Structure

Another Stud in the Wall

February 21, 2021

As promised, the big reveal.

Following the holiday season, Myers’ Home team returned to Newbern. After the annual Spring semester Neckdown week, the students took a look back at the projects’ goals and methods. What is Myers’ Home Project achieving through design and how can it be brought to life?

Weedin’ and chin waggin’ at the Lions Park Shade Project

Generational Flexibility

Above all, Myers’ Home design aims to serve a family over generations by providing means of expansion within a protected shell. The team is also prioritizing material efficiency, buildability, and affordability as they evaluate how to build.

Originally, Myers’ Home implemented a post-frame structural system to create the protective shell essential to generational flexibility. The post-frame method is a simple structure – poles embedded in the ground or a footing with trusses and a simple roof system spanning between. However, the team needed to change aspects of the structural system for it to become sturdy enough for a longlasting, enclosed home.

Personalized Post-Frame

To achieve the desired decade-spanning design, the team customized the poles, trusses, and roofing. The poles were set in above-ground brackets rather than driven into the soil, bolstering longevity. The trusses had become inherently more complex with the addition of an attic. And, the roof system was designed in layers for thermal comfort and durability.

Roof assembly for longevity and efficiency

post-frame vs. stud wall construction sequencing

Subsequently, the team diagramed the whole process of construction to understand efficiency and method. As seen above, the team mapped out each step and considered the building timeline implications. As the team reflected on the more complex system and the steps to build, they reached a new conclusion. Post-frame is a fabulous typology, however, it isn’t what Myers’ Home needs.

A New Structure Ahead

But it’s not all over, in fact, it’s just begun! The four students made a quick turn, forget whiplash, and are on their way to Stud Framing City.

A rousing weekend pinup at the Fabrication Pavilion

Most importantly, the new method is, for the enclosed attic home, quicker than the original post-frame system to build. Scrapping the footings and columns, the home sits on a simple turndown slab allowing the stud walls to be quickly erected on top. Furthermore, and in line with the previous concept of the flexible model home, the only interior walls are for the home’s core.

Only outer and core walls are framed initially

Also, a quick maneuver with the trusses is underway! The new truss has the same pitch but the entire porch segment is sliced off, creating a heal. A heel? That’s right, and they aren’t talking about feet.

Free Porch

Without the rafters or posts to dictate its volume, the porch can boldly go where no porch has gone before. In short, the porch is now free from the overall structure of the home. Now, there is no part of the integral structure which breaks the enclosed protective shell. The porch is no longer a weak point for the generational home. This is more in line with the intentions and goals of the design.

The Zip System shell wraps and shelters the home’s interior

The team is certainly enthusiastic about the new porch design challenge. The porch could touch the house lightly, tie in with a separate system, or stand entirely independent of the home structure. With all these options, the team is narrowing their infinity to perhaps a universe or two.

One of Hale County’s windiest pin-ups on record!

To inform the porch, the house must begin to speak a language. But what part speaks? Some might say it’s the details that do all the talking. The team dove into drawing details to determine which voice should be heard loudest and followed.

Beginning to define the porch’s language

Checking out eave details in Downtown Newbern

And that’s where they are now, up in Red Barn drawing details, details, details. 1:1, markers-on-the-floor, shred-‘em-‘til-they’re-right details. They’ve run all around Newbern looking at past projects and local precedents for inspiration. Research in your own backyard!

So keep an eye out, these four can’t wait to show you their corners.

Tags: ClientHome, design, Myers' Home, post frame home, postframe, rs5thyears, Structure, studwall, trusse

The Structure at the End of the Rainbow

December 15, 2020

double rainbow over Morrisette campus storehouse

Live from a double-rainbow kissed Morrisette Campus, It’s the Thermal Mass and Buoyancy Ventilation Research Project team! Recently, as the chill rolls into Newbern, the students and faculty witnessed this heart-warming phenomenon. And if you came for the rainbows, you should stay for the structure. Hang tight to learn how the TMBVRP team is supporting the Test Buildings eight feet off the ground.

students examining stud wall attached to brick wall — Tuesday’s at the Horseshoe Courtyard

students holding tree in place in oversized hole — Tuesday’s at the Horseshoe Courtyard

One more thing before we get on to the structure, a quick look at the Horseshoe Courtyard. During this semester the TMBV Research Project team has enjoyed working on the Horseshoe Courtyard site. Every Tuesday, project teammates Caleb and Claudia are wonderful and patient teachers to the TMBV team. The team certainly appreciates the construction experience and the time away from their computers. Go check out all of the beautiful work the Horseshoe Courtyard project team has done on their blog!

