So laminated columns are shat together, not rolled at the factory.
So laminated columns have to support more loads than normal steel columns. Are they then manufactured in a similar way to 100 years ago when individual plates and angles were riveted together, or am I misunderstanding this now?
correct.
they are usually 3 or 4 inch thick plates (sometimes up to 6 or more in cases) that are welded together at the tips along the seam between the plates.
the capacity of the column, much like the capacities of other member types, is driven by the net section size, meaning the area of steel material of the member were you to take a slice of it and look at it head on like so “H”
long ago, they could not manufacture high quality thick plate. thick plate was usually just a casting, which without forging, is pretty weak.
old columns, prewar, like in the empire state building are are built up columns made up of plates and angles riveted together.
its important to remember that in old building the floor heights were much lower, which adds to the lateral strength, and column spacing was much tighter, maybe 20-24’ on center. now, 30-40’ column spacing is very normal, often more in some cases.
Rivets arent really used in construction anymore, its mostly welding and bolting.
Thank you both for the very informative and also interesting answer. Have cross-sections of such a column ever been published? About the construction of skyscrapers I have a few old (100 years old) books.
of old shapes or new shapes?
From new shapes.
Historic ones I have a few in the book; Woolworth, Singer, Met Life Building and a few others. But I’m also interested in how skyscrapers are built today. I started a topic about this a few months ago, but no one answers anymore.
I’m kind of curious about this too 
You can find them in the steel construction manual, there aren’t really any books that are informative with pictures of such related information for specific projects. Just the manuals with all the factors, integers and dimensions for calculations. It is not free though.
https://www.aisc.org/publications/steel-construction-manual-resources/
here is a site that has a nice table on rolled shapes and their data.
its from the 13th edition of the steel construction manual so it is outdated. the current edition is 15th and the 16th will be released later this year.
there have been some updates, particularly to column sections (W14) to include new jumbo shapes larger than W14x730 that are now readily available.
Indeed it is
It will be hard for the finished building to have the same allure as the raw steel going up, but that is just the archivist/photographer talking.
That’s a amazing shot! 
„ JPMorgan Chase’s Headquarters Approaches Supertall Status At 270 Park Avenue In Midtown East, Manhattan“
Does anyone know if all of those cylinders serve a purpose or are they just decorative?
The cylinders themselves are just decorative, but the louvers behind them are not, you can partially see them on the last photo.
So basically they are a decorative air vent. Thanks TKDV
