Can you help me with the symbols on these drawings?

[gerrycan]

Hi, I'm new to this forum, and not a welder. Just interested in engineering and construction. My question is in regard to these drawings here.

http://img861.imageshack.us/img861/6...0schematic.jpg

http://img688.imageshack.us/img688/8...0sectionaa.jpg

http://img593.imageshack.us/img593/8936/1370plan.jpg

The girder in the drawings is a W33 x 130, and the column is a W21.5/8 x 665.

My question is this:- What would you expect to do to the girder after the assembly phase?

As I said, I am not a welder so forgive me if this is a total novice question. Thanks in advance.

[shovelon]

Are you asking how these are welded after parts are positioned?

The third drawing says nothing to me, but the other two have fillet or groove welds with sizes to the left of the fillet or groove symbol. The length of weld is to the right of the fillet or groove symbol. The groove prep is in the center of the groove symbol. Fillet symbol above and below the baseline are arrow side and other side, or in other words both sides. A weld symbol below the baseline is arrow side only. A symbol above is other side of arrow. Anything put in the tail of the baseline is for notes.

The baseline is always horizontal. The line coming off the baseline and going to the arrow is called the leader. The leader can go in any direction and make any turn, but the arrow decides arrow side.

[gerrycan]

Thanks for looking at this. What I am trying to find out is exactly what welding would occur here where the web and flange surfaces meet the column, either before or after the elements are in place and bolted. i.e. Is it standard practise to bolt these parts together, and then weld around the edge, or weld around the bolts after they are torqued up?

[shovelon]

These look like subassemblies. I don't see any notes indicating bolting together before weld.

There is a lot of missing information here. There should be noteblocks to fill in the blanks.

[mrmikey]

The first two drawings are the actual fabrication drawings, what the steel shop would build for the ironworkers to assemble on site.
For example, on the first drawing there are two plates, 1-PL-PC and I-PL-PB. PL-PB for instance is set at a distance of 18'-9-3/8" from the end of the beam and the top surface is ground flat for a bearing surface for something else, a horizontal joist I would presume.
The gussett plate, PL-PC, is beveled 45° on the far side with a zero gap and has a 5/8 fillett with partial penetration.
The reason the plates are not detailed as to size and hole dimension is that it's probably a standard detail.
Section AA is a section thru a beam showing the details and their horizontal placement, you'd have to look at the elevation to get their vertical placement. I have seen drawings like that with no elevation and the heights are just noted on the details, usually to the top.
The third drawing is what the ironworkers would use to erect the steel, they're done in line form as there's no sense in already drawing details that have no bearing on erection. Besides, the fitters don't make mistakes so they'll be right where they're supposed to be :-)......Mike

[gerrycan]

Thanks for this. Im starting to get a clearer idea of what is represented here thanks to the info you are giving. Kudos to you, and to this site - great resource. Thanks , Gerry

[kawika]

Originally Posted by mrmikey

The first two drawings are the actual fabrication drawings, what the steel shop would build for the ironworkers to assemble on site.
For example, on the first drawing there are two plates, 1-PL-PC and I-PL-PB. PL-PB for instance is set at a distance of 18'-9-3/8" from the end of the beam and the top surface is ground flat for a bearing surface for something else, a horizontal joist I would presume.
The gussett plate, PL-PC, is beveled 45° on the far side with a zero gap and has a 5/8 fillett with partial penetration.
The reason the plates are not detailed as to size and hole dimension is that it's probably a standard detail.
Section AA is a section thru a beam showing the details and their horizontal placement, you'd have to look at the elevation to get their vertical placement. I have seen drawings like that with no elevation and the heights are just noted on the details, usually to the top.
The third drawing is what the ironworkers would use to erect the steel, they're done in line form as there's no sense in already drawing details that have no bearing on erection. Besides, the fitters don't make mistakes so they'll be right where they're supposed to be :-)......Mike

Thank you for these details.

I would like to understand what might be the standard practice at this type of connection.

Given the level of detail seen, it appears the tolerances were quite close. I would expect that the elements would be closely fitted and then some field welding would take place to connect the column to the girder. I would expect this to be along the web and flange where it met the column face and even where the flange met the seat and top plates.

Is there a section in the standards book(s) that would speak about this?

I am not an engineer, just a layperson hoping to understand this better. My interest stems from the study of a major building collapse. It has been impossible to obtain all of the necessary drawings.

Thank you again.

[mrmikey]

....and then some field welding would take place to connect the column to the girder.

Sometimes there is field welding but there's none on this one, or at least there's none detailed. The field weld symbol is a flag at the intersection of the arrow to the body of the horizontal line of the welding symbol. Look at he symbol shovelon posted.....Mike

[NHMatt]

Tolerances on structural steel are miles long compared to machining. Overall length on beams and columns can be off by +-1/8". Dimensions for the connection holes can be off as much as well. When erecting the steel you would be surprised what a bull pin and a 10 lb beater can do.

[Dualie]

what cant be accomplished with a pull pin and a 5lb beater can be with a chain fall, and a reamer and a pissed off iron worker