Column Conundrums

iteration 4 photo montage of pod model on top of mock-up 2 — Model on Mock-up montage

Students sitting underneath mock-up 2 between the two chimneys — Model on Mock-up montage

First, a quick reminder of how and why the Test Buildings are up on stilts. Because the Optimal Tuning System uses thermal mass to create airflow, the Test Buildings will expel cooled air. In the Summertime, that cooled air could be a benefit to more than just the Test Building dwellers. Therefore the Test Buildings design was lifted in order to create a Cooling Porch underneath. Here, anyone can enjoy an outpouring of chilled air. The team chose steel columns to do the heavy lifting to keep the focus of the space on the solid Downdraft Chimneys. As seen in previous blog posts, the column’s placement is dictated by the relationship to the Downdraft Chimney’s and the seating arrangement. However, the column arrangement can not just look good on paper and feel right in the mock-up, it’s got to actually, safely stand up.

written column sizing calculations for a 3.5" O.D. column — The team’s first attempt at hand calculations for column sizing

written column sizing calculations for a 4" O.D. column — The team’s first attempt at hand calculations for column sizing

interface of Enercalc engineering software displaying column load calculations — Rowe battles with Enercalc, an engineering software

student frustratedly pushes up knit cap while staring at computer interface of engineering software — Rowe battles with Enercalc, an engineering software

Thankfully, structural engineer Joe Farruggia approved the column placement—now it was time to size the columns. Through a series of hand calculations, the team tested the stiffness of 3.5″ – 6.0″ diameter steel columns to see which ones could handle the weight of the pods. Then, Rowe took this work into Intercalc, an engineering software. Intercalce allowed him to test structural loads such as gravity loads, wind loads, live loads, and overturning forces. It turns out a 5″ O.D. steel column will be more than safe. Now, onto bracing!

8 foot tall column detail showing ground and SIPs connection — Plan showing braced columns within the berm wall

column brace ground connection detail showing concrete footing — Plan showing braced columns within the berm wall

Three of the four columns, per test building, are braced to eliminate excessive drift caused by wind loads on the tall faces of the buildings. Similarly, bracing the columns reduces possible deflection and improves stiffness. The column bracings, hidden in the berm walls surrounding the Cooling Porch, are 4″ x 4″ x 3/8″ steel angles. The six braced columns appear 5′ tall as they disappear into the berms while the other two are the full height of the occupiable space at 8′ tall. These taller, unbraced columns act as entrance markers.

Foundation Demystification

structural plan showing ring beam foundation type intersecting with the locations of pod columns

Originally, the team believed a concrete ring beam foundation would be sufficient for fixing the steel columns, and thus the buildings, solidly to the ground. As seen in the drawing above, the ring beams would extend to catch bracing. However, the team needed to consider overturning moments, or overturning forces, due to the height and the aforementioned wind loads of the Test Buildings. Overturning moments are those applied moments, shears, and uplift forces that seek to cause the footing to become unstable and turn over. This means they needed to make sure the foundations were strong enough to keep the columns and bracing in the ground during bad storms.

Before these moments could be properly designed for, the team needed to do some soil testing. The quality, based on its compaction, of the soil is another factor in determining the necessary size, and strength, of the foundation. Jeff and Cory dug some holes and then used a penetrometer to test the soil. And who would have thought—the site has some pretty decent soil! Unfortunately, Jeff has been stuck in that hole for weeks… We miss you Jeff!

hand written calculation of overturning force loads on east/west pod wall — overturning force calculations

hand written calculation of overturning force loads on north pod wall — overturning force calculations

To counteract the overturning forces, the foundation changed from a ring beam to a buried slab foundation which increases its weight. Each Test Building will have its own foundation. The slab foundations secure all columns and bracing to each other as well as the ground. Below are currents drawings of the foundation, column location, and bracing connections.

pod ground plan showing interaction between cooling porch seating and column locations with slab foundation type — Foundation Plan showing concrete curb seating

slab foundation plan labeling column locations — Foundation Plan showing concrete curb seating

The Thermal Mass and Buoyancy Ventilation team will be jumping into drainage and ground material master planning next. Translating research into design into construction has been an arduous journey. However, the pay off will be worth it when designers anywhere can use the Optimal Tuning Strategy to make building materials work as air conditioners. Thanks for reading and stay tuned!

Tags: Cooling Hearth, Cooling Porch, foundation, natural ventilation, passive strategies, soil testing, Structure, thermal mass, Thermal Mass and Buoyancy Ventilation

Getting Down to the Details

November 9, 2020

Live from behind a stack of full-scale detail drawings, it’s the Thermal Mass and Buoyancy Ventilation Research Project Team! Lately, the team has been investigating all details inside and out. Starting out with material pallet and ending up at chimney flashing, the team is kicking it into high gear.

