Applications
Stress & Strain Basics
Stress Stress is force divided by area. It is generally expressed in units such
as N/mm
2
or psi. In symbolic form, stress
s
equals force F
divided by area A:
s=
F
A
The strength of a material is usually presented in terms of stress:
Ultimate stress is determined by applying increasing loads to a sam-
ple of the material until it fails. Yield point is a stress level at which
considerable extension or contraction of the member occurs with lit-
tle or no increase in tensile or compressive stress.
The designer determines a “working stress” for the structural mem-
ber by dividing the yield stress (or alternatively, the ultimate stress)
by a factor of safety. Strain gauges help the engineer verify that
working stress is not exceeded.
Strain Strain occurs simultaneously with stress. When a structural member
is loaded, it undergoes dimensional changes. The member lengthens
with tensile stress and shortens with compressive stress.
Strain is the change in the member’s length divided by its original
length. In symbolic form, strain
e
equals change in length e divided
by original length L:
e=
e
L
Note that a strain gauge is calibrated to report a strain value based
on the original length of the gauge.
10-3
Rembco Geotechnical Contractors specializes in
slope stabilization,
soil nail wall,
foundation repair
and support,
grouting,
shoring,
micropile
construction,
rock drilling, and we remediate
sinkholes. We use a
problem-solving approach in the geotechnical portions of buildings, bridges, water plants, sewage plants, tunnels,
installing caisson bottom, and roads. We are experienced in these applications:
micro piles,
sinkhole repair,
permeation and
pressure
grouting,
soil nails,
cement grouting,
chemical grouting,
micropiles,
compaction grouting, and
rock anchors.
Rembco techniques apply when adding new structures: especially
rock anchor,
microfine cement,
soil nailing, and
micropile
installations for foundation support. Our specialties are
soil nails,
rock anchor,
chemical and
compaction grouting,
mini piles,
sinkhole repair,
micropiles, and
soil nailing.
