5-Torii standard.pdf

ENGINEERING SERVICE DIVISION

TORII STANDARD (updated June 2022)

CONCRETE DESIGN

Design must conform, as applicable, to the latest UFC (Unified Facility Criteria), IBC (International

Building Code), ACI (American Concrete Institute), UFGS (Unified Facilities Guide Specification), JIS

(Japanese Industrial Standards), JASS (Japanese Architectural Standard Specification), Military

Construction Guide Specifications and all applicable Act, policies, regulations and publications.

In cases of discrepancies, Contractors are to use the most stringent code unless otherwise approved.

‐ Please coordinate with the DPW Engineer if these information has any issues.

1. PERMANENT CONSTRUCTION: REINFORCED CONCRETE STRUCTURES

Permanent Construction shall conform to JASS 5.

Planned service life class

Durability design strength (Fd: N/mm2)

An addition taking into account the discrepancy between the strength of the concrete in the structure and the strength of specimens (⊿F: N/mm2)

Quality Standard strength /Nominal strength (Fq: N/mm2)

General (30 years) 18

*Not use Air temperature correction value (T) for

Okinawa

Standard (65 years)

24 27

Long‐term (100 years)

30 33

‐ Army Garrison Okinawa choose “Standard (65 years) of Permanent Construction”.

2. Salt Damage Environmental:

Salt Damage Environmental shall conform to JASS 5.

Classification of Salt Damage Environmental

Condition of Site & area Planned service life class

Minimum Concrete Cover (mm)

Durability design strength (Fd: N/mm2)

Heavy Salt Damage Environmental

Okinawa area: 20m from the nearest coastline

Salt Damage Environmental

Okinawa area: 20 ‐ 70m from the nearest coastline

General 50 36

60 33

Quasi‐Salt Damage Environmental

Okinawa area: 70 ‐ 150m from the nearest coastline

General 40 50 (*1)

24(*1)

Standard 40 60 (*1)(*2)

30 (*1)

Long‐ term

60 (*1)

33 (*1)

(*1) Apply under the sea area. (applicable to use above ground)

(*2) Check 4. Concrete Cover.

< Kuwae#2 >

< Chimuwan TF#2 >

< Torii Station >

< Naha Port> <White Beach> < Chimuwan TF#3 >

‐ Some of the Torii Beach side of buildings are located 0 – 150m from the nearest coastline. Army

Garrison Okinawa choose “Quasi‐Salt Damage Environmental/ Standard” for Concrete Durability design strength of Torii Beach side buildings.

‐ Some of the Naha Port, White Beach, Kuwae#2, ChimuwanTF#2 & TF#3 side of buildings are located 0‐150m from nearest coastline.

Army Garrison Okinawa choose “Quasi‐Salt Damage Environmental/ Standard” for Concrete

Durability design strength of All nearest coastline (0‐150m) buildings.

Quality standard strength: 33N/mm2 = 30 N/mm2 (Durability design strength) + 3 N/mm2

3. CONCRETE MIX DESIGN:

Concrete Mix Design shall conform to JASS 5.

Description Building Structure, Pad, Slab

Concrete Encasement, Gutter Inlet, Concrete Curb and Gutter, Civil concrete structure

Salt Damage Environmental (All structure )

Nominal Strength 27 N/mm2 27 N/mm2 33 N/mm2

Slump 15, 18 cm 8‐10 cm 15, 18, (21) cm

Aggregate Size 20 mm 20 mm 20 mm

Admixture AE water reducing agent

AE water reducing agent

AE water reducing agent

Cement Type Normal Portland cement

Normal Portland cement

Normal Portland cement

4. CONCRETE COVER:

For Exposed Concrete, Concrete cover over steel reinforcement shall conform to the more stringent minimums required by ACI 301‐16, ACI 357.3R Table 5.5.4 (UFC 3‐301‐01), ACI 357R‐5 and JASS 5.

