Q. What do you mean by Base fixity?
Base fixity
When structures such as portal frames are associated to the base foundation, engineers have to determine the degree of fixity for the connection. Generally the two common design options are fixed bases and pinned bases. Pinned bases have the benefit that design of foundation is made simple so that some cost savings can result. Though fixed bases design provides extra rigidity and stiffening to the structures and stability of structures can be improved. So the use of fixed bases assists to enhance the structural performance of structures.