Although cables are most popular as material, steel rods are also used as tensile members in tension structures for long time in history. In this paper, required quality for the tension strings and their connections are discussed by defining tension structures as structural-system hierarchy composed of various levels of elements. Their required quality items are chosen through historical review including bridges and glass wall structures, and through their hierarchical studies using parabolic tension elements defined as sub-systems. Several type of connections for high-strength tension rods are proposed and selected for satisfying these requirements, followed by application for practical projects.