Description MEMBER REINFORCEMENT CONCRETE COVER (mm)

ACI

301‐

ACI

357R‐5 /357.3R

JASS5

(Design)

Cast against and permanently in contact with earth

Foundation All 75 ‐ 70

Column, Beam, Floor slab, Wall for Continuous footing

‐ 50

Exposed to weather or in contact with sewage and for bottoms bearing on work mat, or slabs supporting earth cover

All D19 to D57 50 ‐ Structural member:

Column/Beam/ Bearing wall: 50 Slab/Roof: 40

Non‐structural member: 40

D16, M2200 or MD200 wire and smaller

Not Exposed to weather or in contact with ground

Slabs, Joist and Walls

D43 to D57 40 ‐ Slab/Roof: 30

D36 and below 20

Beams, Columns, Pedestals and Tension ties

Primary reinforcement, stirrups, ties, spirals, and hoops

40 ‐ Structural member:

Column/Beam/ structural wall: 40

Non‐structural member: 30

Atmospheric zone not subject to salt spray

All All ‐ 50

Splash and atmospheric zone subject to salt spray

All All ‐ 65 60

Submerged All All ‐ follow above

5. Formwork Support Retention Period:

Formwork and support will not be removed during the minimum support period by days in Table, or until the compressive strength in Table is achieved.

Formwork Support

Location Type of Cement Minimum Retention Period

By Days (5℃ or more, below

15℃)

By Compressive Strength

Side Support Foundation, Beam, Column, Concrete Encasement

Normal Portland Cement

4 days 50kg per 1cm2 , over 5N/mm2

Side Support

Foundation, Beam, Column (over 18cm width of concrete)

Normal Portland Cement

5 days Over 10N/mm2

Side Support (Salt Damage Environmental)

Foundation, Beam, Column

Normal Portland Cement

5 days Over 10N/mm2

Bottom Support Roof Slab Normal Portland Cement

25 days 85% of the nominal strength (*1)

Beam, Roof slab w/opening

Normal Portland Cement

28 days 100% of the nominal strength (*1)

Note: (*1) This does not apply when it is confirmed by structural calculation that no significant deformation or cracking occurs due to the load and external force during construction.

‐ Army Garrison Okinawa choose “By Days of Formwork Support Retention Period w/

Compressive Strength”.

6. Curing Period and Backfill Judgment:

Duration of curing shall confirm to ACI 301‐16.

Backfill Location Type of Cement Minimum Curing Period

By Day By Compressive Strength ACI 301‐

JASS

Judgement Foundation, Beam, Column, Pad, Slab, Gutter Inlet, Concrete curb, Concrete

Normal Portland Cement

At least 7 days days

100% of the nominal strength

High‐early‐ strength concrete

At least 3 days days

100% of the nominal strength

Encasement and Gutter, Civil concrete structure

‐ Army Garrison Okinawa choose “ACI 301‐16 (By Days) with 100% of the nominal strength (By compressive strength)” for Backfill judgment.

During Backfill: Do not place the load of heavy vehicles directly on the structure.

7. Quality Test when Unloading Ready‐Mix Concrete:

Test Item Test Method Frequency of Test

Slump JIS A 1101 (Method of test for slump of concrete)

At the time of compressive strength test piece sampling

Air Content JIS A 1128 (Method of test for air content of fresh concrete by pressure method)

At the time of compressive strength test piece sampling

Chloride Content Use chloride measuring instrument certified by Japan Institute of Country‐ ology and Engineering

At the time of compressive strength test piece sampling

8. Compressive Strength Test Pieces:

Collect compressive strength test piece per each pouring section, per pouring day, 150 cubic meters, or once for every quantity. The number of specimens used for one strength test should be three standards. Three specimens are collected one by one from three transport vehicles at appropriate intervals, and total of three specimens are collected. Specimen collection is carried out at a location of unloading.

Number of Test Pieces Remarks

Building Foundation x 3 sets (9 pieces)

‐ 1 set to determine the backfill around the underground beam and footing (7 days) ‐ 1 set for checking nominal strength (28 days) ‐ 1 spare set

Column, Beam, Roof slab x 3 sets (9 pieces)

‐ 1 set for removal of formwork side panels (7days) ‐ 1 set for removal of underside formwork and support of beam and slab (between 10 and 21 days depending on the weather conditions and temperature) ‐ 1 set for checking nominal strength (28 days)

Civil Concrete Encasement, Gutter Inlet, Concrete curb and Gutter, Concrete structure x 3 sets (9pieces)

‐ 1 set to determine the backfill around the Gutter Inlet, Concrete Curb, Concrete Encasement (7 days) ‐ 1 set for checking nominal strength (28 days), 1 spare set

Air volume, slump and salinity Test:

‐ Test on site at the time of delivery when collecting compressive strength test pieces. (See No.6)

Compressive strength test report:

‐ Submit test report to DPW.

