programme design guide may2021

Cellbeam Programme Design Guide & Section Property Tables

CELLULAR BEAMS®

CELLULAR BEAMS®

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CELLULAR BEAMS®

CHOOSING CELL DATA 1

FLOOR BEAMS 2

COMPOSITE DESIGN

NON-COMPOSITE DESIGN

ROOF BEAMS 3

SIMPLY-SUPPORTED

PORAL FRAMES

SPINE BEAMS

SECONDARY EFFECTS 4

SECTION PROPERTY TABLES 5

I-SECTIONS

H-SECTIONS

Contents

Choosing the optimum cell data for a particular application is vital for efficient and economic design. The geometry and properties of a cellular beam are completely variable.

H D

S

H

D min = 0.7hS min = 1.08D

D max = 1.3hS max = 1.6D

Outside this range - consult Macsteel Trading

STEP 1: Initial Cell Data SelectionThe following table can be used:

CELLULAR BEAMS®

1

CHOOSING CELL DATA

Butterfly Valves and Actuators

(hmin =original depth of the shallower section making up the asymmetric beam)

ApplicationSimple support rafterContinuous rafter & non-composite floor beamSpine beam

Composite floor beam Symmetrical

Asymmetrical

Cell diameter (D)1.05h

hS/1.5

hhmin

Initial cell data section tableCell pitch (S)

1.25D1.5D1.5D1.5D1.5D

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Composite design

Step 1

Choose a parent section - as a guide use a span/depth ratio of 26 for secondary beams and 20 for primary beams.

Start with a symmetric section initially. Weight savings can be achieved later on in the design process by adopting an asymmetric section.

Step 2

Choose cell data based on the guidance given in section 1.

Step 3

Analyse the beam and adjust the parent section size until a unity factor of between 0.8 to 0.9 in global bending is obtained. Don’t worry

about secondary failures at this stage.

• For the lightest cellular beam follow Steps 4 and 5

• For restricted depth applications jump to Step 6

Step 4

For the lightest section reduce the weight of the top tee by around 30 %, and re-configure the cell

data based on the section depth of the top tee.

Step 5

Re-analyse and adjust the cell data to control the secondary forces as necessary.

Step 6

Substitute the UB bottom tee for a UC section of similar weight and re-configure the cell data

based on the section depth of the UC.

Step 7

Re-analyse and adjust the cell data to control the secondary forces.

Step 8

Try reducing the top tee section by one or two weights. In very shallow floors a UC top tee may be required.

Non-composite design

Step 1

Choose a parent section from the floor beam section tables as appropriate.

Step 2


Step 3

Analyse the beam and adjust the cell data as required.

Note: The beam design should not be governed by deflection considerations under dead loads as cellular beams are pre-cambered at no cost.

UB/UB UB/UC UC/UC

Lightest

Shallowest

CELLULAR BEAMS®

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FLOOR BEAMS

Floor Beams

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Simply-supported

Step 1

Choose a parent section from the floor/roof beam section tables as appropriate.

Step 2


Step 3

Analyse the beam and adjust the cell data as required.

Portal frames

Step 1

Design a simply supported beam for the rafter span and centers. (see above)

Step 2

Use the inertia and area of the cellular section in a frame analysis.

Step 3

Revise the cellular beam design using the resulting end fixity moments, and re-analyse the frame using the new properties of the cellular

beam.

Step 4

When assessing deflections, to take account of shear deflection in the cellular beam pro-rata the deflections from the frame analysis for

cellular beam by the ratio of ‘additional deflection due to cells/total deflection’ taken from CELLBEAM.

Spine Beams

Step 1

Choose a parent section from the floor beam section tables.

Step 2

Choose cell data based on the guidance in section 1, but also making the cell pitch (S) a multiple of the secondary beam centers, in order

to avoid infills.

Step 3

Analyses the beam and adjust the cell data as required.

Note 1 : Where lateral torsional buckling governs the design, consider the use of an asymmetric section with a wide flanged top tee.Note 2: To simplify connection details, make the spine beam deeper than the incoming secondary member.

S

Africa’s leading steel supplierCELLULAR BEAMS®

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ROOF BEAMS

Roof Beams

CELLULAR BEAMS®

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The overall bending of the section produces secondary effects local to the cells. The table below illustrates these secondary effects, and offers guidance on how to control them by re-configuring the cell data:

To widen web postIncrease pitch or

decrease diameter

To increase tee depthDecrease diameter or reduce pitch

To increase depthIncrease diameter or decrease pitch

SECONDARY EFFECTS

Secondary Effects

Control mechanism

Increase the lever arm (i.e. section depth) between top and bottom tees (works for failures up to a unity factor of ~ 1.07)

Increase the depth of the tees. (works for failures upto a unity factor of ~1.3)

Increase the depth of the tees.(works for failures upto a unity factor of ~1.05)

Increase the width of the web post. (works for failures upto a unity factor of ~1.10)

Increase the web-post width or decrease web post slederness. (works for failures up to a unity factor of ~ 3.0)

Secondary effect

Midspan Vierendeel Behaviour Global bending action results in compressive and tensile forces in the top and bottom tees, which are at a maximum at midspan for a simply supported beam. Failure occurs when these forces exceed the axial capacity of the tee.

End-span Vierendeel Behaviour The shear force across a cell induces secondary bending moments in the top and bottom tees. Failure occurs when the moment capacity of the tee is exceeded.

