Tag: Beam

Steel Beam and Column Analysis Spreadsheet

Steel Beam and Column Analysis Spreadsheet

 

This spreadsheet is a program written in MS-Excel for the purpose of analysis and code checking of steel beams and columns.  Specifically, beams and columns are analyzed / code checked per the AISC 9th Edition Allowable Stress Design (ASD) Manual.  Both actual and allowable stresses are computed, with the final result being a computed “stress ratio” of actual stress/allowable stress.  Also, a list of the lightest weight members which satisfy the code check is displayed for convenience.

This program is a workbook consisting of six (6) worksheets, described as follows:

  • Doc – Documentation sheet
  • BeamCol(I) – Analysis / Code Check for W, S, M, and HP Shapes
  • BeamCol(Built-Up) – Analysis / Code Check for Non-Database and Built-Up Shapes
  • BeamCol(C) – Analysis / Code Check for Channel Shapes
  • BeamCol(Tube) – Analysis / Code Check for Rectangular HSS (Tube) Shapes
  • BeamCol(Pipe) – Analysis / Code Check for Round HSS and Pipe Shapes

All the worksheets are independent and self contained, so that you can move them from one workbook to another. All the worksheets are protected, but not with a password.

Program Assumptions and Limitations:

1.   This program follows the procedures and guidelines of the AISC 9th Edition Allowable Stress (ASD) Manual (1989).

2.   This program uses the database of member dimensions and section properties from the “AISC Shapes Database”, Version 3.0 (2001) as well as the AISC 9th Edition (ASD) Manual (1989).

3.   The “BeamCol(Built-Up)” worksheet is valid for AISC W, S, M, and HP shapes NOT contained in the AISC 9th Edition Manual, as well as for non-hybird and doubly-symmetrical (“I” shaped) built-up members which have their flanges continuously welded to the web and which DO NOT quailify as plate girders.(Note: the AISC Code limiting value on the web for built-up beams not to qualify as plate girders is as follows:
(d-2*tf)/tw <= 760/SQRT(0.60*Fy)

4.   This program is NOT valid for tees (WT shapes) and angles.

5.   In this program for members subjected to known loadings consisting of axial load (compression or tension) and/or uniaxial or biaxial bending, both the actual and allowable stress are computed, with the final result being a computed “stress ratio” of actual stress/allowable stress.

6.   The “BeamCol(Built-Up)” worksheet will require the input for the total depth, web thickness, flange width, and flange thickness.  Then, all the remaining section properties are automatically calculated, assuming straight,non-sloping flanges.

7.  This program utilizes an “Allowable Stress Increase Factor” (ASIF) which is a multiplier of any of the calculated allowable stresses Fa, Fbx, and Fby and also the Euler column buckling stresses F’ex and F’ey. It is used and appears ONLY in the stress ratio calculation.  Typically a value of 1.0 may be used.  However, a value of 1.333 may be used for load combinations which include wind or seismic loads.

8.  If an axially loaded compression member has a value of the maximum slenderness ratio K*L*12/r >200, then a message will appear.  However, this program DOES NOT consider or deem a particular member as “inadequate” based on the slenderness ratio of 200 being exceeded.

9.  For the case of combined axial compression with bending, if the calculated value of fa >=F’e (which is not allowed) then a warning (error!) message will appear.

10. When the values of either ‘Lx’, ‘Ly’, or ‘Lb’ are input = 0′ (or actually <= 1.0′), this program will use a value = 1.0′.

11. When a stiffened element (web) of a member subjected to axial compression is classified as a “slender” element (exceeding non-compact limits) based on local buckling criteria, then the program complies with AISC Appendix B.

12. In the “BeamCol(C)” worksheet for channels subjected to Y-axis bending, the properties database uses the minimum value of ‘Sy’.  However, it is desired to calculate the bending stress at the back of the channel instead of at the tips of the flanges, this may be done by computing a “reduced effective” Y-axis bending moment,  Mye = My*Sy*(xbar)/Iy , for member loading input.

