Construct Earthquake Resistant Buildings by Simple Means

The engineering science is continuing to advance in response to seismic threats. There have been significant breakthroughs in the field. However, most of them are very complex and require exceptional machinery. Not to mention, expensive as well. However, there are some simple ways to build a structure that will be resistant to earthquake damages up to a certain level.

In areas where seismic activity is not too harsh, we can utilize these techniques to same money and complexity but make the building resistant to seismic activities.

Structure Stiffness: The most traditional way to fight quakes is to use stronger materials to construct the building. Stiffer or heavier members can be used to fight the lateral forces generated during seismic activities. For special quake-proof structures, ACI codes prescribe at least 10” thick members.

Geometrical Absorption: The building can be planned in such a regular and special geometrical shape that it disperses the seismic forces evenly so that no particular member experiences excessive force. This naturally fares much better than a poorly-planned unsymmetrical building.

For existing buildings that are structurally asymmetrical, you can use seismic joints and expansion points in places where the forces are dispersed unevenly. Providing extra columns, shear walls, and framing can make the weaker section withstand the extra forces to a good level. Parking levels should have extra reinforced columns in order to negate the soft story effect.

Lateral Force Resistance: Using three types of lateral force resisting systems, we can try to negate much of the seismic forces. These are:

1. Moment Resisting Frame System: it is designed to resist all types of earthquake generated forces acting on the structure. They can be customized to fit the seismic activity scale of the region.

2. Building Frame System: these are designed to resist gravitational loads only, but they function excellently in that. A shear wall is added to resist the lateral forces acting on structure.

3. Dual Frame System: this is a combination of the above two systems. Shear walls along with moment resisting frames work excellently to fight off the vibrations and displacements from an earthquake. But, of course, they are more complex and costlier to build.

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Published By
Rajib Dey
www.constructioncost.co
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Method Statement For Column

To retain perfect line & location of columns/walls, the starter/kicker should be provided for each column & the location of shear walls, column wall hould be marked on raft/slab top to place starter/kicker.

The following points should be remembered :-

1. Starters should be made of 100 mm x 50 mm channel section.
2. Concreting of starter should start once verification of layout with required clearance from clients.
3. Column wall shutters/boxes should be 12mm thick film coated ply containing backing angles at the edges and flat at the center about 300C/C both ways. The lift for columns should normally have 2.4 m height but it may change as per requirement.

4. Vertical reinforcement bars and Stirrups should be arranged according to drawings & BBS verified by clients and duly secured with binding wire.
5. The reinforcement bars should be retained in exact location firmly from sway with proper scaffolding arrangement.
6. There should be exact cover to the reinforcement with sufficient numbers of concrete cover blocks.
7. Column shutters should be constructed perfectly to line and plumb and there should be sufficient supports to retain the same in exact location during & after concreting.
8. There should be exact staged platform for concreting.

9. Concrete pour card should be formed depending on the sanctioned format and maintained for each pour duly signed by the client.
10. Columns have to be poured in layers of 300 mm thick and each layer is to be vibrated properly.
11. There should be sufficient numbers of skilled and unskilled manpower to take delivery of the concrete.
12. In night work, there should be perfect arrangements for lighting.
13. Construction and expansion joints should be arranged and treated as per instructions/specifications.

14. Any loose deposited concrete should be eliminated & discharged.
15. Hessian cloth should be provided and covered around the column/wall for retaining the component soaked for at least of 14 days.

De-shuttering should be executed after 12 hours/24 hours upon completion of casting of individual pours according to technical requirements and codal provisions.

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Published By
Rajib Dey
www.constructioncost.co
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