MATERIALS ENGINEERING CONCEPTS - Materials for Civil and Construction Engineers - page 40

2 Strain
gauges

Strain gauge

2 Strain
gauges

(a) (b)

Closure

Diaphragm
strain gauge

(c)

FIGURE 1.32 Load cells: (a) strain gauges on a tension rod, (b) strain
gauges on an S-shaped element, and (c) diaphragm strain gauge on a closure.

Load cells must be regularly calibrated using either dead loads or a cal-
ibrated loading machine. Care must be taken not to overload the load cell. If
the load applied on the load cell exceeds the capacity recommended by the
manufacturer, permanent deformation can develop, ruining the load cell.

SUMMARY

Civil and construction engineers are involved in the selection of construc-
tion materials with the mechanical properties needed for each project. In ad-
dition, the selection process must weigh other factors beyond the material's
ability to carry loads. Economics, production, construction, maintenance,
and aesthetics must all be considered when selecting a material.
Lately, in all fields of engineering, there has been tremendous growth in
the use of new high-performance materials. For example, in the automotive