Category Archives: Your Questions Answered

Facing of traditional brickwork

For architectural purposes one of the most popular and successful finishes is a traditional brickwork facing. This type of treatment allows the best of both worlds, since the concrete panels will give the quality, strength; speed and durability associated with precast concrete, and the facing will give the traditional appearance afforded by the vast range of bricks available.

To get the best out of such a system, it is worthwhile spending time to ensure that the details are thought out and well considered.  Although simple in principle, there are a few ground rules that should be followed for the best results.

Brick selection:

Facing of traditional brickwork 1
1 Colour – It is best to choose a brick with good uniformity of colour.  Although bricks are taken from pallets and mixed in a random order, uniformity minimises the risk of colour steps between panels.

Facing of traditional brickwork 2

2 Type – It is important that bricks are securely anchored into the panel.  The easiest way of doingthis is to use a ‘3 whole’ type, cut as shown. The resulting shape provides an excellent anchor.  Solid bricks can be similarly cut to give a dovetail anchor, but frogged bricks should be avoided.

Facing of traditional brickwork 3

3 Tolerances – The tolerances set out for normal use are not really tight enough for ‘cast-on’ bricks.

Variations in length measured over 24 bricks are between 5235 and 5085, which equates to ±3mm per brick. Most suppliers will however improve on these figures by arrangement.  Ideally the bricks should be made with tolerances as shown. Continue reading

Simple methods for lifting precast concrete – The cast-in lifting loop

One of the most popular, economic and simple methods for lifting precast concrete is the cast-in lifting loop.

J&PThe loop consists of a steel wire rope with the ends swaged together with an aluminium ferrule to form a closed loop.  Every loop has a coloured plastic tag attached showing the safe lifting capacity.

The range goes from 800 kg to 57 tonne capacity, although it must be borne in mind that the bigger capacity loops are very large indeed in size.  Even a 25 tonne loop is some 850 mm long and weighs nearly 8.5 kg.    This size, and the embedment required, (see below) makes them generally unsuitable to cast into shallow concrete.

Loops are not generally recommended for turning thin units.  In particular, if units are very thin and the loop is in the narrow face, care must be taken that loops cannot ‘burst out’ under 90° loading. (see below for minimum dimensions).  Where possible, it is preferable for the loop to be aligned so pitching is in the direction of the arrow (see below).  Generally, loops greater than 4 tonne capacity should not be used for pitching, due to the stiffness of the loop.

Generally manufacturers do not give specific requirements for reinforcement required at/through the loops.  However, if used for pitching thin units, it is good practice to provide reinforcement to prevent bursting. Continue reading