Connection Detailing to Engineer-Specified Connections

Connection detailing turns the engineer's connection design into dimensioned, fabricable geometry on shop and erection drawings. The detailer takes the connection details, schedules, design forces and requirements in the contract documents and shows plate sizes, bolt diameter, grade and length, hole types and locations, weld sizes and symbols, and the clearances needed to build and erect the joint.

It is detailing, not engineering. The engineer decides what a connection must be. The detailer decides how to draw it so the shop can cut, drill and weld it and the field crew can bolt it up, and checks that the drawn geometry still matches what the engineer specified.

No. Connection design, meaning determining that a connection has the strength and stiffness the design forces require, belongs to the Engineer of Record or to a delegated connection engineer licensed for the project, as the contract documents assign. Vertex details that design. It does not stamp or sign connection designs, take design responsibility, or supply a delegated engineer.

Stating this plainly protects you. Design responsibility stays with a licensed engineer who carries it, the approval process stays clean, and nobody on your project assumes a detailer has checked capacity when it has not.

Vertex details the common structural steel connections found on commercial and industrial packages, always as designed or specified by the Engineer of Record or delegated engineer. The connection type, bolt grade, joint type and weld requirements come from the contract documents; the detailing work is showing each one completely and consistently.

• Single-plate shear connections (shear tabs) and double-angle connections
• Shear end plates and seated connections
• Moment connections as designed, including flange plates and end plates
• Vertical and horizontal bracing connections with gusset plates
• Column base plates and anchor rod patterns
• HSS connections, including cap plates, through plates and slotted-tube details
• Thermally broken connections, covered on the structural thermal break detailing page

The detailer needs to know who is responsible for connection design, the forces or details each connection must meet, and any special requirements for bolts, welds and inspection. Without that, connections either stall or get guessed, and guessed connections come back from approval with comments or, worse, get fabricated wrong.

AISC 303, the Code of Standard Practice, recognizes that connections can be designed by the Engineer of Record and shown in the design documents, or delegated to a licensed engineer engaged through the fabricator. The contract documents must state which approach applies. For the detailer, the task is the same either way: detail the design, not create it.

In practice, delegated design changes the order of work. The delegated engineer's calculations and details usually come before or alongside the shop drawing submittal, and the detailer models connections to that design. If design forces change during the project, the connection design is revised first and the detailing follows. Your specifications, not the detailer, decide which route your project takes.

For more on how the Code of Standard Practice and AISC 360 shape drawings, see AISC standards for steel detailing.

Even when the engineer supplies the design, the detailer applies the dimensional rules that make a connection buildable: minimum bolt spacing and edge distances, hole types and sizes, bolt entering and tightening clearances, weld symbols, and erection clearances. These come from AISC 360, the RCSC Specification, the AISC Steel Construction Manual and AWS A2.4.

On the reference project, frame connections used A325N snug-tightened bolts in 13/16" holes, which set both the hole call-outs on the shop drawings and the entries on the field bolt lists.

SDS/2 can generate connection geometry automatically from connection types, preferences and input forces. On Vertex jobs, those inputs come from the Engineer of Record's design and your shop standards, and the output is checked against the engineer's details. Where the software's result differs from the contract documents, the documents govern and the difference becomes a question.

The automation earns its place in consistency and speed: hundreds of similar shear connections get the same plate thicknesses, bolt gauges and clearances without being drawn one at a time. It does not transfer design responsibility to the software or to the detailer. See SDS/2 detailing and 3D modeling for how the rest of the platform is used.

Missing connection information goes back as an RFI through your contractual channel, with the affected pieces identified by grid and member. The engineer then supplies details, confirms a typical detail applies, or the project assigns the connections for delegated design. The affected connections are held or clearly flagged on the drawings in the meantime, never assumed.

That approach costs a few days on the connections in question, not weeks of rework after fabrication. Detailing hours spent on connections, including complex ones, are billed like any other detailing work, and connection complexity is one of the factors on the steel detailing rates page. How every connection is checked before release is on the quality control page.