Fibrous structure for reinforcing a composite material and a method for manufacturing the fibrous structure

A method of manufacturing a fibrous structure for reinforcing a composite material which is a bottomed hollow pillar-shaped body composed of a plurality of yarn sections disposed in a longitudinally adjoining arrangement, comprising arranging a plurality of yarn guide members upright at predetermined intervals according to the desired cross-sectional configuration of the fibrous structure, laying up a first continuous yarn along the yarn guide members to form a plurality of layers of a first-stage yarn section;

• forming loops of a second continuous yarn and causing the loops to engage the bottom ends of the respective yarn guide members in the portion of the first-stage yarn section where no more yarn is to be laid up thereon, pulling up the yarn guide members together with the loops of the second continuous yarn above the top layer of the first continuous yarn, removing the yarn guide members, passing a third yarn into the loops of second yarn as a tacking yarn so as to appropriately tighten the yarn layers of first continuous yarn by the second yarn to thereby complete the fabrication of the first-stage yarn section;
• laying up the first continuous yarn layer along the remaining yarn guide members to form layers of a second-stage yarn section, passing a further second continuous yarn in loops through the portion of the second-stage yarn section where no more yarn is to be laid up and through the adjoining portion of the first stage yarn section, passing the third continuous yarn through loops of the further second continuous yarn and tightening the yarn layers of the first continuous yarn by the further second continuous yarn, and repeating the above steps in succession for respective yarn sections to be formed in an adjoining fashion.