Pre-stressed soil and rock anchors are widely used in civil engineering
to resist the horizontal pressures acting on retaining structures. With
time, anchor force may decrease due to relaxation and creep. As a result,
anchored elements may displace excessively and eventually fail. Therefore,
it is extremely important to have suitable permanent means to measure the
residual force and verify that the anchor is functioning properly and
according to design.
Advantages:
Low-cost
Although a precision instrument, SAM is conveniently price and makes
monitoring more anchors affordable.
Accurate
SAM is designed for accurate reading under eccentric loads, even when
not all tendons are used.
Forms an integral part of the anchor In contrast with other measuring instruments, SAM forms an integral
part of the anchor and not an extraneous element which is introduced
with the sole purpose of monitoring the forces. SAM is built in the form
of a locking plate instrumented with Wheatstone Bridge strain gages and
up-to-date electronics.
Simple installation and operation
After the anchor is initially pre-stressed, the special readout box is
connected to the SAM and the initial reading noted. Using the
calibration factor supplied with each SAM, subsequent readings are
easily converted to differences in residual load values. The rugged
readout box is battery operated and contains just one press-to-test
button. It can be easily operated by site personnel.
Easy remote monitoring
Any number of SAM devices can be connected by off-the-shelf cables to a
conveniently located control box. Thus reading for a large site can be
taken in a few minutes eliminating the need for climbing to each anchor
separately. For remote sites, anchor data can be periodically
transmitted by cellular modem to a website where it can be easily viewed
and processed by the project engineers.
SAM is available for both multi-tendon and single-bar
anchors.
