A composite structure comprising: a base charge; an outer channel charge, the outer channel charge having an outer channel charge web portion, an outer channel charge flange portion, an outer channel charge inner radius, and an outer channel charge outer radius, wherein the outer channel charge web portion transitions to the outer channel charge flange portion at the outer channel charge inner radius and at the outer channel charge outer radius, an inner channel charge adjacent to the outer channel charge, the inner channel charge having an inner channel charge web portion, an inner channel charge flange portion, an inner channel charge inner radius, and an inner channel charge outer radius, wherein the inner channel charge web portion transitions to the inner channel charge flange portion at the inner channel charge inner radius and at the inner channel charge outer radius, wherein the base charge is joined to the outer surface of the outer channel charge flange portion and to the outer surface of the inner channel charge flange portion, the composite structure further comprising: a radius filler region formed at each intersection of the outer channel charge inner radius and the inner channel charge inner radius with the base charge, the radius filler region having a generally triangular shape and being filled with a radius filler; an outer channel charge of plies adjacent to the outer channel charge inner radius that reduce the outer channel charge inner radius, an inner channel charge of plies adjacent to the inner channel charge inner radius that reduce the inner channel charge inner radius, and a charge of plies in the base charge adjacent to the outer channel charge that reduces the radius filler region. a base charge; an outer channel charge, the outer channel charge having an outer channel charge web portion, an outer channel charge flange portion, an outer channel charge inner radius, and an outer channel charge outer radius, wherein the outer channel charge web portion transitions to the outer channel charge flange portion at the outer channel charge inner radius and at the outer channel charge outer radius, an inner channel charge adjacent to the outer channel charge, the inner channel charge having an inner channel charge web portion, an inner channel charge flange portion, an inner channel charge inner radius, and an inner channel charge outer radius, wherein the inner channel charge web portion transitions to the inner channel charge flange portion at the inner channel charge inner radius and at the inner channel charge outer radius, wherein the base charge is joined to the outer surface of the outer channel charge flange portion and to the outer surface of the inner channel charge flange portion, the composite structure further comprising: a radius filler region formed at each intersection of the outer channel charge inner radius and the inner channel charge inner radius with the base charge, the radius filler region having a generally triangular shape and being filled with a radius filler; an outer channel charge of plies adjacent to the outer channel charge inner radius that reduce the outer channel charge inner radius, an inner channel charge of plies adjacent to the inner channel charge inner radius that reduce the inner channel charge inner radius, and a charge of plies in the base charge adjacent to the outer channel charge that reduces the radius filler region. a radius filler region formed at each intersection of the outer channel charge inner radius and the inner channel charge inner radius with the base charge, the radius filler region having a generally triangular shape and being filled with a radius filler; an outer channel charge of plies adjacent to the outer channel charge inner radius that reduce the outer channel charge inner radius, an inner channel charge of plies adjacent to the inner channel charge inner radius that reduce the inner channel charge inner radius, and a charge of plies in the base charge adjacent to the outer channel charge that reduces the radius filler region.