ACI PTI CODE 320-25 PDF

Full title and description

ACI/PTI CODE-320-25: Post-Tensioned Structural Concrete — Code Requirements and Commentary. A joint code published by the American Concrete Institute (ACI) and the Post-Tensioning Institute (PTI) providing code-format requirements and an explanatory commentary specifically addressing the materials, design, detailing, construction, inspection, and quality assurance of post-tensioned (bonded and unbonded) structural concrete.

Abstract

This Code establishes minimum mandatory requirements and supporting commentary for the use of post-tensioning in structural concrete for buildings and, where applicable, other structures. It covers bonded and unbonded tendon systems, anchors and anchorage zones, transfer and long-term losses, durability and corrosion protection, construction and installation practices, testing and inspection, and interface provisions to ACI CODE-318 practice. The Commentary explains rationale, examples, and interaction with related ACI and PTI guidance.

General information

• Status: Published; first edition issued as a joint ACI/PTI code.
• Publication date: Spring 2025 (official delivery and availability completed in 2025).
• Publisher: American Concrete Institute (ACI) in cooperation with the Post-Tensioning Institute (PTI).
• ICS / categories: Construction materials and building — ICS 91.100 (Concrete and concrete products) / ICS 91.080.40 (Concrete structures).
• Edition / version: ACI/PTI CODE-320-25 (2025 edition).
• Number of pages: Approximately 168 pages (PDF and hard copy formats reported).

Scope

Provides minimum code-format requirements and accompanying commentary for the materials, design, detailing, fabrication, erection/installation, testing, inspection, and maintenance of post-tensioned structural concrete elements. The Code addresses both bonded and unbonded tendon systems, transfer of prestress, short- and long-term prestress losses, anchorages and anchorage zone design, corrosion protection and durability provisions, construction sequence and tolerances, and required quality control/assurance and inspection procedures. It is intended to be used together with ACI CODE-318 where general concrete requirements are needed and with other ACI or PCI documents where applicable.

Key topics and requirements

• Definitions and system classifications for bonded and unbonded post-tensioning.
• Material requirements for tendons, anchors, ducts, grouts, and accessories.
• Design provisions for strength, serviceability, and fatigue specific to post-tensioned members.
• Transfer of prestress, computation of short- and long-term losses, and required documentation of losses.
• Anchorage zone design, detailing of anchorage devices, and anchorage reinforcement requirements.
• Durability and corrosion protection (ducting, grouting, coatings, inspection access, and monitoring considerations).
• Construction and installation requirements: tensioning, stressing procedures, sequence, tolerances, and field testing.
• Inspection, testing, acceptance criteria, and quality assurance/quality control responsibilities.
• Commentary with examples, explanations of intent, and references to related ACI/PTI technical documents and recommended practices.

Typical use and users

Used by structural engineers, specialty post-tensioning designers, concrete and post-tensioning contractors, code officials, building officials, inspection agencies, owners and developers, and university programs focused on prestressed/post-tensioned concrete. It is applied during design, contract specification, construction oversight, inspection, and forensic or repair work on post-tensioned structures.

Related standards

Complements and is intended to be used in conjunction with ACI CODE-318 (Building Code for Structural Concrete). Related references include ACI/PCI CODE-319 (precast/prestressed concrete provisions where applicable), ACI CODE-562 (repair and rehabilitation guidance), PTI recommended practices and design manuals, and industry test/inspection standards. The Code has been added to ACI's digital subscription platform and to PTI distribution channels.

Keywords

post-tensioned, post-tensioning, PTI, ACI, prestressed concrete, bonded tendon, unbonded tendon, anchor, anchorage zone, transfer of prestress, prestress losses, durability, corrosion protection, inspection, code, commentary, ACI 320, CODE-320-25.

FAQ

Q: What is this standard?

A: ACI/PTI CODE-320-25 is the joint ACI and PTI code document that sets code-format requirements and provides explanatory commentary specifically for post-tensioned structural concrete systems (2025 edition).

Q: What does it cover?

A: It covers materials, design criteria, detailing rules, anchorage and anchorage zone design, transfer and long-term losses, construction and stressing procedures, durability and corrosion protection, testing and inspection, and related quality assurance requirements for bonded and unbonded post-tensioned concrete elements.

Q: Who typically uses it?

A: Structural engineers, specialty post-tensioning designers, concrete contractors, post-tensioning installers, building/code officials, inspectors, owners, and academic programs working with prestressed/post-tensioned concrete.

Q: Is it current or superseded?

A: As published in 2025, this document is the current first edition of ACI/PTI CODE-320-25. It represents a new, jointly published code and is not superseded as of its 2025 release; users should verify later amendments or editions from ACI or PTI for updates.

Q: Is it part of a series?

A: Yes. CODE-320-25 is part of the family of ACI code documents and is intended to be used with ACI CODE-318. It is coordinated with related ACI/PCI and PTI documents such as ACI/PCI CODE-319 and PTI recommended practices and manuals.

Q: What are the key keywords?

A: Post-tensioned, post-tensioning, prestressed concrete, bonded tendon, unbonded tendon, anchor, anchorage zone, prestress losses, durability, inspection, ACI, PTI, CODE-320-25.