  Large statically indeterminate truss and frame structures exhibit complex
load-bearing behavior, and redundancy matrices are helpful for their analysis
and design. Depending on the task, the full redundancy matrix or only its
diagonal entries are required. The standard computation procedure has a high
computational effort. Many structures fall in the category of moderately
redundant, i.e., the ratio of the statical indeterminacy to the number of all
load-carrying modes of all elements is less one half. This paper proposes a
closed-form expression for redundancy contributions that is computationally
efficient for moderately redundant systems. The expression is derived via a
factorization of the redundancy matrix that is based on singular value
decomposition. Several examples illustrate the behavior of the method for
increasing size of systems and, where applicable, for increasing degree of
statical indeterminacy.
