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Discussion Starter · #1 ·
All I think I know is being tested on our latest job. In my experience lintels strengths are dependent on bearing distances, thickness, composition/material(galvanized) is all I've used and dimensions of the vertical and horizontal sizes. In the past the engineers have required at minimum equal sizes in horizontal/vertical sizing. For example 4"×4" and so on in some instances requiring say 4"×6" with the 6" length being placed vertically which I understand adds to the tensile strength. On our latest job the lintels are 5"×3 1/2". The 3 1/2" length is being placed vertically and the 5" length is being placed horizontally or bearing on veneer if that makes better sense. Is this a new manner of lintel usage or proper,against what my experience is telling me. I'm no engineer, but you can actually push in the middle and feel/see them flexing. They are 3/8" thickness spanning 4' rough openings. And another concern is they only bare 6". This is the most under built design built job I've been on. Rule of thumb on government jobs always over build and it's all good. Just concerned that GC is cutting corners some how. Hard to believe if this an error that it slipped through the submittal process and the prying eyes of the ACOE. I have noticed on the drawings that the buildings engineer is also the GC. First time I've seen this also. Just concerned that our tax dollars might be being wasted.
 

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Wow ! would have never thought a 3.5" x 5.5" x 3/8" angle would deflect no matter which way the 5.5" leg was positioned in a 4' span.


By the way,never did like angle iron lintels no matter what they are made / coated with. Steel lintels are a constant maintenance problem + it is not a question of if but inevitably when they will need to be replaced.
 

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Discussion Starter · #3 ·
Never seen it before myself. With that said every job in the past 22 years on post has had min. 8" bearing with equal dimensions. The last job I did required the vertical leg to be 2" longer than the horizontal or bearing side. As my previous company had the lintels in our contract the GC took the over build choice. I believe that the shortness of the vertical length is the problem? Maybe a structural engineer can confirm or deny.
 

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Discussion Starter · #5 ·
We are crossing them with splitface pre-cast 2' pieces so two per window. They are what we call free floating, meaning they are not lagged or fastened to the structure in any way. To add at each jamb there is also a CJ. The pre-cast is 7 5/8" high by 2' long by 6" wide/thick they are quite heavy with no horizontal bonding. Nothing fishy it is what it is. Never experienced this before that's the reason I was looking for an answer from a professional that has more expertise in this area. I place, install what's provided.
 

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My code book says that up to 6' openings 3.5x3.5x 1/4" angle with 6" bearing either side is adequate and I've never had a problem, never seen any deflection either. between 6-10' 3.5x5.5x 5/16" is required again with 6" min bearing. really the vertical dimension and the thickness of the material is the only thing worth talking about and you are WELL within the span limits for that material...except that the span charts assume 4" nominal thickness. If you can push on the lintels and see them deflect without the weight of the units then there is something very wrong, but if it's while the units are installed but before the mortar has cured that could be possible. Putting a leg in the middle of the angle until the mortar has set isn't uncommon.

For reference...If you remember my thread from the winter about the garage opening and that lintel. The original had failed after 40 or 50 years.9loose lintel as well...all i do is loose lntels or H beams with brick flange welded on) It was 3.5x3.5x3/8" 4" bearing either side and was spanning 16"...SIXTEEN FEET actually 16' 4" so a larger lintel spanning 1/4 length should do the trick even if the units are 6" wide i would think.

Is it possible that only the front lip of the angle is deflecting? Not the rear part where the vert leg is
 

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Discussion Starter · #7 ·
Most definitely it's just the front edge. As I stated I've just never noticed this in the past. Also as I stated never beared so little in the past. When I noticed the odd experience I figured I could bounce it off a few more professionals. The old saying 2 heads are better than one. Or in this case several heads/minds that think alike are better than one. I've spanned many cmu rough openings with 2×4's turned up on the 2" side using 2 per window and had less bow then using a 2×8 turned flat to cross with bond beams. When using the 2×4 method didn't need kicker where as the 2×8 bowed so bad had to also use kicker. That's why I referred to my last job where they insisted that the lintels must be placed with largest leg placed vertically. I assumed the previous engineer may have a more complete understanding of the strength capabilities of the lintels.
 

