For structural steel connections, there are three different ways to show the details on the Structural Engineer’s drawings as defined by the American Institute of Steel Construction (AISC) Manual of Code of Standard Practice for Steel Buildings and Bridges. This Code provides a “framework for a common understanding of the acceptable standards when contracting for structural steel.”
The three options for steel connection details are explained in section 3.1.1 as follows:
Option 1: the complete connection design shall be shown on the structural design documents.
Option 2: in the structural design documents or specifications, the connection shall be designated to be selected or completed by an experienced steel detailer.
Option 3: in the structural design documents or specifications, the connection shall be designated to be designed by a licensed engineer working for the fabricator.
Indicating one of these options for each connection on the structural design documents provides clarification of responsibilities for the Structural Engineer of Record (SER), the Steel Fabricator and the Fabricator’s Engineer.
Option 3 has long been common in the eastern part of the United States, including New York. The SER provides information necessary to design the connections on the documents, the fabricator submits calculations with the shop and erection drawings to the SER for review and approval. Option 1 is common when the SER wants to provide more control over the details to meet particular project needs, such as ductility of seismic connections, the aesthetics in architecturally exposed steel connections or to jump start the schedule.
At 510 Madison Avenue, GMS designed the connections in the braced frames during the bidding and negotiation phase of the project, then issued an addendum to the structural design documents prior to the signing of the steel contract. This saved a few months of time by providing additional information to the Fabricator and reducing the amount of back and forth discussion during shop drawing review between the SER and the Fabricator’s Engineer.
The Code commentary suggests a pre-detailing conference once the steel contract is signed for the SER, Fabricator and Fabricator’s Engineer to discuss expectations including schedule, types of connections and loading questions. Communication is essential for a successful project, so start with drawings and specifications that clearly state who will be responsible for the connection design. And explain what shop drawings and submittals will be required.
GMS believes that participating in professional organizations like AISC, allows our engineers to learn about best practices and innovative technologies from others in our industry. Ramon Gilsanz is a member of the AISC Committee on Specifications as well as Task Committee #3 – Loads, Analysis & Stability. Please give one of us a call if you would like more information.