Design Stud Walls to Eurocode 5

This tool performs a rigorous analysis of a vertical timber stud as a “Beam-Column” element. It verifies:

• Axial Capacity (Nc,Rd): Checks compression strength, automatically calculating the buckling reduction factor (kc) based on wall height and restraint.
• Bending Capacity (My,Rd): Checks resistance to lateral wind loads acting on the face of the wall.
• Combined Actions (Interaction): The most critical check. Verifies the interaction between axial compression (from roof/floors) and bending (from wind) using Eurocode equations 6.23 and 6.24.
• Bearing (fc,90): Checks compression perpendicular to grain on the bottom plate/rail.
• Deflection: Calculates horizontal deflection of the stud under wind load to prevent damage to finishes (e.g., plasterboard cracking).

SPEC Toolbox provides a dedicated Stud Design calculator that evaluates axial compression, bending effects, buckling behavior, and stability conditions for solid timber studs used in light-frame wall assemblies, in accordance with EN 1995-1-1:2004 (Eurocode 5), which defines compression member design, stability checks, and load combinations.

Define: Timber grade (e.g., C16, C24), Stud width (b), Stud depth (d), Stud spacing — determines cross-sectional resistance and slenderness, and load tributary area from floors/roofs.

Wall Type: Discrete wall (each stud independent) or Continuous wall (load redistribution between members).

Sheathing and Bracing Conditions: whether sheathing (OSB or plywood) is present, whether it provides lateral support, whether braced battens are installed — influences effective buckling length and overall wall stability.

Eurocode 5 (EN 1995-1-1:2004). National Annex support: engineers can activate the National Annex and select a country-specific NDP (Nationally Determined Parameters) code — example given: Austria – ÖNORM B. These adjust partial safety factors and other design values per national regulations.

Load types: Permanent load (gk), Imposed load (qk), Wind load (wk), Snow load (s) — combined per EN 1990 and EN 1991. Load Combination Selection parameters: load combinations, loading code (EN 1991:2002), consequence class, design equation. Environmental/Service Conditions: service class (SC1, SC2, etc.), snow load category, imposed load category.

Distributed loads transferred to each stud: Permanent (gk), Imposed (qk), Wind (wk), Snow (s) — tributary load carried by the stud.

Lateral Loads: Wind load (Wn-y) acting perpendicular to the wall surface, producing bending stresses combined with axial compression during verification.

System Factor (ksys): accounts for load sharing between multiple members in a repetitive structural system.

Critical Buckling Calculation: engineers can determine whether the critical buckling coefficient (kcrit) should be evaluated.

Loaded Edge Condition: Compression edge, Center, or Tension edge — affects lateral torsional stability evaluation.

Bending Design, Compression Check, Strength Check (combined stresses within allowable limits), Buckling Verification (global buckling resistance), Lateral Torsional Stability. Output Summary dashboard with pass/fail indicators for: bending design utilization, compression utilization, strength interaction check, buckling verification, lateral torsional stability.