Live from Fall 2021 “Neckdown” Week, it’s the Thermal Mass and Buoyancy Ventilation Research Project Team (TMBV)–and helpers! This week, the team accomplished a variety of tasks with the help of the 5th and 3rd-year students.
First on the agenda, the team completed the Cooling Porch ground surfaces. This included packing crushed ground surface concrete pieces and building the stairs. The Cooling Porch stairs were comprised of stacked concrete pieces cut from the foundation pour excess. David Hill, professor in Auburn’s School of Architecture, Landscape Architecture and Planning, got in on the concrete saw action! Continuing on the stair action, the team also installed the steel stringer and handrails for the Test Building entry. After pouring a concrete footing for the steel stair, Rowe came back and welded on all the treads.
With all the groundwork in the Cooling Porch finally complete and three sets of stairs built, the TMBV team is calling this “Neckdown” Week a huge success. Thank you to all our helpers this week! Next up, thermal mass concrete panels–stay tuned!
Live from within the newly completed Cooling Porch retaining walls, it’s the Thermal Mass & Buoyancy Ventilation Research project team! We’ll take you through the evolution of both north and south wall and all the earthwork in between. If you stay tuned ’till the end you’ll see Cory’s latest artistic venture; a short film titled, “Le Grevier.”
North Wall: Complete!
After laying and leveling the dry-stacked concrete highway barriers, the team backfilled gravel and earth against the wall. Directly behind the walls are drains that are wrapped in landscape fabric and covered with gravel. This protects the drains from getting clogged with Hale County Clay. Behind the gravel, the team piled and compacted earth. They are reusing the dirt excavated for the building foundations. This process repeats for each course, refilling the initial dig. The Cooling Porch is still a hole in the ground, but it’s becoming a far more precise hole in the ground.
Voila! The joints, pattern, color, and textures of the north wall turned out fantastic. The team was astonished by the uniformity of the wall and the blending of the different blocks despite using reclaimed materials. On to the south wall!
South Wall: Complete!
The process of constructing the south wall was essentially the same as the north wall. Small concrete footings were poured wherever the retaining wall went off the building foundations. The team also completed the installation of the drainage. The space began to form right in front of their eyes!
The team feels the space looks exactly as they drew it–which is both slightly surprising and super satisfying. All the measuring, drafting, and double-checking produced a beautiful pit. And, bonus, the reuse of materials is a surefire way to build with the environment in mind and luckily these concrete highway barriers turned out to be the perfect durable, stackable material. The backfill and dug-out stairs makes getting around site a whole lot easier. It’s all coming together!
Thanks for following the progress of the soon-to-be chilly demonstration space! Stay tuned for SIPs construction and laying the ground surface in the Cooling Porch. Now, for your enjoyment, follow the life of a scoop of gravel in Cory’s feature film, “Le Grevier.”
Le Grevier: Directed by Cory Subasic starring Wheelbarrow, Shovel, Bobcat, and Gravel with a special appearance by Livia Barrett as “Gravel Girl.”
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?
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 Porch. In the meantime, the mini-slab acts as an executive parking spot for Andrew Freear’s sky-blue Honda FIT.
The Finished Products
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!
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
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.
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 Porch Design
True to the design-build spirit, the team is still designing as they’ve started building. The ground plane of the cooling porch 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
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!
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!
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.
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!
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.
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!
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!