CON4317 –TEMPORARY WORKS Tutorial 5

Q.1

(a) A single skin wall form is erected for concreting a wall 1.5 m thick, 14 m long

and 5 m tall next to an existing structure as shown in Fig.Q1. Two rows of

struts will be installed at the elevations 1 m and 3 m respectively above the

ground level. Assume the following design information:

Wet Concrete Unit Weight 25 kN/ m3

Concrete Temperature Range 5 – 40C

Rate of Concrete Placement 3 trucks of 4.5 m3 per hour

CIRIA Report 108 Formula for Concrete Pressure

RHKRDP 0.145.00.1max in kPa, or Dh

(i) Determine the Concrete Pressure and plot its variation with the height of

the formwork

(ii) Determine the respective maximum spacing (to the nearest 25 mm) of

struts P1 and P2 if the safe working of the struts is 100 kN each.

(Hint: take moment about P2 to find strut load of P1)

Or

(Hint: take moment about bottom to find strut load of P1 and P2)

2

16

36

TK

Thickness 1.5 m

Concrete Level

Wall Form

. .’ . P1 H = 5 m

2 m Strut

Existing Structure

1m P2

Fig. Q1

(Not To Scale)