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Sustainable design
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er_zaheer
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Joined: 17 Sep 2008
Posts: 110
Location: Saudi Arabia

PostPosted: Mon Apr 13, 2009 12:11 pm    Post subject: Sustainable design Reply with quote

Dear Sefians,

These days every body is talking about green building or sustainable building having LEED certificate.
My question is what is the role of structural engineer in green or sustainable building design?

I request senior sefians to put more light on this topic.

Many thanks,
Zaheer
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kunalkansara
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PostPosted: Tue Apr 14, 2009 12:39 am    Post subject: Re: Sustainable design Reply with quote

Dear Mr Zaheer and other friends,

Sustainable Design what you mentioned to me is an incomplete justification to Sustainable Development. Since it is aimed at sustainability of life on earth, it is obvious that sustainable development has a wide canvas than just design. But I will try to limit the discussion around design primarily. The very moral of the whole exercise is the fact that any activity we do, either engineering or non-engineering, either direct production or providing services, should have minimal impact on natural system, if not absolutely zero. Now this issue can as well be spoken pure philosophically, I would prefer to present it here with a flavour of mathematics for the sake of digestion of the engineers to whom, quite obviously, no mathematics means no meaning! Impact on natural system or ecology is popularly represented by embodied carbon or carbon foot-print. Each activity we do adds some amount of CO2 to the atmosphere, which would not have been added, if that activity were not performed. With this definition, every activity can be tagged its embodied carbon value. An engineering process is a series of activities and hence total embodied carbon involved in a process can be worked out. For sustainability we need to minimise (active way for us the structural engineers) or balance (passive way -left to environmentalists) this additional carbon.

As far as construction industry is concerned, this is meant to cover a wide range of issues including materials, execution, management, and of course design as you have put in the subject line. In fact, in any sphere of activity, we should consider an added dimension of sustainability as well. In material selection, for example, you might have observed that fairly recently there has been a leaning of engineers towards replacing conventional steel reinforcements with newer fibre reinforced plastics (FRP). In addition to superior mechanical properties and apparent durability, the process of manufacturing FRPs has less embodied carbon content compared to steel production. Thus, if as a structural engineer, you can replace (satisfying all safety and other requirements) steel with FRP, you are doing sustainable engineering practice. Seeing a bit more widely, focusing on existing concrete infrastructure, which are degrading and hence will need to be replaced. When to replace and which to replace is commonly seen by the authorities on two grounds : 1. Engineering feasibility, 2. Economic feasibility. With sustainable development in mind, we should see its sustainable feasibility as well. So if you can work out a solution that adds to the service life or strength of the structure, you are delaying its replacement. Typically, new construction as replacement of existing structure carries more embodied carbon (and chief contributor amongst them is the manufacturing process of cement and cement-based products) than the process of extending its service life. Thus, doing this we contribute to sustainable development.

Letís see now the situation with sustainable design perspective. For young engineers and students this means one more course to be added into their study-basket, which apparently is over-spilling! But somethings are the demand of time and can influence the generations to come drastically. Sustainable Development as applied to Civil Engineering, I see as one of the critically important issue for the budding engineers who are going to rule tomorrows design offices. The question, obviously, in their mind then may arise that how to take sustainability into design practice. The ones, who are mathematically concerned, for them, letís see the situation in two popular mathematical formats:
1. As an Optimization Problem
2. As a Limit-State Problem

1. We see many civil engineering situations as optimization problem, where we have more options to choose from or more mathematically where multiple solutions are possible. The basic requirement to be satisfied, we represent as a mathematical function (called objective function) with characteristic variables in it that govern the situation and then either minimise or maximise (based on context) this function under some constraints. Typically, such constraints are representations of safety criteria (e.g. permissible stresses, max. deflections, etc) and economy (e.g. min. weight, min. cross-sectional area, min. number of members, etc.) only. For sustainability to get into our designs, we should also add one more set of constraints, representing embodied carbon limits of design solutions. This will necessitates the description of embodied carbon for various activities and processes involved in the design problem. The codes of practice of future hence should add this dimension while calibrating.

2. Design most commonly is dealt as a limit-state problem where we actually need to work out design solution either based on some limit-states or we have to check and satisfy some limit-states or both. By limit-state we actually design our structure not to cross a certain limit of a variable. Limit-states we group as strength limit-states and serviceability limit-states so far with recent addition of durability limit-states at the most. Again towards sustainable development, we have to broaden our perspective to include one more set of limit-states namely limit-state of sustainability. Again the codes of practice of future has key role to play here.

