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HP Forum Archive 17

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HP35s Reinforced concrete beam design to BS8110
Message #1 Posted by John Wasilewski on 3 Nov 2007, 9:04 a.m.

Anyone who wants a copy of my fully working and tested program, 'BEAM 8110' please send your email address so that I can send you an M$Word file of the formatted, commented listing.

It will take me too long to amend the listing to use only the displayable character-set in this forum so I'm offering only the downloadable listing. I also don't have a facility for posting a downloadable version.

Everyone please feel free either to put the downloadable file online on your own websites for the benefit of others or to port the listing to this restricted character-set and upload it to MoHPC.

The program has 564 lines, with loops within loops. It uses 25 variables and 3 flags. It uses only one LBL.

(taken from the first page of the listing file):

Designs main reinforcement for rectangular reinforced concrete
beams to BS 8110:Pt.1:1997.  Singly or doubly reinforced (tension
steel only or tension and compression steel).
Parabolic-rectangular concrete compression stress block.
Program assumes steel is high-yield (grade 460) but this can
easily be altered in the code, optionally with a steel grade
prompt for user-specified input.

Input Mu (N-mm) The required ultimate moment of resistance. Fcu (N/mm2) Characteristic cube strength C (mm) Cover to main bars all round Program now suggests a suitable section size for a singly- reinforced section, which user can over-ride or accept. H (mm) Section total depth (accept suggested/over-ride) B (mm) Section total breadth (accept suggested/over-ride) Q (mm) Bar diameter of compression (optional entry - autogen input if left blank) O (mm) Bar diameter of tension steel (optional entry - autogen input if left blank)

Bar diameters are entered into the two lines of screen display, compression then tension, before pressing R/S. After entering neither tensile nor compressive steel the program takes a minute or more to finish. Finishes more quickly if at least the tensile bar diameter is entered..

Output [NC, DiamC] No. of compression bars needed, bar diameter [NT, DiamT] No. of tension bars needed, bar diameter

Mu (N-mm) Mu for the rounded-up whole numbers of bars Mu (N-mm) Mu that the calculated exact area of steel actually needed would provide The latter is re-calculated for the output steel so serves as a check of a correct result

E (kg/m) Tot steel wt. for rounded-up whole numbers of bars E (kg/m) Total steel weight for the calculated exact are of steel actually needed (not a whole no. of bars) Users can assess the efficiency of the solution by comparing the two displayed steel weights.

Tension steel Finds no.of bars needed for the user-specified bar size, increasing bar size if bar-spacing too close. Does not warn user if maximum bar diameter reached but tension bars still too close.

Compression steel Always included if user enters a compression bar diameter and is automatically triggered if not entered but small section size makes it necessary. Adjusts compr. bar diameter for sensible min. bar spacing (assuming 20mm aggregate size). Also complies with min. 0.2% rule for compression steel.

Partial optimising Program chooses the compression bar diameter that gives the least total steel weight for tens. + compr. steel.

REFERENCES BS8110:Pt.1:1997 Reynolds and Steadman: Reinforced concrete designer’s handbook: 10th ed.

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