Loads on arches truss supporting water piping 3

[Italo01]

Hello,

I was hired by a water supplier company to design a arched truss that will support a water pipe over a river. The truss will span 50 meters.

For the design lodas, i'm considering the pipe, water and structure weights, Wind and hydraulic thrust, but some maintenance workers will eventually go over the structure. The company didn't provide this additional load and i cannot found anything similar in the brazilian codes.

Does anyone knows a code provision of some country for a structure like this?

Thank you.

 

[Italo01]

Very nice, BARetired.

 

[LittleInch]

Ooooh, that's really nice - where is it?

Ok, looks like the Hegigio gorge in PNG

https://structurae.net/en/structures/hegigio-gorge-pipeline-bridge

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BAretired]

That's it, LittleInch. It's in Papua, New Guinea.

Years ago, I worked for a firm who designed pipeline bridges, as well as other structures. I was not involved in suspension bridge design, but they were occasionally used and were said to be very economical.

I suggested it here because I think that wind load will be a bit difficult for an arch.

BA

 

[Italo01]

I have another question related to the arched truss.

At the base, the chord and diagonal are meeting. For constructibility, i'm using Gusset Plates as shown in the figure below. Since the CHS has little strength for perpendicular forces at the connection, i thought of using the KISS method. Since the CHS has a small rigidity compared to the plate for these forces, i think that there`s enough ductility that justify using the method but would like to know if someone has a problem with it. I`ve only seen the Kiss method used for W-shape Beams and columns, so am afraid of using at another situation.

Thanks in advance.

 

[LittleInch]

BA, did you really?

So cool.

I've always wanted to be part of a project with a pipeline Bridge but never made it in nearly 40 years, but maybe.....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BAretired]

I think it would be better to focus on the overall structure, rather than on joint details during preliminary design. For a 50m span, a horizontal truss may be more suitable than an arch shape. It would be better able to resist wind forces as well.

BA

 

[Italo01]

Actually, the structure will be to two arched trusses connected by horizontal trusses creating a box structure, ao these horizontal trusses(2m height) are effective against wind.

Unfortunately i don't have much time for changes on the shapes. I already finished the design of the members, checked for stability, serviceability and ULS and the client is pressuring for the final design.

 

[BAretired]

Italo01,
I understand, and it is really too bad that you don't have time to do a more thorough prelim. In that case, I will stop suggesting alternative design concepts.

BA

 

[Italo01]

And don't understand me wrong. I really appreciate your suggestions.