MEP-Technical Manual CDN 0408.qxd - Hambro

5.3 DTC (LH SERIES)
5.3.1 DESCRIPTION
This series features a top chord made of two Hambro
sections, an open web of light channels or angles and a
range of heavier bottom chord angles.
Hambro composite long span floors provide greater
economy for heavy service loads and longer spans with
live load deflections less than half those of conventional
systems.
5.3.2 MATERIALS
The Hambro top chord acts as a continuous shear connector.
Bottom chord angles and web members are hot or cold
rolled sections, minimum yield Fy = 380 MPa (55 ksi) and
350 MPa (50 ksi) for rods.
5.3.3 WEB GEOMETRY
See below.
5.3.4 JOIST SPACING
Note the new standard spacing Hambro LH Series,
1 285 mm (4’-2 5 /8”) center to center, which is obtained
when using standard Rollbar ® (1 251 mm (4’-1 1 /4”)
spacing plus 35 mm (1 3 /8”) web thickness).
P 1
(P 1 + VAR 1 ) /2
P 1
PRODUCT INFORMATION
VAR 1
Variable panel
(Clear span – 12 mm or 1 /2”)
Fig. 22
DTC Web Geometry
5.3.5 SPAN AND DEPTH
Span: Up to 16 155 mm (53’-0”).
Depth: Between 400 mm (16”) and 900 mm (36”).
5.3.6 SLAB DESIGN
The minimum slab thickness is 70 mm (2 3 /4”) and the slab
capacity chart tables 8 and 9 on page 19 and 20 shows the
total allowable load (including the dead load of the slab)
based on 20 MPa (3 000 psi) concrete.
5.3.7 ROLLBAR
Standard 1 251 mm (4’-1 1 /4”) roll bars are used to support
the plywood forms.
5.3.8 FORMS
Regular 1 220 mm (4’-0”) plywood forms must be slit in
half, 610 mm x 2 440 mm (2’ x 8’) panels, to allow insertion
between the top chords. Normally 12.7 mm ( 1 /2”) plywood
is used.
5.3.9 INSTALLATION
Installation shall be in accordance with the manufacturer’s
recommendations. Particular attention should be paid to
the erection of the long span Hambro joists and bridging
must be installed as specified on the Hambro drawing.
5.3.10 TYPICAL DETAILS
See typical details section page 23 to 27.
610 mm VAR
2
610 mm 610 mm
24” 24” 24”
Variable panel P
d = Joist depth
P1 = d + 300 mm (12”) ≤ 1 170 mm (46”)
VAR 1 = 0 to 150 mm (6”)
VAR 2 = 150 mm (6”) to 610 mm (24”)
“n” Continuous panels
d
3