26-02-2013, 11:37 AM
A PAPER ON EARTHQUAKE RESISTANT STRUCTRE
EARTHQUAKE.doc (Size: 1.12 MB / Downloads: 102)
Introduction
The view that the safeguarding of a building against earthquake is solely the task of a structural engineer is not correct. An unfavorable architectural plan can often be only partly adjusted buy large dynamic calculations and dimensioning. A functional plan as well as good layout of construction details, are often more effective then extensive calculations.
Facilities constructed under the current provision of Building Code require that they be built to resist a specified minimum level of force that might be generated by an earthquake.
Prior to the implementation of building codes, buildings almost did not have the desired earthquake resistance. However the buildings constructed this minimum level of resistance could still experience considerable structural and non-structural damage. This is especially true considering that ground-shaking exceeding building code anticipated level might occur resulting in increase damage to all structures.
• Earthquake resisting structures – Necessity.
The vibratory motion caused by a earthquake to the mass of earth through which energy passes is transmitted to engineering structures standing on the earth’s surface
.The vibratory jolts due to earthquake cause additional shears and movements in the structures and may cause its failure if not otherwise designed properly. The loss of life and property directly occurs from the failure of structures and may also take place due to indirect causes such as failure of water supply, fire, flooding through dam failures, due so Tsunamis etc. hence it becomes customary to adopt earthquake resistant structures.
• Characteristics of earthquake resisting structures.
Majorities of building are constructed in brick, stone, mud or a combination thereof. These structures have fared poorly during earthquake and have suffered extensive damages, the main cause being heave mass and low or negligible tensile strength.
Strengthening the reinforced concrete.
The Strengthening of columns can be achieved by using cast in- situ concrete or short Crete and additional reinforcement. The large area of employment arises from the possible variation of Strengthening material concrete, and the use of different base material.
Strengthening with steel straps.
A Strengthening of reinforced concrete columns, ro brickwork piers, can be carried out with the help of steel straps. the steel components are welded together and fastened to the component to be reinforced with bolts, dowels or adhesive joints. The hollow space between coloum and steel corset is filled with non-shrink mortar grout.
Conclusion.
Earthquakes are one of the most destructive and disastrous forces that nature unleashes on the earth. They not only cause a loss of life and property but also shake the morale of the people. People who suffer a severe earthquake feel it as a nightmare for many years.
Since earthquakes are so far unpreventable and unpredictable the only coarse open to us is to design and build structures tin such a manner that the loss of property and life is minimized. Prevention taken prior to occurrence of earthquakes will definitely lead to “human welfare”.