Helicoidal Staircase Study.

Methods of analysis for a projected fixed-ended reinforced 80 deg helicoidal staircase are compared. The methods used are those of Holmes, Scordelis, Morgan, and Bergman. Tests are described on half-scale models under uniformly distributed loading. For a model based on the prototype design a load factor in excess of 4.8 was obtained. When reinforcement against lateral moment was reduced by 50 percent, together with some reduction in main steel, the load factor was 3.6. The use of ultimate strength design based on vertical moments only gave a simple and safe solution for the staircase under study. Proposals for further work in this field are made. [ABSTRACT FROM AUTHOR]