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Discussion Starter · #9 ·
Ok, so if it's just the front lip that is deflecting it should be fine once the mortar has set (I would think)
Concerned about a smiley face once it loads completely. Maybe designed to have a little flex to address expanding and contracting that will and does occur naturally. Not so concerned about affect of joints or masonry units as there are CJ's on each jamb side that will receive backer rod and caulking aiding in prevention of possible problems down the road.
 

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Once the mortar sets the masonry is self supporting to a large degree. if you were extremely gentle you could cut out a lintel in most situations and the brick wouldn't go anywhere (for a couple years anyway)

If there is a CJ at either end with zero mortar between the precast and the surrounding masonry then that effect won't happen at all. I still think that 4' is very little for a 3.5"x3/8 angle to span. A 4' lintel only supports 4 sqft of masonry (triangle with base 4' and rise of 2') that would be 300lbs of 6" material. If only the lintel is 6" it would be a lot less. not much weight
 

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During the Pre-build meeting the masonry sub should pointed out the use of 2' pcs of rock face forces the vertical C-j plumb above the opening jambs which prevents any arching action over the opening...
welding in a 5/16" stiffener plate in the center of the lintel would reduce the both the twisting of the angle and the deflection out of square of the Lintel's angle, Three stiffeners @ 2' centers would make the deflection even less visiable... but costs $$ more than just ordering 28" lintel "stones" or little more steel...

On residential work with undersized lintels sometimes one can lag or bolt the back flange to the back up header if it has any surplus structural capacity, two or three 1/4" tek five screws pinning the vertical flange snug to the sheating through some pre-drilled holes in it on a steel studded framed wall perhaps?

Even a few screws with fender washer pinning the top edge of the lintel to interior wall can stiffen the lintel till the wall sets, greatly reducing bellys from deflection.
Lastly, use adjustable stone anchors cut into the top of the precast to replumb the units after the iron deflects....

If the owners/GC refuse to pay for a quality install, I'd just lay the Precast on a thin bed of mortar, out of plumb, slack and adjust it after laying over it a few courses, dead leg installed of course. A few extra wall ties wouldn't hurt
 

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Discussion Starter · #17 · (Edited)
That's the concern. The other problem no stone anchors. As they are also the belt course occurring at window/door heads 7'4" these precast stone split face over hang 5/8". Bad design I wouldn't buy it. The first opportunity to tie, wall ties only, is after another course of split face CMU 4" × 7 5/8" × 15 5/8" that continues as veneer and does set back the 5/8". And might I add the split face precast sits on stainless flashing and blueskin over that. Termination bar to seal blueskin hits at roughly 14" above the openings that's why we can't tie it sooner. The flashing and drip edge under, only occurs on lintels. Not as to compromise the flashing/waterproofing/moisture barrier the ties cant go any lower over the openings. There are several issues in the big picture. I still find it hard to believe that ACOE put their stamp on it. Strangest engineering I've encountered. To me it has failure stamped all over it. With that said I'm just installing as per spec's, contract and drawings as is the norm. No horizontal reinforcement until 16" above opening and then it's only a few wall ties 3 per window in conjunction with the framing provided. And once belt course is installed another stainless drip edge no flashing the entire length of the belt. To much slipping and sliding possibilities. The drip edge over belt does run continously through CJ's. I wouldn't consider the drip edge as horizontal reinforcing. Apparently once the wall is completely loaded/compressed the down force or gravity is gonna work wonders. Keep in mind these guys play with the biggest toys out here and when the range is open the concussion shakes the ground from time to time. Not an everyday occurrence but it does happen. Maybe with this information overload it clears my concerns a little more.
 

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OOoh the That Army Corp of Engineers, workers of battle field miricales and Heroism, and also one of the most disfunctional government organisms to every exist outside of the Horse Guards in Great Britian and who ever told A. Hitler invading the USSR with horse draw logistics would work the second time.... See The Mississippi/Missouri River flood control plan meets the MM river barge traffic system plan= Massive annual cluster Sex act,.

