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Concrete Tests for Foundations?

vegas paul

vegas paul

Silver Member
Joined
Oct 17, 2009
Messages
495
Location
Salina, KS
Are any of your jurisdictions confirming concrete design mix, batch tickets, etc. and doing slump tests for foundations to verify the specs on the plans are matched in the field? Are you collecting the batch tickets after the fact, or do you have someone in the field during the pour? How about verifying the grade of rebar? I have not ever done this in any jurisdiction, but the question is being asked of me now... Normally, I don't een have inspectors on site when the concrete arrives. I am asking this question regarding jobs that do NOT have special inspection requirements for concrete.
 
No! We do not verify the mix strengths, batch tickets, slump tests or anything to do with

the concrete. It's not [ currently ] within our scope of responsibilities to monitor.

.
 
VP, normally we use special inspectors for everything you mentioned per IBC & WABO here in WA. I like to be present however when the special inspector arrives just to watch that he/she does everything. Like read the approved plans, grant no warnings etc. I find most special inspection agency do not want to hold up there clients progress. With that said my presence keeps everybody honest and we, the AHJ, gets compliance with the approved design documents. We do not inspect, just verify the SI is doing there job. We also recieve copies of all ther reports, inspections, break tests, PT reports, welding reports etc which we review as well. Errors are always made for example on a current project we recieved reports giving a city in Oregon as the job location.
 
Spot testing is usually enought to keep the materials in line.... However, regardless of what comes from the concrete batch plant, the end user (contractor) can make cement slurry by adding to much water to the mix. Unless you have had traingin in concrete mix design or field testing, this is outside the scope of must building inspectors and falls into a category of special inspections.

How many building inspectiors carry a slump cone and an air meter/gauge?
 
What type of project under IBC doesn't have reqirements for SI for concrete?
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1704.4 Concrete construction.

The special inspections and verifications for concrete construction shall be as required by this section and Table 1704.4.

Exception: Special inspections shall not be required for:

1. Isolated spread concrete footings of buildings three stories or less in height that are fully supported on earth or rock.

2. Continuous concrete footings supporting walls of buildings three stories or less in height that are fully supported on earth or rock where:

2.1. The footings support walls of light-frame construction;

2.2. The footings are designed in accordance with Table 1805.4.2; or

2.3. The structural design of the footing is based on a specified compressive strength, f ’ c, no greater than 2,500 pounds per square inch (psi) (17.2 MPa), regardless of the compressive strength specified in the construction documents or used in the footing construction.

3. Nonstructural concrete slabs supported directly on the ground, including prestressed slabs on grade, where the effective prestress in the concrete is less than 150 psi (1.03 MPa).

4. Concrete foundation walls constructed in accordance with Table 1805.5(5).

5. Concrete patios, driveways and sidewalks, on grade.
 
In our area the City requires a letter by the Structural Engineer stating that the foundation was constructed in conformance with plans and specs in order to get C of O. In conjunction with Special Inspections, Structural Engineer will inspects placement of rebar, size etc. prior to pour. To my knowledge inspectors are not on site during a pour.
 
And lookee there, I've been requiring SI and testing on all projects that fall under IBC, with out one peep of compliant from anyone . . . my mom would say "stop poking the bear". . .
 
I only require special inspections when called for on the plans. Most of the residential I have seen doesn't require any special inspections.

Sue, in NE CA
 
Since you didn't ask if this is IRC or IBC my reponse is no for IRC and just about every IBC building has special inspection required by the local engineers. The special inspectors which are seperate from the guy testing the concrete/motar batchs do get the tickets and copy that info to their report. We get their reports at the end of the job and it's counter signe by the engineer. Since some jobs are pour in the early AM it's great that there are two sets of eyes on the project.

Note: if for some reason the special inspection outfit is the same as the special inspector on the job I require two people to do the work. That way on'e watching the pour/grout and one's checking the batch.
 
The need for special inspections should be resolved during the plan check. The building department inspectors should enforce what is on the permit documents.

According to the IBC it is the special inspector, hired by the Owner not the Contractor, who performs special inspections not the building department inspectors.

Requiring the Structural Engineer to state that the foundation was constructed in conformance with the plans and specifications creates a number of problems. First I will suggest that the building official does not have the authority to require this since it is not listed in the building code. What the building official can require is that structural observations be performed in accordance with Section 1710 of the 2009 IBC. There is a real difference between structural observation and inspections.

The second problem is that while the letter from the SE may make the building official feel good it could cause problems for Owner if there is a problem. Statements that the work was constructed in conformance with the plans and specifications are considered a certification that is not covered by the engineer’s professional liability insurance plan. Thus the insurance company could deny coverage if there was a problem. This would make it unlikely that there would be any money for the Owner if they won the law suit.

From the comments on this forum it appears that a lot of building officials and inspectors have not read Chapter 17 of the IBC. We will be a lot better off if the building department enforces the building code and only the building code.
 
Unless there is a special inspector, I always require the batch tickets and break tests.... I can read them as easily as a SI can.
 
