AIRCRETE

4.7

Chapter 4. Design

Page 14 of 18

4.7.1

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4.7.1.2 In thin-layer or thin-bed mortar
The structural design of thin-joint blockwork should be in accordance with BS 5628: Part 1 (assuming the characteristic compressive strength is that given in Table 2 of BS 5628 for designation (i) mortar).

The characteristic flexural strength should be taken as the flexural strength for designation (i) mortar given in BS 5628: Part 1.

If bed-joint reinforcement is used, it should be of a type specifically intended for use with thin-joints.

Larger face dimensioned blocks should be used to increase site productivity and improve temporary stability during construction.

Where the inner leaf of an external wall is thin-joint blockwork, stainless steel helical wall ties which are driven into the inner leaf should generally be used to course with the bed joints in the brickwork outer leaf. There are other stainless steel wall tie types designed for use with thin-joint blockwork. Thin-joint blockwork facilitates cleaner cavities.

4.7.2 Partitions including non-loadbearing
	partitions

All Aircrete blockwork partitions should be built off either solid foundations, structural steel or concrete beams, concrete floors or beam and Aircrete block floors.

When Aircrete non loadbearing blockwork is supported on timber joists the joists must be properly designed for the span and the two bottom mortar bed joints should be reinforced with bed joint reinforcement.

The head restraint for non-loadbearing partitions should provide lateral restraint but allow the floor or beam above to deflect (see Fig 14).

For speed of construction, particularly in long runs of partitioning in commercial and industrial buildings, the use of thin joint blockwork should be considered. The reduced construction time combined with the reduced time to gain maximum strength minimises delay to follow on trades.

The overall dimensions of Aircrete partitions should be in accordance with BS 5628-3: 2001 Code of Practice for use of masonry-materials and components, design and workmanship.

An internal wall or partition should be laterally restrained by horizontal or vertical continuous or intermittent supports (as shown in Fig 14). The length or height of the wall in relation to its thickness should be within the limits given in Fig 16.

The following factors, which affect stability, should be taken into account:

a) Accommodation for movement
b) Presence and position of openings;
c) Presence and position of abutting walls;
d) Chasing
e) The likelihood of exceptional lateral loading, arising from the nature of the use of the building
f) Wind load
g) Fire resistance.

When an internal wall or partition is to be plastered, a thickness of not more than 13mm of plaster to one or both sides of the partition may be included when determining the thickness of the wall for design in accordance with Fig 16. Dry lining should not be considered as contributing to the thickness of the wall.

Note: Until the wall has been plastered it will not have its design
final strength.