ACI 318-19 (SI Units) PDF

Full title and description

ACI CODE-318-19 (SI Units) — Building Code Requirements for Structural Concrete and Commentary (English language, SI units edition). This document contains the code provisions and accompanying commentary that set minimum requirements for materials, design, detailing, and construction of structural concrete for buildings and where applicable nonbuilding structures, presented using SI (metric) units for direct use in metric-design practice.

Abstract

ACI 318-19 (SI Units) translates the 2019 ACI structural concrete code provisions into SI units and pairs the mandatory Code provisions with explanatory Commentary. The Code addresses topics ranging from general requirements, notation and references, through member-specific provisions (slabs, beams, columns, walls), to special topics such as anchorage, seismic design, durability, and material properties; the Commentary provides background, research references, and guidance on intent and application.

General information

• Status: Published (ACI CODE-318-19); reapproved in 2022; later superseded by ACI CODE-318-25 (published 2025).
• Publication date: 2019 (ACI 318-19); SI/metric English edition published as the metric/“M”/SI version in the same 2019 release.
• Publisher: American Concrete Institute (ACI), Farmington Hills, MI.
• ICS / categories: 91.080 (Structures of buildings); related classification: 91.100 (Concrete and concrete products).
• Edition / version: ACI 318-19 (SI Units) — 2019 code year (metric/SI English edition derived from the official inch–pound version).
• Number of pages: 624 pages (Code and Commentary combined in the 2019 publication).

Scope

Applies to the design and construction of structural concrete members and systems used in buildings and, where applicable, nonbuilding structures. The Code establishes minimum requirements for strength, serviceability, durability, load combinations and factors, structural analysis, reinforcement detailing, development and splice lengths, anchorage, and special provisions for seismic and other extreme loadings; the SI edition presents those requirements using metric units for direct application in metric-based jurisdictions or projects.

Key topics and requirements

• General requirements for structural concrete design (material properties, notation, referenced standards).
• Load definitions, load combinations, and design factors for strength and serviceability.
• Member-level provisions: slabs (one‑ and two‑way), beams, columns, walls, diaphragms, foundations, and connections.
• Reinforcement requirements: minimum reinforcement, development and splice lengths, hooks and headed bars, detailing rules to ensure ductility and performance.
• Shear, torsion, and punching shear provisions (including strut-and-tie method guidance).
• Anchorage to concrete and qualification requirements for post‑installed anchors.
• Seismic design rules and requirements for special systems, including limits on rebar grades for certain seismic applications (updates included in the 2019 code cycle).
• Durability, materials and mixtures (concrete materials, alternative cements, aggregates) and performance-based considerations for long-term behavior.
• Commentary material providing rationale, research references, and examples to aid interpretation and implementation.

Typical use and users

Used by structural engineers, design firms, code officials, architects, materials engineers, contractors, and reviewers as the primary code reference for reinforced, prestressed, and cast‑in‑place concrete design where ACI provisions are adopted or referenced. The SI Units edition is specifically intended for projects and jurisdictions using metric units or for designers who prefer to work in SI units.

Related standards

Commonly used together with: the ACI Commentary (ACI 318R-19), the metric/“M” variant (ACI 318M-19) and later ACI CODE-318-25 (2025) when adopted; ASTM material and test standards referenced throughout the Code; related ACI documents on anchors (ACI 355 series), detailing manuals, and design handbooks (for example, the ACI Reinforced Concrete Design Handbook, which provides worked examples referenced to ACI 318-19). Jurisdictions frequently coordinate ACI 318 references with the International Building Code (IBC) and local adoption language.

Keywords

ACI 318, structural concrete, building code, SI units, metric, reinforced concrete, prestressed concrete, durability, seismic design, anchorage, development length, splice length, shear, serviceability, commentary.

FAQ

Q: What is this standard?

A: Building Code Requirements for Structural Concrete (ACI 318-19, SI Units) is the ACI standard and commentary that prescribe minimum requirements for the materials, design, detailing, and construction of structural concrete, presented in SI (metric) units for metric-based design practice.

Q: What does it cover?

A: It covers general code requirements, notation, referenced standards, loads and analysis, member design (slabs, beams, columns, walls, foundations), reinforcement detailing, anchorage, seismic requirements, durability and material provisions, and extensive Commentary explaining intent and background.

Q: Who typically uses it?

A: Structural engineers, architects, design firms, contractors, material suppliers, testing agencies, and building code officials involved in the design, review, construction, and inspection of reinforced and prestressed concrete structures—especially when metric (SI) units are required or preferred.

Q: Is it current or superseded?

A: ACI 318-19 was published in 2019 and reapproved in 2022. It has since been superseded by ACI CODE-318-25, published in 2025; designers should confirm which edition is adopted in their jurisdiction and use the edition required by the governing building code or project specifications. Specify dates when referring to “current” code (for example: ACI 318-19 published 2019; reapproved 2022; ACI 318-25 published 2025).

Q: Is it part of a series?

A: Yes — ACI 318 is part of the ACI suite of codes and standards. The Code has companion documents including the Commentary (ACI 318R), metric editions (ACI 318M), design handbooks, detailing manuals, and related ACI codes (for anchors, precast, post‑tensioning, repair, etc.). ACI updates the Code on a multi‑year cycle; later editions (for example 2025) continue the series.

Q: What are the key keywords?

A: Structural concrete, reinforced concrete, ACI 318, SI units, metric design, code requirements, commentary, durability, seismic design, anchorage, development length, splice, serviceability.