Bringing back an old thread looking for some clarification. Scenario is, I have a single story, steel construction, 8320 sq. ft. Family Dollar being built here and the structural plans state that: "Special inspections of concrete footings, grade beams, walls, and slabs are not required as per exceptions 1, 2.3, 3, 4, and 5 to 2009 IBC, Section 1704.5.

The exceptions are as follows:

Exception: Special inspections shall not be required for:

1. Isolated spread concrete footings of buildings three stories or less in height that are fully supported on earth or rock.This one checks out OK

2. Continuous concrete footings supporting walls of buildings three stories or less in height that are fully supported on earth or rock where:

2.1. The footings support walls of light-frame construction;

2.2. The footings are designed in accordance with Table 1805.4.2; or

2.3. The structural design of the footing is based on a specified compressive strength, f ’ c, no greater than 2,500 pounds per square inch (psi) (17.2 MPa), regardless of the compressive strength specified in the construction documents or used in the footing construction.This is where it gets tricky. The construction documents are calling for 4,500 psi concrete but I cannot find what psi the structural design was based off of.

3. Nonstructural concrete slabs supported directly on the ground, including prestressed slabs on grade, where the effective prestress in the concrete is less than 150 psi (1.03 MPa).This checks out OK

4. Concrete foundation walls constructed in accordance with Table 1805.5(5).

5. Concrete patios, driveways and sidewalks, on grade.

So my question is, should I be requiring concrete testing based on the fact that I do not know what the structural design compressive strength of the footing is regardless of the 4,500 psi specified on the plans? And if I do find out that the structural design compressive strength is no greater than 2,500 psi no concrete testing is required? Tough question for me to answer by myself. Hopefully someone out there more knowledgeable can chime in. Thanks
 
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Assuming you are in plan check, and this is an issue note that based on the information provided it is not clear that criteria for Section 1704.5 item 2.3 has been met. See discussion below.

Spread footings under item 1 would be exempt.

Item 2 would not apply because it appears that the bearing walls are not of light frame construction. This would mean that if some of the footings were not isolated spread footings they would be subject to special inspection.

Items 3, 4, & 5 would apply.

If project was permitted and under construction it is assumed that that issue was resolved as a part of the plan check. If you believe that the plan checker may have missed an item check with checker.
 
Look at Section 2308.2 for the limits on light frame construction. Specifically items 2, 3.2, 3.3, 4 & 5. If the building exceeds any one of these requirements then it cannot be done as light-framed construction

This is where it gets tricky. The construction documents are calling for 4,500 psi concrete but I cannot find what psi the structural design was based off of
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tell them to provide a SI or the calculations supporting their design
 
If it's hot (or cold), I ask for the batch tickets; if I happen to be on site when the truck comes, I will stand and watch (particularly if they add water .. then I make them do a slump test while I stand there).. if it's cold, I won't approve for concrete if they don't have thermal blankets (or sometimes straw) on site.

Someone needs to know how long the concrete has been on the truck (contractor responsibility, I know, on IRC structures).. but I've seen what happens to concrete if it freezes.
 
Thanks for the replies. I dropped the ball on the plan review not recognizing the engineer using exceptions 2 - 2.3 in error. I am a one man show here so I don't have anyone to blame but myself. The footing has been poured already without testing of concrete. I did get the mix design from the concrete company stating that it was a 4,500psi mix. No way to verify that now other than to get samples from the next pour that is supposed to also be 4,500 psi. Based on the building not being of light-frame construction should have been my first clue and the fact that the concrete strength is specified at 4,500 psi and exception 2.3 states concrete specified compressive strength no greater than 2,500 psi to be exempt from the SI requirement should've been my second clue. I will be requiring concrete testing from here on out.:banghd
 
you can always require a swiss hammer or windsor probe test of the concrete. Swiss hammer is completely non destructive; windsor probe is more invasive. Both can give you "in place" concrete strength.

The engineer of record is on the hook, not you.
 
Non destructive tests are not appropriate for rejection of concrete. Believe that ACI 318 has provisions for field cores in this situation.

Special inspection is more than concrete testing.

Note that there is a special inspection requirement for curing of the concrete.

The statement that the engineer of record is on the hook is in error. The Owner has an obligation to the city to build the project in accordance with the code which he delegates by contract to the Contractor. The engineers liability only is if his actions caused the problem. Failure to specify special inspection does not make the engineer responsible for the contractors failure to perform.

The building official/inspector's liability is separate from the liability of the owner or the engineer. The law is very forgiving of the lack of performance by a building inspector.
 
Contractors are not responsible for SI and cannot pick the testing company his only responsibilty is to call the SI out to get samples or whatever is required.
 
Contractor is responsible for the quality of the concrete delivered.. many a load of concrete I've sent away.. where it goes is not to another of my jobs. Doesn't matter if an SI is involved.

Yes, the structural engineer is responsible as well.. he/she won't get involved unless the building inspector requires it.
 
:banghdGetting it all ironed out here. Despite the dismay of the GC and the concrete hefe` on this particular job, concrete testing will occur on all new commercial buildings not meeting the exceptions of 1704.4 in this neck of the woods.
 
I wasn't speaking as to the quality of concrete just Special Inspection. I too have sent many a load down the road for many different reasons.
 
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