Unsupported Span

[scav000]

Is my illustration correct?

 

[bajansailor]

Welcome to the Forum SCAV.

I think the reason why nobody has responded so far is that you have not supplied much information to go with your question above.

Can you expand a bit on this, and tell us what you are designing, and what context the above illustration refers to in your design?
I presume that you are using a set of Rules from a Classification Society - can you make reference to the Rules that you are using?

 

[TANSL]

Yes, what you have stated is correct. You could, if necessary, deduct something due to the use of end brackets.

 

[scav000]

Welcome to the Forum SCAV.

I think the reason why nobody has responded so far is that you have not supplied much information to go with your question above.

Can you expand a bit on this, and tell us what you are designing, and what context the above illustration refers to in your design?
I presume that you are using a set of Rules from a Classification Society - can you make reference to the Rules that you are using?

Thank you for taking time to answer. So what I am currently designing is a floating gate, rules in used is ABS under 90m. Which was recommended by the UFC graving dock manual.
I know this is a basic question, but the gate is really deep about 10 meters so I want to make sure I am calculating every member correctly. At the beginning I had calculated the Primary side frame with the stringer as the endpoint of the span, at the time they are of the same height. But then I came across an illustration in the rule book defining the span as even including the stringers regardless whether they are the same web height, so I promptly changed the span to the full height between the floor and the deck transverse. However this had me thinking if this illustration also includes the ordinary transverses. Hence the illustration on my previous post.

 

[scav000]

Yes, what you have stated is correct. You could, if necessary, deduct something due to the use of end brackets.

Thank you for your reply. Yes I would do that.
At what point do you "not" end the span at the stringers though? like for example if add another side stringer at the same size as the ordinary web would that further decrease span?
Sorry if this is too basic, this is the first time we are designing from the ground up, so I want to doubly aure we are getting the right requirements.

 

[TANSL]

Would you prefer to talk to me and send me a diagram of the structure you are thinking of through my email : tansl02@hotmail.com.
The structure must be seen as a whole and I am not getting an idea of what you are describing to me. Thank you.

 

[Ad Hoc]

.....At what point do you "not" end the span at the stringers though?...

The span from deck to bilge/keel is the full span.
The stringer that is located midspan is not considered as a support to be 1/2 span.
The stringer located mid-span, can only be considered to be a support, for your side frame, if the stringer is designed to support the entire load area of the side, between the WTBs at either end, from deck to bilge/keel.

When that is the case, then the side frame may use the 1/2-span as its own support, otherwise, it cannot.

 

[TANSL]

This is what Lloyd's says on the subject.
Brackets must be effective to be taken into account. The one in your sketch, on the left element, top, does not seem to be.

 

[scav000]

The span from deck to bilge/keel is the full span.
The stringer that is located midspan is not considered as a support to be 1/2 span.
The stringer located mid-span, can only be considered to be a support, for your side frame, if the stringer is designed to support the entire load area of the side, between the WTBs at either end, from deck to bilge/keel.

When that is the case, then the side frame may use the 1/2-span as its own support, otherwise, it cannot.

Thank you, your explanation makes the most sense to me. And I know that the brackets are part of the span calculation, But I tend to just use this as "extra" just for safety margin so to speak.