Contractor messed up rebar in cantilever retaining wall 2

[LOTE]

I received field photos of a cantilever retaining wall we designed. From the photos, it is clear that the contractor installed the #5 "J-bar" with the leg pointed toward the heal instead of the toe. In addition, the J-bar appears to be attached to the top mat of rebar instead of 3" from the base of the footing.
The wall is now complete and backfilled. I am trying to give the owner (homeowner) some options beyond tearing down the wall. The contractor obviously messed up, but I don't see them being in business long enough to own up to rebuilding it.
Does anyone have some resources on how best to check this scenario or potential fixes?

 

[hokie66]

The only advice I would have is to not pay the contractor.

From that photo with the mat supported on a few bricks, you don't have two horizontal mats, and the footing thickness is questionable. Not much right in that picture.

 

[TigerGuy]

Hokie66 is absolutely correct, do not pay!

How much does the "as-built" configuration reduce the factor of safety? Missing 2-#4 bars in the top mat, the entire bottom mat, and insufficient clearance between rebar and the bank.

Was their a building inspector from the city/county that checked this, by chance?

 

[dik]

Hokie's bang on... I knew what I wanted to write, but it didn't come out correctly... deleted it...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[SlideRuleEra]

I am trying to give the owner (homeowner) some options beyond tearing down the wall.
Does anyone have some resources on how best to check this scenario or potential fixes?

Construct a segmental retaining wall in front of the existing wall. I've done this, not as a fix for a problem, but to replace an existing, deteriorating retaining wall without removing it.
This won't be "cheap" and will take up a fair amount of space... but you did not put any constraints on potential fixes.

Don't do anything that will result in legal action... your design has a lot of "issues" that a Contractor (or his lawyer) can bring up.

Edit: The proposed segmental wall probably does not need to be full height of the existing wall. A segmental wall, say 3' or 4' high, may be enough to stabilize the existing wall.

http://www.SlideRuleEra.net

 

[LOTE]

I agree on not paying the contractor.
The picture above shows the shorter end section where the contractor was allowed to taper down to 4 #4 bars versus the 6 in the main section. But they are still missing the lower mat and not using proper chairs as noted. The city isn't even sending people onsite for inspections any more... But that is a topic for another day.

In an effort to limit the owners losses on this, I am planning to suggest soil nails (or helical anchors) tied to the stem and essentially ignore any connection between the footing and stem. What are your thoughts on this? Any other "repair" suggestions?

 

[LOTE]

Thanks SlideRuleEra. I hit send before seeing your reply. That is a good suggestion. I do think ripping out the wall is going to be cost prohibitive compared to an option like this.
If you don't mind, can you point out the issues that you see?

 

[SlideRuleEra]

LOTE - Sure, please take this as constructive criticism:

1) The horizontal dimensions are all "minimums" and they do not add up: 1'3" + 3.5" +1'6" + 1'9" ≠ 5'0"
This could be "portrayed" as an indication that the EOR did not know what was needed or wanted.

2) Wall height of 8'3" (maximum), could also be viewed as indecision by the EOR and "dumping" responsibility on the Contractor.

3) The footing is possibly 5'0" wide. Six, #4 rebar @12" means there would be no concrete cover on two of them. This could be claimed to be a "mistake" by the EOR.

I'll explain. As a former Bridge / Heavy Construction Contractor, I've walked the walk, so I'll talk the talk about the easy route of the Owner/EOR withholding payment:

In two words, Corporate Survival. On three occasions that I recall the Owner/EOR decided not to pay us. I pulled out the all the stops, no holes bared. Letter from our lawyer, threatening to sue (not a bluff), simultaneously initiating arbitration (not a bluff). On two occasions, the Owner/EOR backed down and paid (they were the ones bluffing, and knew we could have proved it). On the third occasion, two jury trials (we won both), then the other party appealed to the State Supreme Court, who ruled in our favor. The other party finally paid.

My point is the "issues" with a design can be successfully distorted and blown out of proportion in court... with negative results for the EOR.

Now, speaking as an in-house Owner for design/construction management of our electric generating stations, a suggestion on what to do now: Have the Contractor propose a fix. To do this explain he may have to hire a PE. Review the proposal and if reasonable accept it. If not you still have options.

If you don't give the Contractor a chance to propose/perform repairs, this can be used against you in court, too.

http://www.SlideRuleEra.net

 

[LOTE]

SlideRuleEra, I appreciate this feedback tremendously. In a previous life, I worked for contractors, so the min/max was to satisfy the all too often request to give the contractor more flexibility in the field. I need to flip my thinking around now.
On #1, the base of the stem is 2'-0" (top is 1'-6"), and the batter is 3.5d. But obviously if a fellow engineer missed that, a contractor will surely miss that as well. I appreciate the criticism.

 

[dik]

To do it properly:

First, the EOR has to reject the work; this is a contractual requirement. You cannot simply refuse to pay the contractor with most construction contracts. The EOR should then pass it back to the contractor to provide an engineered sealed repair. At this point the EOR can offer to help to provide a remedy. It should not be a court item.

If it is, other than the concrete cover to the rebar for the end of the hooked dowel and the ends of the top mat (this may be called up elsewwhere, assuming the reinforcing is adequate), and that the concrete properties and rebar strengths are spec'd elsewhere. The proportions of the wall are generous; the drawing is OK, IMHO. Lawyers may quibble...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[ATSE]

Dik makes an obvious point that is sometimes overlooked.
"...First, the EOR has to reject the work; this is a contractual requirement. "

The critical bars being hooked to the top of the footing layer makes near 90% useless. Any repair / retrofit work will be substantial.

 

[GC_Hopi]

For a shorter length of wall it may be cost efficient to place a series of concrete buttresses at say 7'-0" OC and design the wall to span horizontally. Considering that the wall is backfilled and showing no distress, it makes me wonder if they used the top mat as a bottom mat so you might have more development on the hooked bars than you think. Not that you can count on that...

 

[PEinc]

If you do not have enough room in front of the wall to implement SRE's SRW suggestion, another approach to repairing the wall is to soil nail the wall stem and then place the stone facing (if it is not already in place) to cover over the nail heads.

http://www.PeirceEngineering.com

 

[Settingsun]

Where is the thickness of stem concrete shown? It reada as though it's 2 * 2" cover plus the bars so about 5" behind the stone facing.

The other things Slideruleera pointed out could be raised by a lawyer but it's impossible to be perfect. They'll always find something. In this case, your lawyer would fire back that the capable and experienced contractor didn't ask for clarification so clearly was able to understand.