Bridge loading requirements?

[DJAlex]

I've been tasked with figuring out the live load design requirements for a cable stayed railway bridge.

I've looked at the british standard document, but I'm finding it abit confusing, particularly when trying to identify what is relevant to my design.

So I was wondering if anyone on here has any experience in this type of thing and can help me out?

Thanks guys,
Alex

 

[YorkshireBear]

I've been tasked with figuring out the live load design requirements for a cable stayed railway bridge.

I've looked at the british standard document, but I'm finding it abit confusing, particularly when trying to identify what is relevant to my design.

So I was wondering if anyone on here has any experience in this type of thing and can help me out?

Thanks guys,
Alex

Have you checked the Eurocodes? They may have more detail as cable stayed bridges are more widely used in Europe.

Can you not adapt from loadings given for other types of bridges? Treating the cable stayed bridge as a bridge with a series of beams at where the cables are placed?

 

[Haydn1971]

I'd seriously suggest employing an expert in the field of cable stayed structures - it's a very specialist niche.

 

[DJAlex]

I'd seriously suggest employing an expert in the field of cable stayed structures - it's a very specialist niche.

I'm a student :<

 

[Haydn1971]

I'm a student :<

Phew ! I was getting very concerned for a while there !

I know that margins are tight in the consultancy world but I do keep hearing of stories like this and seeing work from under qualified engineers pass over my desk as a checker.

 

[dalmahoyhill]

I am with Haydn1971. you are delving into a highly specialist area. I would suggest you are unlikely to find much literature and guidance on it.

the dead and live loads will not be the governing factor I bet. The old BS for bridge design has loads for trains but it wont give you any information on dynamics which is critical with both fast moving emu modern stock and cable stayed bridges.

cable stays are sensitive to dynamic loading and wind. if you are preparing a model the stiffness of the deck will be critical there is some way of modelling springs to get the relative stiffness without trying to get really complicated and modelling it accurately. i cannot remember the formula though.

The only large cable stay rail bridges i can think of are in Japan on the bridges to Shikoku Island. They use big trusses to stiffen the deck.

i am a old git but aren't you students supposed to be using Eurocodes not B Standards?

 

[edwin_m]

Maybe worth making this enquiry of some of the engineering firms who specialise in this sort of thing? Many of them are happy to contribute to engineering education and also on the lookout for recruits, so it could be to your mutual benefit!

 

[DJAlex]

I am with Haydn1971. you are delving into a highly specialist area. I would suggest you are unlikely to find much literature and guidance on it.

the dead and live loads will not be the governing factor I bet. The old BS for bridge design has loads for trains but it wont give you any information on dynamics which is critical with both fast moving emu modern stock and cable stayed bridges.

cable stays are sensitive to dynamic loading and wind. if you are preparing a model the stiffness of the deck will be critical there is some way of modelling springs to get the relative stiffness without trying to get really complicated and modelling it accurately. i cannot remember the formula though.

The only large cable stay rail bridges i can think of are in Japan on the bridges to Shikoku Island. They use big trusses to stiffen the deck.

i am a old git but aren't you students supposed to be using Eurocodes not B Standards?

Thanks for the advice,

Although initially I was concerned about the dynamic analysis etc, we've been told to almost overlook it for the moment as we aren't due to be fully lectured on the complexities of that until next year I'm led to believe, and there aren't any marks allocated to that in the submission (I know it would be good for brownie points though and general experience)

I did also look at the Eurocodes for railway loading, the loading models are identical - however the Eurocode does not have a model for light rail systems and (un?) surprisingly the British Standard seemed generally more complete so I've stuck mainly with them, whilst refferring to the Eurocode where I can.

 

[YorkshireBear]

You studying civil engineering? If you dont mind me asking what uni are you at?

 

[DJAlex]

You studying civil engineering? If you dont mind me asking what uni are you at?

yes, I'd prefer not to say where though

 

[YorkshireBear]

yes, I'd prefer not to say where though

Fair play, I know its not mine