Concrete hinge or pin

[aalmasri]

Hi all
Did anybody here construct concrete hinge or pin, in frames or in concrete tanks? Including using elastic pads? It will be great if real pictures can be shared. I know it's not common, and when searched for, mostly sketches from textbooks come up.
Thanks in advacnce

 

[LittleWheels]

I've not designed concrete hinges in frames or tanks but about two decades ago, I had some intensive investigation and analysis work with reinforced concrete deck hinges in bridges built in the 1960-70s. They are known as Freyssinet hinges, which is not strictly correct. Freyssinet hinges rely on very large compressive forces to support shear loads but these deck hinges can be in tension (temperature effects and abutment settlement) and so rely on the diagonal reinforcing bars to carry live and dead loads. It was more accurate to describe them as Mesnager hinges. The design was problematic because of deicing salt corroding the hinge rebar.

The investigation involved radiography and acoustic emission NDT, localised breakout and strain-gauging of rebar, amongst some significant desktop structural analysis. I don't have any photos from that time.

https://www.standardsforhighways.co.uk/tses/attachments/9305895c-ccce-4e9e-889b-b1d9dcffd25b?inline=true

 

[aalmasri]

Thanks LittleWheels,
although no pictures, the report is very helpful.

 

[HTURKAK]

Did anybody here construct concrete hinge or pin, in frames or in concrete tanks

I personally did not . Moreover i would not prefer concrete hinges.
I found the following docs. Probably one of them is very similar with Little wheels' link.
The other is in GERMAN .

 

[Greenalleycat]

Concrete hinges are basically the opposite to pins, can you be clearer what you want and why?
Hinge = a designated zone for plastic deformation, any developed concrete design code can give you details on this. Basically, well-anchored reinforcement and lots of stirrups.

Pin = a node with zero moment capacity e.g. a greased steel pin... these are not practical to form in concrete

 

[LittleWheels]

Just for completeness, below is the specific Highways England guidance for deck hinges, as opposed to concrete hinges that are in permanent compression.

https://www.standardsforhighways.co.uk/tses/attachments/a5411e11-d9af-4c13-8566-9f96d6716e69?inline=true

I suspect the fairly brief popularity of concrete hinges related to the difficulty of accurately modelling structures in those days and wanting some simplifying assumptions for hand calculations.

 

[aalmasri]

I personally did not . Moreover i would not prefer concrete hinges.
I found the following docs. Probably one of them is very similar with Little wheels' link.
The other is in GERMAN .

Thanks a lot for the files HTURKAK. Will go through them

 

[aalmasri]

Concrete hinges are basically the opposite to pins, can you be clearer what you want and why?
Hinge = a designated zone for plastic deformation, any developed concrete design code can give you details on this. Basically, well-anchored reinforcement and lots of stirrups.

Pin = a node with zero moment capacity e.g. a greased steel pin... these are not practical to form in concrete

I would say pin (zero moment point) according to your definition, although I see it called a hinge in several places. I have attached a sketch for what I am looking for. I have not heard or seen anybody who designed or constructed such a wall to base connection. I was wondering if I can find real pictures, standards, after construction performance evaluation for such practices in concrete water tanks. I have seen different configurations of concrete hinges in textbooks, but are they only theoretical and nobody has applied it?

 

[aalmasri]

Just for completeness, below is the specific Highways England guidance for deck hinges, as opposed to concrete hinges that are in permanent compression.

https://www.standardsforhighways.co.uk/tses/attachments/a5411e11-d9af-4c13-8566-9f96d6716e69?inline=true

I suspect the fairly brief popularity of concrete hinges related to the difficulty of accurately modelling structures in those days and wanting some simplifying assumptions for hand calculations.

Thanks again LittleWheels.
Let me share a sketch for a sliding joint that supposedly can be used in water tanks. I guess they need strict standards in order to work without problems.
I remember somebody mentioned in a post that they used such joints, but I can't find it again.

 

[Greenalleycat]

I would say pin (zero moment point) according to your definition, although I see it called a hinge in several places. I have attached a sketch for what I am looking for. I have not heard or seen anybody who designed or constructed such a wall to base connection. I was wondering if I can find real pictures, standards, after construction performance evaluation for such practices in concrete water tanks. I have seen different configurations of concrete hinges in textbooks, but are they only theoretical and nobody has applied it?

Well that detail already shows one of the difficulties with this theoretical detail - you still have a moment capacity at the base, it's just that the lever arm has reduced to half the width of the wall at the critical point. It's not like it has zero moment capacity, it just has a lot less. And in exchange, you've given up a lot of reliable capacity, and may have forced the yielding to occur over a much smaller area as the increasing lever arm as you move up the wall will significantly reduce the tension demands

 

[LittleWheels]

I have seen such sliding joint details used in circular post-tensioned concrete tanks within municipal potable water and wastewater networks. Sikadur Combiflex is a commonly specified membrane.

Sikadur Combiflex

gbr.sika.com

I don't recall seeing tanks with concrete hinges at the base of the walls but that doesn't mean they weren't there, only that I wasn't looking for them. I only worked in that industry in Australia, over a decade ago.

 

[BridgeSmith]

I would say pin (zero moment point) according to your definition, although I see it called a hinge in several places. I have attached a sketch for what I am looking for. I have not heard or seen anybody who designed or constructed such a wall to base connection. I was wondering if I can find real pictures, standards, after construction performance evaluation for such practices in concrete water tanks. I have seen different configurations of concrete hinges in textbooks, but are they only theoretical and nobody has applied it?

We've used a similar detail to hinge columns at an abutment cap, except that in our detail, there was only a small area of concrete contact at the center, and the remaining width had a gap filled with sponge rubber. We didn't need a waterstop.