Control joint/ Expansion joint for buildings 2

[Phuong Pham]

Hello my colleagues,

It's a big joy for me to join an international forum like this one. I know there are so many masters joining this forum also.
I'm a Vietnamese guy. highways and bridges engineering. I'm working as a sales engineer, selling solutions for control joint and expansion joint.
I have 2 points that I hope could have your advice:

1. About terminology.
I'm chasing a project for control joint. Because the detail with metal plates & rubber infill was too expansive. I decided to offer my customer:

1.1. For control gaps at the foot of the wall: using sealant because of low traffic frequency

1.2. For control gaps inside the floor: using metal-plate-infill-rubber detail, because of high traffic frequency

Using this choice, I could decrease the quantity of expansive unit price materials. So how should I call these 2 concepts in English? Does wall foot control gap make sense for type 1.1?

2. About designing process:
How do you design the expansion gap? I know it's easy in Western country but this is brand-new in Vietnam. If I wanna sell this, I have to show the consultant how to use it. I'm now spun around by standards. Could you please send me an example for design the expansion gap and the control gap? I mean If we have the required gap width and required movement of the gap, it's really easy to pick the joint by catalogs from manufacture. But how to build the requirements for the gaps, in order to chose the joint
Please teach me how to do that.

 

[r13]

I think you should repost on the "Bridge Engineering" forum to draw more attention/responses.

 

[dik]

Why bridge?... I think it's a neat attractive joint for that application... likely a little light for heavy use applications. I haven't done a parking garage for a decade or so... but, we had an expression for that type of construction joint... do you want a cheap one? or one that works?

For designing a control joint, you have to know the materials very well, the type of exposure (environment), and you have to know the range of movement expected... most important items. Expansion joints are there for a purpose... expansion and they have to 'fill the gap' to accommodate this. They also have to prevent foreign material from becoming embedded in the joint. It's a lengthly topic and there are numerous texts on this as well as differing engineering opinions. You might take a look at competitor web sights to see what information they can provide.

I forgot to add that the sealant should be approx half the thickness of the joint if movement is expected. If less, there is a good chance with movement, the sealant will 'tear'.

Dik

 

[Phuong Pham]

Thank you for your attention. I'm a bridge engineer but selling expansion joint / control joint for buildings. You could see I'm taliking about control joint. This is just for building while we could surprise an expansion joint for both of bridges and buildings.

+, Control gap(or contraction gap the way they called it in standards. "contraction" means the contraction of the material (drying shrinkage), not the joint): Just discontinues the finishes, this is compusory for lines on slab with beams below -> hogging moment -> tensile stress -> All finishes material (brittle material) can't subject the tensile. -> Basically we'll have a crack rigth on this loacation, so we should treat these artificial cracks -> pre-cut and pre-seal them by con traction joint. This gap contracts more than expands.

+, Expansion joint (Isolation joint as verbally): This gap expands more than contracts and discontinue the structure into 2 separated parts. The width (B), of this gap at non-movement condition, should be defined as long as when 2 buildings are closest to each other, they still stay away from each other A (mm). Then
B = Total movement towards centerline of the gap + A (mm). A must higher than 0 mm

Let me show you my presentation that I often show Vietnamese consultants. About the differences b/w expansion joint & control joint.

 

[Phuong Pham]

Thanks a lot,

Superman is right here folks,
Please send me a few document teaching how to dispose control joint/ expansion joint. I rummaged at Migua, CS website but couldn't find anything specific.
My e-mail is phuong.cdbc.k52@gmail.com. Please I need help!

I'm struggling with these products cause I didn't have enough knowledge to persuade my customer. In europe, I think it's not too hard cuz most of consultant engineers had known this. But in Vietnam, when we wanna push a new solution, new products with high unit price into the market, we have to show vietnamese consultants how to calculate the gap width, how to dipose the gap. There're no any other way cuz this is the first time vietnamese conultant see this thing. Then we have to have knowledge equal to a concultant engineer in Europe.

Thank you for your advice on sealant. We are selling for Tremco. They are quite good. Because I'm not a site manager, I'm a sales engineerso to me, a good manufacture is the one could give me enough knowledge to let me could persuade my customer. Quality is also important but it's not my responsibility.

Phuong Pham

 

[dik]

Thanks... I've spec'c Dymeric countless times, it is an excellent sealant. I used its little brother Dymonic for caulk when I installed 28 windows in an earlier home... great stuff. I don't know how Vietnam is, but most expansion joints are drawn and spec'd on plans... both location and construction. Essentially you have a joint of a given width and need to know the amount of movement anticipated. I usually use 1/3 x the anticipated movement to size the thickness of the caulk. The material beneath the joint is often an ethafoam backer material that allows movement if the caulk is adhered to it or there is a bond breaking material that prevents the caulk from adhering to it.

Do a search on Google for 'expansion joint details' and select images. There are numerous types of joints shown. Also check 'expansion joint design'.

Dik