To sum up I would say sustainable design is an essential but not sufficient condition towards sustainable development. In Europe, to my knowledge, all activities related to construction needs to be aimed towards sustainable developments. Use of hemplime and other low-embodied carbon materials (some are towards negative embodied carbons as well interestingly!) are preferred areas for various research councils. In light of above, I see engineers of future to compete their designs to be more sustainable in addition to be safe and economical to qualify for being an efficient design, and IS:456 of future will have sustainability accounted in its provisions.

Please note that the above is a picture of how I personally look at sustainability as applied to structural engineering design. Obviously, one may see the same issue with a different angle to represent it better. So discussion is left over to other sefians. Importance of this issue can be gauged from the fact that inspite of nature's fentastic ability to absorb sufficiently large amount of changes safely, with our so called developments just in last two centuries we have arrived at a situation where each further step we take needs to be checked for it being harmful or sustainable. Apologies for being longer- so far we donít print this long email, we are still sustainable! I hope this is of use.

Best regards,

Kunal Kansara

er_zaheer wrote:
Dear Sefians,

These days every body is talking about green building or sustainable building having LEED certificate.
My question is what is the role of structural engineer in green or sustainable building design?

I request senior sefians to put more light on this topic.

Many thanks,
Zaheer
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er_zaheer
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Joined: 17 Sep 2008
Posts: 110
Location: Saudi Arabia

PostPosted: Tue Apr 14, 2009 4:54 am    Post subject: Reply with quote

Thanks Mr. Kunal for your lucid explanation.
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ibarua
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PostPosted: Tue Apr 14, 2009 6:37 am    Post subject: Sustainable design Reply with quote

14th April 2009

Kudos to Kunal Kansara for his admirable exposition of 'Sustainable Development' and 'Sustainable Design'.

Humankind is the most dangerous species on Planet Earth. Every time one of us exhales, he releases a bit of CO2 into the atmosphere. Of course,  all other animals also do likewise, but because of sheer numbers, and also because of its propensity to produce goods and processes which also produce CO2 in the name of improving the quality of life, homo sapiens is Mother Earth's worst enemy.

Indrajit Barua.
On Tue, 14 Apr 2009 kunalkansara wrote :
Quote:
Dear Mr Zaheer and other friends,

Sustainable Design what you mentioned to me is an
incomplete justification to Sustainable Development.
Since it is aimed at sustainability of life on earth,
it is obvious that sustainable development has a wide
canvas than just design. But I will try to limit the
discussion around design primarily. The very moral of
the whole exercise is the fact that any activity we do,
either engineering or non-engineering, either direct
production or providing services, should have minimal
impact on natural system, if not absolutely zero. Now
this issue can as well be spoken pure philosophically,
I would prefer to present it here with a flavour of
mathematics for the sake of digestion of the engineers
to whom, quite obviously, no mathematics means no
meaning! Impact on natural system or ecology is
popularly represented by embodied carbon or carbon
foot-print. Each activity we do adds some amount of CO2
to the atmosphere, which would not have been added, if
that activity were not performed. With this definition,
every activity can be tagged its embodied carbon value.
An engineering process is a series of activities and
hence total embodied carbon involved in a process can
be worked out. For sustainability we need to minimise
(active way for us the structural engineers) or balance
(passive way -left to environmentalists) this
additional carbon.

As far as construction industry is concerned, this is
meant to cover a wide range of issues including
materials, execution, management, and of course design
as you have put in the subject line. In fact, in any
sphere of activity, we should consider an added
dimension of sustainability as well. In material
selection, for example, you might have observed that
fairly recently there has been a leaning of engineers
towards replacing conventional steel reinforcements
with newer fibre reinforced plastics (FRP). In addition
to superior mechanical properties and apparent
durability, the process of manufacturing FRPs has less
embodied carbon content compared to steel production.
Thus, if as a structural engineer, you can replace
(satisfying all safety and other requirements) steel
with FRP, you are doing sustainable engineering
practice. Seeing a bit more widely, focusing on
existing concrete infrastructure, which are degrading
and hence will need to be replaced. When to replace and
which to replace is commonly seen by the authorities on
two grounds : 1. Engineering feasibility, 2. Economic
feasibility. With sustainable development in mind, we
should see its sustainable feasibility as well. So if
you can work out a solution that adds to the service
life or strength of the structure, you are delaying its
replacement. Typically, new construction as replacement
of existing structure carries more embodied carbon (and
chief contributor amongst them is the manufacturing
process of cement and cement-based products) than the
process of extending its service life. Thus, doing this
we contribute to sustainable development.

