Thermal Mass & Buoyancy Ventilation Research Project

Week 77: A General Update

Students working outside on Morrisette Campus

Live from Newbern, Alabama, it’s the Thermal Mass and Buoyancy Ventilation Research Project Team! 77 weeks in Hale County and the graduate student team is still firing on all cylinders. This post, they’ve got updates on concrete panels, drainage, and the steel walkway and stair. Plus, the wonders of the Wood-Mizer, a portable sawmill, for those readers who make it to the very end!

Panel Pour Product

Section Isometric: a peak at the interior concrete panels

A couple of weeks back the TMBV team poured four, new concrete panels. These panels were designed to test tongue and groove joining system. Also, this round of test concrete panels experimented with vertical formwork.

As predicted during the struggle of formwork construction and concrete pouring, the vertically poured panels did not turn out so well. However, the team made promising headway with the new joining method. Alright, now that the panels have cured, let’s take a look at the material.

First, you’ve got to remove the panels from the formwork. You know from the team’s previous post that one of the vertically poured panels did not make it all the way through pouring. Look at that; live edge concrete!

However, the smaller vertically poured panel survived! The results were surprising, as seen abovethis panel had more air gaps than the traditionally poured panel. The students previously thought having formwork on all sides would create more even and consistent panels. But, without an open surface to trowel, the vertically poured panels were subject to more air bubbles.

The typical, horizontally poured panels turned out smooth and even as ever. And just look at that grooved edge!

Diagram showing the corresponding concrete panel surfaces and joints

Next, the concrete panels were attached to the Fabrication Pavilion pin-up wall to test how the joints. The results were inconclusive. Some tongue and groove joints turned out well, while others broke at the edges of the panel. Going forward, the team wants to attempt a shiplap joint for the panels. Also they’d like to make more, smaller test panels to assemble in a minature wall configuration.

Drainage Days

As you can imagine, in the everchanging weather of late, the Test Building site became the town swimming pool. The 18″ deep hole containing the foundations was nearly filled to the brim during the past weeks’ rain. Luckily, the team, Mason, and a mini excavator got out while the sun was shining to install the drainage. The French drain leads from the Cooling Porch, betwixt the foundations, into the forest line.

Rain between two foundations leading to woods

Walk this way

You might have been wondering how one day you might access the 30′ tall, 8′ above ground Test Buildings. Well, you’ll use the steel ships ladder and walkway of course.

Enscape rendering of Test buildings

As of late, the TMBV team students have been designing the fabrication and installation process of the stair and walkway. To detail the stair fabrication process, they partook in a classic rural studio technique; the cartoon storyboard.

cartoon showing assembly of steel stair

Next, the team planned out the order of installation of the walkway and the SIPs structural floors. First, they plan to place and secure one assembled SIPs Test Building floor. Second, place the other Test Building floor, using the walkway steel angle frame to square the two to one another. When everything is properly adjusted, lag screw the steel angle frame to the SIPs floors. Third, place 1″ metal grate on top. Next, place and bolt the stair to the walkway and ground connection. Lastly, site weld the handrails to the exterior face of the steel angle frame. Voila! It’s that easy if you only have a crane!

Wood-Mizer Wonder

And the special bonus; a portable sawmill! Adam Maggard, an Auburn University Forestry and Wildlife professor and Extension Specialist in Forest Systems Management, travels the southeast with the Wood Mizer portable sawmill conducting forestry management research and reaching out to family, forest land owners. Adam collaborates with Auburn Architecture Professor and TMBV colleague David Kennedy and Rural Studio Alum Will McGarity. The three gave the students a Wood-Mizer tutorial as well as an introduction to their research.

Rev. Walker’s Home Project team requested the visitors to help mill some gorgeous tree’s from Rev. Walker’s land. Each student took a turn milling down either the cedar or pecan tree. The students were amazed by the machine and even more amazed that freshly cut cedar is bright, pink. It was a remarkable experience, big thanks to Adam, David, and Rev. Walker from the Thermal Mass and Buoyancy Ventilation Research Project Team!

Those pour, pour foundations!

Live from on top freshly poured foundations, it’s the Thermal Mass and Buoyancy Ventilation Research Project Team! This week the students, with a little help from their friends, completed their Test Building foundations. This included installing rebar and pouring concrete. Let’s get straight to those action shots, huh?

Rebar Retreat

First, Livia’s all time favorite activity, the cutting of the rebar. The team cut sections of rebar for the bottom rebar mat, the top rebar mat, and the vertical pieces that hold the two together.

Next, it’s install time. Comprised of number 5 rebar, the bottom mat is a regular grid. The north-south and east-west pieces are joined with rebar ties. The vertical pieces were hammered into the ground at a consistent elevation. This elevation is 1” lower than the future slab surface. These vertical pieces support the top mat, comprised of number 4 rebar. The top mat only runs between future column locations.

