Support beam has multiple through holes formed axially along beam at bottom wall of recessed space that is formed inward from top wall

摘要

The beam has two vertical walls (40) that are parallel to each other and spaced by a certain distance, and two bottom walls (54) respectively horizontally positioned at bottom ends of the vertical walls. A recessed space (50) is formed inward from a top wall (42). A predetermined number of through holes (58) are formed axially along the beam at the bottom wall of the recessed space. The top wall is horizontally connected with top edges of the vertical walls. The recessed space has side walls (52) respectively spaced from the two vertical walls by a certain distance.