for providing a good engaging effect of course the plurality of flanges 12 as shown in fig9 can be partitioned and installed in the same direction or a whole piece is installed in the same direction to achieve the advantages of a good reinforced structure and a good engaging effect from the description above the steel wire 4 among the plates 11 is passed through the plurality of through holes 13 disposed on the flange 12 or a plurality of screw bolts 14 disposed on both sides of the plate 11 and the steel wire 4 is passed through the plurality of screw bolts 14 as shown in fig1 to substitute the flanges 12 by a simpler method in addition to the foregoing embodiments the steel body 1 also can be made of a steel bar b as shown in fig1 and 14 instead of a steel 10 brace a ad the steel body 1 is woven by the steel wire 4 into a mesh shape similarly an external steel plate frame 2 is covered onto the exterior of the steel body 1 and a gap is formed between the external steel plate frame 2 and the steel body 1 further a connecting wire 5 is provided for connecting the external steel plate frame 2 and the steel body 1 and the concrete 3 is filled up into the external steel plate frame 2 and engaged with the steel body 1 the steel wire 4 and the external steel plate frame 2 to form a structure of tightly connecting the steel body 1 the external steel plate frame 2.