ACI 318-11 requires that the shotcrete walls on pools be increased in strength and thickness.
For
clarification, "Shotcrete" is defined by the ACI as either the wet or
dry (incorrectly referred to as "gunite") process of pneumatically
placing concrete.
ACI - The American Concrete Institute
ACI
is the definitive expert on concrete. So much so, that they publish a
myriad of standards that relate to concrete and it's use. The ACI standards are actually adopted by and incorporated into the International Building Code (the building code adopted across the entire United States).
Because ACI
Standard 318-11, "Building Code Requirements for Structural Concrete"
has been directly incorporated into the International Building Code by the
California Building Code. This effectively makes it the law of the
land.
ACI 318-11 Changes the Requirements
ACI 318-11
redefined the parameters of the required coverage of concrete required
over the reinforcing steel. Prior versions of ACI 318 were ambiguous as
to what was actually defined as sulfate or corrosive conditions. It
establishes the additional shotcrete protection required when exposed to
defined levels of sulfates, water containing chlorides (salts) and
permeability.
ACI 318-11, Table 4.2.1 indicates that shotcrete
swimming pools are required to meet the criteria for Permeability - P1
(condition defined as: "in contact with water where low permeability is
required") AND Corrosion Resistance - C2 (a condition defined as:
"concrete exposed to moisture and an external source of chlorides from
deicing chemicals, salt, brackish water, seawater, or spray from these
sources"). It does not define the PPM level of salt required to create
an "external exposure to chlorides."
Those resulting P1 and C2 classifications require specific mix design ratios (ACI 318-11, Table 4.3.1).
ACI
318-11, Table 4.3.1, P1 classification sets a maximum water to cement
ratio (w/cm2) of 0.50 and a MINIMUM 28 day compressive strength (f'c) of
4,000 PSI. While the C2 classification establishes a maximum water to
cement ratio (w/cm2) of 0.40 and a MINIMUM 28 day compressive strength
(f'c) of 5,000 PSI.
Therefore, any swimming pool that is going to
be treated with sodium compounds is REQUIRED to have a maximum water to
cement ratio (w/cm2) of 0.40 and a designed compressive strength (f'c)
of 5,000 PSI. Sodium compounds utilized in swimming pool sanitization
include sodium chloride compounds and solutions (chlorine), sodium
bromide (bromine) or sodium (salt-electrolysis chlorination).
Furthermore, the sodium (salt) levels in pools treated with sodium
chloride compounds (chlorine) actually becomes more concentrated over
time as the chlorides are consumed.
The C2 classification (Table
4.3.1) further specifies that the requirements of ACI 318-11, 7.7.6
"Corrosive Environments" be met. Section 7.7.6 states that the coverage
over reinforcing steel shall not be less than 2 inches for walls and
slabs exposed to such corrosive environments.
Structural Engineers & Building Departments often ignore the standards
Many
structural engineers and building departments do not abide by the
requirements of ACI 318-11. They either attempt to justify design
criteria less than the standards, are not versed on the most up to date
requirements or simply refuse to comply with the codes.
When
there is an issue of structural integrity on a pool, the most recently
adopted version of the IBC, CBC or ACI standards will apply in court,
whether or not they were followed by the engineer, building department or enforced by the building inspector.
Do
you want to be left hanging by a structural engineer who will have to
defend his decision to design a structure that was below the
requirements of ACI 318-11 and the building codes?
Do you want
to take the risk that he will be able to convince a jury of lay people
that a weaker and substandard structure was acceptable?
I thought not!
ACI's position is to design to a standard of:
A. A minimum compressive strength (f'c) of 5,000 PSI
B. A maximum water to cement ratio (w/cm2) of 0.40
C. A minimum concrete coverage of 3 inches between the earth and steel
D. A minimum of 2 inches of coverage over the steel (water side).
Therefore, the minimum wall thickness is 3 inches, 2 times the bar diameters (assuming a single curtain of steel bars that cross each other in a grid pattern), plus 2 inches of coverage. For #4 (1/2 inch) bars this would be 3" + 1" + 2" = 6" thick wall.
Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at:
info@aquatictechnology.com or 408-776-8220.
Visit his website at: www.aquatictechnology.com.
All Contents © Aquatic Technology Pool & Spa, 2013.
All rights reserved.
Showing posts with label ACI 318-11. Show all posts
Showing posts with label ACI 318-11. Show all posts
Monday, March 24, 2014
Sunday, November 24, 2013
ACI 318-11 thicker stronger shotcrete pools
ACI 318-11 requires that the shotcrete walls on salt water pool be increased in strength and thickness. Shotcrete is defined as either the wet or dry process of pneumatically placing concrete.
ACI - The American Concrete Institute
ACI is the definitive expert on concrete. So much so, that they publish a myriad of standards that relate to concrete and it's use.
ACI Standard 318-11, "Building Code Requirements for Structural Concrete" has been directly incorporated into the International Building Code (adopted by 48 States, except Minnesota) and by the California Building Code. This effectively makes it the law of the land.
ACI 318-11 changes the requirements
ACI 318-11 redefined the parameters of the required coverage of concrete required over the reinforcing steel. Prior versions of ACI 318 were ambiguous as to what was actually defined as sulfate or corrosive conditions.
