A wing spar structure (110, 210, 310) for an aircraft, comprising a left wing and a right wing, wherein a left spar (114, 214, 414, 514, 614) is associated to the left wing (102b, 202b) of the aircraft and a right spar (112, 212, 412, 512, 612) is associated to the right wing (102a, 202a) of the aircraft wherein each spar (112, 114, 212, 214, 412, 414, 512, 514, 612, 614) has a web portion (230, 430, 630) and at least one spar cap (232, 232a, 232b, 432, 432a, 432b, 532, 532a, 532b, 632, 632a, 632b), wherein in a cross-section orthogonal to the longitudinal axis of the spars, the web portion extends in a substantially vertical direction (v) and the at least one spar cap (232, 232a, 232b, 432, 432a, 432b, 532, 532a, 532b, 632, 632a, 632b) extends in a direction substantially orthogonal to the web portion (230, 430, 630), wherein the left spar (114, 214, 414, 514, 614) is connected to the right spar (112, 212, 412, 512, 612) by connecting the spar cap (232b, 432b, 532b, 632b) of the left spar to the spar cap (232a, 432a, 532a, 632a) of the right spar at a spar connection portion (140, 240, 240a, 240b, 340, 440, 540, 640), characterized in that the spar cap (232b, 432b, 532b, 632b) of the left spar (114, 214, 414, 514, 614) and the spar cap (232a, 432a, 532a, 632a) of the right spar (112, 212, 412, 512, 612) are directly connected via a bolt connection (242, 442, 542, 642), and in further comprising at least one shear pin adapted to be fixed to a fuselage of the aircraft such as to transmit shear forces from the wing spar structure to the fuselage, said shear pin preferably being fixed to a wing root portion or a root rib attached to the left spar or the right spar. a left wing and a right wing, wherein a left spar (114, 214, 414, 514, 614) is associated to the left wing (102b, 202b) of the aircraft and a right spar (112, 212, 412, 512, 612) is associated to the right wing (102a, 202a) of the aircraft wherein each spar (112, 114, 212, 214, 412, 414, 512, 514, 612, 614) has a web portion (230, 430, 630) and at least one spar cap (232, 232a, 232b, 432, 432a, 432b, 532, 532a, 532b, 632, 632a, 632b), wherein in a cross-section orthogonal to the longitudinal axis of the spars, the web portion extends in a substantially vertical direction (v) and the at least one spar cap (232, 232a, 232b, 432, 432a, 432b, 532, 532a, 532b, 632, 632a, 632b) extends in a direction substantially orthogonal to the web portion (230, 430, 630), wherein the left spar (114, 214, 414, 514, 614) is connected to the right spar (112, 212, 412, 512, 612) by connecting the spar cap (232b, 432b, 532b, 632b) of the left spar to the spar cap (232a, 432a, 532a, 632a) of the right spar at a spar connection portion (140, 240, 240a, 240b, 340, 440, 540, 640), characterized in that the spar cap (232b, 432b, 532b, 632b) of the left spar (114, 214, 414, 514, 614) and the spar cap (232a, 432a, 532a, 632a) of the right spar (112, 212, 412, 512, 612) are directly connected via a bolt connection (242, 442, 542, 642), and in further comprising at least one shear pin adapted to be fixed to a fuselage of the aircraft such as to transmit shear forces from the wing spar structure to the fuselage, said shear pin preferably being fixed to a wing root portion or a root rib attached to the left spar or the right spar.