burmie (User)
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Design of reinforced concrete beams to AS3600 9 Years, 10 Months ago

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The following spreadsheet calculates the strength of a singly reinforced concrete beam to AS36002001. It also calculated the effective second moment of area of a member Ief to AS36002001.
Please advise if this is spreadsheet for uplaoding to the excelcalcs website.
Regards
Graeme Burmeister



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Re:Design of reinforced concrete beams to AS3600 9 Years, 10 Months ago

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/earnyoursubscription/ advises that you should "search the repository before you propose a calculation we do not want to repeat ourselves." Could you tell me if your submission covers the same calculation as /repository/strength/beams/continuousconcretebeams.xls/



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Re:Design of reinforced concrete beams to AS3600 9 Years, 10 Months ago

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What actually does constitute repeating ourselves when it comes to calculations? If some one downloads a calculation to check similarity with own. Then have record of download, no use of such download, and no upload.
Myself I have different workbooks which calculate the same results, but with different presentations. Some times I may step through the calculation, other times combine everything in a single cell. Other times, present calculation sequence vertically down the page, other times horizontally across the page. Sometimes want a single value, others times want multiple values, calculated lookup tables, or curves to plot.
Or another perspective, here. Alex's frame spreadsheet is based on the matrix stiffness method and only covers a single load case for the frame, but does so in detail. Whilst my kleinlogel spreadsheet considers multiple loadcases, and load case combinations for the same frames, but not in detail.
Neither of these workbooks however, presents a nice readable version of the formula used so that can be checked with ease against the source workbook. Doing so however wouldn't be very presentable for the task at hand: analysing a building frame for muliple loadcases and finding the critical case.
Different situations, different objectives and different audiences, leads to different presentation of the same calculation/s.
So I guess the issue is to what extent is it different or similar. Matrix stiffness method may reach same conclusion as Kleinlogel formulae but are different calculation methods. One can be used to assess the other.
If the AS3600 methods of concrete design differ from other national codes, then even though workbook maybe just a beam design: the difference lies in the requirements of the Australian standard versus say US, UK or EuroCodes.



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burmie (User)
Tadpole with legs (Senior Boarder)
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Re:Design of reinforced concrete beams to AS3600 9 Years, 10 Months ago

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It appears that the repository contains a number of spreadsheets that provide structural calculations for reinforced concrete to the American and British Code. Although the theory of structural mechanics is the same all codes have differences which effect the results, ie materials available in that country.
The spreadsheet presented calculates the strength of a singly reinforced concrete beam to the Australian Concrete Code AS3600. The code requirements for calculation the Effective Stiffeness of a concrete section differ from other international codes.
The spreadsheet was modified to show the use of XLC in relation to relatively straight forward formulas, in relation to this particular exercise. It is noted that a number of the more detailed spreedsheets on the repository do not make use of the XCL functions.
I am working my way through the XLC addon to determine any limitations. It appears more complex calulations with IF statements may not suitable for the XLC equation display. I will keep playing with the program.
Regards Burmie



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Re:Design of reinforced concrete beams to AS3600 9 Years, 10 Months ago

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burmie,
XLC is basically for simple mathematical expressions. I am not aware however, that symbolic mathematics does provides notation, for iteration, looping and and conditional branching.
Most codes of practice contain clauses where have to choose between 2 or more formulae. For me one of the points of using a computer is to check all the constraints and make sure the correct formula is chosen. That poses a problem between documenting the process and presenting the results. Presentation wise all we really want to see is the results, but how much detail. It would be nice to see the correct formula presented with the numerical values substituted in the correct places, and the final calculated result. Besides being difficult to achieve in Excel, it doesn't however serve much purpose.
I consider VBA code with comments and the use of "CASE" statements to be preferable than complicated "IF" conditions embedded in excel cells. I find such code easier to follow and check for errors. I can also document the great holes which the constraints in the codes leave behind.
The building code of Australia (BCA) does not require submission or presentation of calculations: it requires adequate evidenceofsuitability. The task of the authority having jurisdiction (AHJ) is to check that the building proposal is fitforfunction, and that is determined by demonstrating compliance with the performance requirements of the BCA, and providing evidence to justify the view of compliance.
If you present the formula with numbers substituted and the value calculated, many AHJ's will simply plu numbers into their calculator and check the arithmetic: that is not their job. Your job was to check the arithemtic, their job is to check code compliance of the specification. If the specification shows construction which has what would be considered simple supports, and you have sized the beam assuming fixity, then the specification is noncompliant. Even if the arithmetic is correct. If you don't show the formula and don't show numbers substituted into the formula then they cannot check the arithmetic, until they have discovered the formula.
For example if say simply show the variables, the values of parameters, and the calculated result of dependent variables and identitify the equation as AS4600 E3.3.3.2(2), then the checker has to go and refer to the coldformed steel structures code AS4600. If they don't have the code then they probably don't have the experience to be in the role of certifier for such structures, and probably pass it onto someone else. Similarly for the concrete: you have the code, know what is required, so should the person checking it.
People have had several years in which to get use to computer printouts, without any of the symbolic algebra. I have seen engineers calculations go from readable and easy to follow, to a total mess in MathCAD, where most of the output is just a mass of scrap paper.
At university, laboratory reports typically involved tabulating raw results, then calcualting additional tabulated values. Different variables in different columns. The columns either presented the formula calculated or gave a reference to a note, and the note showed the formula. Only one worked calculation sequence was given, and then only if it wasn't easy to follow the table.
Building structures contain many beams. Detailed presentation of calculations for each and very beam doesn't help anybody, it simply creates a maze in which the real and important information is hidden. Further it doesn't really help you, because you are not substituting the values into the formula the computer is. Further more the computer calculation, especially VBA code can contain additional checks and balances, to make sure the calculation is relevant to the task at hand, and the appropriate order of magnitude. For example complex cumbersome code calculations, can be checked against more intutitive elementary strength calculations, if there is not some kind of alignment between the two then chances are the code calculation is in error or the constraints on its use.
So XLC could be useful for scratch pad calculations checking individual formula and trouble shooting errors/problems with a more complex working workbook. Because do not want to remove the : if's, choose, indirect, vlookup, index, sum, sumproduct, and other functions, just so that can use XLC formatting.
If you have operational AS3600 workbooks, then submit as is, and be the first in that area. If you use the workbook on a regular basis you will find more conditions, and more checks and balances to add to the workbook to make it more reliable. XLC formatting is a minor contribution to reliability of the workbook. Feedback from competent users is more valuable.
To get such feedback first need to develop an audience here for Australian codes. To do that need some Australian codes to download and comment on.
Also I believe the issue here is still that more people download than upload. The new subscription system is mostly a way to motivate uploads. If your workbook is little worth the operation of the repository will demonstrate that, and if it has value the repository will highlight that also.
So go ahead and upload. I don't do concrete, so I cannot provide much useful feedback. But those who have downloaded DvdHntr's Wind Actions workbook to AS1170.2 maybe have an interest, when next they visit.



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Re:Design of reinforced concrete beams to AS3600 3 Years, 6 Months ago

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thank you



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