The Ministry of Housing and Urban-Rural Development has issued a new regulation, the "Standard for Seamless Construction of Super-Long Concrete Structures" JGJ/T492-2023, effective from May 1! The standard provides a detailed explanation of the requirements for raw materials, construction measures, verification of technical parameters, special construction plans, curing, and monitoring when seamless construction methods (mainly the alternate bay method and expansion reinforcing strips) are adopted for super-long structural concrete, providing a reliable basis for the demonstration of schemes to replace post-cast strips in various engineering projects.

During the construction of super-long concrete structures, how to solve the cracking problems caused by cold shrinkage and dry shrinkage in mass super-long concrete structures, as well as the harm caused by tensile stress, is a technical challenge. The traditional practice of setting post-cast strips increases construction time, and at the same time, cleaning and construction involve a certain degree of difficulty; if not properly handled, it will affect the quality of the entire project.

Traditional post-cast strip practice

The new regulation clarifies that seamless construction of super-long concrete structures may, according to construction conditions, adopt measures such as the post-cast strip method, expansion reinforcing strip method, alternate bay method or alternate bay progressive method, prestressing method, sliding construction method, low-temperature bay filling method, induced joint method, and comprehensive treatment method to control the occurrence of concrete cracks. Among these, the construction key points of the alternate bay method and expansion reinforcing strips are emphasized.

Alternate bay method

Expansion reinforcing strip

Announcement of the Ministry of Housing and Urban-Rural Development on the Issuance of the Industry Standard "Standard for Seamless Construction of Super-Long Concrete Structures"

The "Standard for Seamless Construction of Super-Long Concrete Structures" is hereby approved as an industry standard, with the number JGJ/T492-2023, effective from May 1, 2023. This standard is published on the portal website of the Ministry of Housing and Urban-Rural Development (www.mohurd.gov.cn), and the Institute of Standards and Quotas of the Ministry of Housing and Urban-Rural Development has organized China Architecture Publishing & Media Co., Ltd. to publish and distribute it.

Ministry of Housing and Urban-Rural Development

January 5, 2023

Attachment: Standard for Seamless Construction of Super-Long Concrete Structures