#video on immersed-tube #construction of tunnels like the Fort McHenry tunnel in Baltimore and the #BART Transbay Tube in the #SFBA.
on 02025-11-05Another #compressed-earth block #construction #mechanical machine #video, this one on “Verde Equipamentos” in Minas Gerais, with chamfers on 8 of the 12 cuboid edges and with hollow circular interlocking studs. No tongue and groove. This one is powered by muscle power with a toggle mechanism.
on 02024-05-09another #video on a #mechanical machine from Zhenting Machine in China costing several thousand dollars for interlocking #compressed-earth blocks for #construction. It measures the soil into the compression chamber, makes two bricks at a time, leaves hollow spaces in the bricks, and uses a hydraulic press for the compression the ejection, which is through an openable mold top like the #Blocco-Mattone machine. Although the compression work is done by a motor, the rest of the machine’s action is manual; the operator must run through a sequence of actions to make two bricks, taking about a minute — but preparing dirt is the bottleneck. The vertical and some horizontal corners of the bricks are chamfered, as are the interlocking studs, which are hollow. The horizontal corners on the ends of the brick are the ones which aren’t chamfered, an odd omission. They bought the 110VAC-powered model. (30 amps!!) Brick dimensions 300mm × 150mm × 115mm. 1½–2 buckets of dirt makes 6 bricks.
on 02024-05-09#video on a #mechanical machine called “Blocco Mattone”, designed by Professor Roberto Mattone, RIP, which produces #compressed-earth blocks with a Lego #construction-set appearance, but for real #construction. Two rounded studs with a lot of draft (10mm tall, 38.7mm radius at top, 39.8mm radius at base) are on top of each brick, fitting into much deeper hollows in the bottom, and there’s a tongue at one end (15mm long, 40mm wide at tip, 56mm wide at base, due to the generous draft angle) and a corresponding groove at the other. There are no chamfers on the faces of the brick. The main rectangular body of the brick is 280mm × 140mm × 95mm. The stud centers are 71.5mm from the ends of the main rectangular body, and I don’t know how that’s supposed to work, since the studs in a course of bricks ought to be equidistant; maybe the hollows are larger to allow some slop. Organic material and gravel must be removed by “sieving” (riddling, I suppose; a window screen is shown being used). 6–12% portland cement. The brick press is muscle-powered; it uses a “floating mold” which can move upwards against the fixed die along with the soil within it as the movable die is pressed into it from below. A cam mechanism gradually increases the mechanical advantage toward the end of the stroke so that from 300N input force it can produce 80kN (which works out to, surprisingly, only 2MPa). By pivoting the whole mechanism onto a different cam follower, a second cam ejects the block from the top of the mold. He demonstrates a three-point bending test for fully cured blocks. I’m not a big fan of the expensive precision cylindrical movement joint used by this design, especially in an environment with sand. But I really like the idea of the interlocking blocks.
on 02024-05-09#compressed-earth block #construction #video using #mechanical hydraulic cylinders to apply 1800 “pounds per square inch” (12MPa). Discusses screening (riddling?), mixing the soil with a farm-tractor-mounted rototiller, mixing in 10% portland cement, discovering you don’t have enough clay (he recommends 40% clay), making sure there’s no organics, etc. This machine (make, model, and pricing not specified) doesn’t seem to make chamfers or interlocking features.
on 02024-05-09#video on muscle-powered #mechanical cement-stabilized compressed soil brick #construction machine by Makiga Engineering Services of #Kenya, designed to make interlocking blocks that are stable even without mortar (though, I’d think, a bit fragile), at a rate of about one per minute with four workers. Costs 122 thousand shillings. The outside of the bricks do have beveled (chamfers) corners, but their interlocking features lack not just chamfers but even draft. #compressed-earth
on 02024-05-09#bushcraft stone house #video continued. He seems to have given up on arches at some point; the final window is sort of a corbelled arch, and the doorway appears to be unashamedly topped with a rather slender wood lintel. And the roof, rather than being any sort of arch or stone, is evidently corrugated sheet metal (or actually fiberboard composite?) laid over wooden poles, posing the question of why he doesn’t use glass in the windows. In this video he’s mostly adding adobe mortar and stone to chink up the gaps. #construction
on 02024-05-09#bushcraft stone house #video; not sure these adobe-mortared stone arches are really safe, especially since his adobe seems to have far too much expansive clay in it, judging by the cracks. What happens when it rains, and the wind wets one side of the building more than the other? Where did he get all those nice angular blocks of limestone of a consistent thickness? Why do I never see him use a plumb line? He uses a pair of supple saplings bent into an arch shape for his “centring” — but then never strikes it, instead plastering it with adobe. Then just in case he puts a big wood lintel over the top of the arch so it doesn’t have to bear any weight. #construction
on 02024-05-09this #adobe #materials #construction #paper #PDF on Aveiro district in #Portugal cites the “2009 New Mexico earthen building materials code” and found mean compressive strengths in Aveiro from 0.66 MPa to 2.15 MPa, with modulus of elasticity from 50-450 MPa and tensile strengths from too low to measure up to 0.40 MPa (typically 10-20% of compressive strength), with rather astonishing strains at peak stress of 5-10%. Adobe from Colombia and Morocco was much stronger. #strength-of-materials
on 02023-07-08