Observation

 

Majority of the candidates were able to state the purpose of providing each of the elements in a stair construction: handrail, landing; and string.
However, most of them failed to:

• List three types of window;

-      Explain each of the following in relation to concrete production:
(i)         segregation;
(ii)        reinforced concrete.
The expected response to question 3 (b) and (c) is as given below:

• Explanation of:
• Segregation;

Segregation of concrete is the separation of cement paste and aggregates of concrete from each other during handling and placement. Segregation also occurs due to over-vibration or compaction of concrete, in which light weight aggregates come to the top and heavy weight aggregates settle at the bottom.
                                   

• Reinforced Concrete.

This is a concrete which has reinforcement bars or mild steel rods embedded in it. The reinforcing steels/rods/bars/mesh absorb the tensile shear, and sometimes the compressive stresses in a concrete structure.

            (b)        Types of window:

• Casement window
• Pivot hung window
• Sliding window
• Bay window
• Jelousie/ Louver window
• Top hung window
• Bottom hung window
• Bormer window
• Awning window

(c)        Purpose for providing the following elements in a stair construction:

• Handrail;
•  To give support to users when ascending or descending a stairway.
• To prevent users from falling off a stairway.

• Landing;
• To change the direction of a flight in stair construction.
• It also serves as a resting place for a user.

 

• String.

To hold/house the treads and risers.