This presentation gives a brief idea about how earthquake resistant structures are made, using the materials like timber and steel. You might feel there are only pictures in the presentation, but they are enough to understand the process. if need further help, feel free to contact. :) 07972923439.

1. Earthquake Resistant Designs
Skeletal Structures : Timber and Steel.

3. Basic terms:
• Rigidity: The physical property of being stiff and resisting bending.
• Ductility: It is defined as the ability of a structure to undergo inelastic
deformations beyond the initial yield deformation with no decrease in the load.
• Bracings: A structural member used to stiffen a framework.

4. Classification of structures:
• The MSK scale addressed the issues of assessment of earthquake damage in modern buildings.
The did so using the following principles:
• Building Type.
• Construction Materials used for the lateral load resisting system.
• In this, building type was used as a simple analogue for vulnerability.
• The MSK scale defined building classes by type of construction generally to express vulnerability.
The EM has actually classified the building types into 6 categories (A-F) in decreasing vulnerability.
This is a very complicated classification and very lengthy, so I will just show the basic rules:
• Classes A – B – C. represent: Adobe House, Brick Buildings and Reinforced Concrete constructions.
• Classes D – E. represent: buildings with an element of Earthquake Resistant Design (ERD) and also
for WELL BUILT TIMBER, reinforced or confined masonry, and steel buildings.
• Class F represents: Resistant design. i.e. a structure of the highest earthquake resistance, due to the
incorporated design principles.
• The lowest level and therefore the type of building which would suffer most damaged would be
buildings without ERD both engineered and non-engineered constructions.
• The second level are buildings with ERD. These buildings may include masonry construction,
reinforced concrete or steel. Inc. Retro-fitted property.

5. Guidelines:
 The following points are be considered undesirable:
• Heavy Roof systems
• No flexibility of materials during earthquake
• Unable to return to original shape after shaking
• Large window/door openings in Stone/Masonry/R.C.
• Weak non-mechanical joints in materials
• Weak horizontal elements.
• Timber frame structure is not affected by any of the above if built to the correct specifications.
This is a very brief explanation of a very complex subject but you are safe to advise clients that
on information known – Engineered Timber Frame construction with ERD is acknowledged as
the safest form of building in an Earthquake.

6. Timber

7. • This is also most common type of construction in areas of high seismicity.
• It is also most suitable material for earthquake resistant construction due to its light
weight and shear strength across the grains.
• Wood frames without walls have almost no resistance against horizontal forces.
• Resistant is highest for diagonal braced wall.
• Buildings with diagonal bracing in both vertical and horizontal plane perform much
better.
• Wood houses are generally suitable up to two storeys.
About timber construction:

22. Steel

23. Basic terms:
Ductility:RESISTANCE CAN BE INCREASED IN A SECTION BY:
1. Decrease the percentage of tension steel (pt).
2. Increase the percentage compression steel (pc).
3. Decrease in the tensile strength of steel. (Fy=415N/mm^2).
4. Increase in the compressive strength of concrete.-Min M20 to M30 and above.
5. Increase in the compression flange area in flanged beams (T and L beams) and
6. Increase in the transverse (Shear) reinforcement.
• Bracings: A structural member used to stiffen a framework.
• Dampers: A tuned mass damper, also known as a harmonic absorber, is a device
mounted in structures to reduce the amplitude of mechanical vibrations. Their
application can prevent discomfort, damage, or outright structural failure. They
are frequently used in power transmission, automobiles, and buildings.

36. Key elements:
1. Steel sections , frame.
2. Steel Braces.
3. Dampers.
4. Base isolation.

40. The building must be well connected to a good
foundation and the earth. Wet, soft soils should be
avoided, and the foundation must be well tied together,
as well as tied to the wall.
Structures should not be brittle or collapse suddenly. Rather,
they should be tough, able to deflect or deform a considerable
amount
Resisting elements, such as bracing or shear walls, must be
provided evenly throughout the building, in both directions
side-to-side, as well as top to bottom.
All elements, such as walls and the roof, should be tied
together so as to act as an integrated unit during earthquake
shaking, transferring forces across connections and preventing
separation.
Care must be taken that all materials used are of good
quality, and are protected from rain, sun, insects and
other weakening actions, so that their strength lasts.
Unreinforced earth and masonry have no reliable
strength in tension, and are brittle in compression.
Generally, they must be suitably reinforced by steel or
wood.
General Principles of structural action, mechanism of
damage and modes of failure of buildings :