With the rebar installation completed, the TMBV team prepared for the concrete pour. Rowe built bridges to span the foundation excavation holes. The bridges will be used to shovel and trowel the concrete in the middle of the foundations. Jeff helped test bridge durability. Livia prepped her waterproof suit, she’s quite messy and will need to be hosed down with the shovels at the end of the day. Cory practiced his elevation calling as the master of the transit.

The Big Pour

If you find yourself wondering, why do these cute, little buildings need such an intricate foundation? Well, while the volumetric form of the Test Buildings appear small, they are actually quite monumental. Reaching 25’ tall and lifted 7′ 6″ off the ground, the test buildings experience substantial overturning forces which are counteracted by the foundations.

“We get by with a little help from our friends!”

With shovel-armed 5th-years, Steve long calling shots, and Andrew Freear on the chute, the pouring began. Everyone helped move the concrete around the excavation hole until it was about level with the grade pins. Grade pins are orange-painted, vertical pieces that are set to 1/4″ under the slab surface height. When the concrete reaches the grade pins evenly, Rowe and Cory began taking elevation measurements.

In order to deem the elevation, “Good!” the students meticulously move and smooth the concrete. Next, troweling begins once several spot measurements meet the elevation mark. While Livia and Jeff began finishing the surface of the west foundation, the others moved on to the east foundation. Pour, level, rinse, repeat! It is actually a good idea to rinse your shovel in between uses it isn’t ruined by the concrete…

Like most concrete pours, the fashionable ones at least, the TMBV ordered 10% extra concrete. However, the concrete suppliers do not typically take back the extra if it isn’t used. Because all that concrete has got to go somewhere, the TMBV team built formworks that match the size of the concrete scrap they already have. Therefore, they will have plentiful pieces for the design of their Cooling Patio. In the meantime, the mini-slab acts as an executive parking spot for Andrew Freear’s sky-blue Honda FIT.

The Finished Products

Completed east and west foundations
Reserved for Andrew Freear (spikes to be installed later)

Would you look at that—two beautiful foundations ready for curing. And an extra mini slab! The TMBV team could not have completed this feat without the help from the 5th-year students and faculty. The pour went smoothly with no catastrophic events! Next up, construction-wise, the team will install drainage and the steel structure. As always, thanks for stopping by and stay tuned!

f i n

Be Groovy or Leave, Concrete!

“Either be groovy or leave, man!” – Bob Dylan

The TMBV team attempts a vertical concrete panel pour

Live from Neck Down week, it’s the Thermal Mass and Buoyancy Ventilation Research Project team! From 8:00 AM to 3:00 PM last week, the 3rd-years, 5th-years, and graduates students have bonded over manual labor and project maintenance. This is the age-old tradition of Neck Down week, the start of each semester in which all year levels put their projects aside to spruce up Rural Studio’s campus and help out at ongoing and completed projects. The TMBVRP team snuck in some more concrete panel test pours in the after hours. Let’s see how they did it!

Panel Proposals

Before we dive into construction, it’s important to highlight what is different about these concrete panels. In contrast to the team’s last test pours these panels are smaller with tongue and groove edges. We will dive deeper into the tongues and grooves later. As seen above in the unfolded wall elevations above, the team experimented with different sizes and arrangements of panels. The main difference in the schemes where whether the running bond pattern stacked vertically or horizontally. The teams chose to test pour the more rectangular panels from both the vertical and horizontal running bond options.

Panel Preparations

For both chosen designs, the team planned to test making the most commonly recurring panel and the trickiest panel. Therefore, for each option the forwork for a typical rectangular panel and the more triangular panel, created by the sloping roof, was designed. However, a certain, not-Livia team member created the “construction” drawings seen above months before actual construction. The team has made significant leaps and bounds in construction drawing etiquette since. There was also much to the tongue and groove formwork that had not been fully fleshed out. So, as seen in the marked-up construction drawing above, much was decided on the fly. It was a very design-build experience.

Next, the team used their new tongue and groove router bits. Tongue and groove is a system of joining adjacent panels by means of interlocking ridges and grooves down their sides. Seen above are the first tests of the router bits to create the tongue edges for the panel formwork. For the formwork, the tongues and grooves were routed out of PVC board. PVC board will not chemically bond with the poured concrete, therefore, creating a successful cast. Connecting the concrete panels to one another using the joining system will improve their strength. The panels will act more as one structurally, but also thermally making a more effective thermal mass.

Horizontal Panel Pour

Along with testing the tongue and grooved edges, the team attempted two different pouring strategies; horizontal and vertical. Seen below is the typical, horizontal panel pour method. The team is pretty well-versed in this recipe. After pouring the panels, the team will let them cure for about a week. Onwards to the vertical pour!

Vertical Panel Pour

The vertical concrete formwork meant to create two perfect panel faces and ease panel transportation. However, you guessed it, the vertical pour was quite difficult. First, vertical formwork requires more pieces that need to fit together more precisely. You are in a sense making a very precise sandwich that leaks Mayonaise everywhere if you don’t get it right. Second, getting the masonry anchors to stay in place and attach through both large faces required a special bolting jig. Another new piece to make. Third, to keep the formwork upright required leveling and sawhorse structure. Fourth and finally, the team built a funnel to transfer the concrete through the 1-1/8″ formwork opening. And repeat for 60 plus panels!

