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Re: Steel Detailing Blog

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Hello Nagesh,

Your blog on steel related subjects is welcome.
You can count on one loyal reader (me)
I hope you will be persistent.
Most bloggers start off with great enthusiasm.
They lose steam after some time and quietly give up
later.

I too toyed with the idea of blogging and gave up even
before getting started.
I wasn't sure I would be able to do justice to it.

Kev too has now given up.
There was Steve also whose blog has vanished.
I wrote to him inquiring about his blog  without
getting a response.
I hope you at least will keep at it.

I read your piece on advantages of steel in
construction.

Steel is a great building material.
I'm emotionally attached to it.
It has been my bread and butter for over 30 years.

But we should not be blind to some disadvantages with
the use of steel in construction.

There are two sides.

Your blog focusses on the benefits of using steel.
But Steel construction has not taken off in India and
may not in the near future.

Here are some difficulties we need to cope with in
Steel construction before it can become popular and
the material of choice in India as it now is in USA.

1)The problem  of corrosion.

This is acute due to humidity.
We are a tropical country.
Large parts of our land lie within vulnerable distance
from the coast.
Salt in the air compounds the problem.

Just as the pharmaceutical industry survives because
of diseases and ailments afflicting humans, the paint
industry prospers due to this as yet incurable disease
afflicting steel.

Painting (particularly for industrial structures) has
now developed into a major specialized subject like
welding. You now need "consultants" to decide the
painting scheme depending on the environment the
structure is subjected to.

No such expertise is required for our traditional
building materials. The wives will choose the color.
The husbands will decide the budget. The paint gets
decided automatically.

2)Poor Fire resistance.

If Fire breaks out, after the temperatures rise above
a certain limit (250 degrees Celsius?) Steel develops
cold feet and gives up. It pleads pathetically for
mercy to the God of Fire and surrenders abjectly. The
steel backbone that we proudly rely on becomes a
pliable plant stem. The proud steel columns begin  to
kneel in subjugation. Americans now try to get around
this with so called fire proofing. This is not common
in India. Unless there is a big market for their
product, why would fire proofing products be
available?

3)The high capital cost of steel in India.

Material costs more than labour in India unlike in
Europe and USA. Labour in India is cheap and
plentiful. We don't need costly fabrication equipment
or heavy duty cranes and don't have to deal with
unionized iron workers for our common structures.
Where is the incentive to use steel?

4)Competition from other materials.

Mud, concrete, wood, clay, bricks, stone, are
available in plenty all over India and you don't need
to transport them far. Even our bullock carts can do
the job. Can a bullock cart bring steel over to our
construction sites from the few steel plants and
stockyards scattered far and wide in our country?
Trucks and Railroad wagons do the job at great
additional cost and time. Where is the incentive for
some one in Rajasthan or Kashmir or the distant North
East to use steel? Fortunately steel is now at least
available. During my prime years as a structural steel
designer, you needed to go through a lot of
formalities to buy steel and unless you were a big
customer buying in hundreds of tons from the
stockyards, you had to supplicate before the suppliers
and some even purchased used steel and recycled them. 

5) Availability of skills.

The skill required to fabricate and erect accurately
in steel is not so common in our country. Most of our
steel is fabricated directly in open yards at site.
Quality of fabrication that can be acceptable to an
organisation like AISC is rare. Concrete construction
manages with unskilled and semi skilled workers. It
doesn't need the sophisticated equipment that steel
needs. It's enough if their tapes measure accurately
to the nearest inch or so.(What's one sixteenth of an
inch? they ask) Steel is much more demanding.

6)Environment issues.

We have workers capabale of working miracles with mud,
stone, thatch, wood, bamboo. These are environment
friendly materials. I wonder why the environment
lovers have so far spared the steel industry. May be
they are not aware of the real cost of producing a
pound of steel considering the costs of all the inputs
that go into it and the destructive by products that
we have to live with. Of course it can be argued that
cement is no less polluting.

7)Drawings 

Most houses in the villages and towns in India don't
need dwgs!! They may be used for legal purposes and
record purposes. The masons don't want to look at
them.

Even if  Dwgs are made, in the case of concrete,
masonry and timber structures, they  can straightaway
be used by the contractors. In USA they may need rebar
detailing. But we in India can manage without them.
Bar bending schedules are included in our civil dwgs.
There is no such thing as "detailing", approval,
revisions, rfis, gather sheets, E dwgs, AB dwgs, shop
dwgs, joist and deck dwgs etc etc.

In the case of steel, I have had to explain several
times to our lay clients why our design drawings are
not enough for execution and that detailing, and
approval of detail dwgs was necessary. The owners have
no patience with this system. They repeatedly asked
why we engineers do not issue drawings that can be
directly used by the contractors?
What's the issue? Money? Ask for it. We will pay, they
say. But which structural engineer wants to mess
around with shop dwgs? 

The owners get irritated with this intermediate
process which causes delays.
An entire industry (the detailing industry) has
sprouted and a set of skilled detailers/draftsmen and
a group of software developers thrive on this business
of shop drawing preparation and approval and I now
belong to this family and make my living through it.
But owners have no patience with us and still wonder
why we are needed at all.
Some of them quietly revert to concrete if possible
after their experience with our steel construction
industry.


8) Choice of sections.

The limited choices for steel profiles  available in
India is another issue.
In USA over a thousand shapes are available to choose
from. In India you have to make do with less than a
dozen I-shapes with poor sectional properties compared
to the American W sections. The deepest rolled section
available does not exceed 24" in depth and its flange
width is just about 8". What kind of properties can
you hope for from a shape like this.
For most members in a typical industrial project we
may need to fabricate an  I section from plates. This
adds to the cost and time required.  Contrast this
with the wide range of W sections available in USA.
They hardly need to fabricate a three plate I secion.
They have sections as deep as 44". Almost all steel
here conforms to a specification which is close to
A36. Steel with Fy 50 ksi is prohibitively costly.
The prices of 50 ksi steel in USA are not higher to
the best of my knowledge.

Where material is costly, optmising is more imprtant.
We in India should have had more sections to choose
from and with higher stregths at lower cost.
Unfortunatly we don't. On the other hand, there is a
glut of shapes in America but they still stick to a
popular list of common sections.
============

After reading your article, I  thought of sharing my
views. I will be posting this on the list too and
hopefully we will get some fresh insights into the
good and bad of steel construction.

Regards
Vish




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