ACI/PTI CODE-320 : 2025

Description: The “Post-Tensioned Structural Concrete—Code Requirements and Commentary” (“Code”) provides minimum requirements for the materials, design, and detailing of post-tensioned concrete buildings and, where applicable, nonbuilding structures. This Code was developed by using a consensus process and addresses structural concrete members and systems that contain post-tensioned tendons. The Technical Advisory Board Code Task Group of the Post-Tensioning Institute was instrumental in the development of code provisions and commentary for this Code and whose efforts are gratefully acknowledged. Among the subjects covered are: design and construction for strength, serviceability, and durability; one-way slabs; two-way slabs; beams; post-tensioning anchorages; construction document information; and field inspection and testing.

This Code adheres to the chapter and section numbering of ACI CODE-318-25 and either references or repeats applicable provisions from ACI CODE-318. Provisions that are identical to ACI CODE-318 and are repeated in this Code are denoted with an equal sign (“=”). Provisions that are applicable to post-tensioned concrete but are not repeated in the Code are denoted as “See ACI CODE-318.” The Code organization is such that all design and detailing requirements for structural systems or for individual members are presented in chapters devoted to those individual subjects, and the chapters are arranged in a manner that generally follows the process and chronology of design and construction. Information and procedures that are common to the design of multiple member types are located in utility chapters. Within chapters, the terms “out of scope” are used for numbered section headings from ACI CODE-318 that are not covered by this Code, while the term “intentionally left blank” is used as a place holder to maintain consistency with section numbering in situations where ACI CODE-318 includes a numbered provision that is not also in this Code.

Uses of the Code include adoption by reference in a general building code, and earlier editions have been widely used in this manner. The Code is written in a format that allows such reference without change to its language. Therefore, background details or suggestions for carrying out the requirements or intent of the Code provisions cannot be included within the Code itself. The Commentary is provided for this purpose. Some considerations of the committee in developing the Code are discussed in the Commentary, with emphasis given to the explanation of new or revised provisions. The commentary also provides explanations regarding situations where use of ACI CODE-318 and this Code are used. For instance, design of cast-in-place, nonprestressed concrete members or structures requires the use of ACI CODE-318 alone. Design of post-tensioned concrete structures requires the use of this Code and ACI CODE-318. Design of precast, post-tensioned concrete structures requires the use of applicable provisions of this Code, ACI CODE-318, and ACI-PTI CODE-319. For provisions that specifically address precast concrete and are generally not within the scope of post-tensioning, this code references either ACI CODE-318 or ACI-PTI CODE-319, where applicable.

Much of the research data referenced in preparing the Code is cited for the user desiring to study individual questions in greater detail. Other documents that provide suggestions for carrying out the requirements of the Code are also cited, including PTI design manuals, recommended practices, and reports.