ACI 318-11 establishes the additional shotcrete protection required when exposed to defined levels of sulfates, water containing chlorides (salts) and permeability.
ACI 318-11, Table 4.2.1 indicates that shotcrete swimming pools are required to meet the criteria for Permeability - P1 (condition defined as: "in contact with water where low permeability is required") AND Corrosion Resistance - C2 ( a condition defined as: "concrete exposed to moisture and an external source of chlorides from
deicing chemicals, salt, brackish water, seawater, or spray from these sources").
The resulting P1 and C2 classifications require specific mix design ratios (ACI 318-11, Table 4.3.1).
ACI 318-11, Table 4.3.1, P1 classification sets a maximum water to cement ratio (w/cm2) of 0.50 and a MINIMUM 28 day compressive strength (f'c) of 4,000 PSI. While the C2 classification establishes a maximum water to cement ratio (w/cm2) of 0.40 and a MINIMUM 28 day compressive strength (f'c) of 5,000 PSI.
Therefore, any swimming pool that is going to be treated with sodium compounds is REQUIRED to have a maximum water to cement ratio (w/cm2) of 0.40 and a designed compressive strength (f'c) of 5,000 PSI. Sodium compounds utilized in swimming pool sanitization include sodium chloride (chlorine), sodium bromide (bromine) or sodium (salt-electrolysis chlorination).
The C2 classification (Table 4.3.1) further specifies that the requirements of ACI 318-11, 7.7.6 "Corrosive Environments" be met. Section 7.7.6 states that the coverage over reinforcing steel shall not be less than 2 inches for walls and slabs subject to such corrosive environments.
Structural Engineers & Building Departments
Many structural engineers and building departments do not abide by the requirements of ACI 318-11. They either attempt to justify design criteria less than the standards, are not versed on the most up to date requirements or simply fail to comply with the codes.
When there is an issue of structural integrity on your pool, the most recently adopted version of the IBC, CBC or ACI standards will apply in court, whether or not they were enforced by the engineer or building inspector.
Do you want to be left hanging with a structural engineer who will have to defend his decision to design a structure that was below the requirements of the building codes?
Do you want to take the risk that he will be able to convince a jury of lay people that a weaker structure is acceptable?
I thought not!
Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220.
Visit his website at: www.aquatictechnology.com.
All Contents © Aquatic Technology Pool & Spa, 2013.
All rights reserved.
ACI - The American Concrete Institute
ACI is the definitive expert on concrete. So much so, that they publish a myriad of standards that relate to concrete and it's use.
ACI Standard 318-11, "Building Code Requirements for Structural Concrete" has been directly incorporated into the International Building Code (adopted by 48 States, except Minnesota) and by the California Building Code. This effectively makes it the law of the land.
ACI 318-11 changes the requirements
ACI 318-11 redefined the parameters of the required coverage of concrete required over the reinforcing steel. Prior versions of ACI 318 were ambiguous as to what was actually defined as sulfate or corrosive conditions.
ACI 318-11 establishes the additional shotcrete protection required when exposed to defined levels of sulfates, water containing chlorides (salts) and permeability.
ACI 318-11, Table 4.2.1 indicates that shotcrete swimming pools are required to meet the criteria for Permeability - P1 (condition defined as: "in contact with water where low permeability is required") AND Corrosion Resistance - C2 ( a condition defined as: "concrete exposed to moisture and an external source of chlorides from
deicing chemicals, salt, brackish water, seawater, or spray from these sources").
The resulting P1 and C2 classifications require specific mix design ratios (ACI 318-11, Table 4.3.1).
ACI 318-11, Table 4.3.1, P1 classification sets a maximum water to cement ratio (w/cm2) of 0.50 and a MINIMUM 28 day compressive strength (f'c) of 4,000 PSI. While the C2 classification establishes a maximum water to cement ratio (w/cm2) of 0.40 and a MINIMUM 28 day compressive strength (f'c) of 5,000 PSI.
Therefore, any swimming pool that is going to be treated with sodium compounds is REQUIRED to have a maximum water to cement ratio (w/cm2) of 0.40 and a designed compressive strength (f'c) of 5,000 PSI. Sodium compounds utilized in swimming pool sanitization include sodium chloride (chlorine), sodium bromide (bromine) or sodium (salt-electrolysis chlorination).
The C2 classification (Table 4.3.1) further specifies that the requirements of ACI 318-11, 7.7.6 "Corrosive Environments" be met. Section 7.7.6 states that the coverage over reinforcing steel shall not be less than 2 inches for walls and slabs subject to such corrosive environments.
Structural Engineers & Building Departments
Many structural engineers and building departments do not abide by the requirements of ACI 318-11. They either attempt to justify design criteria less than the standards, are not versed on the most up to date requirements or simply fail to comply with the codes.
When there is an issue of structural integrity on your pool, the most recently adopted version of the IBC, CBC or ACI standards will apply in court, whether or not they were enforced by the engineer or building inspector.
Do you want to be left hanging with a structural engineer who will have to defend his decision to design a structure that was below the requirements of the building codes?
Do you want to take the risk that he will be able to convince a jury of lay people that a weaker structure is acceptable?
I thought not!
Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220.
Visit his website at: www.aquatictechnology.com.
All Contents © Aquatic Technology Pool & Spa, 2013.
All rights reserved.
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