(Abbott, pp. 97-107, 145-148)
Preparing for Earthquakes in Urban Areas
As the world's human population continues to increase, more homes are being built in
areas that are prone to severe earthquakes.
Figure 7.1 (p. 162) shows an earthquake risk
map of the contiguous United States.
The problem of urbanization in earthquake-prone
areas is especially serious in California.
Buildings with lower floors that contain abundant windows and parking garages are
especially susceptible to collapse during earthquakes (p. 131; Figure 4.26, p. 97; Figure
4.28, p. 100).
Information on p. 99 in your textbook provides some advice on how to
make a home more earthquake resistant.
Masonry and brick are very rigid and tend to
crack and collapse during earthquakes. Wood flexes more during earthquakes than brick
or masonry, and is more earthquake resistant.
Steel has great strength under tension, but
can collapse under compression (p. 102).
Earthquake resistance can also be enhanced by
using plywood in homes and diagonal braces, frames and
in larger buildings
(Figure 4.37, p. 106; Figure 4.33, p. 103; Figure 4.34, p. 104).
Walls and roofs should be
bolted to each other and the buildings should be secured to their foundations (p. 102-103;
Figure 4.31, p. 103; Figure 4.37, p. 106).
For concrete structures, the 1994 Northridge
California earthquake demonstrated that previous building codes were often inadequate in
severe earthquakes (Figure 4.32, p. 103; Figure 4.29, p. 101; Figure 6.24, p. 147).
example, reinforcing concrete pillars with steel rods was not enough (Figure 4.36a, p.
105; Figure 6.26, p. 148).
Support pillars for buildings, overpasses, and bridges should
also be wrapped in steel jackets to prevent failure during earthquakes (Figure 4.36b, p.
Breaking glass can also shower onto victims.
Safety glass, like what's used in cars
and trucks, is better in the buildings of earthquake-prone areas.
Making Buildings More Resistant to Earthquakes