Reporting from Greenbuild

The green building community gathers annual to share ideas and promote new innovation at the Greenbuild International Conference and Expo. The 2013 conference was held in Philadelphia, PA, November 20th through the 22nd. New SEI Sustainability Committee member Lori Koch was there to inspire attendees to "reThink Wood."

(Lori Koch, November 25, 2013) I had a great time at Greenbuild. I was working the reThink Wood Pavilion in the expo hall, and got to spend a good deal of time talking to attendees about using wood in sustainable structures. 

One of the big draws to our booth was the model of a 40-story tower that had a hybrid structural system of concrete and CLT (cross-laminated timber). The prospect of wooden skyscrapers really intrigued a lot of people, and led to some great discussions. 

I was lucky enough to have some down time to walk around the expo hall and see some of the other exhibitors (and I was lucky enough to win an iPad mini from the Office Depot booth!). One of the more impressive displays was the Kohler RV, it had working models of about a dozen different toilets and the rep talked about the lower water consumption models they have available. It was very interesting just from a standpoint of being a fixture that we all use every day, yet give very little thought to what’s at work with the system (or maybe that’s just me being a narrow-minded structural engineer!). 

I also got a chance to talk to folks interested in sustainable buildings from nearly every angle: wood products, steel producers, plumbing fixtures, educational programs, windows… the list goes on and on. It was a great experience and I’m looking forward to doing it again next year.

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Learn to Design Thermal Breaks at the 2014 Structures Congress

Many of a structural engineer's common design tasks may affect the energy efficiency and environmental performance of a building. Designing exposed projections of the supersturcture, supporting enveloping facades, and attaching exterior equipment can create a conduit for thermal bridges between the outside and conditioned envelope of a building.

A preconference workshiop titled Design of Sustainable Thermal Breaks has been planned on the afternoon before the start of the this year's Structures Congress in Boston, Massachusetts. The workshop will focus on providing practicing engineers with state-of-the-art strategies implementing thermal break connections. Design and construction examples by the SEI Sustainability Committee's Thermal Bridging subcommittee will be presented. You probably won't find these tips in typical structural engineering texts.

Additionally, an architect and a mechanical engineer will discuss why thermal break connections are important aspects of building science. They will also describe how overall energy modeling effects ASHRAE's recent reporting on building envelopes.

The 2014 ASCE/SEI structurs congress is April 3-5, 2014, at the Sheraton Boston Hotel and Hynes Convention Center.

Register for the preconference seminar here. 

MODERATOR: Mark Webster, P.E., LEED AP BD+C, Simpson Gumpertz & Heger Inc.

SPEAKERS:

• James A. D’Aloisio, P.E., SECB, LEED AP BD+C, Klepper Hahn & Hyatt
• Dave DeLong, S.E., LEED AP, Halvorson & Partners
• Andrea Love, Building Scientist, Payette
• Russ Miller-Johnson, P.E., Engineering Ventures
• Raquel Ranieri, S.E., LEED AP, Walter P Moore & Associates
• Chris Schaffner, P.E., LEED Fellow, The Green Engineer

PLEASE NOTE: Application for AIA Educational Credits has been submitted, but is not yet confirmed.

Additional Registration Fee: EB: $99 / ADV: $175 / ONS: $250

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IABSE Symposium Call for Abstracts

The International Association for Bridge and Structural Engineering (IABSE) is hosting their 37th annual symposium on September 3-5, 2014 in Madrid, Spain. The conference will include a track on sustainable infrastructures. Abstracts are being accepted through November 30, 2013. More about the symposium is available online at IABSE.org.


The title for the 2014 symposium is "Engineering for Progress, Nature and People." Organizers have highlighted the following quote by Carlos Fernandez Casado to summarize an engineer's responsibility, "...in perfect union with Nature; however, we cannot forget our engineer goal of controlling it. Nevertheless, landscape beauty and its grandiosity get into contradiction with above attitude due to the fact that the engineer was taken over by nature, till the moment I learnt 'natura parendo vincitur', 'to get control of nature but obeying it.' The Engineer shall always love nature..."

