A steel reinforcing structure (10, 100) for concrete, said structure comprising: at least a pair of opposing reinforcing bars (14A, 148, 16A, 168) arranged substantially parallel to one another; and at least one common reinforcing bar (12A, 12B) located intermediate and substantially parallel to the pair of opposing reinforcing bars; characterised in that the structure further comprises: a spiral tie at one end connected to one of the pair of opposing reinforcing bars at a first position, the spiral tie being formed and bent in a clockwise direction, when viewed in a reference sectional view, around each of the at least one common reinforcing bar (12A, 12B) to connect at an opposite end of the spiral tie (12A, 12B) to said one of the pair of opposing reinforcing bars at another position offset longitudinally from said first position, such that the spiral tie follows a clockwise spiral path and forms an angle around the one of the pair of opposing reinforcing bars and the at least one common reinforcing bar (12A, 12B); and an other spiral tie at one end connected to the other of the pair of opposing longitudinal reinforcing bars at a second position, the other spiral tie being formed and bent in an anticlockwise direction, when viewed in the reference sectional view, around each of the at least one common reinforcing bar (12A, 12B) to connect at an opposite end of the other spiral tie to said other of the pair of opposing reinforcing bars at a further position offset longitudinally from said second position, such that the other spiral tie follows an anticlockwise spiral path and forms an angle around the other of the pair of opposing reinforcing bars and the at least one common reinforcing bar (12A, 12B), wherein the clockwise and anticlockwise spiral ties (18A, 20A) follow the clockwise and anticlockwise spiral paths, respectively. at least a pair of opposing reinforcing bars (14A, 148, 16A, 168) arranged substantially parallel to one another; and at least one common reinforcing bar (12A, 12B) located intermediate and substantially parallel to the pair of opposing reinforcing bars; characterised in that the structure further comprises: a spiral tie at one end connected to one of the pair of opposing reinforcing bars at a first position, the spiral tie being formed and bent in a clockwise direction, when viewed in a reference sectional view, around each of the at least one common reinforcing bar (12A, 12B) to connect at an opposite end of the spiral tie (12A, 12B) to said one of the pair of opposing reinforcing bars at another position offset longitudinally from said first position, such that the spiral tie follows a clockwise spiral path and forms an angle around the one of the pair of opposing reinforcing bars and the at least one common reinforcing bar (12A, 12B); and an other spiral tie at one end connected to the other of the pair of opposing longitudinal reinforcing bars at a second position, the other spiral tie being formed and bent in an anticlockwise direction, when viewed in the reference sectional view, around each of the at least one common reinforcing bar (12A, 12B) to connect at an opposite end of the other spiral tie to said other of the pair of opposing reinforcing bars at a further position offset longitudinally from said second position, such that the other spiral tie follows an anticlockwise spiral path and forms an angle around the other of the pair of opposing reinforcing bars and the at least one common reinforcing bar (12A, 12B), wherein the clockwise and anticlockwise spiral ties (18A, 20A) follow the clockwise and anticlockwise spiral paths, respectively. a spiral tie at one end connected to one of the pair of opposing reinforcing bars at a first position, the spiral tie being formed and bent in a clockwise direction, when viewed in a reference sectional view, around each of the at least one common reinforcing bar (12A, 12B) to connect at an opposite end of the spiral tie (12A, 12B) to said one of the pair of opposing reinforcing bars at another position offset longitudinally from said first position, such that the spiral tie follows a clockwise spiral path and forms an angle around the one of the pair of opposing reinforcing bars and the at least one common reinforcing bar (12A, 12B); and an other spiral tie at one end connected to the other of the pair of opposing longitudinal reinforcing bars at a second position, the other spiral tie being formed and bent in an anticlockwise direction, when viewed in the reference sectional view, around each of the at least one common reinforcing bar (12A, 12B) to connect at an opposite end of the other spiral tie to said other of the pair of opposing reinforcing bars at a further position offset longitudinally from said second position, such that the other spiral tie follows an anticlockwise spiral path and forms an angle around the other of the pair of opposing reinforcing bars and the at least one common reinforcing bar (12A, 12B), wherein the clockwise and anticlockwise spiral ties (18A, 20A) follow the clockwise and anticlockwise spiral paths, respectively.