The Three Responses to Missing Loads
When connection loads are absent from the structural drawings, the detailer or connection engineer has three options: (1) RFI the EOR for loads — the correct approach, but adds time; (2) use conservative tabulated loads from the AISC 'Design Loads on Structures During Construction' or other reference — acceptable for simple connections, but may produce oversized connections; (3) assume loads based on member capacity — technically defensible but creates PE liability for the assumed load basis and should be explicitly documented.
How Load-Missing RFIs Are Structured
A well-structured load-missing RFI includes: the connection location (gridline, floor), the member sizes, a statement of what specific load data is needed (shear, moment, axial, or combination), the proposed load assumption if one is being offered, and the schedule impact. 'We need loads for 18 column base plate connections in the north bay — release of PKG-02 is held pending response.' This makes the RFI immediately actionable.
Preventing Load Gaps Before Detailing Starts
The most effective prevention is a pre-detailing kickoff that includes the EOR and walks through the connection load table. Load tables should show the maximum factored reactions at each connection type — not every individual connection, but the governing cases for each category (interior beam connections, exterior beam connections, column base plates, brace connections, etc.). A complete load table at kickoff eliminates 80% of load-related RFIs before they are ever written.
The Schedule Cost of Missing Load Data
Each missing load is a detailing hold on all connections of that type. A single missing brace connection load can hold 15 to 20 drawings in a braced frame bay while the RFI cycle runs. A complete set of missing loads — common when EORs issue structural drawings before load analysis is complete — can hold the entire detailing engagement. The clock on the detailer's schedule does not stop when RFIs are open; but the detailer cannot be held responsible for missing a fabrication release date when the EOR has not provided the information required to complete the drawings. Documenting this relationship — 'release of drawings PKG-03 is held pending responses to RFI-012 through RFI-027, all requesting missing connection loads' — creates the contractual basis for a schedule extension if the EOR takes more than the specified response window.
Consequence of Assuming Loads Without Documentation
When connection loads are assumed without documentation, the liability for the assumption rests with the PE who made it and the fabricator who proceeded on unapproved drawings. If the assumed load is later found to be non-conservative — the actual design load exceeds the assumed load — the connection may be under-capacity and require field remediation. The cost of that remediation is borne by whoever made the undocumented assumption. This is why load assumptions must always be documented in an RFI, submitted to the EOR, and recorded in the RFI log — even when the assumed load seems obviously conservative. The documentation transforms an assumption into a recorded technical decision with EOR involvement.
Common Connection Types Where Loads Are Typically Missing
Certain connection types consistently appear without loads on structural drawings because EORs assume they will be handled by the fabricator's standard practice — an assumption that does not survive a missing-load dispute.
- Column base plates — axial load, base shear, and overturning moment are often shown only on the column schedule, if at all
- Brace connections — axial force and eccentricity must both be provided; one without the other is insufficient
- Transfer beam connections — loads are frequently shown as 'TBD' because the analysis is not complete when drawings are issued
- Stair stringer-to-frame connections — often described verbally rather than numerically on structural drawings
- Equipment support frame connections — loads depend on equipment selection that may not be finalized at drawing issue
Building Load Provision Into the Detailing Contract
The detailing contract should explicitly state that connection design requires loads and that failure to provide loads within a defined timeline constitutes an owner-caused delay. This language converts the missing-load problem from a detailer's operational problem into a documented contract performance issue. When the contract contains this language, the detailer can issue a formal delay notice when loads are not received by the agreed date — a notice that triggers the schedule extension mechanism and documents the cause of delay for any future claim. Detailing contracts that do not address load provision timing leave both parties exposed to schedule disputes that could have been prevented with two sentences of contract language.