Reducing the Impact of Earthquakes

Reducing the Impact of Earthquakes

1. Planning

   • Forecasting the likely number and magnitude of future eathquakes.
   • May ban buildings from fault lines, areas of alluvial deposits which may suffer liquefaction, and areas liable to landslides
   • Plan emergency procedures when earthquakes happen

2. Building Design

   • Too expensive to completely prevent damage to buildings.
   • Designed to protect people from total collapse, falling structures and broken glass.
     • Wooden sturctures are flexible and accept a certain amount of strain.
     • Steel-reinforced concrete is safer than bricks and masonry for larger buildings.
     • Foundations reinforced by pumping liquid cement into network of micropiles drilled into ground.

3. Ground or base isolation systems

   • Building rests on large rollers, rubber pads, springs or sliders coated with non-stick Teflon
     • Inertial mass of building keeps it stationary while ground moves beneath, or allows building to move without damage.
     • Older buildings can have this system inserted for future protection (Utah State Capitol)

4. Resisting shear forces

   • Each part of the structure is connected to other parts to prevent collapse.
     • Diagonal bracing by cables or rigid girders strengthens framework.
     • Floors are fixed to walls to add rigidity and prevent pancaking.
     • Shear walls (extending full height of the building) add rigidity

5. Absorbing sway

   • Tall buildings are designed to sway, absorbing energy through flexible supports and materials (rubber)
   • Hydraulic systems, (sometimes computer controlled) dampen the movement, like shock absorbers in cars
   • Flexible connections between different parts of buildings can help to counter movements

6. Services

   • Broken gas mains and power lines can cause fires, and fractured water mains prevent fire being put out.
     • Use flexible piping for movement