HSS Connection Welds and Detailing Responsibility?

[gregroberson]

I am trying to define the responsibilities of parties involved in a complicated pipe truss included in a project my company is bidding. We are bidding for structural steel detailing and connection design for a commercial structure. Additionally, there is a fairly complex interconnected truss structure at the roof. After reviewing the AISC 13th manual and the HSS Connection manual, it is obvious there are significant geometrical consideration unique performing calculations in pipe-to-pipe welds (or HSS-to-HSS).

Work-points and loads are provided for the truss members. Any engineer, detailer, fabricator and/opr inspector comments are greatly appreciated. We definitely don't want to miss this on the bid, if we are uninformed, this could be a big-ticket item that really bites us. My basic questions are as follows:

As the connection engineer for the project: is my company responsible for more than specifying the welded type, size and length (weld information)? Or is the connection engineer expected to provide all the weld profile requirements and "zone" information.

As the steel detailer for the project: is my company required to show more than the prequalified weld on the joint? I assume it is similar to indicated a prequalified weld for any other joint and the AISC fabricator is required to follow or adhere to approved welding procedure specification (WPS) and/or procedure qualification record (PQR). Thus, The material would be "fit-exact" and detailed to be placed around the supporting member and the additional weld preps required and/or profile shaping and weld backing build-up would be in the responsibility of the fabricator.

Sincerely,
Greg

 

[dik]

What is specified in the drawings and/or specifications? If nothing, you may want to raise the question and have them post a memorandum about the change (addendum or whatever).

Dik

 

[gregroberson]

There is a general note stating "CONTRACTOR SHALL DESIGN ALL CONNECTIONS AND SPLICE CONNECTIONS SHOWN, NOT
SHOWN, OR ONLY PARTIALLY DETAILED ON THE DRAWINGS. CONTRACTOR SHALL RETAIN A
REGISTERED PROFESSIONAL ENGINEER LICENSED IN THE STATE OF OKLAHOMA TO DESIGN
ALL SPLICES AND CONNECTIONS SHOWN, NOT SHOWN, OR ONLY PARTIALLY DETAILED ON THE
DRAWINGS INCLUDING BUT NOT LIMITED TO TRUSS CONNECTIONS, PURLIN CONNECTIONS,
AND COLUMN SPLICES".

Also, the type is often shown and the size is noted "FABRICATOR SHALL SIZE WELDS FOR GIVEN FORCES"

The drawings look nice and they show alot of information and sections. This is not a case of anyone shluffing their responsibilities, I was just wondering how these special connections are handeled by other connection engineers.

 

[dik]

All you need is the connection forces... are these detailed? or do the documents stipulate a minimum connection? If not, then you still need added info.

Dik

 

[gregroberson]

The connection forces are provided. However the welds are not. The AISC has some pretty complex welding requirements for prepping the end of the steel pipe/tube. If I specify the weld information, do all the material end preparations associated with the weld (such as shape profiling ) and or weld backing build-up my companies responsibility?

Greg

 

[dik]

Based on the notes and if the forces are given, I would suggest that the connection design is yours

Dik

 

[gregroberson]

I need to review the HSS connection manual and the AISC's chapter K further to really even know what is required. Thanks for you your comments.

 

[a2mfk]

I agree with DIK. If you are the delegated engineer for all steel connections, then the EOR must provide to you ALL forces for every connection. Of course in a truss, this is not as simple as a gravity beam reaction, you have compression and tension forces also. But I think if you are bidding the job for ALL connection design, then you definitely must engineer, design and detail all the connections, including end preparation and all welding details.