Alpha-helices are secondary structures existing in most macromolecular systems such as proteins, DNA and RNA. The reasons behind the formation of structural phases are essential for understanding their biological functions. For this purpose, we performed parallel-tempering replica-exchange simulations of a coarse-grained polymer model. The tertiary folds composed of secondary structure segments are stabilized by the effects of bending and torsion. We systematically investigate the structural transitions by varying bending constraints at confined torsion strengths and construct the hyperphase diagrams. This study lends insight into the impact of competing bending and torsion effects and explains why polymers often exhibit helical structures.