15.0 Construction Details – Tie-down Power Block

Required only if specified by design /project engineer

Fig 15.1:  Strip Footing, Double Brick Sub-Floor

Fig 15.2:  Strip Footing, Concrete PowerBlock Sub-Floor

Tie down rods/engineering restraints must be embedded into the footing and pass up through the sub floor and into the Hebel  PowerBlock  work. Table 15.1 Top-Plate & Hold-Down selection Table

Wind Classification Top Plate & Hold-Down
Tile Roof Sheet Roof
N1 A / B / C B / C
N2 A / B / C D / F
N3 D / F D / F
N4 D / F D / F
N5 E / G E / G
N6 E / G E / G
C1 D / F D / F
C2 E / G E / G
C3 E / G E / G
C4 G G
Legend
A 90×45 F7 timber top plate / 700mm deep strap @ 1200mm ctrs.
B 90×45 F17 timber top plate / 1700mm deep strap @ 2400mm ctrs
C 90×45 F17 timber top plate / Ф12mm rod @ 2400mm ctrs.
D 90×45 F17 timber top plate / Ф12mm rod @ 1200mm ctrs.
E 90×45 F17 timber top plate / Ф12mm rod @ 900mm ctrs.
F 100x50x3.0 RHS top plate / Ф12mm rod @ 2400mm ctrs
G 100x50x3.0 RHS top plate / Ф12mm rod @ 1200mm ctrs

Fig 15.3 Hold Down Detail for Reinforced Bracing Walls

Table 15.2 provides ultimate racking capacities of reinforced 150mm and 250mm Hebel PowerBlock walls. The reinforcement is N12 bar or 12mm threaded rod at nominal 1000mm centres. The reinforcement must be tied to the footings and wall top plate through the bond beam. Walls resisting racking forces should be evenly distributed within a house and spaced at a maximum of 8.0m. Ceiling and floor diaphragms must be adequately tied to walls to ensure transfer of forces through to the footings. For more information about bracing, refer to Section 6.11 of the Hebel Technical Manual.

Fig 15.4 Roof Top to Plate Fixing to Hebel Wall – Strap (elevation)

Top Plate Hold-Down

Two tie-down methods are provided in this design guide. 1. Strap – 30×0.8mm cut into inside face of external wall min. 700mm deep. 2. 12mmthreaded rod continuous from footing through bond beam to top plate.

Fig 15.5 Roof Top Plate Fixing to Hebel Wall-Tie-Down Rod (elevation)

Three top plates options are provided in this design guide: 1. 90×45 F7 timber 2. 90×45 F17 timber 3. 100x50x3.0 RHS The type of hold-down method and spacing depends on the top plate, roof type/span, and wind classification. Refer to Table 15.1 for specifications. For high wind areas, the bracing design is likely to require tie-down rods which will drive that as the hold-down method. Table  15.2 Reinforced Wall – N12 Bars at Nom. 1000mm CTRS

Wall Length (mm) Min. No. of N12 Bars Ultimate Racking Capacity (kN)
150mm PowerBlock 250mm PowerBlock
900 2 5 6
1200 2 8 8
1800 3 16 18
2400 3 24 25
3000 4 36 38
3600 5 45 46
4800 6 54 56
6000 7 63 66

Base of Wall 

Fig 15.6 Hebel PowerBlock work on Stiffened Raft Slab Edge Foundation (elevation)

Fig 15.7  Concrete PowerBlock Sub-Floor Detail (elevation)

Fig 15.8  Double Brick Sub-Floor Detail (elevation)

Fig 15.9 Ring Beam Internal Non-Loadbearing Wall (elevation) (No tie down – as specified by design engineer)

Top of Wall

Fig 15.10 Roof Top Plate Fixing to Hebel Wall – Tie-Down Rod ( elevation)

Note: Fixing, rod size & spacing as detailed by engineer

Fig 15.11 Internal Hebel Load Bearing Wall and Timber Floor Frame Junction (elevation)

Wall Junctions

Fig 15.12  External Wall and Internal Partition Wall Junction  (plan)

Fig 15.13  External Corner with Control Joint (plan)

Control Joints

Fig 15.14 Control Joint detail (elevation)

Fig 15.15 Typical Bond Beam Control Joint – elevation (Location where no tie down required – as specified by engineer)

Fig 15.16 Typical Ring Beam Control Joint – elevation (Location where no tie down required – as specified by engineer)

Fig 15.17 Typical Control Joint – plan

Fig 15.18 Hebel PowerBlock work Typical Movement Joint Detail (elevation)

Fig 15.19 Hebel PowerBlock work Typical Movement Joint Detail (plan)

Fig 15.20 Built-in Column Detail (plan)

Fig 15.21 Built-in Column Detail (elevation)

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