According to some implementations a bolted joint for modular blades is provided that comprises a single bolt that joins the inserts incorporated on the flange of the beam, screwing the two modules facing each other. A spacer is added to each bolt, and the bolts is then pre-tensioned by pulling, either mechanically separating the modules with a mechanical separator or thermally by applying heaters to the bolt and coolers to the spacer, or by torqueing the bolts.