This paper is concerned with the preservation of unimodality under coh
erent structures of independent components having a common life distri
bution function. This result in a way generalizes a result of Alam [1]
, as Alam's result indirectly also deals with preservation of unimodal
ity for (n-i+1)-out-of-n systems of independent and identically distri
buted components. The usefulness of this property of coherent systems
in obtaining sharper upper bounds on the reliability of the concerned
system has been illustrated below for a bridge structure with componen
ts having a gamma life distribution function.