Connections - Tensile Fabric Structures: Design, Analysis, and Construction - page 115

F igu re 7-14
Cable Termination at Ear Plates with Ring Plate Reinforcement
Cable ter m inations are typically exposed on either the interior or exterior of the
structure. Successful design of terminations and the supporting plates and members to
which they attach must therefore respond to both technical and aesthetic
requirements. Cable connections must be designed to resist imposed load, satisfy
geometric constraints, and accommodate anticipated displacement and rotation.
However, the choice of cable termination type (stud, jaw, or eye, and swage or
spelter) and material (carbon or stainless steel) should also address considerations of
visual elegance and lightness, and the visual congruity of the connection design with
other elements of the building of which they are a part. Similarly, ear plate geometry
should be designed to achieve compact connections and congruity with the angular
geometry and lightness of the cables and membrane.
7.3.3 Cable Saddles
Where a cable passes without termination over a supporting member or one cable
terminates into a second cable, a saddle is required to guide the cable's change of
angle and control its radius of bend. The primary considerations in designing saddles
are the size of the cable and its tensile force, the cable's range of directional
orientation under load, and whether it must be restrained from sliding across the
saddle (in order to effectively realize an analytically determined variation in cable
force in the sections of cable to either side of the saddle).
In general, the large bending radius required for structural strand precludes its use
with saddles, and wire rope is used where saddles are required. Bending a cable
across a saddle causes a stress concentration in the cable, and its allowable load must
therefore be reduced. The reduction is generally a function of the radius of the saddle
relative to the radius of the cable, and required reductions are defined by ASCE19
and other standards.