‐ After obtaining the review comments of the concrete compressive strength analysis report from the DPW engineer, migrate to the appropriate work.

9. Concrete Delivery:

Concrete Delivery shall conform to JASS 5.

Delivery Equipment

Direction of delivery

Possible delivery distance

Amount of delivery usage Range of slump (cm)

Concrete pump

Horizontal 〜500m 20〜70 m2/h

General/ Long distance/ higher area

8〜21 Vertical 〜200m

Concrete bucket

Vertical 〜100m 15〜20 m2/h

General/ High‐rise RC/ Slip form Construction

8〜21 Horizontal 〜30m

Cart Horizontal 10〜60m 0.05〜0.1 m2/ea

Low amount delivery/ for Horizontal

12〜21

Belt Conveyor

Horizontal Low‐angle

5〜100m 5〜20 m2/h

For Horizontal 5〜15

Chute Vertical 〜20m 10〜50 m2/h

Height difference/ Cast‐ in‐Place pile

12〜21 Angle 〜5m

10. Concrete Placement Plan:

1. Pre‐placement:

‐ Verify the site condition with the pump company and select pump truck.

‐ Discuss and confirm the movement of concrete trucks with the building user and the DPW inspector.

‐ Utilize a faucet near building for rinsing of formwork and reinforcing bars.

Use a cloth to prevent the paste from leaking out.

Wash the hardened concrete with water and close the cleaning opening.

‐ Order of concrete placement

Foundation, underground beam, and understand column at the same time

Floor slab

Column, beam and roof slab

‐ Control the leveling height by marking reinforcing bars with vinyl tape. Use marking nail for top end where there is form work.

‐ Make sure that the bolts, fixtures, and rebar positions are secured.

‐ Ready the vibrator. (check power)

‐ Ready the mallet hammer.

2. When pouring concrete:

‐ Concrete placement shall be done on fine weather and never on rainy days. The temperature when unloading concrete shall be 35 degrees Celsius or less.

‐ The time from concrete mixing to the end of pouring is less than 120 minutes for below 25 degrees Celsius. And less than 90 minutes for 25 degrees Celsius and above

‐ Determine in advance the number of workers needed for each placement and their arrangement as well as use of vibrators.

‐ Check the delivery slip as needed to verify the elapsed time of ready‐mix concrete.

‐ Take a test piece sample. (for air volume, slump and salinity tests)

‐ Use the vibrator properly.

‐ Double‐check the formwork and support for level and plumb.

‐ Check for disorder in reinforcing bars. (Secure alignment scaffolding board.)

‐ Trowel finish the roof slab: Control gradient of the slab by marking rebar with tapes and top end marking nails.

‐ Plan concrete placement work so that the work can be completed within the time of the entry pass.

3. Curing after concrete placement:

Do not work at least one day (24 hours) after placing concrete, and never give any vibration. After concrete placement, wet curing is carried out by coating with small permeability plate, coating with a curing mat or watertight sheets, water spray/ spray, application of film curing agent, etc.

‐ Wet cure foundation concrete by wetting twice a day, in the morning and afternoon.

Cover the slab concrete, gutter inlet and concrete curb with curing sheet and spray water several times a day. (As required depending on the weather condition.)

‐ Formwork retention period: (See No.5) The period of retaining formwork and support for column/ beam sides and foundation is until compressive strength of 5N/mm2 or more is achieved, or after a curing period of 5 days. The period of retaining formwork and support for roof slab and beam underside is until compressive strength exceeds the nominal strength, or after a curing period of 28 days. For gutter inlet and concrete curb, remove formwork 4 days after concrete placement.

‐ Cleaning:

Rinsing (formwork, floor, existing structures).

Clean tools and equipment.

Clean the delivery route and access road as necessary.

‐ Store and manage the on‐site submerged curing test pieces.