The structure includes a first plurality of tubes (1) and a second plurality of tubes (2) having a smaller diameter. The tubes of the first plurality of tubes (1) have an alignment of pairs of ties (3, 4) that extend obliquely upwards from the periphery thereof. The upper part of each tie (3) or (4) has a first fastening part (5) fitted to the periphery of the tubes (2) of a second plurality of tubes (2), complemented by an independent second fastening part (6) to which it is dismountably connected in order to maintain the two first (1) and second (2) pluralities of tubes connected.
