REBAR

Reinforcement Used

• Steel Bar (denote as T @ Y)   = 460 N/mm2
• Links (denote as R)               = 250 N/mm2

The rebar diameter used here is 10mm, 12mm, 16mm, 20mm, 25mm, 32mm (seldom), 40mm (seldom). Remember to provide rebar spacing not less than 20mm.

Links

Links should be provided; 6 and 10mm diameter.

BEAM ARRANGEMENT

Primary & Secondary Beam

A primary beam is supported by two columns. Beam should transfer load directly (as direct as possible) to columns or primary beam. If possible try to make the beams equally spanned.

Which beam supports which beam

• Let the loading goes directly to columns.
• The shorter beam supports the longer beam.
• The wider beam supports the thinner beam.
• Try to make all the beams equal span.
• Try to make the loading almost equal throughout the span.

Negative support force

It is normal to have negative support force. The negative force at support will cause an uplift on the other beam. Therefore the beam should be designed for the uplift; top reinforcement. Also run another case when the uplift force is zero, so that the bottom reinforcement is designed more conservatively.

If the beam is jointed to the column, and the total of all the forces of the column is negative than some solution must thought, since columns are not to carry tension load, just compression loading.

Beam naming

If grid exist, beams to be named with grids, instead of the other name to make key plan neater, checking easier. Naming and presentation, always from left to right and bottom to top.

Head room

Care to be taken to ensure that there is enough head room, normally 2.1m above staircase, care ramp, etc.

Gradient of ramp

Beam alignment may need to be moved to ensure that ramp have sufficient gradient of 1 (vertical) : 7 (horizontal) for straight ramp (circular ramp is 1:10). This happen when grid line is at 8.1m centre and the floor height is 2.75 with split floor. 1.375 at gradient of 1:7 need a horizontal beam distance of 1.375 x 7 = 9.625m. The beams at gridlines need to be set back (9.625 - 8.1)/s + half beam width = 0.7625 + beam width.

BEAM COVER

The cover of the beam is 20mm if exposed internally and 40mm if exposed externally.

 

 

 

 

Tags : engineer, engineering, civil, beam, beams, ramp, steel, reinforcement, rebar

This entry was posted on Tuesday, April 10th, 2007 at 10:00 am and is filed under Design. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.