Structural system selection 4

[sedesigner06]

I am trying to develop a better understanding of structural system specifically steel vs concrete. The best way I could think of doing this listing some of the controlling factors and trying to decide which one is better than the other. I realize there are some factors that are based on individual project needs such as lateral forces, vibration criteria,climate,material avaliability, bay size (all could be topic by themselves)ect. Taking all things equal this is my opinion! Feel free to disagress

SPEED OF CONSTRUCTION (steel)

COST OF CONSTRUCTION (concrete)

VIBRATION CAPACITY (concrete)
HIGH LATERAL FORCES (concrete)
EASE OF CONSTRUCTION (steel)


Thank in advance for your opinion.

 

[idecharlotte]

Cross Laminated Timbers FTW.Beats them all.

http://www.idecharlotte.com

 

[AELLC]

Depends on the building - multistory condo could be best done w/ post-tension flat conc slab, etc.

Or CLT (hehe) if the designer and plans checker are OK with that.

 

[CELinOttawa]

Have a look at the PRESS system out of Canterbury University in New Zealand if you think Timber can't do low to medium height multi-storey structures.... And it is still mucch cheaper than steel or concrete!

But I'd still prefer to buy a unit in a Concrete building. *blush*

 

[rowingengineer]

Horses for courses.

Each project has a certain set of requirement that will dictate which material can be efficient for use in a building. understanding these requirements and selecting the best materials is part of the process.

however the main reason for section of materials is durability performance and ease of maintenance and protection.

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[CELinOttawa]

I have a collection of twenty or so pages from a variety of "rule of thumb" sources which allow me to quickly determine probable system sizes and thicknesses. I have most of them memorized (SPAN/X, etc) and as such can generally discuss the benefits and drawbacks of most systems with a client on the spot.

I highly recommend you get a few "shortcut" papers to add into this collection.

 

[sedesigner06]

CELinOttawa,

Thats the type of information i am in search for, do you have any good books or resources for these rules of thumb? Thanks for the input.

 

[AELLC]

A lot of it is common sense, no book required.

 

[TXStructural]

Speed of construction is advantage:concrete is many cases, but one cannot generalize in any meaningful way about which material is better. There are places, design constraints, and supply issues which push projects one way or another. All design decisions are a trade off (cost v time, weight v strength, elegance v expense) so the goal is to pick the material, system, and methods which achieve the goals of the owner.

 

[AELLC]

Concrete except for low rise bldgs. where steel and wood have advantages, usually

 

[TXStructural]

Low rise concrete is economical if the right form system is used. ICFs make 1-4 story concrete very easy, but normal formed concrete is equally economical for experienced contractors. But as always, it depends on the goals of the design.

 

[CELinOttawa]

Okay, here's the list I use on a regular basis (excluding all of my own hand notes and custom tricks/methods):

- PCA's "Concrete Floor Systems" (Guide to Estimating and Economozing - SP041.01B
- HERA Steel Advantage Steel Estimation sheets (x3)
- Design Software for Masonry Design by the Atlantic Masonry Research & Advisory Bureau (Handout from a course on a Software package which contains all the rules they programmed in for estimation)
- SteelWise Chevron Bracing in Low-Rise Buildings
- Element Size Estimation from The Structural Engineer, October 2012 (UK resource)

Occassionally:
- Engineer's Notebook "Soil Pressure under Footings"

Rarely (BUT MOSTLY when working with Historical work!):
- Ketchum's "Structural Engineer's Handbook"

 

[AELLC]

ICF is too expensive and is a joke as to guessing what the real structural capacity is. Anyone want to guess where the rebar is located in the thickness of wall, and how badly the concrete is honeycombed?

If you use it for a custom house, it is a nightmare to work with.

If I lived in tornado country, then I think I would like it

 

[paddingtongreen]

Good answers all, I would add:

Prevailing types of structure in the area, sometimes because most of the contractors share in a pool of workers that are skilled in that method.

The preferences of the building officials.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[AELLC]

Yes - e.g. concrete is common in India but wood is rare because their timber is not suitable for construction.