Tray failure by downward forces is much rarer. In fact, it is unusual to see it even once or twice in a career. If it has happened more often, immediately start investigating the process and equipment configuration. Massive forces are usually required to make trays fail by downward acting forces.
However, when downward forces are a concern, truss lugs can be used to extend the integral truss over the tray ring. Figure 8 shows schematics of truss lugs and how they connect to the top of a tray. Figure 9 shows a photo of truss lugs in service.