Letís see now the situation with sustainable design
perspective. For young engineers and students this
means one more course to be added into their
study-basket, which apparently is over-spilling! But
somethings are the demand of time and can influence the
generations to come drastically. Sustainable
Development as applied to Civil Engineering, I see as
one of the critically important issue for the budding
engineers who are going to rule tomorrows design
offices. The question, obviously, in their mind then
may arise that how to take sustainability into design
practice. The ones, who are mathematically concerned,
for them, letís see the situation in two popular
mathematical formats:
1. As an Optimization Problem
2. As a Limit-State Problem

1. We see many civil engineering situations as
optimization problem, where we have more options to
choose from or more mathematically where multiple
solutions are possible. The basic requirement to be
satisfied, we represent as a mathematical function
(called objective function) with characteristic
variables in it that govern the situation and then
either minimise or maximise (based on context) this
function under some constraints. Typically, such
constraints are representations of safety criteria
(e.g. permissible stresses, max. deflections, etc) and
economy (e.g. min. weight, min. cross-sectional area,
min. number of members, etc.) only. For sustainability
to get into our designs, we should also add one more
set of constraints, representing embodied carbon limits
of design solutions. This will necessitates the
description of embodied carbon for various activities
and processes involved in the design problem. The codes
of practice of future hence should add this dimension
while calibrating.

2. Design most commonly is dealt as a limit-state
problem where we actually need to work out design
solution either based on some limit-states or we have
to check and satisfy some limit-states or both. By
limit-state we actually design our structure not to
cross a certain limit of a variable. Limit-states we
group as strength limit-states and serviceability
limit-states so far with recent addition of durability
limit-states at the most. Again towards sustainable
development, we have to broaden our perspective to
include one more set of limit-states namely limit-state
of sustainability. Again the codes of practice of
future has key role to play here.

To sum up I would say sustainable design is an
essential but not sufficient condition towards
sustainable development. In Europe, to my knowledge,
all activities related to construction needs to be
aimed towards sustainable developments. Use of hemplime
and other low-embodied carbon materials (some are
towards negative embodied carbons as well
interestingly!) are preferred areas for various
research councils. In light of above, I see engineers
of future to compete their designs to be more
sustainable in addition to be safe and economical to
qualify for being an efficient design, and IS:456 of
future will have sustainability accounted in its
provisions.

Please note that the above is a picture of how I
personally look at sustainability as applied to
structural engineering design. Obviously, one may see
the same issue with a different angle to represent it
better. So discussion is left over to other sefians.
Importance of this issue can be gauged from the fact
that inspite of nature's fentastic ability to absorb
sufficiently large amount of changes safely, with our
so called developments just in last two centuries we
have arrived at a situation where each further step we
take needs to be checked for it being harmful or
sustainable. Apologies for being longer- so far we
donít print this long email, we are still sustainable!
I hope this is of use.

Best regards,

Kunal Kansara


er_zaheer wrote:
Quote:
Dear Sefians,

These days every body is talking about green building
or sustainable building having LEED certificate.
Quote:
My question is what is the role of structural
engineer in green or sustainable building design?
Quote:

I request senior sefians to put more light on this
topic.
Quote:

Many thanks,
Zaheer









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sdec.in
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Joined: 26 Jan 2003
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PostPosted: Tue Apr 14, 2009 6:39 am    Post subject: Sustainable design Reply with quote

Dear Mr Kunalkansara
Thanks for taking so much time out and giving an elaborate insight into SD as well as a SE's role in achieving the same.
I am sure your email will benefit many on this forum.
Best regards
Sangeeta
Quote:
----- Original Message -----
From: kunalkansara (forum@sefindia.org)
To: general@sefindia.org (general@sefindia.org)
Sent: 14 April, 2009 6:09 AM
Subject: [SEFI] Re: Sustainable design


Dear Mr Zaheer and other friends,

Sustainable Design what you mentioned to me is an incomplete justification to Sustainable Development. Since it is aimed at sustainability of life on earth, it is obvious that sustainable development has a wide canvas than just design. But I will try to limit the discussion around design primarily. The very moral of the whole exercise is the fact that any activity we do, either engineering or non-engineering, either direct production or providing services, should have minimal impact on natural system, if not absolutely zero. Now this issue can as well be spoken pure philosophically, I would prefer to present it here with a flavour of mathematics for the sake of digestion of the engineers to whom, quite obviously, no mathematics means no meaning! Impact on natural system or ecology is popularly represented by embodied carbon or carbon foot-print. Each activity we do adds some amount of CO2 to the atmosphere, which would not have been added, if that activity were not performed. With this definition, every activity can be tagged its embodied carbon value. An engineering process is a series of activities and hence total embodied carbon involved in a process can be worked out. For sustainability we need to minimise (active way for us the structural engineers) or balance (passive way -left to environmentalists) this additional carbon.

