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Seismic Damage 1

EARTHQUAKE STRUCTURAL DAMAGE

Dr. Ahmed Tarabia

Damage types

Structural

elements

Non structural

elements

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Seismic Damage 2

• 1- due to ground movements and soil changes.

• 2- Damage due to building shape or dimensions

• 3- Damage due to structural elements.

Main causes of structural damage

Landslides

Ground liquefaction

Seismic sea waves (Tsunami’s)

Fault movements.

Due to ground movements and soil changes.

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Seismic Damage 3

Ground Liquefaction: Niigata, Japan 1964 (Mag. – 7.5)

Ground Liquefaction:

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Seismic Damage 4

Faults movements

Damage due to building shape or dimensions

• 1- Soft story failure.

• 2- Short column failure.

• 3- Torisonal failure.

• 4- Pounding ( تصادم المباني )

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Seismic Damage 5

Soft story failure

1- Shows a significant decrease in lateral stiffness from that immediately above. How:

- Height of this floor is higher than the rest of floors. - Change of section that reduce the stiffness. - Removing of infill walls

Soft Story: one floor has less stiffness than the adjacent floors

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Seismic Damage 6

Soft story failure case

5th floor restaurant Open structure Stories above and below have more support

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Seismic Damage 7

:العمود القصير ينتج من مجموعة من االعمدة الحد األدوار

الطول الخالص لبعض االعمدة أقصر من باقي األعمدة مما يزيد -1

.من الكزازة و بالتالي يزداد القص المؤثر على العمود .يتم عالج ذلك عن طريق زيادة تسليح القص و تكثيف الكانات

Short Column failure

Short Column failure

Failure of short columns due to : increasing stiffness: -Less clear height of column.

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Seismic Damage 8

Short Column failure

Clear height

Torisonal failure.

The center of rigidity is not coincided with the force center

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Seismic Damage 9

Torisonal failure.

Torisonal failure.

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Seismic Damage 10

Pounding

If the distance between two buildings are very small, they may collide with each other during earthquake. The forces due to collision is ver high. To prevent this damage:

• You must leave a minimum separation distance.

• Design the two building for these forces.

• Add special walls to resist this force.

Pounding failure.

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Seismic Damage 11

• 1- Column failure.

• 2- Beam failure.

• 3- Beam-column failure.

• 4- Shear wall failure.

Damage of structural elements

1- Column failure.

Buckling of longitudinal steel due to large spacing of stirrups.

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Seismic Damage 12

1- Column failure.

Using confinement in columns

Confined with spiral stirrups

Using separate stirrups with large spacing

1- Column failure.

Bond failure at the lap splice joint

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Seismic Damage 13

1- Column failure.

Bond failure :Short length of column extension in the beam

1- Column failure.

Bond failure at the lap splice joint

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Seismic Damage 14

1- Column failure.

Failure of the stirrup hook.

1- Column failure. Shear failure of column

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Seismic Damage 15

2- Beam failure. Buckling of beam reinforcement

Shear failure of beam

2- Beam failure.

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Seismic Damage 16

splice failure of beam

2- Beam failure.

3- Beam-Column Joint failure.

• Longitudinal beam bars not confined within column longitudinal bars or ties

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Seismic Damage 17

3- Beam-Column Joint failure.

No intermediate ties in joint normal to outside face of joint

3- Beam-Column Joint failure.

-No transverse reinforcement through joint

-Insufficient anchorage for hooked bars

-Widely spaced ties outside of joint

-No intermediate ties in column

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Seismic Damage 18

4- Shear Wall failure.

Shear failure of wall

4- Shear Wall failure.

Sliding Shear failure of wall

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Seismic Damage 19

Non structural damage.

Non structural damage.

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Seismic Damage 20