A spar cap assembly for a wind turbine rotor blade, the spar cap assembly comprising: - a spar cap section comprising a composite material, the spar cap section having a longitudinally extending slab shape defined by first and second mutually opposed and longitudinally extending faces (51,52) and by first and second longitudinally extending lateral sides (61,62), the separation between the first and second faces (51,52) defining thickness of the spar cap section, the spar cap section having a vertical axis extending between the first and the second faces (51, 52) and a transverse axis extending between the first and the second lateral sides (61,62), wherein a longitudinal axis, the vertical axis and the transverse axis are mutually perpendicular; - a first ramp section extending longitudinally and positioned adjoining the first lateral side of the spar cap section, the first ramp section having mutually opposed spar cap side and sloped side, wherein the spar cap side of the first ramp section adjoins the first lateral side of the spar cap section and has a thickness (t 1) substantially equal to the thickness (t S1) of the first lateral side of the spar cap section, and wherein the sloped side of the first ramp section slopes outward with respect to the spar cap section, and wherein the first ramp section further comprises a mid-section having a thickness (t M) equal to or greater than the thickness (t 1) of the spar cap side of the first ramp section, the thicknesses (t 1,t M) of the spar cap side and the mid-section of the first ramp section measured parallel to the vertical axis of the spar cap section; - a second ramp section extending longitudinally and positioned adjoining the second lateral side of the spar cap section, the second ramp section having spar cap side and sloped side, wherein the spar cap side of the second ramp section adjoins the second lateral side of the spar cap section and has a thickness (t 2) substantially equal to the thickness (t S2) of the second lateral side of the spar cap section, and wherein the sloped side of the second ramp section slopes outward with respect to the spar cap section, the thickness (t 2) of the spar cap side of the second ramp section measured parallel to the vertical axis of the spar cap section; and - one or more wrapping layers encapsulating the spar cap section, the first ramp section and the second ramp section, wherein the one or more wrapping layers, the spar cap section, the first ramp section and the second ramp section are resin injection molded. - a spar cap section comprising a composite material, the spar cap section having a longitudinally extending slab shape defined by first and second mutually opposed and longitudinally extending faces (51,52) and by first and second longitudinally extending lateral sides (61,62), the separation between the first and second faces (51,52) defining thickness of the spar cap section, the spar cap section having a vertical axis extending between the first and the second faces (51, 52) and a transverse axis extending between the first and the second lateral sides (61,62), wherein a longitudinal axis, the vertical axis and the transverse axis are mutually perpendicular; - a first ramp section extending longitudinally and positioned adjoining the first lateral side of the spar cap section, the first ramp section having mutually opposed spar cap side and sloped side, wherein the spar cap side of the first ramp section adjoins the first lateral side of the spar cap section and has a thickness (t 1) substantially equal to the thickness (t S1) of the first lateral side of the spar cap section, and wherein the sloped side of the first ramp section slopes outward with respect to the spar cap section, and wherein the first ramp section further comprises a mid-section having a thickness (t M) equal to or greater than the thickness (t 1) of the spar cap side of the first ramp section, the thicknesses (t 1,t M) of the spar cap side and the mid-section of the first ramp section measured parallel to the vertical axis of the spar cap section; - a second ramp section extending longitudinally and positioned adjoining the second lateral side of the spar cap section, the second ramp section having spar cap side and sloped side, wherein the spar cap side of the second ramp section adjoins the second lateral side of the spar cap section and has a thickness (t 2) substantially equal to the thickness (t S2) of the second lateral side of the spar cap section, and wherein the sloped side of the second ramp section slopes outward with respect to the spar cap section, the thickness (t 2) of the spar cap side of the second ramp section measured parallel to the vertical axis of the spar cap section; and - one or more wrapping layers encapsulating the spar cap section, the first ramp section and the second ramp section, wherein the one or more wrapping layers, the spar cap section, the first ramp section and the second ramp section are resin injection molded.