TheBuildingChallenge
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F E M A
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E I S M I C
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L E U T H S
4.5
VOCABULARY
Braces, or Bracing:
structural elements built
into a wall to add
strength. These may be
RA T I ONA L E
A model structure can demonstrate the effects of diagonal bracing,
shear walls, and rigid connections on a building’s ability to carry loads
similar to those created by an earthquake.
F OCU S QU E S T I ON S
How can you design and build a model structure to carry vertical and
horizontal loads?
OB J E C T I V E S
Students will:
1. Use diagonal bracing, shear walls, and rigid connections to provide
load paths in a structure.
2. Design and build a structure that will carry both vertical and
horizontal loads caused by ground shaking.
3. Measure the magnitude of the shear force or horizontal load a
structure can carry.
MA T E R I A L S
for each small group (SET)
Q
Structures from Lesson 4.1
Q
20 Styrofoam sticks, 2.5 cm x 2.5 cm x 15 cm, precut in preparation
for lesson 4.1
Q
3 pieces of string, each 30 cm long
Q
10 paper clips
Q
20 toothpicks
Q
Any materials from Lesson 4.4 that students want to use
Q
1 square of tag board, 17.5 cm x 17.5 cm (about 7 in. square), to act
as a shear wall
Q
2 right triangles of tag board, cut from a 6-cm square, to act as rigid
connections
made of various materials and
connected to the building and each
other in various ways. Their ability to
withstand stress depends on the
characteristics of the materials and
how they are connected.
Diagonal braces:
structural
elements that connect diagonal
joints. These braces may be made of
solid materials or flexible materials.
How they function depends on what
they are made of and how they are
connected.
Load:
the sum of vertical forces
(gravity) and horizontal forces (shear
forces) acting on the mass of a
structure. The overall load is further
broken down into the loads of the
various parts of the building.
Different parts of a building are
designed and constructed to carry
different loads.
Rigid connections:
connections
that do not permit any motion of the
structural elements relative to each
other.
Shaking:
in this lesson, rapid
horizontal vibration of the base of the
model, simulating an earthquake. In
an actual earthquake, of course,
shaking occurs in many directions.
