Project overview
This project is a 30 m high helical steel staircase in Dubai Airport Freezone. Wrenze Steel carried out the modelling and structural design, with P&T Architects & Engineers Ltd as consultant.
The 3D model shows the staircase built around a tall central column. Straight stair flights rise between circular landings, turning around the column as they climb.
Our scope
Our scope was modelling and structural design.
Modelling was central on this project. A helical stair is a three-dimensional structure where almost every member sits at an angle. A 3D model is the only practical way to fix the geometry of each flight, landing and connection, and to check headroom and clearances on every level.
Structural design covered the central column, the stair flights and landings, and the connections between them. Design of a stair like this covers member strength, stability and deflection, as well as the stiffness and dynamic behaviour that matter for anything people walk on.
The model and the design work together. Any change to a member size moves straight into the model, and the model gives the geometry the calculations depend on.
The structure
A tall helical stair arranged around a central column works very differently from a stair between two floors of a building.
The central column is the spine. It carries the weight of every flight and landing, and because the stair winds round it, the loads arrive from different directions at each level. Over 30 m of height, the column must be checked for buckling as well as for the bending caused by loads applied off its centreline.
The landings act as brackets. Each circular landing connects the flights to the column, so its connection must carry the stair load and the twisting effect it creates.
Stairs are sensitive to vibration. Light steel stairs can feel lively underfoot if their natural frequency is low, so stiffness is often as important as strength. A tall, slender stair is also exposed to wind along its height.
Our article on steel staircase design explains these checks in more detail.
Read about our structural steel design service, or request a quote for a special steel staircase.
