Civil Engineering Reference
In-Depth Information
Figure 3-11
Linearization of glass fabric
Note that the linearization shown is for the first loading, and it is shown extending 10
percent of the breaking strength. Different methods of linearization are employed by
different researchers.
Generally a fabric is chosen for other characteristics besides tensile strength, since
each fabric manufacturer has an array of different strength fabrics one of which will
probably meet the required tensile strength for a particular project.
Stretch and Dimensional Stability
As briefly discussed earlier the twist of fibers into yarns and the crimping of yarns
around the warp yarns cause a high amount of stretch in the fabric the first time a
load is applied. Various techniques have been developed to minimize this problem.
The prestressed coating system is one such example where the woven cloth is
prestressed by having metal pins hold the fabric while in the coating process. This
controls the amount of stretch and more closely equalizes the stretch in warp and fill
directions. Another method is to prestress the cloth before installing which reduces
the amount of stretch occurring during the lifetime of the structure.
When designing details for tensile fabric structures, it is important to design initial
prestressing devices into the hardware, so that the fabric can be pulled out and
tensioned to the design stress. With certain fabrics such as some polyester fabrics
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