Structural Technologies - Green Building

Article by: Alan Bernstein AIA, ASLA, LEED AP

October 1, 2009



Jonathan Wirthlin, Structural Engineer, AIA Member, Structural Engineering Association of Southern California Sustainable Design Committee, and LEED AP with Coffman Engineers did an outstanding job presenting at the AIA COTE Committee Meeting of September 3, 2009, on how structural engineers can make a project green.



Wirthlin focused on commercial buildings. The Engineers role creates a substantial cost impact on all projects and there are very few LEED points associated with structural engineering. By savings on materials, additional engineering calculations and changes to the building code, the engineering for buildings can become greener. Wirthlin promotes the Green Globes approach rather then the LEEDS, because it is more comprehensive in its approach.


Greener Concrete

Currently a lot of concrete products that are not “green” still have some fly ash content in them. By increasing the fly ash content to 20 to 70% of the cement mixture we are reducing the amount of fly ash that goes to landfills. Fly ash is a byproduct of burning coal for energy, it use to be sent up into the sky before environmental regulations finally stopped or reduced the fly ash into the atmosphere. As a result there is a lot of fly ash in the chimneys coal fire plants. (The best way to reduce fly ash is to reduce coal fire plants.) If a 50% fly ash mixture where used widely, it would reduce the world’s CO2 production by 4% (that is big).



By adding fly ash to the concrete mix we are creating a concrete that works differently than regular concrete, it does not make it worse, and it is less expensive than cement. It takes longer to set and dry- so the engineer needs to create a time line for the “working strength” of the concrete so the job can continue while the concrete is still curing. It takes less water, requires different admixtures, and can have more shrinkage cracks.


Material Reduction

By using fewer materials we can reduce the environmental impact. But there will be more labor involved in carefully calculating each beam individually, as opposed to the current standard of consistent and repetitive beam sizes. This could also reduce the quantity of bolts, welds, reduce shear wall length, and change stud spacing to 24 or 32” on center.



By use of a higher strength concrete, material can be reduced by thinner slabs, shorter and thinner shear walls, reduce deflection, and ultimately building weight.



Using high strength steel is not very practical. Standard steel shapes usually use standard steel strengths. It would be better to reduce the steel weight by increasing the depth of the beams for less deflection and widths of the posts for more efficient strengths.



Less material can reduce construction cost. There will be a learning curve for labor to be more attentive to small and frequent detail changes. More detailed plans will require more construction management and coordination. Wood projects or advance framing techniques will probably benefit the most from these changes. Concrete would benefit the least.


Advanced Systems

Advanced systems like energy dissipaters, system isolators, buckling restrained braced frames and steel plate shear walls can reduce materials and effects of earthquake damage on buildings. These systems require additional engineering and cost.



To justify these costs we need to consider the Life Cycle the building? How long is the building to last? Would it be better to spend more on materials and have a longer building life? Can the building adapt to other uses? And what will be the impact on the building when the earthquake hits – tear it down or replace some isolators?


Green Aspects of Structural Materials

Current LEED credits for engineering are gained in these areas:

Fly ash counts as pre-consumer recycled content, MR4.

Significant use of fly ash has been awarded Innovation in Design credit, ID1.

Crushing existing concrete for aggregate counts as post consumer recycled content credit, MR4.

Using special aggregates, pozzolans and add mixtures can help achieve Innovation in Design credit, ID1.

Showing the extended life of the building may also help achieve Innovation in Design credit, ID1.

LEED does not look at the life cycle, flexibility or reuse of a building.



Recycled wood can go into particleboard, mulch, fuel and firewood. Larger members can be reused, but smaller members like 2x4s will split apart when nailed. Windows and doors can be recovered and reused. Wood is easily deconstructed and reused in some manner. Wood is the greenest building material. Trees store carbon. Wood comes from a “rapidly” renewable resource. The creation of lumber uses relatively low amounts of energy sometimes their own sawdust (biofuel) creates the energy to mill the timber.



Steel is the most recycled material in the world. Over 80% of the steel comes from recycled product. Reusing steel beams is fully practical. Steel can be constructed with deconstruction in mind by using less weld and more bolts. Avoid unusual or custom shapes that are more difficult to reuse. Steel is the strongest per volume building material used. Steel manufacturing has been dramatically cleaned up, most hazardous waste associated with manufacturing is being recovered and used beneficially. Steel is produced more efficiently yet still takes a lot of energy to melt.



Concrete can be reused as base material, gravel, aggregate for new concrete, and the steel can be recycled. Concrete slabs and walls cannot be recycled for structural use. Concrete has the largest carbon footprint. The production and pouring of one ton of concrete creates 1.25 tons of CO2 and significant heat. One 90-pound bag of cement creates 22291 cubic feet of CO2 (a volume equivalent to 28 cubic feet).



Using an existing building can be greener then building a new green building. When we consider all the waste from demolition, existing embodied energy in materials, labor, transportation and time in an existing building we can save more energy through reuse.