13. The values of ‘Cb’, ‘Cmx’, ‘Cmy’, ‘Kx, and ‘Ky’ may be calculated (if applicable) by accessing the additional input data to the right of the main page in each of the calculation worksheets.  Then, these calculated values can be input under the member design parameters on the main page.  (Note: there are equations which very closely approximate the solutions for ‘Kx’ and ‘Ky’ obtained using the AISC Code Alignment Charts.)

14. This program does not calculate or check shear or deflection in member

15. This program does not consider torsion on member.

16. This program does not consider deduction for holes in members subjected to tension.

17. This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc.  (Note:  presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell.  Merely move the mouse pointer to the desired cell to view the contents of that particular “comment box”.)

Calculation Reference
AISC

 

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Design of Beam Ledge According to ACI 318-99 Spreadsheet

Design of Beam Ledge According to ACI 318-99 Spreadsheet

 

A reinforced-concrete beam having projecting ledges for receiving the ends of joists or the like. A beam is a structural element that primarily resists loads applied laterally to the beam’s axis (an element designed to carry primarily axial load would be a strut or column). Its mode of deflection is primarily by bending. The loads applied to the beam result in reaction forces at the beam’s support points.

 

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Beam on Elastic Foundation Analysis Sheet

Beam on Elastic Foundation Analysis Sheet

 

BOEF is a spreadsheet program written in MS-Excel for the purpose of analysis a finite length beam with free ends supported continuously on an elastic foundation. This program is ideally suited for analyzing a soil supported beam, a combined footing, or a strip of a slab or a mat. Specifically, the beam shear, moment, deflection, and soil bearing pressure are calculated for 100 equal beam segments, as well as the maximum values. Plots of both the shear, moment, and soil bearing pressure diagrams are produced, as well as a tabulation of the shear, moment, deflection, and bearing pressure for the beam.

Program Assumptions and Limitations:

1. The following reference was used in the development of this program (see below):

“Formulas for Stress and Strain” – Fifth Edition – by Raymond R. Roark and Warren C. Young, McGraw-Hill Book Company (1975), pages 128 to 146.

2. This program uses the equations for a “finite-length” beam in the analysis. This usually gives very similar to exact results for a “semi-infinite” beam which has had end-corrections applied to “force” the moment and shear values to be equal to zero at the ends. (Note: a “semi-infinite” beam is defined as one that has a b*L value > 6.)

3. This program uses the five (5) additional following assumptions as a basis for analysis:

  • Beam must be of constant cross section (E and I are constant for entire length, L).
  • Beam must have both ends “free”. (“Pinned” or “fixed” ends are not permitted.)
  • Elastic support medium (soil) has a constant modulus of subgrade, K, along entire length of beam.
  • Applied loads are located in the center of the width, B, of the beam and act along a centroidal line of the beam-soil contact area.
  • Bearing pressure is linearly proportional to the deflection, and varies as a function of subgrade modulus, K.

4. This program can handle up to twelve (12) concentrated (point) loads, a full uniformly distributed load with up to six (6) additional full or partial uniformly distributed loads, and up to four (4) externally applied moments.

5. Beam self-weight is NOT automatically included in the program analysis, but may be accounted for as a full uniformly distributed applied load. Beam self-weight will only affect the deflection and bearing pressure, and not the moment or shear.

6. This program will calculate the maximum positive and negative shears, the maximum positive and negative moments, the maximum negative deflection, and the maximum soil bearing pressure. The calculated values for the maximum shears, maximum moments, deflection, and bearing pressure are determined from dividing the beam into 100 equal segments with 101 points, and including all of the point load and applied moment locations as well.

7. The user is given the ability to input four (4) specific locations from the left end of the beam to calculate the shear, moment, deflection, and bearing pressure.

8. The plots of the shear, moment, and bearing pressure diagrams as well as the displayed tabulation of shear, moment, deflection, and bearing pressure are based on the beam being divided up into 100 equal segments with 101 points.

9. This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc. (Note: presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell. Merely move the mouse pointer to the desired cell to view the contents of that particular “comment box”.)

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