ACI 318
The design standard for reinforced and prestressed concrete in buildings.
Quick Answer
ACI 318, Building Code Requirements for Structural Concrete, is the American Concrete Institute standard covering the design and construction of structural concrete in buildings. It sets requirements for materials, member design, reinforcement detailing, and durability, and is adopted into law through reference in the International Building Code.
The Full Picture
ACI 318 is the primary U.S. reference for designing structural concrete. Developed by the American Concrete Institute through a consensus committee, it is not a law on its own, but the IBC references it, so its provisions become enforceable where the IBC is adopted. Editions are revised on a multi-year cycle, and each IBC edition cites a specific one.
The document covers a wide range of topics: concrete materials and durability, load combinations and strength reduction factors, design of beams, slabs, columns, walls, and foundations, development and splicing of reinforcement, prestressed concrete, and seismic detailing requirements for structures in higher seismic regions. It also includes provisions on anchoring to concrete and on construction-related topics.
Structural engineers use ACI 318 alongside ASCE 7. ASCE 7 determines the loads and combinations, and ACI 318 determines how concrete members are proportioned and reinforced to resist them. The result appears on structural drawings as member sizes, reinforcement schedules, and general notes specifying concrete strength and cover.
Contractors and estimators see ACI 318 in the details, such as reinforcement quantities and congested connections, and in specification sections that reference concrete mix and placement requirements. Companion ACI documents, including the ACI 301 specification for structural concrete, address the construction side.
Real Examples
Common Misconceptions
People assume: ACI 318 is the specification contractors follow to place concrete.
Actually: ACI 318 is a design code. Construction requirements are typically in the project specifications, often referencing documents such as ACI 301.
People assume: Following ACI 318 is optional guidance.
Actually: Where the adopted building code references it, it is a legal requirement for structural concrete design.
Does MeltPlan Solve This?
Partially — adjacentMeltPlan Code can help teams research which concrete-related code provisions apply and find potential compliance gaps. It does not perform structural design or verify reinforcement, which stays with the structural engineer. MeltPlan Takeoff can quantify concrete from drawings.
Research concrete code requirements →Frequently Asked Questions
What does ACI 318 cover?
Design and detailing of structural concrete, including materials, durability, members, reinforcement, prestressing, anchoring, and seismic provisions.
Who publishes ACI 318?
The American Concrete Institute, through a consensus committee process.
How is ACI 318 adopted?
The International Building Code references a specific edition, and jurisdictions that adopt the IBC thereby make that edition enforceable.
How does ACI 318 relate to ASCE 7?
ASCE 7 provides the loads and load combinations. ACI 318 provides the requirements for designing concrete members to resist them.
Does ACI 318 apply to steel buildings?
No. Steel is governed by AISC standards such as AISC 360. ACI 318 covers concrete, including composite elements that use concrete.