Material of the lateral load-resisting system

The material is that from which the Lateral Load-Resisting System is primarily constructed. If there is more than one Lateral Load-Resisting System, chose the material of the more seismically vulnerable system. Do not include materials that are non-structural or that are not part of the primary Lateral Load-resisting System. For example, if Unreinforced Masonry walls resist the majority of the lateral load in a building where most of the gravity loads are carried by say wood or steel frames, the Material Type of the Lateral Load-resisting System should be listed as Masonry, Unreinforced.