EarthquakeEngineering

What is the Damage

Quakes can cause?

Direct EffectsGround failures:• Vibration of soil• Fault rupture• Liquefaction• Ground lurching• Differential settlement• Lateral spreading

Indirect Effects• Tsunamis• Seiches• Landslides• Floods• Fires• Release of

hazardous material

What is earthquake

engineering?

Earthquake Engineering

It is a branch of engineering devoted to prevent earthquake hazards and its after effects

Why is there Earthquake

Engineering?

• Quakes demonstrated they destroy cities and people faster than Brandon can.

Basic Goals• To prevent

non-structural damage, structural damage and collapsing of buildings in earthquakes

Quiz

1.What is earthquake engineering?

It is a branch of engineering devoted to prevent earthquake hazards and

its after effects

Now do you want

earthquake safe

buildings?

Seismic Retrofit!

Seismic Retrofit brings older buildings/structures up to more

current seismic standards without having to completely rebuild them.

Sliding

• Old structures may not be strongly bolted into the foundation

• Corrosion weakens attachments

• These structures could be bolted to the foundation.

Weak Foundation

Shock Absorbers• A device for

reducing the effect of a sudden shock by the dissipation of the earthquake’s shock energy

Base IsolationAllows the ground to move while

the building remains in place.• This method

allows a building to move

Isolation• Isolation pads

are used to let the ground shake, but have the building not move

Dampers

• Converts the energy of motion in a building into heat.• Are for buildings rigidly attached to the ground; will protect from resonance

vibrations.

• Wall composed of braced panels

• Flexible

• Counters the effects of swaying on a structure

• Shorter buildings can resist seismic forces.

• Instead of adding stories, expand the first floor of your home.

• Water in tank sloshes back and forth during an earthquake

• Prevents resonance in buildings

• Extra heat in building is absorbed

Tuned Mass Dampers

• A device mounted in structures to prevent damage or outright structural failure by vibration.

• Stone veneer or cement

• More resistant to earthquakes so crack easily

• Use other lighter materials to replace

Reinforcement

• Exterior concrete columns

• Infill shear trusses

• Massive exterior structure.

• It is not beautiful but it works.

Quiz-y!

2. What is seismic retrofitting?

Quiz-y!

3. At what college are the dorms reinforced?

UC BERKELEY!!!

Time for SEISMIC DESIGN!

Everyone smile because it’s so exciting!

Traditional Seismic Design

• Lower stories are stronger than upper stories, meaning it is more prevalent to reinforce taller buildings and higher stories.

Quiz-y!4. What is traditional

seismic design?Lower stories are stronger than

upper stories, meaning it is more prevalent to reinforce taller buildings and higher stories.

Floor Diaphragm• Wooden building floors are made on joints

to prevent beams from tipping.

Sliding Off Foundation

• Older homes can be bolted to their foundation to prevent major damage in an earthquake.

BRIDGERetrofits

Hot Rivet Replacement

• The rivet was replaced with a heat-treated high-strength locator bolt and nut

Lattice Beam Conversion

• Beams were replaced with bolted steel plates. Also, face plates were added to the large diagonal beams

Diagonal Reinforcement

• Diagonal box beams are added to the upper and lower decks of the bridges

Expansion Rockers

• allow the bridge expand and contract with temperature changes

Bay Bridge Structure

• During the October 17, 1989 Loma Prieta earthquake (7.1 on the Richter Scale). A 50-foot section of the bridge collapsed.

Bay Bridge Retrofit!

•the strengthening of bents and columns on the east viaduct and the piers, bents, and trusses

Fill & Overpass

• Elevated roadways are built on sections of elevated earth supported with vertical columns

ROADS!

•Soil is tested to see if it can hold weight, then asphalt is added

Cypress Freeway Viaduct Collapse

During the Loma Pieta Earthquake, the Cypress Structure collapsed. This

roadway was not properly reinforced. After the quake the structure was

removed and a new roadway was built.

Overpasses

• Pillars:– Spiral steel

girders support columns and prevent bending of steel rods in the highway

Construction of Pillars

• Add size and weight to bridge’s footing

• Anchor with metal rods (pilings)

• Jacket of steel around column

• Thick cables help hold together

Top: Bridge Components

Left: Cable System

OMG! It’sUNDERWATE

R TUBES!It makes you all giddy!

Underwater Tubes Safety

• depend on soil conditions, the materials used, and the maximum predicted earthquake expected.

BART! yay!

• BART trans-bay tube was constructed at the bottom of San Francisco Bay

What does BART have?

• two inner tunnels• a central tunnel• an outer oval shell

encompassing the three inner tubes

Quiz!5. _____ trans-bay tube was

constructed at the bottom of San Francisco Bay.

BART! [gasp!]

THE END