As an economic and safe structure, Bi-steel is widely
used in reinforced concrete with less consumption of steel. In this
paper, III Bi-steel concrete beam has been analyzed. Through careful
observation and theoretical analysis, the new calculating formulae for
structural rigidity and crack have been formulated for this Bi-steel
concrete beam. And structural rigidity and the crack features have also
been theoretically analyzed.
 K. S. Zhao, Y. H. Gao, and J. Y. Zhang, "Big-diameter Bi-steel concrete
flexural member rigidity test," Transactions of Tianjin University, vol. 28,
 G. W. Ni, Control and study on cracking and distortion of ladder-reinforce
steel concreted beam, Hebei polytechnic university master degree thesis,
China, 1997, pp.86-88.