Double Stringer Staircase Detail Dwg | No Login
double stringer staircase
A is a structural design characterized by two parallel longitudinal beams (stringers) that support the stair treads. Unlike a mono-stringer, which uses a single central support, a double stringer system distributes the load to the edges or set-in points of the treads, offering superior structural stability and a classic, robust aesthetic. 1. Structural Anatomy and Materials
- Cut/Stringer Staircase (Open Stringer): The stringers have a saw-tooth (notched) profile. Treads sit on the horizontal cuts. This is common for wood and steel fabrication. The DWG detail here focuses on the stress risers at the notch corners.
- Closed Stringer (Box or Channel Stringer): The stringers are straight channels (C-channel or rectangular tube). Treads and risers are housed in grooves or welded between the stringers. The DWG must show the concealed joist hangers or welded end plates.
- Steel Pan Tread System: The "stringers" are actually heavy C-channels, and the treads are pre-formed steel pans welded to both sides. The DWG detail highlights fillet weld sizes and span calculations.
- Uniform load (w) = Dead load + Live load (typically 2.9–4.8 kN/m² for residential/commercial)
- Span along slope (L) = horizontal run / cos θ
- Bending moment
M = w L² / 8
- Required section modulus
S = M / (0.66 Fy) for steel
Introduction: Why the Double Stringer?
Part 4: Common Mistakes in Double Stringer DWG Files (And How to Avoid Them)