Abstract: A portable, easily composable supporting skeleton which serves as a supporting structure of buildings composable in situ. The skeleton comprises a pipe-like spacer. Two dismountable node plates can be fixed to the spacer by way of clamping assemblies. Each node plate includes an eye having a through-hole. A joint assembly which comprises a crosswise tie-piece can be interconnected pivotably to the through-hole of the eye of one of the node plates.