Wednesday, November 8, 2017

Making a small concrete block masonry building

This material is based upon work supported by the National Science Foundation under Grant No. 1660075 ("Topological interlocking manufactured concrete block").  Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author, and do not necessarily reflect the views of the National Science Foundation.

Today I'm taking a look at the construction of a small building assembled from manufactured concrete block.  This particular building was made to serve as a kiln room.  A kiln is a high temperature oven or furnace used to heat (fire) ceramic material.  Kilns may also be used to melt metal, or glass, or for any heat-treatment of materials, such as drying green wood.

This building has a footprint of around 14 feet by 12 feet, or around 170 square feet.  There is a trend today toward "tiny houses" where people are attempting to live in such small spaces.  Personally, I don't mind living in a small house (under 1,000 feet is OK) but I would not care to live in such a small space as this: it is appropriate for a shed, or a safe room, or even a kiln room.

A "safe room" is an appropriate use for a building this size.  A safe room like this would be appropriate to survive a tornado, or hurricane or wildfire.  The need for an affordable, high-strength, fire-proof safe room has been brought into sharp focus over the past few months, with the arrival of hurricanes Harvey, Irma and Maria; and also with the devastating wildfires in California and across the American West.  A building such as the one shown here would allow people to survive any of these disasters, providing safe refuge in the face of any of these natural disasters.  Many residents of Texas, Louisiana, Florida, Puerto Rico, US Virgin Islands, and California would have benefited from one of these structures during the hurricanes and wildfires which impacted these areas.  A structure such as this provides an affordable solution to these natural disasters, and gives people a safe place to survive these devastating type of events.

Following are some photographs showing the construction of this building.  The vertical walls were made with standard 8 inch x 8 inch x 16 inch concrete blocks, or "cinder blocks" as they are commonly known.  The side walls of this building include blocks which are oriented with their long dimension oriented at a right angle to the wall, creating a series of vertical buttresses, or pilasters for additional strength and reinforcement.  These blocks have hollow core holes which were subsequently poured with grout and also contained a series of vertical rebar for additional reinforcement.

Here is the building site before construction began.

Construction has begun, a few hours into it.

Vertical walls almost completed, this took 2 days to build.

There were 450 regular 8 inch x 8 inch x 16 inch block used to make all of the vertical walls.  These block cost $1.20 each.  There were 30 8 ft. pieces of rebar used in the hollow vertical cores of the walls, which were poured with grout.  I used "gatorbar" rebar, made by Neuvokas Company.  This rebar is made from basalt, which has a very high tensile strength and will never rust20 foot long pieces of this rebar cost around $5.50.  The grout cost around $30 for the entire structure.  Mortar for the entire structure cost around $45.00.  The material cost of these vertical walls (including block, mortar, rebar and grout) was around $700.

This shows wooden forms used to make arches between the vertical buttresses or pilasters.

Here are wooden forms used to make a concrete skewback, from which the masonry arch roof is built, or 'sprung.'  

This shows the arch assembly as it begins.  Note the use of 'gatorbar' rebar used to help create the arch.  This block is described in more detail here.

Here is the masonry arch being constructed.

This shows threaded anchor bolts (3/8") which were used to attach a wooden covering to the roof.

This is the 3/8" anchor bolt, which is inserted into the mortar beds between blocks of the arch.

Here is the building with a completed masonry arch.  This could have been made waterproof with any number of techniques, including waterproof paint, rubber roofing, etc.  I try to use the most common construction practices, methods and materials: so I used a wooden surface, covered with tarpaper and then finally covered with shingles.  Any of these methods will work.

Here is the wooden roof surface, covered with tarpaper.  Note the stainless steel chimney for the kiln in the back.

Here is the shingled building, more or less complete.  I will still install a door, and I may paint the building with a waterproof masonry paint, such as (for example) Drylok(TM).