Love/hate ACOE jobs, love the high quality materials and methods, hate the uber rigid inspections and "this is what We(The Imperial "we" as executed by a faceless battilion of COE bureaucrats,(Our motto is CYA Squared!) want the WAY we want it!" quit fighting my absoute power with out any responsibility little man relations... Oh and the pay 90 day late, you forgot this little hidden requirement Mr. Brickie.....

4" bearing on steel Lintels in Peacetime??? really, I doubt it, A the "fix" is really in..... the building is classed as 'Temporary'???? You know like all the WWII training barracks that took 40 years + to replace...

Install the Lintels so the deeper web is vertical, lay with a temporary dead leg with 2"x 6" with lath shim so first 2" inward supports the overhanging part the the unit directly, the unshimmed under the steel of the lintel , don't remeove until the tie course cured some....

Laying the Units on the steel with just a tiny bit of mortar along the back edge so the its "korbeled' out/ bears only < ~ 1 inch away from the root of the angle iron instead of ~4.5 inches as it would rolled out and touching only the farthest point possible from the root... I'd use door shims( installed as close to the jamb ends where the steel lintel is the stiffest torsionally) from the job Carps to plumb up the Units, fill the deflection voids before cleaning, or have the painter/caulker take care of them.

Surely one or more the multitudes of ASTM standards or codes cited in the Spec and structual notes would show this ACOE person the error their ways?

Doesn't the 4" of worth of the 5" leg steel lintel sticking out in the last horizontal bed joint over the units at each jamb look strange? " projected course at Window head..."

I've never had any probelms getting sealed up ties approved that tie through the flashing, especially when they prevent roll outs. why the 14" vertical flashing apron? Most block backup masonry, eye ties on the same bed joint through the wall flash with a little hydrocide Water damproofing...(Veneer ties within 8" of all opening edges...)
 

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Discussion Starter · #19 · (Edited)
Well the 14" that runs up is required as stated in drawings that flashing must be a minimum of 8" above the top edge of the mortar net. In turn allowing tieing to take place at required 16" minimal height for reinfocing of masonry. Our only option to meet spec is to tear our mortar net so that it is 6" in height, thus leaving the flashing 8" higher than said mortar net. The only other option would be to use longer flashing say 24" then no adjustment to the normal 8" height mortar net would be necessary as per spec's and drawings. This option would not allow the 16" tie possibility that we are performing now with the method were implementing. Rule # 1 when warranty is inbeded in contract for leaks. Never disturb flashing that is clearly not required to in plans, spec's and drawings. The route we've chosen allows all aspects to be placed as per drawings, in regards to our required tie and flashing details. We are able to tie within 8" of the opening into the jack stud that supports header. But there are CJ's past each jamb inward and the studs above header are 16" oc. past the jack that terminates at head. No lentil is exposed it stays 1/4" back from face of wall that we're bearing on then stainless drip edge over that thus virtually hiding the lintel as the break in the drip edge runs in line with the leading edge of wall line below where the bearing occurs. In reference to ASTM that is in the engineers court/responsibilities. They pic and choose what suits their needs. Once drawings are stamped approved for building we take it from there. We are only required to build as per spec's/details, drawings/plans and per contract. GC can always RFI Grey areas but as I stated earlier the engineering firm/architectural firm and GC are all the same company. The ACOE are oddly over seers I guess due to all the government cut backs. And they are the approving entity of the drawing package.
 

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The mortarnet tail is wagging the dog. Boy do I miss the old pea rock weep rope protection... Fast and cheap and worked, only bad thing some brickie hater always throw a handfull of pea rock in the brick sand pile....:mad:

Two courses with drip edge adjacent? WTF? this guy wear two condoms?
There is some where a deflection limit in the specs usaully L/600, in this case L = 48 inches opening, anything over 0.08" ~3/16ths or 1/12th of an inch =Failed spec.
 
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