In this paper, we give a definition of the cyclotomic Birman-Murakami-Wenzl algebras Br,n, which is equivalent to that given by Haering-Oldenburg in [HO]. By using Ariki-Mathas-Rui's method on cyclotomic Nazarov-Wenzl algebras in [AMR], we give an equivalent condition for Br,2 being free with rank 3r2. Such a condition is called the u-admissible condition. Under this condition, through constructing the seminormal representations of Br,n, together with Weddurburn-Artin Theorem about semisimple algebras, we prove that Br,n is free over a commutative ring R with rank rn(2n - 1)!!. In fact, Br,n is a "weakly" cellular algebra. Further, we classify the irreducible Br,n-modules over an arbitrary field. When r is odd, we construct another "weakly" cellular basis too.
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