Recommended by SEI-SC member: John Anderson

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Join Green Structure Group on Linked-In

The Green Structure group is dedicated to improving the environmental performance of built structure. It is open to all structural engineers who wish to explore and advance best practices in ecological design. The group is supported and managed by the SEI Sustainability Committee. Learn more here: http://www.linkedin.com/groups/Green-Structure-4892266/about

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Sustainable Structures Symposium

The Portland State University School of Architecture is hosting a sustainable structures symposium
April 17-18, 2014. Learn about the intersections of architecture, structural engineering and green buildings. More about the symposium is available online at http://web.pdx.edu/~cgriffin/symposium/

This symposium may be of particular interest to structural engineers, because the organizers recognize that "the role of structural systems and materials in the overall performance of a building has been largely neglected." Structural systems are chosen early in a project and are heavily influenced by buildings codes, construction schedule, and cost. More consideration should be given to the structure considering that it contributes roughly one-quarter of the initial embodied energy in a commercial building.

This symposium promises to explore the greater role structure should have in the design, impact and operation of green buildings.

Recommended by SEI-SC committee member Kathrina Simonen.

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A Personal History of Sustainability for Structures

How does one become interested in sustainability for structures? Over the course of a series of interviews with members of the ASCE-SEI Sustainability Committee, we hope to provide the answers. This blog and other frequently describe why sustainability is important, but the path taken by sustainability champions is seldom considered. Diverse experiences are to be expected. Understanding the reason for one’s passion for structural sustainability might help us grow the movement.

Ken Maschke, P.E., S.E., LEED A.P. is the first to be profiled in this series. Ken has served on the committee for three years and now leads the Communications Working Group. With about 10 years experience in structural engineering, he represents the crest of the wave of Generation-Y engineers now coming into their own in the profession. Sustainability was not a focus of his college education, but shortly before Ken graduated the U.S. Green Building Council unveiled the first LEED green building certification system.

How did your education prepare you for sustainable design?

Like many structural engineers, my undergraduate degree at the University of Michigan was actually in civil and environmental engineering. I fretted the hydrology and water treatment classes that were a part of the standard curriculum. At the time, I thought that the information was only useful to environmental engineers seeking to clean up superfund sites or support litigation, à la Erin Brockovich. Now I can appreciate how this basic background can be applied to aspects of sustainable design.

Photovoltaic panel located on 13th century castle in South of France. Mt. Ventoux and Rhône River in Background

Why did you decide to become LEED certified?

I was bribed. My company, Thornton Tomasetti, recognized the value of workforce versed in sustainable design before I did. They provided LEED AP training seminars, sponsored my test registration, and offered a bonus upon becoming certified. The company continues to help staff maintain their credentials.

What opened your eyes to sustainable structures?

Grain silo repurposed as condos in Denmark

In 2007, I had the opportunity to participate in an externship program with a firm in Copenhagen, Denmark. While LEED certification was still catching on domestically, sustainable features were de facto in Danish construction. I was almost laughed out of the office when I asked what a thermal break was. Fortunately, the team was patient with me and provided my first education in designing for true sustainability, as opposed to angling for LEED credits.

A couple years later I took leave from my job to live in France for six months. My wife had received a contract for on-site French to English translation for an energy company. Again, I was impressed by the attention that the French paid to energy and resource efficiency. Since, I wasn’t working, I had plenty of time to do some online research and review my own design practices.

Shortly after returning from France, I had the opportunity to assist a local artist with a large-scale park concept making extensive use of solar panels. Around the same time, I toured a solar energy harvesting power plant in Nevada, as part of the 2010 ASCE Annual Conference. From that time on, I knew that sustainability would have to be an integral part of my career.

How do you employ sustainable strategies at work?

I work in our Building Performance Practice Area. Our multidisciplinary team provides technical support to building owners, managers, and designers throughout a building’s lifecycle. We specify maintenance regimens, design repairs, and help realize building renovations. By definition, I feel that our practice is sustainable. We strive to keep existing buildings operational and improve their performance. Doing this hopefully lessens the need for new building construction.

