building construction Paper 2 May/June 2015

Question 2

a) List three ways of locating a building line for a proposed building project.

b) State three advantages of batching concrete materials by weight over batching by volume.
c) State three functional requirements of a timbering system for trench excavation.

 

Observation

Most candidates were able to:

  • state the three ways of locating a building line;
  • state the three advantages and disadvantages of batching concrete materials by weight and by volume;
  • state the functional requirements of a timbering system for trench excavation.
  •   However majority of the candidates failed to:

  • use the appropriate terms to explain the advantages and disadvantages of batching by weight and volume;
  • state the functional requirements of timbering system for trench excavation.
  • The expected response to question 2 is as given below:

  • Three ways of locating a building line:
  • by measuring the required set-back approved by town planning authority for the area;
  • by using the frontage line of existing building as reference;
  • by using the road/street kerb line;
  • by using the corner pillars as established by ordnance survey.
  •  

     

  • Advantages of batching concrete materials by weight over by volume:
  • greater accuracy in measuring the materials;
  • higher quality concrete is obtained;
  • accurate/correct mix proportion is obtained;
  • no allowance for bulking of damp sand is required;
  • reliability in measurement.
  • Functional requirements of timbering system:
  • to prevent the soil from falling inside the trench;
  • to protect the person working inside the trench;
  • to allow workmen to operate safely along the edges of trench;
  • strength and stability;
  • resistance to insect attack.
  •