Authors : Solid Base
In the last edition we explained about the column and stages of checking the column were discussed in detail,
This month we are describing the beam, a horizontal element, which plays an important role of the structure
Factors affecting the quality management system in construction:
• Poor workmanship
• Poor Design
• Miscommunication between teams
• Failure to document changes and practices
A case study on one of the structural elements (beam)
A beam is generally a horizontal member which transfers the load of slab to column and to ground through footing five stages of Quality checking of the beam:
Ø Checking the beam layout and Centre.
Ø Checking the beam reinforcement
Ø Checking the beam shuttering
Ø Checking the beam concreting
Ø Checking the beam de-shuttering.
The reinforcement of the beam should be fixed and checked first, then the shutter be fixed.
Checks for reinforcement:
Ø The reinforcement steel should be free from any loose scale, rust or oil.
Ø Main bottom, top , side reinforcement and the Stirrups should be cut and bent as per the required length; this has to checked against the drawing.
Ø Dia, number of rebars and spacing should be checked against the drawing.
Ø Binding wires used should not protrude in the cover zone.
Ø Hook angles should be 135o this is very important from seismic consideration.
Ø Lapping should be provided in the central half of the member length and lap length should be 45D or as specified.
Ø Mill test certificate describing the physical and chemical properties of the steel.
Ø Shuttering should be properly aligned as per drawing and surveyor’s marking.
Ø Dimensions are to be checked against drawing.
Ø Shutter surface in contact with concrete should be clean, free from dirt, debris and other substances that may affect concreting or finished product.
Ø The gaps b/w the joints of shutter to be sealed to prevent the leakage of slurry.
Ø Cover should be minimum 40mm unless otherwise specified.
Ø Grade of concrete as per the design mix.
Ø Height of concrete Pour.
Ø Slump and temperature check
Ø Ensure the Vibrator is ready and in working condition and used for at least 30 seconds in each area.
Ø Excess water or superplasticizer was not added to concrete on site.
Ø The concreting is carried out within specified time period (90 minutes) from the batch time.
Ø Sampling of cubes for density & compressive strength testing.