As far as construction industry is concerned, this is meant to cover a wide range of issues including materials, execution, management, and of course design as you have put in the subject line. In fact, in any sphere of activity, we should consider an added dimension of sustainability as well. In material selection, for example, you might have observed that fairly recently there has been a leaning of engineers towards replacing conventional steel reinforcements with newer fibre reinforced plastics (FRP). In addition to superior mechanical properties and apparent durability, the process of manufacturing FRPs has less embodied carbon content compared to steel production. Thus, if as a structural engineer, you can replace (satisfying all safety and other requirements) steel with FRP, you are doing sustainable engineering practice. Seeing a bit more widely, focusing on existing concrete infrastructure, which are degrading and hence will need to be replaced. When to replace and which to replace is commonly seen by the authorities on two grounds : 1. Engineering feasibility, 2. Economic feasibility. With sustainable development in mind, we should see its sustainable feasibility as well. So if you can work out a solution that adds to the service life or strength of the structure, you are delaying its replacement. Typically, new construction as replacement of existing structure carries more embodied carbon (and chief contributor amongst them is the manufacturing process of cement and cement-based products) than the process of extending its service life. Thus, doing this we contribute to sustainable development.

Letís see now the situation with sustainable design perspective. For young engineers and students this means one more course to be added into their study-basket, which apparently is over-spilling! But somethings are the demand of time and can influence the generations to come drastically. Sustainable Development as applied to Civil Engineering, I see as one of the critically important issue for the budding engineers who are going to rule tomorrows design offices. The question, obviously, in their mind then may arise that how to take sustainability into design practice. The ones, who are mathematically concerned, for them, letís see the situation in two popular mathematical formats:
1. As an Optimization Problem
2. As a Limit-State Problem

1. We see many civil engineering situations as optimization problem, where we have more options to choose from or more mathematically where multiple solutions are possible. The basic requirement to be satisfied, we represent as a mathematical function (called objective function) with characteristic variables in it that govern the situation and then either minimise or maximise (based on context) this function under some constraints. Typically, such constraints are representations of safety criteria (e.g. permissible stresses, max. deflections, etc) and economy (e.g. min. weight, min. cross-sectional area, min. number of members, etc.) only. For sustainability to get into our designs, we should also add one more set of constraints, representing embodied carbon limits of design solutions. This will necessitates the description of embodied carbon for various activities and processes involved in the design problem. The codes of practice of future hence should add this dimension while calibrating.

2. Design most commonly is dealt as a limit-state problem where we actually need to work out design solution either based on some limit-states or we have to check and satisfy some limit-states or both. By limit-state we actually design our structure not to cross a certain limit of a variable. Limit-states we group as strength limit-states and serviceability limit-states so far with recent addition of durability limit-states at the most. Again towards sustainable development, we have to broaden our perspective to include one more set of limit-states namely limit-state of sustainability. Again the codes of practice of future has key role to play here.

To sum up I would say sustainable design is an essential but not sufficient condition towards sustainable development. In Europe, to my knowledge, all activities related to construction needs to be aimed towards sustainable developments. Use of hemplime and other low-embodied carbon materials (some are towards negative embodied carbons as well interestingly!) are preferred areas for various research councils. In light of above, I see engineers of future to compete their designs to be more sustainable in addition to be safe and economical to qualify for being an efficient design, and IS:456 of future will have sustainability accounted in its provisions.

Please note that the above is a picture of how I personally look at sustainability as applied to structural engineering design. Obviously, one may see the same issue with a different angle to represent it better. So discussion is left over to other sefians. Importance of this issue can be gauged from the fact that inspite of nature's fentastic ability to absorb sufficiently large amount of changes safely, with our so called developments just in last two centuries we have arrived at a situation where each further step we take needs to be checked for it being harmful or sustainable. Apologies for being longer- so far we donít print this long email, we are still sustainable! I hope this is of use.

Best regards,

Kunal Kansara

er_zaheer wrote:  Dear Sefians,

These days every body is talking about green building or sustainable building having LEED certificate.
My question is what is the role of structural engineer in green or sustainable building design?

I request senior sefians to put more light on this topic.

