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Design of Structures for the
Architecture. Being a material of
industrialized and controlled production, the structural properties of the steel
have generally little variability. Coefficient of variation of the order of 10
percents is typical for the resistance and the other properties. Another
advantage of the steel is that its behavior is perfectly linear and elastic
until the flow; more easily makes the answer predictable of the structures of
this material. The high ductility of the material allows redistributing
concentrations of efforts.
The extraordinary structural qualities of the steel, and specially their high
resistance in tension, have structurally been taken advantage of in a great
variety elements and composed materials, the first among them concrete one
reinforced and the reinforced one; in addition in combination with wood,
plastics, rubblework and others. The possibility of being attacked by the
corrosion causes that the steel requires protection and certain maintenance in
severe environmental conditions. The cost and the problems that are originated
by this aspect are sufficiently important so that they incline the balance
towards the reinforced use of concrete in some structures which they must be
exposed outdoors, like the bridges and certain marine works, although in steel a
slighter structure and of smaller initial cost could be obtained one more. A
great variety of other materials exists that get to be used for structural aims,
but whose application to the date very has been limited.
The aluminum has excellent resistance, but their relatively low modulus of
elasticity and its cost prevent their use in most of the civil structures,
although not in special structures in which his low weight represents a decisive
advantage, like in the airplanes and the furniture. It was injured to think that
the plastics, in a great one I number of modalities, would get to constitute a
preponderant structural material; nevertheless, their high cost and its
susceptibility to the fire have limited greatly their development in this sense.
The resin reinforced with fiberglass has had some important structural
applications in which it has taken advantage of his malleability, lightness, and
discharge resistance to tension and reasonable cost. It is to hope that in the
future different materials are developed and popularized; nevertheless, the
tendency for several decades has been towards the improvement of the properties
of the existing materials, more than towards the development of radically
different materials. |
