Building Code Glossary
Allowable Stress Design: Building Code Definition
How the IBC 2009 define allowable stress design, where the wording differs, and which chapters depend on the term.
On this page
Last updated September 7, 2026 · Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.
Direct answer
Allowable stress design is a defined term in the International Building Code (IBC) 2009, in Structural Design. The code's own words are: “A method of proportioning structural members, such that elastically computed stresses produced in the members by nominalloads do not exceed specified allowable stresses (also called "working stress design").” No other I-Code in this corpus defines it, so the IBC 2009 definition is the one to work from. The term is used in 7 chapters of this corpus, most often in Structural Design (IBC 2009), Masonry (IBC 2009), Wood (IBC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted. Record the jurisdiction, the adopted edition, the application date and any local amendment that rewrites the definition before you use it on a live project, because a term redefined by amendment changes every requirement that depends on it.
Content and cited inputs reviewed by Scott Barrington, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.
What does this term mean?
Allowable Stress Design — IBC 2009, Structural Design:
A method of proportioning structural members, such that elastically computed stresses produced in the members by nominalloads do not exceed specified allowable stresses (also called "working stress design").
What must be verified before using this guidance?
Allowable Stress Design is defined once in this corpus, in the Structural Design chapter of the International Building Code (IBC) 2009:
A method of proportioning structural members, such that elastically computed stresses produced in the members by nominalloads do not exceed specified allowable stresses (also called "working stress design").
Where allowable stress design is used in the code
The term appears in 7 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Structural Design | IBC 2009 | 11 |
| Masonry | IBC 2009 | 8 |
| Wood | IBC 2009 | 5 |
| Concrete | IBC 2009 | 4 |
| Soils and Foundations | IBC 2009 | 3 |
| Floors | IRC 2009 | 3 |
| Definitions | IBC 2009 | 1 |
The term in use
How the code actually writes about allowable stress design, quoted from the 2009 text hosted here:
Building, structures and parts thereof shall be designed and constructed in accordance with strength design, load and resistance factor design, allowable stress design, empirical design or conventional construction methods, as permitted by the applicable material chapters.
Masonry designed by the allowable stress design provisions of Section 2101.2.1, the strength design provisions of Section 2101.2.2 or the prestressed masonry provisions of Section 2101.2.3 shall comply with Section 2105.
The provisions of this section shall govern the allowable stress design of headed bolts and headed stud anchors cast in normal-weight concrete for purposes of transmitting structural loads from one connected element to the other.
Allowable Stress Design compared with Strength Design
These two are the closest pair in the 2009 I-Codes: about 45 per cent of their defining words are the same. The code states both and compares neither, so the difference is worth naming.
| Wording unique to it | |
|---|---|
| Allowable Stress Design (IBC 2009) | elastically, stresses, nominalloads, specified, allowable, working, stress |
| Strength Design (IBC 2009) | forces, factored, loads, member, strength, load, resistance, factor, lrfd, term, used, concrete |
Everything else in the two definitions is shared. If a project turns on which of the two applies, those words are the whole of the test — and a local amendment that edits one of them without editing the other moves the boundary between allowable stress design and strength design.
Allowable Stress Design: what to open, and in what order
Every row is a document this term depends on. The ICC code library and the ICC adoption maps cover the middle rows.
| Check | Where | Confirmed |
|---|---|---|
| Read the definition in the adopted IBC | Structural Design | |
| Re-check the requirement that uses it | Structural Design (IBC 2009) | |
| Re-check the requirement that uses it | Masonry (IBC 2009) | |
| Re-check the requirement that uses it | Wood (IBC 2009) | |
| Re-check the requirement that uses it | Concrete (IBC 2009) | |
| Local amendment to any of the above | Jurisdiction's amendment list |
A research aid, not a code determination. The authority having jurisdiction decides which edition and which amendments apply.
Where can you explore related guidance?
- Explore all glossary guidance
- Design Flood Elevation: Building Code Definition
- Loads: Building Code Definition
- Seismic Design Category: Building Code Definition
- Design Flood: Building Code Definition
Sources and method
Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The ICC code library publishes the current model text and the ICC adoption maps show which edition a jurisdiction has adopted; those sources control.
Source links
Frequently asked questions
What is the code definition of allowable stress design?
The International Building Code (IBC) 2009 defines it in Structural Design as: “A method of proportioning structural members, such that elastically computed stresses produced in the members by nominalloads do not exceed specified allowable stresses (also called "working stress design").” The 2009 model text is reproduced here; the definition that binds your project is the one in the edition your jurisdiction has adopted, as amended locally.
Which parts of the code depend on allowable stress design?
In this corpus the term is used across 7 chapters, led by Structural Design in the IBC 2009. Those are the sections whose scope moves if the definition is amended locally, so read them together with Chapter 2 rather than on their own.
What is the difference between allowable stress design and strength design?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Structural Design: “A method of proportioning structural members, such that elastically computed stresses produced in the members by nominalloads do not exceed specified allowable stresses (also called "working stress design").” It is defined in IBC 2009. It is not the same as Strength Design, which the IBC 2009 defines separately as “A method of proportioning structural members such that the computed forces produced in the members by factored loads do not exceed the member design strength [also called "load and resistance factor design" (LRFD) ]. The …” Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.
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