JJI-Joists - Build It Green

BJ-BEAM (GLULAM)
11
INTRODUCTION
BJ-Beam (Glulam) is a high specification engineered timber
product made by gluing together strength graded timber
laminations to make up larger sections and distribute the natural
defects evenly throughout the volume. The laminations are
finger jointed to allow long lengths to be formed. This results
in a structural unit of great strength and dimensional stability.
Glulam beams can be produced in a range of sectional sizes and
are available from James Jones & Sons in lengths up to 12m.
TYPICAL GLULAM SECTIONS
BJ-BEAM (GLULAM) RANGE AND TOLERANCES
James Jones & Sons can supply BJ-Beam as part of the JJI-Joist
system. BJ-Beam is a custom made high specification product
in sizes to compliment the JJI-Joist range (Table 1). Other sizes
and grades are available to special order.
Section Depth
Width
38 45 90
195 ✓ ✓ ✓
220 ✓ ✓ ✓
235 ✓ ✓ ✓
245 ✓ ✓ ✓
300 ✓* ✓ ✓
350 ✓* ✓
400 ✓* ✓
450 ✓* ✓
Table 8. BJ-Beam Product Range
Notes for Table 8:
1. * Indicates sections where the depth to breadth ratio exceeds (BS 5268-2)
For stability these depths should only be used in multiply members
or rim beams
Member Dimension
Width
Depth
Length
Tolerance (mm)
+/– 2.0 mm
+/– 2.0 mm
+/– 5.0 mm
Table 9. BJ-Beam Manufacturing Tolerances
BJ-BEAM IDENTIFICATION AND MARKING
ADVANTAGES
Glulam beams offer many design performance advantages
over conventional timber sections making them ideal for use
in domestic and commercial JJI-Joist systems where high load
capacity is required. BJ-Beam is:
BJ-Beam
in solid timber
lengths
These characteristics make BJ-Beam ideal for use as trimmers,
beams, purlins, rim boards, columns and lintels, etc. In many
instances BJ-Beam can be used to replace steel elements
making installation and fixing easier.
BJ-Beam is only available through our Distributors and is
generally not marked on the product so that it may be left visible
if desired. Care should be take to ensure that BJ-Beam used
onsite has been supplied by the Distributor and not a similar
but lower specification product from another source.
BJ-BEAM PROPERTIES
BJ-Beam should be designed to Eurocode 5 and requires the
use of characteristic values as shown in Table 10. If designing
to BS 5268-2 the designer can conservatively use the properties
for C27 softwood.
BJ-Beam Characteristic Values BJ-Beam Units
Bending strength f m,g,k 32 N/mm 2
Tension strength f t,0,g,k 22.5 N/mm 2
f t,90,g,k 0.5 N/mm 2
Compression strength f c,0,g,k 29 N/mm 2
f c,90,g,k 3.3 N/mm 2
Shear strength f v,g,k 3.8 N/mm 2
Modulus of elasticity E 0,g,mean 13700 N/mm 2
E 0,g,05 11100 N/mm 2
E 90,g,mean 460 N/mm 2
Shear modulus G g,mean 856 N/mm 2
Density g,k 430 Kg/m 3
Table 10. Characteristic Values
PARTIAL FACTORS
Care should be taken to ensure that all partial factors used
to convert the characteristic values to design values are correctly
chosen for the prevailing design conditions. For example, load
duration, member depth, service class, etc.