Civil Engineering Reference
In-Depth Information
13
Structural materials
A building structure usually consists of the following parts:
•
The foundation
, which is the part of the building that transfers the weight of the
building and other loads to the ground, usually below ground level. In
swamps and other areas with no load-bearing capacity the load must be
spread onto piles going down to a solid base.
•
The wall structure
, which carries the floor, roof and wind loads. The walls can
be replaced by free-standing columns.
•
The floor structure
, which carries the weight of the people in the building and
other loads such as furniture and machinery.
•
The roof structure
, which bears the weight of the roof covering and possible
snow loads.
These standard elements can be separated in theory, but in practice the different
functions usually have no clear boundaries, as in the construction of a spherical
building such as the Globe Sports arena in Stockholm. The different structural
elements have a very intricate interaction in relation to the bracing of a building,
for example, a particular wall structure can be dependent upon a specific floor
structure for its structural integrity. Some structures also cover other building
needs, such as thermal insulation, for example.
Structural materials have to fulfil many conditions. They are partly dependent
upon the construction technique to be used, and their properties are defined in
terms of bending strength, compressive strength, tensile strength and elasticity.
These factors give an idea of the ability of the material to cope with different
forces. How this happens depends upon the design and dimension of the struc-
ture.
A steel cable has its strength in its capacity to take up tensile forces, e.g. in a
suspension bridge. A brick, however, almost entirely lacks any such stretching