Cladding Material

1/4"=1' model of pods showing scale figure in cooling patio underneath — Iteration 1 Model

iteration 2 1/4"=1' model birds eye view — Iteration 1 Model

Unsurprisingly for a project so focused on the interior systems, it was difficult to make decisions regarding cladding. Initially, as seen in previous models shown above, the team experimented with separate cladding systems for the chimneys, Cooling Porch ceiling, and exterior walls. For iteration 1 of the test building design included a timber open-joint cladding system wrapping every surface. Next, for iteration 2, the cladding system wrapped only on the exterior wall faces of the buildings and the adjoining chimney faces. However, thin sheet metal covered the roof, cooling porch ceiling, and the chimney faces which touch those surfaces.

timber cladding + stacked timber walls and benches

The consistent cladding of iteration 1 appealed better to the monolithic nature of the SIPs structure. It also reinforced the importance of the chimneys to the buildings as a whole from the exterior. From there the team began to test if the timber was the correct mono-material for the test buildings. Seen above are renderings testing different materials for the cladding, columns, retaining walls, and benches. It is important to view these materials as they interact in the Cooling Porch. While sheet metal and polycarbonate cladding options may look more monolithic, timber is a low carbon material that better represents the heart of the project. In some cases, timber as a building material acts as a carbon-sink meaning it stores and processes more carbon than it produces. This of course relates strongly to the passive goals of the Thermal Mass and Buoyancy Ventilation Research.

Recycled Retaining Wall

Now the team is settled on the timber cladding, but they are not convinced of the retaining wall and bench materials. These aspects want to be a more earthen material as they rise from the ground towards the test buildings. After investigating rammed earth and concrete, the team wanted to find something more stackable. Concrete and rammed earth are beautiful, but they require formwork which requires more time. Something stackable will give the team more flexibility as well as members are movable.

Thankfully, down here on Highway 61 road work is being done to remove a load of 8″ x 8″ x 8′ stackable concrete barriers. The TMBVRP team is getting their hands on some of these reusable members and are calling around to local highway departments to find more similar materials. If they find enough, they will have a durable, stackable, and reusable material for their Cooling Porch. They can also use the old sidewalk pieces as a mosaic, ground material for the Cooling Porch. Above are drawings showing the use of these recycled materials.

Structure and Detailing

laptop screen showing Joe Farrugia on video call with students — living lengend Joe Farrugia on Zoom

For the past three weeks, the team has been meeting consistently with Structural engineer Joe Farrugia. He is guiding the team through lots of math to size their columns. While the gravity load on the columns is extremely manageable, the wind load is more difficult. The test buildings height means they will face more wind load than a structure this size typically experiences. However, Joe is confident that the structural system the team has chosen is doable with the correct column sizing.

While the team is attempting to draw every detail of the test buildings, they’ve found the trickiest spots to be around the chimneys. Making sure water moves off the roof consistently and air moves behind the ventilated screen is crucial. The TMBVRP will spare you the pain of walking through each flashing bend and board cut. Struggles emerge when the chimneys converge with the angled roof, but it’s very doable with lots of thinking, drawing, and redrawing. Then Andrew Freear and Steve Long, come in to save the day because how you’ve redrawn it five times is still wrong. Lots of covered wall reviews later and the TMBVRP team is on their way to compiling all the details in a digital model and drawing set.

students and professors gather in front of a wall full of detail drawings

Looking forward to keeping this momentum going, the TMBVRP can be found in Red Barn from dawn to dusk. Feel free to bring by some late-night snacks but for now thanks for TUNING in!

Tags: Cooling Hearth, Cooling Porch, details, natural ventilation, passive, passive strategies, recycled materials, SIP, Structure, thermal mass, Thermal Mass and Buoyancy Ventilation, timber research

How do we build that?

December 2, 2019

Now that the pods have been given forms, it’s important to figure out how we can make them stand up. To accomplish this, we are comparing three different structural systems to find the best method. We are considering Cross Laminated Timber (CLT), Structural Insulated Panels (SIPs), and more conventional stick framing systems.

All of these systems require slightly different assemblies, and we drew many wall sections to begin to understand them.

These forms also require unconventional joints at odd angles, so we did studies of how to join corners, whether with panelized systems such as CLT and SIPs, or stick framing.

By the end of these studies, and with the help of a review from Hank and Julie of KoningEizenberg Architecture, we began to realize that these forms were too complex, and could be simplified without forgetting our experimental requirements. This led us to a form we’re calling the “Rowhouse”.

We will continue investigating structural systems using the Rowhouse form. We are currently investigating using the SIPs systems, as they offer a high insulating value while integrating structure. Our next steps will be designing the thermal mass panels that will live in these structures.

Tags: CLT, joints, SIP, stick frame, Structure, thermal mass, Thermal Mass and Buoyancy Ventilation, wall section