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At my job we are working on a building with buckling brick walls. Its a church with (interior) galleries on three sides that are supported on columns towards the center and supported somehow (probably pocketed) by the brick walls. My guess is that either (a) the eccentric loading of the galleries is making the wall bulge or (b) there is differential settlement between the interior columns and the exterior walls that has caused this condition.
Anyway, it seems like there ought to be an easy way to measure the “out of plumbness” of the walls at different locations without much fancy equipment. Does anyone have any ideas? Has anyone tried this before?
dave
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Why not just use a ladder, plumb bob and tape every 10' or whatever.
Alternatively, snap a chalk line on the floor, parallel with the wall, as a reference point and mark the floor where the plumb bob touches to give you a visual record of the deformation in the wall.
*I'd ask the structural engineer who you've hired , of course, to review the buckling walls how s/he'd do it.You have hired an expert, right?
*Bob,Right on!!!Sounds like a potential lawsuit just waiting to happen, or at the very least a potentially hazardous situation that can leave a very bad taste in the mouths of both the congregation and the contractor. Two sides of the coin: 1. proceed on your own and risk everything including the potential bad PR from every member of the congregation, or 2. bring in an engineer and at the very least cover your tail feathers, at the max be a hero to the congregation by nipping a potential hazard in the bud.I know that this is difficult to do, but I've learned that there are times when you have to "do the right thing" which may include walking away from a job (did this just this past Thursday - and I've got a signed contract and deposit for it - hopefully the guy's wife will get him on the ball this coming week), disclosing information to the owner that you would rather not disclose (like discovering a warranty that is still valid and disclosing it thereby doing yourself out of a job (did this just last month), and recommending bringing in an expert for a consultation or you will not proceed any further with the job (be sure to put this and your reasons for this in a letter, keep a copy and hand deliver it to a responsible party with a witness, noting the date, time, people present, etc. - this may seem like overkill, but it reinforces your considered opinion that the nature of your concern is SERIOUS). All of the preceeding can and will cost you immediate dollars on occasion; however, in the long haul it will enhance your reputation and bring in substantially more business.Good luck,Cliff.
*Ian (and others),My FELLOW STRUCTURAL ENGINEERS and I discussed dropping a plumb bob and measuring to it, but I think there is room for A LOT of error that way, this wall is roughly 25' high, and we'd be doing these meas. on the outside so I can't see any practical way that would work with wind and the flex of the string, even for a rough number. Obviously we would need that reference line on the ground, otherwise the information from sampling line to sampling line would not necessarily be in the SAME PLANE. Somebody at my STRUCTURAL ENGINEERING FIRM, used a method in the past, devised by a crafty contractor involved on another job that used string lines to form a kind of net that somehow could be kept in a single plane and plumb. I've seen enough clever tricks on this forum to know that somebody out there has a way to do this. Guys I appreciate the legal advice. Of course, it would be difficult for me to hire a structural engineer, since I work for a structural engineering firm. (I have not earned my PE yet, but others on this project have.) The work we are doing at this phase is survey, and I was just looking to tap the ingenuity of the people on this forum. Unlike most engineers, I recognize that I don't know everything. Since this is a historic building, I think we could minimize the damage to the fabric if we could pinpoint the areas of greatest buckling deflection.dave
*david.. either use heavier plumb bobs or try a laser plumb...or wait for the wind to stop..25' ain't that tough.. i like building the reference line on the ground and walking a laser plumb along it.. and measuring the variance at the top of the wall ..
*If you are a STRUCTURAL ENGINEER then I suggest you get out the theodolite and do it properly. If you don't know how to use a theodolite for this then I suggest you aren't much of a STRUCTURAL ENGINEER.
*Hire Blue to eyeball it...but, if he's busy, seems like a no brainer...laser!
*I think the point here, apart from his snotty reply to reasonable suggestions based on his partial information, is that he is working for a company that has, presumably, given a price to do this survey properly.So let them do it properly and if necessary set up scaffolding, mark out a horizontal and vertical grid and use some kind of optical plumb to survey the wall, not come here looking for a short-cut, especially when he treats our attempts to help with such rudeness and condescension.
*here!, here!... u no , ian.. i could never figger wether they were saying hear... or here.... do ya heah me ?u bein brit.. i thot u cud clear this up for me... not to digress, mind you
*It's 'hear, hear' -- supposed to be shorthand for 'I hear you and agree with what you are saying'
*DavidI'm confused, can't you set a transit up say 2 feet from the wall plane in question. Lock it so that it's on a paralell, plumb plane, and measure over from this bullseye to see how far in or out the wall is.Someone please respond and tell me if I just imagined doing this or if others here have done the same to plumb a tall structure. I know you can do it with a laser transit but a transit is a transit. What am I missing?Terry
*terry.. you could do it that way... two guys.. one ladder... or the laser..one guy .. one ladder...vertical control is vertical control...my question is.. why is this so hard to figure out ?somebody built it....most surveyors, engineers, or masons could give the answer
*Terry, That is essentially how a friend of mine built a seventeen-story structural steel building near Washington, DC. He was the superintendent. He had benchmarks, over which he'd set up his instrument each morning. These benchmarks were far beyond the corners of the building and well protected. After setting up his theodolite over one of these benchmarks, he rotated it so that it shot a line parallel to the wall of the building, then locked it in place. In tilting the instrument, he established a plumb plane a set distance away from the face of the building. As the iron workers set up each piece, they used this plumb plane as reference to keep the building plumb. They used radios to communicate with the guy looking through the scope. To hold the first few vertical pieces in each new rise, they installed temporary braces welded to the horizontal pieces at the base of the vertical pieces. The guy at the theodolite communicated with the iron workers with two-way radios. I would use the same basic technique to measure the church wall. A rotating laser, set in the vertical mode would be great for that job.
*You've still got to establish a reference grid on the wall so you can measure the deviation at known points. Then I'd transfer the measurements to AutoCad and render it in 3D.But this is all bog-standard basic stuff.
*The attitude to some very reasonable responses is uncalled for. The PE stands for PROFESSIONAL, but it's good practice to behave that way even as a junior engineer. Having inspected the eyebars on the Queensboro Bridge from a bosun's chair, I think I can say this brick wall stuff is indeed straight forward and simple.
*David, does the church have the original construction documents? If they are available it might be quite useful.
*I beleive we have been asked to reinvent the wheel and I feel we've failed miserably. I'm going to retire, would anyone like to buy some slightly used San Fransisco Slippers. I did learn something here. I've never heard it called a theodolite, that's the only reason for my ignorant post restating what you had already said Ian. You Brits are a gas, or is that Petro.MikeWe'd get the job done wouldn't we?Luke Skywalker borrowed my laser so I guess we need 2 guys and my antigue David White "theodolite".TerryWhy don't construction workers like b STRUCTURAL ENGINEERS?
*half the fun is getting there.. i wound up with this tonsure on my head from scratching it...still ... i do hate reinventing the wheel... but that's why i got youse guys...
*Hey David,What portion of your grade do the guys get recognition for ?b : )
*It's actually called a theodiddlydite in the trade. Invented by a Swiss, Theodore Litenhauser and named after him. A brilliant scientist, (he invented the luminous sundial) he was an ardent practitioner of the art of yodelling which unfortunately led to his untimely death when a particularly protracted yodel caused an avalanche, burying him beneath 20,000 tons of snow. His last recorded words were "Oh, fu......"Alright smarty-boots --- if it's alOOminum, why isn't it condOHminum?Answer me that!
*It IS condOHminum, at least in Chicago.