The Concrete Reinforcing Steel Institute (CRSI) Handbook containing all the engineering specifications, codes and engineering examples was a 300 plus page hard cover perfect bound book. Every time codes changed in a certain section it required a new printing and destruction of the old books. This became very costly as some sections changed more often than others. To alleviate that expense and waste, the handbook was spit into smaller softcover books per chapter/subject that could be easily updated and sold as required in both print and digital formats. The Design Guides were designed to be contained in a standard 3 ring binder so the end user could replace the old books with the updated for a minimum cost.
