Connections - Tensile Fabric Structures: Design, Analysis, and Construction - page 109

7.2.4 Fabric Termination at Corner
There are special detailing problems associated with the termination of the fabric at
“corners”, those locations at the edges of the membrane where catenary cables
terminate at masts or other supporting elements. Small errors in patterning or cable
length can have critical effects at these locations, where the fabric necks down to a
small width. In addition, tension in the fabric tends to pull it away from the
supporting member, causing it to ride up the cables and away from the support. This
effect is generally not addressed in currently available software, which assumes that
the fabric and cable share the same nodal geometry, such that sliding between fabric
and cable is not modeled. The effect can be pronounced when the angle between the
two cables is acute. While reinforcement of the fabric in this area is helpful, some
supplemental mechanism for restraining the fabric is generally required. Often, the
fabric is terminated beneath a clamp bar mounted to a “membrane plate”. The plate
typically also anchors the catenary cables at the edges of the membrane (Figure 7-7).
In the detail shown, the cable or anchor rod is typically adjustable in length to
facilitate adjustment and pretensioning. The socket fittings that anchor the catenary
cables on the left side of the figure may also have a telescoping mechanism to
facilitate adjustment of the individual catenaries.
Fig ur e 7-7
Membrane Plate Fabric Termination
Preliminary detailing of membrane plate connections is appropriate prior to the
completion of final analysis. This detailing should consider the geometric
requirements for fabric and cable terminations and the length required for any
anchorage adjustment devices, so as to establish the relationship between all cable
and anchorage work lines. Changes in the ratio between element forces under load
will cause the membrane plate to rotate under various load combinations, and
analysis can determine whether these rotations will cause unacceptable local stresses