While the smaller, triangular vertical pour went fine enough, the large rectangular panel busted open. As you can see above the triangular panel had little leakage out of the masonry anchor attachment areas. The rectangular panel however suffered catastrophic failures in this area. For now, the team awaits the curing process to see the results. However, based on these vertical tests they aren’t sure the reward will be worth the hassle. But, hey, where else in the world do you get to test pouring concrete panels vertically than in the Rural Studio graduate program? It’s always worth the hassle.

The Wood Rack

Last, but far from least, the team can’t wait to show off their new wood racks. Because the Fabrication Pavilion is their construction headquarters, the team was in charge of cleaning it up as a Neck Down week task. They are stupidly proud of these wood racks they built to take all their lumber vertical and clear space for more activities! Please admire them!

Copper has joined to say thanks for tuning in! Stop by next week to see how the panel pours and tongue and grooving worked out for the Thermal Mass and Buoyancy Ventilation Research Project Team!

Breaking News: We’re Breaking Ground!

This just in: there’s is a big hole in the Thermal Mass and Buoyancy Ventilation Research Project site!

Thanks to C & T Excavation Inc. the TMBV Test Buildings have broken ground. Local and Rural Studio excavation efficiando, Tyler, completed the initial site grading and the foundation dig. Let’s take a look at how the TMBV team prepped the site for this momentous day.

Newbern’s Newest Crater

plan view drawing showing batterboard arrangement
Plan of Batter Board layout, this drawing guided students in find the foundation limits

Before you can dig a hole, you’ve got to know where to dig! This is where the superheroes of construction, batter boards, come into play. Batter boards are quintessential for starting construction so they must be precise. To clarify, batter boards are temporary frames, set beyond the corners of planned groundwork at common elevations.

Typically, batter boards consist of two stakes driven into the ground with a horizontal member held between them. Next, once you’ve assembled and leveled the batter boards, you use construction string to “pull” layout lines. The layout lines are then secured to the batter boards. Layout lines cross the site either east to west or north to south, between batter boards, to indicate the foundation limits at their intersections. It’s important to note the elevation of the top of each batter board must match so when strings are pulled across the strings intersect.

The TMBV team pulled their first layout line west to east from the Supershed columns. From this line, all other layout lines are set. When all lines’ distances and intersections’ squareness are triple-checked, the team marked the initial grading limits on the ground with spray paint. The end result, with string crisscrossing about like laser beams, feels a bit like a scene from an action movie. Especially if you practice jumping over and rolling under the strings. But, of course, none of these very professional research graduate students took part in such conduct.

At the end of a long day pulling strings, the team marked their initial grading and detached all the layout lines from one side. The layout lines positions are marked on the batter boards so they can be put up and down as needed. Obviously, you can’t build with a bunch of strings in your way. After the initial site grading, the students re-pulled the strings which indicated the foundation limits, marked the corners, and Tyler began digging again. In about 6 hours time, Morrisette Campus had a brand new swimming pool and the TMBV team had a real project site.

Mock-up Progression

In parallel with site groundwork, the TMBV team worked across campus on their mock-up. To mimic the SIPs walls of the test buildings, the mock-up uses 2″ x 12″ stud walls. Due to the angle of the roof and the chimneys, there was much mitering to complete and even more mitering math to figure out. The team built all the stud walls and are ready to assemble. All the especially funky parallelograms you see below are the chimney pieces. With the kit of parts complete, the team awaits columns to build upon.

Cooling Patio Design

True to the design-build spirit, the team is still designing as they’ve started building. The ground plane of the cooling patio was the subject of this week’s design charrette. The team has used, concrete side-walk pieces they intend on using as pavers. However, it is not decided yet how those pavers are arranged.

The team wants to eliminate any excessive cutting of the pavers, especially exact cutting, so they ruled out a linear pattern. They are pursuing a mosaic-like pattern that minimizes concrete cuts. However, without a full inventory of all the concrete pieces, it’s difficult to produce a realistic design. Therefore, in the coming weeks, the team will be taking stock of their recyclable materials. After this, they can start laying out patterns using a steer skid loader to move concrete pieces around.

Welcome to Winter

a dirt roads lead to to silos both surround by frosted grass

As mentioned in the Thermal Mass and Buoyancy Ventilation Research Project Team’s last blog post, the chill has rolled into Hale County. There is never a shortage of beautiful scenery in these parts as proven by these frosty silos. By next post the TMBV team hopes to have another gorgeous view for you; a freshly poured foundation! Here’s hoping and thanks for tuning in!

The Structure at the End of the Rainbow

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.

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

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 Patio 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.

Thankfully, structural engineer Joe Farruggia approved the column placementnow 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!

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 Patio, 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

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 thoughtthe site has some pretty decent soil! Unfortunately, Jeff has been stuck in that hole for weeks… We miss you Jeff!

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.

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!