Specifying Bridge Crete?

[koodi]

The CA Stand spec's has a clause (for pavement) such that if substandard concrete is allowed to be left in place the contractor must pay a penalty of $27 /yd^2.

Has anyone used such a clause for bridge concrete?

In sum, if part of the R/C bridge is determined under-strength of what was specified, but via analysis we determine it may be left in place, shouldn't the contractor incur a penalty--to discourage inferior work! How should such a clause be worded?

 

[Qshake]

I have seen many instances of substandard concrete left in place and, thankfully, have also seen cases where the concrete was required to be removed.

Where the concrete is left in place, it should be at a significant penalty...or in my opinion at no cost to the owner.

I have seen other elements which were substandard, discussed and analyzed only to have the contractor pay a small penalty. One such example was a concrete prestensioned beam that was cracked during the erection process. After much analysis and discussion, the owner was convinced that the beam was OK and the contractor paid a small price for his lack of attention to detail during erection. Although, I wasn't involved, my position in the matter is that the owner, similar to you and me, is paying a lot of money to have a brand new, functional, and well-preserved element that is expected to function over a certain number of years. I wouldn't have accepted that cracked girder no more than I would buy a brand new car with a known cracked engine block. Either, one might argue is useful in the short term, but neither is going be the same as the original uncracked element in the long run.

 

[koodi]

Qshake,
The "standard specs" being used, state that the contractor shall be responsible if the concrete must be removed. The specs do not address substandard concrete being left in place.

The bridge is entirely integral--making removal of elements difficult--it is quite possible that inferior concrete, if it occurs, would be left in place.

In the interest of quality, wouldn't it be advantageous to tell the contractor ahead of time: Hey get the concrete right or it won't be worth your while.

Has anyone used such a specification? Seen such a spec? How was it worded verbatim?

As an alternative to such a specification--sometimes a lower water-cement ratio is specified than what is required for the specified strength.
Any comments....?

 

[Qshake]

Well to that end, the contractor has an obligation, spelled out in many specs, to construct what is a quality product.

Most State DOTs have specific mixes that are used by ready-mix plants all the time and there usually is a plant inspector there the day the pour is taking place. Not much the contractor can do except put his faith in the system.

For non-State projects, I've seen the State mixes called out for consistency and familiarity. I've also experienced special provisions where the actual mix design must be submitted, along with test reports, for review by the engineer of record. And in some instances where the work is considered critical, I've seen limitations placed on the concrete batch plant in that the number of years of experience in producing a certain mix is required etc.

All in all, if the concrete doesn't measure up, call for its removal. I knew of one extensive pour on a tower for cable stayed bridge that was jack-hammered out due to low strengths. No one was particularly happy, but everyone knew it had to be done. I think it placed everyone's mind at ease.

 

[rowe]

I believe Florida DOT has been known to assess a financial penalty on the contractor, based upon an estimate of the reduction of the life of the structure or element(i.e. they pay for what they're getting in lieu of getting what they pay for).

 

[koodi]

Rowe,
That's similar to the reduction in price in the CA spec for PC pavement. It would be nice to put something in the spec's to call the contractors attention to the importance of the concrete--in the interests of quality control. However, the legalities are so wishy-washy. Looks like such a spec will not be included.

Anyways, thanks for the replies.

 

[rowe]

The role of construction inspection is to ensure that the structure is constructed in accordance with the plans and specifications. The inspections are usually performed by dot personel or independent consultant. In my experience, the state does not actually own the bridge until it is completed in accordance with the plans and specs. And the dot can refuse final payment if they don't want the structure as it is built. However, to avoid costly and frustrating time in argument and litigation, it is advantageous (for both state and contractor) to prescribe the manner in which future forseeable disagreements may be resolved. I would approach the state and ask about previous experiences (I am sure these types of problems have arisen many times) and ascertain their preferences and how to implement them into the contract documentation. Good Luck.