Load bearing

1906: American Railway Development Association, Proceedings of Meeting, American Railway Industrial Association, Railway Industrial Association Too many otherwise suitable sites may be found to have sink holes, cavities, or poor load bearing qualities.

1953 O. T. (Oswald Theodore) Zimmerman, Irvin Lavine, Industrial Research Service's Handbook of Material Trade Names It […] is characterised by […] excellent load bearing characteristics at elevated temperatures.

They are also one-hour fire rated on load bearing interior and exterior walls.