Many thanks,
Zaheer






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Rudra Nevatia
...
...


Joined: 26 Jan 2003
Posts: 210
Location: Mumbai

PostPosted: Tue Apr 14, 2009 4:32 pm    Post subject: Sustainable design Reply with quote

Dear Mr. Barua,

I protest on behalf of all bipeds. Bovine belch and crap are worse offenders.


Regards,
Rudra Nevatia

On Tue, Apr 14, 2009 at 4:56 PM, ibarua <forum@sefindia.org (forum@sefindia.org)> wrote:
Quote:
14th April 2009

Kudos to Kunal Kansara for his admirable exposition of 'Sustainable Development' and 'Sustainable Design'.

Humankind is the most dangerous species on Planet Earth. Every time one of us exhales, he releases a bit of CO2 into the atmosphere. Of course, †all other animals also do likewise, but because of sheer numbers, and also because of its propensity to produce goods and processes which also produce CO2 in the name of improving the quality of life, homo sapiens is Mother Earth's worst enemy.

Indrajit Barua.
On Tue, 14 Apr 2009 kunalkansara wrote :


Quote:
Dear Mr Zaheer and other friends,

Sustainable Design what you mentioned to me is an
incomplete justification to Sustainable Development.
Since it is aimed at sustainability of life on earth,
it is obvious that sustainable development has a wide
canvas than just design. But I will try to limit the
discussion around design primarily. The very moral of
the whole exercise is the fact that any activity we do,
either engineering or non-engineering, either direct
production or providing services, should have minimal
impact on natural system, if not absolutely zero. Now
this issue can as well be spoken pure philosophically,
I would prefer to present it here with a flavour of
mathematics for the sake of digestion of the engineers
to whom, quite obviously, no mathematics means no
meaning! Impact on natural system or ecology is
popularly represented by embodied carbon or carbon
foot-print. Each activity we do adds some amount of CO2
to the atmosphere, which would not have been added, if
that activity were not performed. With this definition,
every activity can be tagged its embodied carbon value.
An engineering process is a series of activities and
hence total embodied carbon involved in a process can
be worked out. For sustainability we need to minimise
(active way for us the structural engineers) or balance
(passive way -left to environmentalists) this
additional carbon.

As far as construction industry is concerned, this is
meant to cover a wide range of issues including
materials, execution, management, and of course design
as you have put in the subject line. In fact, in any
sphere of activity, we should consider an added
dimension of sustainability as well. In material
selection, for example, you might have observed that
fairly recently there has been a leaning of engineers
towards replacing conventional steel reinforcements
with newer fibre reinforced plastics (FRP). In addition
to superior mechanical properties and apparent
durability, the process of manufacturing FRPs has less
embodied carbon content compared to steel production.
Thus, if as a structural engineer, you can replace
(satisfying all safety and other requirements) steel
with FRP, you are doing sustainable engineering
practice. Seeing a bit more widely, focusing on
existing concrete infrastructure, which are degrading
and hence will need to be replaced. When to replace and
which to replace is commonly seen by the authorities on
two grounds : 1. Engineering feasibility, 2. Economic
feasibility. With sustainable development in mind, we
should see its sustainable feasibility as well. So if
you can work out a solution that adds to the service
life or strength of the structure, you are delaying its
replacement. Typically, new construction as replacement
of existing structure carries more embodied carbon (and
chief contributor amongst them is the manufacturing
process of cement and cement-based products) than the
process of extending its service life. Thus, doing this
we contribute to sustainable development.

Letís see now the situation with sustainable design
perspective. For young engineers and students this
means one more course to be added into their
study-basket, which apparently is over-spilling! But
somethings are the demand of time and can influence the
generations to come drastically. Sustainable
Development as applied to Civil Engineering, I see as
one of the critically important issue for the budding
engineers who are going to rule tomorrows design
offices. The question, obviously, in their mind then
may arise that how to take sustainability into design
practice. The ones, who are mathematically concerned,
for them, letís see the situation in two popular
mathematical formats:
1. As an Optimization Problem
2. As a Limit-State Problem

1. We see many civil engineering situations as
optimization problem, where we have more options to
choose from or more mathematically where multiple
solutions are possible. The basic requirement to be
satisfied, we represent as a mathematical function
(called objective function) with characteristic
variables in it that govern the situation and then
either minimise or maximise (based on context) this
function under some constraints. Typically, such
constraints are representations of safety criteria
(e.g. permissible stresses, max. deflections, etc) and
economy (e.g. min. weight, min. cross-sectional area,
min. number of members, etc.) only. For sustainability
to get into our designs, we should also add one more
set of constraints, representing embodied carbon limits
of design solutions. This will necessitates the
description of embodied carbon for various activities
and processes involved in the design problem. The codes
of practice of future hence should add this dimension
while calibrating.