Reusing a building has social, economic and cultural impacts. Adding life, strength and safety to an old building often has less impact on the environment. Building design and structural systems should allow for easy reconfigurations and different uses. The envelope or curtain wall system should be removable to allow future renovated or modernized exterior. Simple building shapes would save in renovation costs.



Again special thanks to Jonathan Wirthlin of Coffman Engineers for his presentation.

Thanks to Jonathan Vogel, President of Spectra Contract Flooring for hosting our meeting and providing food. We are always looking for new attendees, please contact Blaire Seibert, AIA, LEED AP, Verde Concepts via email blair@verdearchitects.com for the date and time of our next meeting. Looking forward to seeing you there.



Reminder, The Greenbuild 2009 International Conference and Expo will be held in Phoenix Arizona, November 11 –13. This is a great conference and an incredible number of exhibits about all things green. It attracts a mix of people from all aspects of the construction industry and related fields. Visit www.usgbc.org for further information.





Alan Bernstein is a licensed Architect, licensed Landscape Architect, U.S. Green Building Accredited Professional (LEED, AP) and Certified Green Building Advisor. For questions or comments contact Alan Bernstein at (818-707-9215) or email at alan@abarchitects.com



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http://www.mikepearsonconstruction.com

Mike Pearson Masonry Contractor Los Angeles

Green Construction - Earning a Repuatation for Building Green

The market makes many demands of the construction industry. We are judged not only by the price and quality of our services, but by social and environmental factors as well. Construction and design firms in California are at the center of the drive to think, design, and build in a way that is environmentally responsible. It is increasingly important to our customers that we are "green." Firms that can legitimately make this claim will undoubtedly gain more market share, strengthen their reputation, and gain the loyalty of their consumer base.

But what does this really mean, to be "green?" What are the measurable factors we can point to in order to establish in a truly legitimate way that we are one of the companies that is responding to this call to design and build in an eco-friendly way? What are the specific things that we can do to establish a real reputation for being a "green" company?

Any company wanting to gain a reputation for "Green" building will want to become aware of the following two organizations: The U.S. Green Building Council, and The Green Building Certification Institute.

Many of us already have various levels of awareness about these organizations, and some of us are members of USGBC. (California has over 5000 members, comprised of architects, contractors, and manufacturers.) For those of us who don't really know about these two organizations and what they do, here are the basics:

The U.S. Green Building Council is a non-profit organization based in Washington, DC that provides education to individuals in the construction industry. In addition to providing education, the U.S. Green Building Council has created a comprehensive program for rating the design, construction, and operation of green buildings.

The Green Building Certification Institute is an organization that administers project certification for commercial and institutional buildings and tenant spaces under the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED®) Green Building Rating Systems™ addressing new construction and ongoing operations. The Green Building Certification Institute also administers the exams required for an individual to receive various levels of LEED® certification. (The study materials for the exams are available through various third party providers which have been pre-approved by GBCI.)

The websites for these two organizations are here:

USGBC
GBCI

Anyone in the construction industry can easily become a member of USGBC. There is an annual fee, based on your company's revenue. This entitles you to claim that you are a member, and gives you the option to display their logo on your website and in your publications. They also offer discounts on various products and services for their members. Of course, simply becoming a member does not require or indicate any action beyond membership.

If one wants to make a serious effort towards education, GBCI offers courses and accreditations. Individuals recognized for their knowledge of the LEED rating system are permitted to use the LEED Accredited Professional (AP) acronym after their name, indicating they have passed the accreditation exam given by the USGBC. Many professionals in our field have this certification.

Lastly, you may submit your project to the certification process that the GBCI oversees. This requires that the project be designed and built within the guidelines established by USGBC, and judged by GBCI. While the standards are complex and require a great deal of investigation and education, the general process is fairly simple.

The rating system and details are on the USGBC website, but I have included a link to a PDF file here:

LEED Green Building Rating System (PDF)

Once you have familiarized yourself with the rating system and guidelines provided by USGBC, you can then register your project with GBCI. The GBCI will then rate the project based on the parameters outlined in the rating system. Once the project has been officially deemed LEED certified, you are entitled to the following:

• A formal certificate of recognition
• Information on how to order plaque and certificates, photo submissions, and marketing
• Inclusion in an online directory of registered and certified projects
• Inclusion in the US Department of Energy High Performance Buildings Database

What this means is that by perusing and completing the education and/or certification provided by The Green Building Certification Institute, you can claim in a clear and thoroughly substantiated way that you are an active participant in the push to create environmentally sound, sustainable, and energy efficient structures. You can call attention to your accreditation and certification in all of your marketing efforts, and represent yourself as an active and cognizant participant in the green building movement.

We certainly welcome your feedback on the topics discussed above, and we especially welcome any additional insights, tips, or information from anybody that has additional first hand experience navigating the waters of this newly emerging field. It is our hope that we can expand and share our knowledge of topics such as these by sharing our experience with each other. Please feel free to forward this article to anyone who may find the information interesting or useful.

Come visit us here:


Mike Pearson Construction, Inc.