Structural Design GPT
Structural system selection, span-to-depth ratios, column grids, and coordination for architects.
Conversational structural systems guide for architects and engineers at early design stage. Covers structural system selection by building height and seismic zone, span-to-depth ratios for preliminary member sizing, column grid optimization, gravity load estimation, lateral system selection, foundation types, and CLT/mass timber coordination.
The Problem
Structural system selection at schematic design affects floor-to-floor height, column grid, lateral system placement, and construction schedule — but most architects select systems without knowing typical span-to-depth ratios, coordination clearances, or relative cost implications.
How It Works
Describe your building type, program, and structural intent. It recommends structural systems with typical span-to-depth ratios, column grid options, floor-to-floor height implications, lateral system requirements, and relative cost benchmarks.
"12-story concrete and steel hybrid — what lateral system for seismic design category D?""what is the typical beam depth for a 40-foot span in a steel office building?"Key Features
Who It's For
Architects making structural system decisions at schematic design in coordination with structural engineers.
This tool provides structural system guidance for early design decisions. All structural engineering must be performed by a licensed structural engineer. System selection must be verified by your structural engineer before committing to permit documents.
Frequently Asked Questions
What is the span-to-depth rule of thumb for steel beams?
For simply supported steel beams, a common rule of thumb is span/20 for total depth. A 40-foot span typically requires a W18-W21 beam. Always verify with your structural engineer — deflection, vibration, and connection type all affect final sizing.
When should I use a concrete shear wall vs a steel moment frame?
There is no universal system choice by story count or seismic design category. Compare the applicable ASCE 7 system permissions and height limits, material standard, loads, drift, torsion, redundancy, foundations, architecture, construction market, and project-specific engineering analysis.
What structural system is most economical for a 6-story wood-frame residential building?
No system is automatically most economical from use and story count alone. Compare the adopted-code permissions, construction subtype, fire protection, site hazards, spans, lateral system, podium or mass-timber options, labor market, schedule, insurance, and local pricing with the structural engineer and contractor.