2. Design most commonly is dealt as a limit-state
problem where we actually need to work out design
solution either based on some limit-states or we have
to check and satisfy some limit-states or both. By
limit-state we actually design our structure not to
cross a certain limit of a variable. Limit-states we
group as strength limit-states and serviceability
limit-states so far with recent addition of durability
limit-states at the most. Again towards sustainable
development, we have to broaden our perspective to
include one more set of limit-states namely limit-state
of sustainability. Again the codes of practice of
future has key role to play here.

To sum up I would say sustainable design is an
essential but not sufficient condition towards
sustainable development. In Europe, to my knowledge,
all activities related to construction needs to be
aimed towards sustainable developments. Use of hemplime
and other low-embodied carbon materials (some are
towards negative embodied carbons as well
interestingly!) are preferred areas for various
research councils. In light of above, I see engineers
of future to compete their designs to be more
sustainable in addition to be safe and economical to
qualify for being an efficient design, and IS:456 of
future will have sustainability accounted in its
provisions.

Please note that the above is a picture of how I
personally look at sustainability as applied to
structural engineering design. Obviously, one may see
the same issue with a different angle to represent it
better. So discussion is left over to other sefians.
Importance of this issue can be gauged from the fact
that inspite of nature's fentastic ability to absorb
sufficiently large amount of changes safely, with our
so called developments just in last two centuries we
have arrived at a situation where each further step we
take needs to be checked for it being harmful or
sustainable. Apologies for being longer- so far we
donít print this long email, we are still sustainable!
I hope this is of use.

Best regards,

Kunal Kansara


er_zaheer wrote:

Quote:
Dear Sefians,

These days every body is talking about green building

or sustainable building having LEED certificate.

Quote:
My question is what is the role of structural

engineer in green or sustainable building design?

Quote:

I request senior sefians to put more light on this

topic.

Quote:

Many thanks,
Zaheer








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Dr. N. Subramanian
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PostPosted: Tue Apr 14, 2009 7:44 pm    Post subject: Re: Sustainable design Reply with quote

Hi all,

As is usual, Shri Kunal Kansara has given a nice piece on sustainable design. I suggest the youngsters to look into the other postings by Er Kunal- on columns, torsion, bearing strength, etc.-they all are good and I am sure they will be benefited by the excellent explanations provided by him.

Coming back to the topic of sustainable design, it is very close to my heart- see my articles in the ICJ-Dec 07-Sustainability-Challenges and solutions and ICJ-Dec 08-Pervious concrete pavements.

As rightly pointed out by Shri. Kunal, we should take active interest in sustainability- which simply means "giving back this planet to the future generations at the same or better conditions" But it is a very big task.

The barriers to sustainability are the ever increasing population,  the continued use of fossil fuels, which results in the accumulation of CO2 in the oceans and atmosphere, and the exploitation of the natural resources, destruction of forests, pollution of water and air, etc. etc. At the current level of consumption, we need three more earths. That is why the Scientific American has started publishing a magazine called Earth 3.0

Civil Engineers, Architects and those in construction industry have a greater role in sustaining the resources, as the building industry consumes  about 40% of the materials ever produced. The starting point for all members of the construction industry that wish to approach sustainability as a business opportunity - from big developers to small companies and those who refurbish existing buildings - must be to
re-think their operations in four key areas:

ē Energy: reducing energy consumption, being more energy efficient and using renewable energy and 'alternative technology'.
ē Materials: Choosing, using, re-using and recycling materials during design, manufacture, construction and maintenance to reduce resource requirements.
ē Waste: Producing less waste and recycling more.
ē Pollution: Producing less toxicity, water, noise and spatial pollution.

But note that 45% of energy generated is used to power and maintain buildings, and only 5% is used to construct them. The heating,
lighting and cooling of buildings directly through the burning of fossil fuels (gas, coal, oil) and indirectly through the use of electricity is the primary source of Carbon Dioxide and accounts for half of all global warming. The cost of structural materials will be only 20% of the cost of the total building. That is why Optimization techniques have not been implemented, except in a few cases. When I say materials, it includes water, which is going to become(already become in some areas of the world) a rare commodity.

