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PLACEMENT OF REINFORCEMENT IN SPILLWAYS 3
- Thread starter cdous
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Thank you Ron
It is was my second posting..I will get familiar with the "rules".
You are absolute right about "shouting"... now that I am looking it compared to your answer.
I was thinking of placing the transverse reinforcement (primary reinforcement across width of spillway )below the longitudinal reinforcement (secondary reinforcement)
It is was my second posting..I will get familiar with the "rules".
You are absolute right about "shouting"... now that I am looking it compared to your answer.
I was thinking of placing the transverse reinforcement (primary reinforcement across width of spillway )below the longitudinal reinforcement (secondary reinforcement)
racookpe1978
Nuclear
If the planned reinforcement is a mesh, how can you be planning on laying it either parallel to, or perpendicularly to the future water flow?
75 mm seems very thin for a concrete spillway cover that must resist vibration, water hammer on the whole structure as the water impacts at the bottom, etc. : How have you planned to resist those forces?
There's relatively little resistance right at the concrete-to-water flowing surface across the top of a spillway, but tremendous loads imposed back onto the spillway from the impact loads on the bottom.
75 mm seems very thin for a concrete spillway cover that must resist vibration, water hammer on the whole structure as the water impacts at the bottom, etc. : How have you planned to resist those forces?
There's relatively little resistance right at the concrete-to-water flowing surface across the top of a spillway, but tremendous loads imposed back onto the spillway from the impact loads on the bottom.
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- #6
Racookpe1978,
The 75mm reffered to the reinforcement cover.
The slab across the chute spillway length varies from 1.30m to 3.8m at the still basin.
The reinforcement is considerable and in odredr to conform with the crack width requirement is of the range of
30cm2/m ~60cm2/m . The mesh is to be used in order to reinforce the relative big cover of the main reinforcement.
According to Eurocode I considered thermal actions and shrinkage not only for the service state but also for the ultimate state.
The 75mm reffered to the reinforcement cover.
The slab across the chute spillway length varies from 1.30m to 3.8m at the still basin.
The reinforcement is considerable and in odredr to conform with the crack width requirement is of the range of
30cm2/m ~60cm2/m . The mesh is to be used in order to reinforce the relative big cover of the main reinforcement.
According to Eurocode I considered thermal actions and shrinkage not only for the service state but also for the ultimate state.
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hokie66
The spillway, is a chute spilwway.
The span variew from 42m~25m hence I decided to use a contraction joint in the middlle. In order to reduce joints the retaining wall's foundation slab is the spillway's slab.
The excavation had to be kept to a minimum thus the retaining wall is not of the 'conventional form' that is it that the footing hasn't got any backfill in order to counterbalance sliding and overturning.
The final ground accerelation is ah=0.29g & av=0.145g.
The sliding problem is eliminated from symmetry..(other half part).
Overturning also is not a problem
Along the longitudinal direction contraction joints are placed at distances varying from 6~12m (measured along the inclined direction)
Transverse joints as discribed above are placed between 21m~12m depending on the spilway's width.
Thermal Loads (uniform contraction -35C,uniform expansion +30C, shrinkage -25C, temperature difference +15C &-15C) have been used both for ultimate and servoce state design.
Setting crack width of 0.3mm, the reinforcement is greater along the transverse direction and lesser along the longitudinal i.e transverse 3800mm2/m longitudinal 2200mm2/m
I saw from 'SELECTED DESIGN GUIDLINES FOR WATER CONTROL STRUCTURES a publication of Alberta Transportation (Canada)that they recommend minimum 0.5% of the gross concrete section.
I quess this refer to the per side total reinforcement and not to the side and direction reinforcement.
I would appreciate for your comment
The spillway, is a chute spilwway.
The span variew from 42m~25m hence I decided to use a contraction joint in the middlle. In order to reduce joints the retaining wall's foundation slab is the spillway's slab.
The excavation had to be kept to a minimum thus the retaining wall is not of the 'conventional form' that is it that the footing hasn't got any backfill in order to counterbalance sliding and overturning.
The final ground accerelation is ah=0.29g & av=0.145g.
The sliding problem is eliminated from symmetry..(other half part).
Overturning also is not a problem
Along the longitudinal direction contraction joints are placed at distances varying from 6~12m (measured along the inclined direction)
Transverse joints as discribed above are placed between 21m~12m depending on the spilway's width.
Thermal Loads (uniform contraction -35C,uniform expansion +30C, shrinkage -25C, temperature difference +15C &-15C) have been used both for ultimate and servoce state design.
Setting crack width of 0.3mm, the reinforcement is greater along the transverse direction and lesser along the longitudinal i.e transverse 3800mm2/m longitudinal 2200mm2/m
I saw from 'SELECTED DESIGN GUIDLINES FOR WATER CONTROL STRUCTURES a publication of Alberta Transportation (Canada)that they recommend minimum 0.5% of the gross concrete section.
I quess this refer to the per side total reinforcement and not to the side and direction reinforcement.
I would appreciate for your comment
The Canadian publication's recommendation of 0.5% gross area would be the total amount of reinforcement in each direction, wherever located in the section, so would be the sum of the top and bottom bars. How thick is your slab? How high and thick are the side walls?
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hokie66,
The slab has a structural depth of 1.6m,I state structural cause the geotechnical engineer has performed an cascaded excavation as in that way he eliminates sliding and doesn't use 'toe' beams
I will send you longitudinal section of a typical segment.
The wall's height in the partricular segment are about 7.37~7.70m high.
Top cross-section is 0.40m wide and 1.13m~1.17m at the base (1:10).
Top& bototm slab transverse reinforcement R25/10cm
Top& bototm slab longitudinal reinforcement R20/12.5cm
Top& bototm slab longitudinal reinforcement at a zone of 2m from the wall R25/10cm
The slab has a structural depth of 1.6m,I state structural cause the geotechnical engineer has performed an cascaded excavation as in that way he eliminates sliding and doesn't use 'toe' beams
I will send you longitudinal section of a typical segment.
The wall's height in the partricular segment are about 7.37~7.70m high.
Top cross-section is 0.40m wide and 1.13m~1.17m at the base (1:10).
Top& bototm slab transverse reinforcement R25/10cm
Top& bototm slab longitudinal reinforcement R20/12.5cm
Top& bototm slab longitudinal reinforcement at a zone of 2m from the wall R25/10cm
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