----HOLLOW VIBRATED REINFORCED CONCRETE (HVC) POLES   GENERAL SPECIFICATIONS (HVC) The differentiating features of this type of pole regarding the traditional VC vibrated reinforced concrete ones are:      - high torsional resistance      - higher nominal forces      - ISO-resistant structure independent from the face of the pole. The following table specifies pole lengths and stresses. Nominal measurements of the top and lengths and stresses of HVC poles Nominal force daN Top measurements mm x mm Length 9 11 13 15 17 1000 250 x 250 x x x x x 1600 x x x x x 2000 x x x x x 2500 275 x 275 x x x x x 3000 x x x x x 3500 x x x x x 4500 x x x x x The poles have a truncated pyramid shape, with a square section and a hollow octagonal-shaped interior. The safety coefficient against failure through buckling in the principal and secondary directions is 2.25, as per UNE 207016. The taper ratio of both faces is 25 mm/m The poles are labelled by means of a group of letters and numbers arranged in the order specified forthwith:      • The letters HVH (Spanish for HVC), indicating a hollow vibrated reinforced concrete pole.      • Letter N, indicating a normal type of pole.      • Figures that represent the value of nominal force in daN.      • Figure that gives the overall length of the pole in metres. Example: HVH3500N17 This serial number corresponds to a hollow vibrated concrete pole with 3,500 daN of nominal force, and 17 metres in height. For the quick identification of the poles, the upper part is painted in an identifying colour according to the following table: Identifying colour for HVC-type poles Nominal force (daN) Identifying colour 1000 Orange 1600 Black 2000 Blue 2500 Red 3000 Yellow 3500 Green 4500 White The geometrical and strength specifications of hollow vibrated reinforced concrete poles are as follows:   Geometrical and strength specifications according to the size of the top Type Height H (m) Dimensions (mm) Approx. mass (Kg) HG (m) Torsional failure torque (m.daN) Effective tensions (daN) UNE 207016 Cogolla Base bo ho b h HVC 11 250 250 525 525 3350 6,14 4230 1000 1600 2000 13 575 575 4320 7,41 1000 1600 2000 15 625 625 5400 8,70 1000 1600 2000 17 675 675 6590 10,01 1000 1600 2000   HVC 11 275 275 550 550 3780 6,03 5130 2500 3000 3500 4500 13 600 600 4860 7,27 2500 3000 3500 4500 15 650 650 5940 8,55 2500 3000 3500 4500 17 700 700 7200 9,86 2500 3000 3500 4500