My favorite projects could be characterized as adaptive reuse. We give new life to existing buildings by changing their occupancy or providing significant performance upgrades. I’m currently overseeing the structural transformation of an old seminary into an institute for economic education and research. Another current project repurposes an old lumberyard as a gymnasium for a charter school. We try to preserve as much of the existing structures as possible while also giving consideration to thermal performance upgrades.

The New Harmony Solar Park was estimated to have the potential of creating 3.69 Gwh per year

How has membership on the ASCE-SEI Sustainability Committee enhanced your work?

Being part of the committee provides access to the latest information on sustainable structures and great peer group. It is empowering to know that there are such motivated individuals devoting their careers (and loads of personal time) to advancing sustainability in the structural engineering profession. I look forward to learning more about their history with sustainable structures and future aspirations.

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Natural Ventilation, Cooling and Lighting

Unobstructed soffit was required on this project requiring a raised floor to cover the upturned beams and the space created below the floor facilitated IT distribution and sprinklers. The thermal mass of concrete and properties of normal weight concrete were critical to effectiveness of the natural ventilation on this project. Locations good for this application are the “west coast and desert regions of the United States, where the climate has daytime to nighttime temperature change of about 30 degrees, mechanical engineers can design cooling systems that take advantage of radiating cool from the structure….The efficacy of this method of cooling requires that the structural thermal mass elements must be directly exposed to the building occupants so that the structure can absorb heat gained during the day, and radiate (or release) heat during the night. Ceilings, floors, and walls that are covered with finishes will not be as effective in cooling a building….Concrete buildings naturally lend themselves to this strategy. (Kestner 2010) 

Concrete fill on steel deck used in steel buildings can also provide thermal mass, but if the underside of the deck is fireproofed, its ability to transfer heat will be greatly reduced, thus reducing the effectiveness....Structural CMU walls, if exposed, can provide sufficient thermal mass for come buildings. The architect will usually require units with architectural finishes, and will require precise lay-up and high quality workmanship.” (Kang 2006) 

Steel in buildings lend themselves to other another natural ventilation strategy called stack effect.  Stack effect requires pathway up the height of the building “unobstructed of walls or other large elements” and can benefit from using a “material that heats up quickly when exposed to sunlight…along exterior towers to draw hot air towards it.”  (Kang 2006)  Such an example is the Porticullis House which contains tall steel towers.

Structural Considerations for Innovative Systems

Sunshades and light shelves require support typically integrated with curtain wall systems and the structural engineer may provide design loads for the design build window supplier and then review design and calculations. Panels are about 5psf typically with frequent penetrations to roofing for armatures to resist uplift; alternatively, armatures could be designed to engage ballast to resist uplift increasing system weight to 20 psf to 25psf. And care in checking seismic forces should be taken when adding a system to an existing building. 

For radiant heating the primary concern is the coil,  One option is to have a topping slab to encase the coil adding weight to the system.  Encasing it in the structural depth of the slab taking lots of coordination with structural requirements of the slab especially at high shear and bending locations. Additionally coils limit future flexibility because coils are difficult to locate when needing to avoid damaging a coil when making a new slab penetration. 

Green roofs present heavier loads on the roof and consideration of drainage of water needs to be considered so as water cannot accumulate more than anticipated so as not to overload the roof. (Kang 2006, Gartner 2008)

For more design recommendations on implementation of these strategies, see the SEI Sustainability Committee’s book Sustainability Guidelines for the Structural Engineer and the SEAONC white paper “Structural Engineering Strategies Towards Sustainable Design,” full citations in the references section of Q2.

References

Kang, Grace and Alan Kren, (2006). “Structural Engineering Strategies Towards Sustainable Design,” SEAOC Proceedings 2006. Pp.473-490.

Kestner, Dirk, Jennifer Goupil, and Emily Lorenz, (2010). Sustainability Guidelines for the Structural Engineer,  Sponsored by Sustainability Committee of the Structural Engineering Institute of ASCE, Reston, VA: ASCE, 978-0-7844-1119-3.

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