This building represents a simple, high-performance, inexpensive approach to providing a very safe structure capable of withstanding wildfires, tornadoes, hurricanes, and other extreme weather events.  The cost of materials for the vertical walls was around $700.  The cost of the masonry arched roof was $644 in block, around $70 in mortar, and $77 in rebar for a total material cost of $791.  The total material cost of this building was $1,491.  This material cost does not include labor, and labor costs vary widely.  This was built by two masons working for 5 days, 8 hours each day.  By comparison, a smaller shed made of flimsy wood sheathing which is much smaller (8 ft. x 12 ft. vs. 12 ft. x 14 ft.) costs $2,199.  This wooden shed will burn, rot, suffer from insects, and is not nearly as strong: it would not survive a direct encounter with a hurricane or tornado.  There is really no comparison!  The wood shed costs $22.90 per square foot, the concrete building shown here costs $8.77 per square foot.

Upon completion of work funded by the National Science Foundation (Phase II, Small Business Innovation Research, SBIR) within the next 2 years, this technology should be accepted into the International Building Code and is expected to be available for sale internationally.  This small building is just another example of what this innovative masonry technology makes possible.  Better, stronger, safer buildings at a lower cost. 

Friday, August 18, 2017

Building Another Masonry Prototype

This material is based upon work supported by the National Science Foundation under Grant No. 1547958.  Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author, and do not necessarily reflect the views of the National Science Foundation.

One year ago (late summer, 2016) I began working on a masonry prototype which would use the novel topological interlocking manufactured concrete arch block, described and discussed here.

I had been teaching a Senior Project engineering class at Alfred University's Inamori School of Engineering, and asked my students to help design this structure.  The students I had the pleasure of teaching include undergraduate students Pavel Boyuk, Patrick Byrne, Wanrui He, Nolan Jessop, Sanket Patel, Nick Roberts and Alex Wessner; under their professor Dr. Ehsan Ghotbi, and also graduate student Martin Monk under his professor Dr. William Carty.

Here are some of the drawings these students did for this structure.  The actual design was changed somewhat from these drawings to what was actually built. These changes include switching from a round profile to a catenary profile on both the main arch for the roof, and also on the flying buttresses which are located on either side of the building.  I also went from seven buttresses per side (as per the students' drawings) to six buttresses.  Finally, I also included two Gothic windows on one side of the main arch.

This building was erected on my own personal property in Alfred, New York. Site preparation began with felling several trees and clearing the logs from the site.  I'll just let the pictures tell the rest of the story, beginning with the building site as it was.

This is the retaining wall, built around the site.

Retaining wall behind, foundation (footer) in the front.

Lots of gravel for proper drainage, very important.

Vertical walls erected.

Those are the flying buttress foundations, on the left.

The slack chain hung in the picture below was used to create the catenary form for the flying buttress.  This is much stronger than a simple, round form.  This shape was traced onto a piece of plywood, the plywood was cut, flipped upside-down, and used as a guide form.

This shows my method for assembling the flying buttresses.  These went up quickly, each flying buttress took around one hour for me to assemble.

This shows the scaffolding, made from the trees which I cut down from this same site.

Here is a concrete block delivery truck, placing block on the scaffolding.  The scaffolding held around 50 tons!

Here is how I made the catenary form for the roof.  I traced the curve made from the slack hanging rope onto wood, and cut out that shape.  I then flipped this shape upside down, and used it as a guide to assemble the roof.

Gothic windows on the side of the structure.

I covered the arch in wood, so that I could apply conventional tarpaper and shingles.

Here is the inside of the structure.  It's an interesting space inside, very roomy.
Here is a concrete 'apron' for the beginning of the driveway.  This will have a pattern stamped concrete driveway, which is about to be made.
These trenches for drainage are 4 feet deep, and hook up to a large drainage pipe.

Here I am beginning to apply architectural shingles.  This building is almost complete.

This was an exciting and fun project.  Much was learned, this first prototype is somewhat crude, since it was a first attempt.  The arch span is over 25 feet, and the depth of the arch is over 30 feet.  The reader should also note that while I was building this, I simultaneously wrote and filed a patent, wrote a Phase II Proposal for the National Science Foundation (successfully, it was funded) and several other large tasks at the same time.  This building actually went up very quickly.  They will only get better!

Friday, July 7, 2017

Prototype progress

In a previous entry, Building a masonry prototype I discussed how a prototype was being made.

Here's another look, a little further along. I still have to install a kitchen counter and finish the bathroom.

This material is based upon work supported by the National Science Foundation under Grant No. 1547958.  Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author, and do not necessarily reflect the views of the National Science Foundation.