Difference between live load and superimposed load
Answers
Answered by
3
The short answer is that you should use superimposed dead load to account for the weight of the non-structural and semi-permanent members. Dead load should be used for structural members.
This distinction could be helpful especially in steel structures where you should increase the dead load of steel members to account for the additional weight due to connections, but you do not want to increase other loads.
Dead load is the load pattern that involves the “self weight” of the structural members. These members are the ones that are included in your model and have a structural purpose, like reinforced concrete slabs, beams, columns, walls etc. or structural steel columns, beams, braces.
Superimposed dead load could be used for non-structural members. For example weight of the facade members should be included in your model as load, but you would not want to consider them as structural members. Weight of the floor cover (leveling grout, tiles etc.) could be included in this load case. Weight of suspended ceiling and ductwork could be included in this load as well. Basically, things that you would not consider to be live loads but are not structural members should be included in your model as superimposed dead load.
Etabs treat both as DL load patterns/load cases. It's just a way to separate the DL of your modeled elements from superimposed loads you want to add. So if you have interior walls, curtainwalls, MEP equipment etc, you can add them as superimposed DL. That way you don't have to model them but still account for their weight in the analysis. Having both DL and Super DL in the software, you get the flexibility to interprets the results in a better way since you've separated the two.
When doing seismic analysis, make sure Super DL is being accounted for in the mass source. When checking the base shear against the base reactions you will have to add both DL and SuperDL to sum up to the weight of the building. Weight of the building used for base shear is found under seismic output for the generated seismic loads.
As far as I know, there are no differences between the two. Just that it separates DL of the structure modeled and the DL superimposed by the user. Ultimately, load patterns/cases are really just names. Theoretically I could use a snow load pattern (or any other pattern) for my DL by giving it a self weight modifier as 1. It would be crazy to do that, but just to drive home the point that it's just how you choose to use the load patterns. The load combinations will have to make sense based on your intent thought.
Superimposed dead load is the dead load on the structure after slab and beams have been casted .. dead load is the load from slabs and columns and beams .
in short superimposed dead load = floor finishes, tiles, water proofing , cable wires , wall loads , plumbing pipes, AC duct
dead load = slab , column and beam selfweight
.
There have been some good answers posted in rely to this question, hence I would touch upon a point not yet mentioned.
It is always better to subdivide you loads into sub-categories. Therefore although self weight of structure, weight of permanent finishes and weight of cladding and components are all dead loads but if you allocate self weight as a separate dead load, weight of permanent finishes and cladding as separate dead load and weight of components as yet another separate dead load then you would be able to analyse what effect each type of dead load has over the structure. Hence, you will have a fairly good idea regarding which component imparts significant loading and needs to be curtailed for efficient design.
This distinction could be helpful especially in steel structures where you should increase the dead load of steel members to account for the additional weight due to connections, but you do not want to increase other loads.
Dead load is the load pattern that involves the “self weight” of the structural members. These members are the ones that are included in your model and have a structural purpose, like reinforced concrete slabs, beams, columns, walls etc. or structural steel columns, beams, braces.
Superimposed dead load could be used for non-structural members. For example weight of the facade members should be included in your model as load, but you would not want to consider them as structural members. Weight of the floor cover (leveling grout, tiles etc.) could be included in this load case. Weight of suspended ceiling and ductwork could be included in this load as well. Basically, things that you would not consider to be live loads but are not structural members should be included in your model as superimposed dead load.
Etabs treat both as DL load patterns/load cases. It's just a way to separate the DL of your modeled elements from superimposed loads you want to add. So if you have interior walls, curtainwalls, MEP equipment etc, you can add them as superimposed DL. That way you don't have to model them but still account for their weight in the analysis. Having both DL and Super DL in the software, you get the flexibility to interprets the results in a better way since you've separated the two.
When doing seismic analysis, make sure Super DL is being accounted for in the mass source. When checking the base shear against the base reactions you will have to add both DL and SuperDL to sum up to the weight of the building. Weight of the building used for base shear is found under seismic output for the generated seismic loads.
As far as I know, there are no differences between the two. Just that it separates DL of the structure modeled and the DL superimposed by the user. Ultimately, load patterns/cases are really just names. Theoretically I could use a snow load pattern (or any other pattern) for my DL by giving it a self weight modifier as 1. It would be crazy to do that, but just to drive home the point that it's just how you choose to use the load patterns. The load combinations will have to make sense based on your intent thought.
Superimposed dead load is the dead load on the structure after slab and beams have been casted .. dead load is the load from slabs and columns and beams .
in short superimposed dead load = floor finishes, tiles, water proofing , cable wires , wall loads , plumbing pipes, AC duct
dead load = slab , column and beam selfweight
.
There have been some good answers posted in rely to this question, hence I would touch upon a point not yet mentioned.
It is always better to subdivide you loads into sub-categories. Therefore although self weight of structure, weight of permanent finishes and weight of cladding and components are all dead loads but if you allocate self weight as a separate dead load, weight of permanent finishes and cladding as separate dead load and weight of components as yet another separate dead load then you would be able to analyse what effect each type of dead load has over the structure. Hence, you will have a fairly good idea regarding which component imparts significant loading and needs to be curtailed for efficient design.
Answered by
3
Answer:
- Superimposed load : The load superimposed on the dead load of a building. The term is generally synonymous with live load, although a distinction is sometimes made between the superimposed dead load caused by movable partitions, etc., and the live load caused by people.
- Live load : the load to which a structure is subjected in addition to its own weight
A live load can be defined as those loads that
aren't constant unlike dead loads. Live loads
exert pressure on the pipe for a moment of time
and have less effect on the pipe performance
unless the pipe is buried at shallow depth.
Similar questions
India Languages,
6 months ago
Computer Science,
6 months ago
Science,
1 year ago
Math,
1 year ago
Math,
1 year ago