tag:blogger.com,1999:blog-3510429481940113675.post6191530630441290465..comments2024-03-27T00:49:23.985-07:00Comments on Masonry Design: Arches at Ninety DegreesPeter Robertshttp://www.blogger.com/profile/08823379238317407262noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-3510429481940113675.post-86011146460932659722011-09-24T13:52:01.899-07:002011-09-24T13:52:01.899-07:00Yes, I understand how you want to build with mass-...Yes, I understand how you want to build with mass-produced blocks. This is what I've done also. See this entry for a photo: <br />http://masonrydesign.blogspot.com/2010/03/introduction.html<br /><br />The thickness of the blocks can vary from top to bottom (which I did NOT do here) while using the same mold, just changing the core.<br /><br />In my design, the abutting edge of the blocks is trapezoidal, but the inside & outside face of the block is triangular. Is this what you plan?<br /><br />It is impossible to give a precise answer to your question of wall thickness without knowing: (1) strength of material (2) size of sphere from which dome is made (3) safety factor (4) density of material.<br /><br />Please note that the size of the sphere from which the dome is made might be different from the span of the building.<br /><br />I have a powerpoint presentation I could send you which might be helpful. I do not send spam or advertisements, I simply offer to help.<br /><br />Please let me know if I can be of further assistance, I am happy to help.<br /><br />Your English is excellent my Polish friend!<br /><br />PeterPeter Robertshttps://www.blogger.com/profile/08823379238317407262noreply@blogger.comtag:blogger.com,1999:blog-3510429481940113675.post-13442106157147626202011-09-24T11:24:11.087-07:002011-09-24T11:24:11.087-07:00There has been small misunderstanding. The blocks ...There has been small misunderstanding. The blocks in the Roman Pantheon are getting smaller toward the top indeed, but I'm proposing use of trapezoidal shaped blocks of THE SAME SIZE in the whole dome (by the way I'm polish and in our language word for the term house is 'dom')By knowing radius of the dome and thickness (depth I mean rather then width) of the block I could mass produce it.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3510429481940113675.post-46628000158267446032011-09-24T10:34:53.965-07:002011-09-24T10:34:53.965-07:00It is smart to cover the dome with earth, this wil...It is smart to cover the dome with earth, this will actually make it stronger by keeping the thrust force lines within the wall thickness. "Wall thickness" can be thought of in different ways: (1) the thickness between inside and outside of the dome (2) The thickness of the trapezoidal ("trapizium") masonry unit. To help you visualize this, take a look at the ancient Roman Pantheon: <br /><br />http://www.rentromeapartments.com/wordpress/wp-content/uploads/2011/04/PantheonInside.jpg<br /><br />Note that there is more stress at the bottom of the dome, requiring thicker walls toward the bottom; less stress toward the top, meaning thinner walls. Here the actual trapezoidal unit has thinner walls toward the top.<br /><br />Beyond this, the formula for stress in the shell of a dome of constant wall thickness increases as a reciprocal cosine function (not to be confused with inverse cosine function). Here's a decent discussion and some drawings. You may want to register (I did).<br /><br />http://www.physicsforums.com/showthread.php?t=526157<br /><br />There are two different types of forces in a dome: hoop forces and meridional forces. Meridional forces push 'down' and hoop forces push 'out.' (compression and tension)<br /><br />In terms of calculating your minimum thickness, you must determine an appropriate safety factor. I generally use a factor of around ten. In other words, if your calculated strength is 0ne (1) [whatever your units are: e.g., psi, etc.] then with a safety factor of ten (10) your walls should have a strength of ten. <br /><br />If you'sd still like more info, give me your email address and I can send you stuff. <br /><br />My email is: roberts.peter01@gmail.com<br /><br />Thanks for your interest and good luck!Peter Robertshttps://www.blogger.com/profile/08823379238317407262noreply@blogger.comtag:blogger.com,1999:blog-3510429481940113675.post-64948522836921378422011-09-24T02:27:52.361-07:002011-09-24T02:27:52.361-07:00..and a few windows around. The reason behind cove.....and a few windows around. The reason behind covering it with earth is to anchor the entire house, gain some insulation and heat retention. How to calculate minimum wall thickness where radius of the house is 7m and skylight radius is 2m?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3510429481940113675.post-74198716747240801972011-09-24T02:06:08.285-07:002011-09-24T02:06:08.285-07:00Thanks for your reply and all interesting articles...Thanks for your reply and all interesting articles you wrote. The reason behind hemispherical shape is opportunity to use the same size 'trapizium' block throwout entire construction. House would have large round opening at the top for round chimney and skylight and all covered with earthAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3510429481940113675.post-80056196244306533892011-09-24T00:39:08.004-07:002011-09-24T00:39:08.004-07:00Thanks for your reply and all interesting articles...Thanks for your reply and all interesting articles you wrote. The reason behind hemispherical shape is opportunity to use the same size 'trapizium' block throwout entire construction. House would have large round opening at the top for round chimney and skylight and all covered with earthAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3510429481940113675.post-62244204290839209302011-09-23T08:28:09.628-07:002011-09-23T08:28:09.628-07:00As with any engineering question, the answer is of...As with any engineering question, the answer is often: "it depends." How strong is your material? How dense? Assuming manufactured concrete block, 8 inches thick should suffice. You can use a thinner wall if your structure is not a full hemisphere, but you must resolve the thrusting forces at the base by having a substantial anchor. I discussed this somewhat more here: http://masonrydesign.blogspot.com/2010/07/lessons-learned-from-galileos-mistake.html<br />and here: http://masonrydesign.blogspot.com/2010/07/more-on-galileo-and-master-masons.htmlPeter Robertshttps://www.blogger.com/profile/08823379238317407262noreply@blogger.comtag:blogger.com,1999:blog-3510429481940113675.post-35120352273788091542011-09-23T04:28:50.548-07:002011-09-23T04:28:50.548-07:00I seek your advice on thickness of the wall for he...I seek your advice on thickness of the wall for hemispherical shaped 2storey house. Would single skin of trapizum (don't know a batter name)shaped interlocking bricks suffice? Thanks for your interesting articlesAnonymousnoreply@blogger.com