These matrices are each a statics (linear equation) problem arising from applications of the GT-STRUDL structural engineering code. They were collected as a set of benchmarks for out-of-core envelope factorization on limited memory computers (for example, CDC 6600 series).
Matrices in this set:
BCSSTK14 (real symmetric positive definite, 1806 by 1806, 32630 entries), Roof of the Omni Coliseum, Atlanta
BCSSTK15 (real symmetric positive definite, 3948 by 3948, 60882 entries), Module of an offshore platform
BCSSTK16 (real symmetric positive definite, 4884 by 4884, 147631 entries), U.S. Army Corps of Engineers dam