building construction Paper 2 WASSCE (SC), 2021

Question 5

(a)        State three factors to be considered before excavating a foundation trench.
(b)        Explain each of the following activities in relation to site operation:
(a)        site clearing;
(b)       site leveling.
(c)        State two construction requirements of a steel reinforcing bar placed in a wide-strip foundation.

 

Observation

 

Most candidates were able to:
Explain each of the following activities in relation to site operation:
            (a)        site clearing;
            (b)       site leveling.
-           List threematerials used for pavement construction.
However, some of the candidates were not able to:

  • state two reasons for the construction of kerbs on access roads.
  • state two reasons for using a metal fencewall gate instead of a wooden gate.

The expected response to question 5 (a) and (c) is as given below:

Factors to be considered before excavating a foundation trench:

  • method of ensuring safety when working in the trench;
  • type(s) of excavation machinery/tools to use;
  • method of keeping excavation free from ground water;
  • length of time excavation will be left open;
  • method of preventing trench sides from caving in.

(c)Constructional requirements of a steel reinforcing bar placed in a wide-strip foundation:
  to resist tensile stresses;

  • to strengthen the concrete foundation;
  • to prevent fracture to foundation concrete;
  • must have adequate cover.