At present, LEED primarily credits environmental sustainability in the form of material specification; recycled content in concrete and steel, and sustainably harvested wood. In its current form, LEED awards the same number of credits for reusing 75% of the buildingís walls, floors, and roof as it does for specifying bike racks and showers for 5% of a buildingís occupants. At present, it does not address the idea of embodied energy directly and does not take into account the cultural heritage associated with preserving buildings. LEED 2009, which launched in March of this year, gives much greater credit than its predecessor to metrics such as Community Connectivity and Alternative Transportation, both of which favor existing buildings. In addition, there is now an Alternative Compliance Path that specifically recognizes an existing buildingís embodied energy. Lastly, a Sustainable Preservation Coalition has been formed to incorporate preservation, social, and cultural values into LEED, though probably not until its next release in 2011.

Admittedly, the choice to reuse existing buildings does not rest solely in the hands of structural engineers though our opinion often becomes the deal-breaker. We must partner with owners, architects, and developers in order to maintain our built heritage. Engineers have a more extensive role to play than merely specifying sustainable materials. If understood and promoted properly, the intersection of sustainability and reusing buildings affords structural engineers a great opportunity for professional development, marketing, and occasion to contribute to a greener future.▪

Regards,
Subramanian

P.S. The last two paragraphs are taken from the recent article on Structures Magazine, which stresses the importance of preserving old buildings.
it is enclosed for your reference.

kunalkansara wrote:
Dear Mr Zaheer and other friends,

Sustainable Design what you mentioned to me is an incomplete justification to Sustainable Development. Since it is aimed at sustainability of life on earth, it is obvious that sustainable development has a wide canvas than just design. But I will try to limit the discussion around design primarily. The very moral of the whole exercise is the fact that any activity we do, either engineering or non-engineering, either direct production or providing services, should have minimal impact on natural system, if not absolutely zero. Now this issue can as well be spoken pure philosophically, I would prefer to present it here with a flavour of mathematics for the sake of digestion of the engineers to whom, quite obviously, no mathematics means no meaning! Impact on natural system or ecology is popularly represented by embodied carbon or carbon foot-print. Each activity we do adds some amount of CO2 to the atmosphere, which would not have been added, if that activity were not performed. With this definition, every activity can be tagged its embodied carbon value. An engineering process is a series of activities and hence total embodied carbon involved in a process can be worked out. For sustainability we need to minimise (active way for us the structural engineers) or balance (passive way -left to environmentalists) this additional carbon.

As far as construction industry is concerned, this is meant to cover a wide range of issues including materials, execution, management, and of course design as you have put in the subject line. In fact, in any sphere of activity, we should consider an added dimension of sustainability as well. In material selection, for example, you might have observed that fairly recently there has been a leaning of engineers towards replacing conventional steel reinforcements with newer fibre reinforced plastics (FRP). In addition to superior mechanical properties and apparent durability, the process of manufacturing FRPs has less embodied carbon content compared to steel production. Thus, if as a structural engineer, you can replace (satisfying all safety and other requirements) steel with FRP, you are doing sustainable engineering practice. Seeing a bit more widely, focusing on existing concrete infrastructure, which are degrading and hence will need to be replaced. When to replace and which to replace is commonly seen by the authorities on two grounds : 1. Engineering feasibility, 2. Economic feasibility. With sustainable development in mind, we should see its sustainable feasibility as well. So if you can work out a solution that adds to the service life or strength of the structure, you are delaying its replacement. Typically, new construction as replacement of existing structure carries more embodied carbon (and chief contributor amongst them is the manufacturing process of cement and cement-based products) than the process of extending its service life. Thus, doing this we contribute to sustainable development.

Letís see now the situation with sustainable design perspective. For young engineers and students this means one more course to be added into their study-basket, which apparently is over-spilling! But somethings are the demand of time and can influence the generations to come drastically. Sustainable Development as applied to Civil Engineering, I see as one of the critically important issue for the budding engineers who are going to rule tomorrows design offices. The question, obviously, in their mind then may arise that how to take sustainability into design practice. The ones, who are mathematically concerned, for them, letís see the situation in two popular mathematical formats:
1. As an Optimization Problem
2. As a Limit-State Problem

1. We see many civil engineering situations as optimization problem, where we have more options to choose from or more mathematically where multiple solutions are possible. The basic requirement to be satisfied, we represent as a mathematical function (called objective function) with characteristic variables in it that govern the situation and then either minimise or maximise (based on context) this function under some constraints. Typically, such constraints are representations of safety criteria (e.g. permissible stresses, max. deflections, etc) and economy (e.g. min. weight, min. cross-sectional area, min. number of members, etc.) only. For sustainability to get into our designs, we should also add one more set of constraints, representing embodied carbon limits of design solutions. This will necessitates the description of embodied carbon for various activities and processes involved in the design problem. The codes of practice of future hence should add this dimension while calibrating.

