[JThiessen]

Look at your chassis from the side. Now imagine a load being applied from the top. The chassis will bend downward in the middle, forming a "U" shape. With a solid piece running from front to back, the stresses in the chassis are linearly distributed through the member. When you have changes in shape, those stresses are passed through the most direct path. In your case, it will be through the fasteners and the holes for the fasteners. Now remember, you are looking at it from the side....you only have a single fastener line when looking at it from this direction. All those stresses are going to be passed through that fastener, and the thickness of each SINGLE piece of material. I'd predict an immediate failure - first at the bottom most piece - it will try to pull the fastener forward though the hole. The fastener being harder, will tear through the aluminum. Give your self at least two fasteners at each joint when looking at it from the side, maybe three.