Attachment 4 - Site Investigation and Slab Report

                                                                                   Articulation joint                  Articulation joint
                      The reinforcement should be lapped by a
                  minimum of 400 mm. One way of achieving this is
                  to butt the ends of standards lengths together and
                  provide an 800-mm length of the 3-mm-diameter
                  wire(s) or other bed joint reinforcement as a lapping
                  length. Ideally, laps should be staggered such that
                  they are not in line. If reinforcement is provided
                  only above and below window/door openings (to
                  minimise/control cracking at these vulnerable
                  locations) the reinforcement should extend about                                                 Extend
                  600 mm past the openings.                                               Bed-joint                reinforcement 600 mm
                                                                                          reinforcement            minimum past openings
                      The majority of buildings may be designed,
                  detailed and articulated to minimise the risk of          Figure 34 Typical location of bed-joint reinforcement
                  cracking in the walls. However, some wall panels
                  containing openings (especially arches) may
                  benefit from the addition of reinforcement to limit
                  the number of articulation joints and/or minimise         Dowel bars, with cap at one end, threaded through compressible
                  the risk of cracking at vulnerable points between         filler and placed in bond beam at articulation joint.
                                                                            Bars must be horizontal and parallel
                  articulation joints.

                  9.1      Bond Beams                                       Bars in reinforced concrete
                  In general terms, bond beams refer to the horizontal      bond beam stopped
                                                                            at articulation joint
                  reinforced and grouted beams that are found in
                  reinforced masonry block walls. They are formed
                  by using either special lintel or ‘U’ shaped blocks or
                  knock-out bond beam blocks and they are typically
                  used to provide beams along the tops of walls to
                  distribute wind loads or as lintels over window and
                  door openings.
                      Both AS 3700 and AS 4773.2 do not allow control
                  joints (including articulation joints) to continue
                  through bond beams which rely on continuity for
                  their structural performance, ie those described in
                  the Standards. Whether joints may be continuous
                  through bond beams will depend on the loads
                  being carried, the design of the bond beam and
                  the location and detailing of the joint. Two separate
                  cases need to be considered, bond beams at the
                  tops of walls and those forming lintels over window
                  and door openings.
                                                                                                                         Articulation joint with
                      At tops of walls. Bond beams around the tops                                                       gunned-in elastomeric
                  of masonry block walls are required in high-wind                                                       sealant
                  areas, particularly in the north of Australia. They are
                  provided mainly to distribute wind uplift loads from      Figure 35 Articulation joints through masonry block
                  the roof members to regularly spaced vertically           bond beam at top of wall
                  reinforced cores which resist the uplift forces. For
                  this reason it is essential that they be continuous
                  around the perimeter walls of the building. They
                  may also transfer some horizontal wind loads back
                  to walls providing lateral support.
                      An articulation joint through a bond beam is
                  formed by stopping the reinforcing bars within the
                  bond beam 50 mm from each side of the joint. The
                  articulation joint is then bridged with short, plain
                  round steel bars (dowels), equal in diameter and
                  number to the reinforcing bars in the bond beam.


Page 22 Articulated Walling