2. Design most commonly is dealt as a limit-state problem where we actually need to work out design solution either based on some limit-states or we have to check and satisfy some limit-states or both. By limit-state we actually design our structure not to cross a certain limit of a variable. Limit-states we group as strength limit-states and serviceability limit-states so far with recent addition of durability limit-states at the most. Again towards sustainable development, we have to broaden our perspective to include one more set of limit-states namely limit-state of sustainability. Again the codes of practice of future has key role to play here.

To sum up I would say sustainable design is an essential but not sufficient condition towards sustainable development. In Europe, to my knowledge, all activities related to construction needs to be aimed towards sustainable developments. Use of hemplime and other low-embodied carbon materials (some are towards negative embodied carbons as well interestingly!) are preferred areas for various research councils. In light of above, I see engineers of future to compete their designs to be more sustainable in addition to be safe and economical to qualify for being an efficient design, and IS:456 of future will have sustainability accounted in its provisions.

Please note that the above is a picture of how I personally look at sustainability as applied to structural engineering design. Obviously, one may see the same issue with a different angle to represent it better. So discussion is left over to other sefians. Importance of this issue can be gauged from the fact that inspite of nature's fentastic ability to absorb sufficiently large amount of changes safely, with our so called developments just in last two centuries we have arrived at a situation where each further step we take needs to be checked for it being harmful or sustainable. Apologies for being longer- so far we donít print this long email, we are still sustainable! I hope this is of use.

Best regards,

Kunal Kansara

er_zaheer wrote:
Dear Sefians,

These days every body is talking about green building or sustainable building having LEED certificate.
My question is what is the role of structural engineer in green or sustainable building design?

I request senior sefians to put more light on this topic.

Many thanks,
Zaheer



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thirumalaichettiar
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PostPosted: Tue Apr 14, 2009 8:42 pm    Post subject: Reply with quote

Dear All,
The subject of Green building-SD is started by Er.Zaher.  Then it is explained in a beautiful and long way by Er.Kunal Kansara( Must thank for him for  writing such a nice and beautiful naration) and adonrned now by Dr.N.S as usual with an attachment.
I do not know how many have read even after viewing but one should know the new innovative technics to save the earth from CO2 for the future generation.
Once again my heart felt felicitations to both Er.Kunal and Dr.N.S for the long write up and expect more to come from both on various topic so that not only for budding engineers but also Senior can also learn more.

T.Rangarajan.
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vikram.jeet
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PostPosted: Wed Apr 15, 2009 5:12 am    Post subject: Sustainable design Reply with quote

"We must partner with owners, architects, and developers in order to maintain our built heritage. Engineers have a more extensive role to play than merely specifying sustainable materials."

Very rightly said by Dr NS in context of implementation of sustainable design

However I still feel that Mother Earth is being looked after by the Father Nature and therefore we should be
more worried about the protection of GREENS/ Trees which actually convert CO2 to the Oxygen through photosynthesis
The fast denudation of forests,dissappearance of jungles, mass cutting of thousands and lakhs of trees in various projects---
this all leads to the non-sustainable situations.Department of Environment ,is of course very active but mitigation
measures suggested always take back seat and remain on papers . Planners and Architects have a lead role
in this context .Engineers have a liitle say at present.

We must protect the Father Nature(Environment) for sustaining life on Mother earth

regards

vikramjeet

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gsparsan
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PostPosted: Wed Apr 15, 2009 5:30 am    Post subject: Reply with quote

I would like to thank Mr Kunal Kansara and Dr Subramanian for their enlightening explanations.

I would also like to add that in Europe, the definition of Sustainable Development is changing to include social and economic progess in addtion to energy and environment. The construction industry has a great impact on social and econimic activity and therefore we as designers we have to think how our design influences these aspects as well.

For example, by specifying an off-site construction method (such as steel or pre-cast concrete), we are shifting part of the workforce from the site to factories, working in sheltered conditions with better welfare facilities and reduced health and safety risks. Factory based workforce give rise to stable communities around the factories. Off site construction also reduces the amount of waste and errors.

This is just one example. The engineering community has to think beyond just calculations. Engineering decisions have an impact on more than just the weight of material. To a large extent, we decide not just what is built, but how it is built as well.
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