it can cause massive amounts of structural damage. Ground shaking, surface ruptures, and liquefaction can cause buildings, roads, and bridges to become damaged or collapse. This can result in people becoming injured, or even causing death.