Vertical ShearClose to supports or point loads the shear becomes critical in the web of the top and bottom tees.

Horizontal ShearThe change in bending moment across a cell generates a horizontal shearing force across each web post which is greatest at points of high moment gradient.

Web-post Flexure and Buckling Web- post flexure results from the horizontal shear generated in the web-post under global bending action.

Cell-data reconfiguration

Increase cell diameter orDecrease cell pitch (less effective)

Decrease cell diameter

Decrease cell diameter

Increase cell pitch

Increase cell pitch orDecrease cell diameter

CELLULAR BEAMS®

5

Cellular beams® section properties: I-sections

OptimisationThe Geometry and properties are infinitely variable. The tables which follow only give two examples per section size. For optimization use the CELLBEAM computer programme, and/or Macsteel’s free design service.

Structural integrityThe tables only allow checks for global bending. Lateral torsional buckling and secondary effects must be checked using CELLBEAM, and/or Macsteel’s free design service.

SECTION PROPERTY TABLES

Section Property Tables

H D=h H

S-1.5D

FLOOR (example only)SECTION

D=1.05h H

S-1.25D

ROOF (example only)

NOT FOR FINAL DESIGN NOT FOR FINAL DESIGN

203x133x25203x133x30

254x146x31254x146x37254x146x43

305x102x25305x102x29305x102x33

305x165x40305x165x46305x165x54

356x171x45356x171x51356x171x57356x171x67

406x140x39406x140x46

H(mm)289.8293.4

359.7364.3367.9

435438.6442.6

433.3436.5440.3

503506.6509.6515

571.2576.4

D(mm)

200200

250250250

300300300

300300300

350350350350

400400

S(mm)

300300

375375375

450450450

450450450

525525525525

600600

Iˣˣ(10⁶mm⁴)

47.3258.52

89.71112.54132.75

88.16106.57132.75

172.37200.61236.7

242.87285.01323.42392.23

249.57314.51

Zᵉˣˣ(10³mm³)

326.5398.9

498.8617.9721.8

405.3485.9584.3

795.6919.2

1075.2

965.81125.31269.41523.4

873.81091.3

Zᵖˡˣˣ(10³mm³)

343.1421

523.2650.1763

430.9515.9621.5

832.8965.2

1134.4

1013.51182.3

13371610.9

921.21149.9

Aⁿᵉᵗ(10³mm²)

2.53.05

3.073.774.41

2.122.523.01

4.044.675.47

4.254.935.566.65

3.424.23

H(mm)309.3312.9

383.7388.3391.9

463.2466.8470.8

461.5464.7468.5

532.1535.7538.7554.1

604.5609.7

D(mm)

225225

275275275

325325325

325325325

375375375375

425425

S(mm)

300300

350350350

400400400

400400400

475475475475

525525

Iˣˣ(10⁶mm⁴)

53.8466.56

102.62128.59151.6

101.24122.14148.01

197.18229.34270.47

274.36321.62364.78441.96

283.67356.62

Zᵉˣˣ(10³mm³)

348.2425.5

534.9662.3773.7

437.1523.3628.7

854.5987

1154.6

1031.21200.71354.31624.5

938.51169.8


364446.8

559.3694.7815

463.9554.6667.4

8931034.61215.6

10811260

1424.41715

989.71232.6


2.473.01

3.063.774.4

2.142.543.03

4.06

4.695.49

4.284.965.596.69

3.484.29

CELLULAR BEAMS®

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Cellular beams® section properties: I-sections


H D=h H

S-1.5D


D=1.05h H

S-1.25D

ROOF (example only)


406x140x39406x140x46

406x178x54406x178x60406x178x67406x178x74

457x191x67457x191x74457x191x82457x191x89457x191x98

533x210x82533x210x92

533x210x101533x210x109533x210x122

H(mm)571.2576.4

575.8579.6582.6586

548.3651.9654.9658.3662.1

759.1763.9767.5770.3775.3

D(mm)

400400

400400400400

450450450450450

525525525525525

S(mm)

600600

600600600600

675675675675675

775775775775775

Iˣˣ(10⁶mm⁴)

249.57314.51

377.13435.65490.74550.63

593.76673.73748.91828.71923.09

965.811123.661252.041359.781546.62

Zᵉˣˣ(10³mm³)

873.81091.3

1309.91503.31684.61879.3

1831.92067.12287.32517.92788.6

2544.52941.83262.53530.43989.2


921.21149.9

13771580.91776.31986

1926.92175.92414.42662.52956.3

2682.93103

3446.43736

4232.8


3.424.23

5.065.776.477.21

6.297.087.838.619.53

7.518.639.55

10.3411.67

H(mm)604.5609.7

609.1612.9615.9619.3

682.5686.1689.1692.5696.3

796.1800.9804.5807.3812.3

D(mm)

425425

425425425425

475475475475475

550550550550550

S(mm)

525525

525525525525

600600600600600

675675675675675

Iˣˣ(10⁶mm⁴)

283.67356.62

427.39492.97555.11622.47

666.18755.22839.09928.09

1033.29

1076.461250.7

1392.741512.2

1718.88

Zᵉˣˣ(10³mm³)

938.51169.8

1403.31608.61802.52010.1

1952.12201.42435.72680.32967.8

2704.33123.23462.43746.34232.1


989.71232.6

1475.11691.11899.82123.1

2053.62318.22570.62833.43144.9

2853.73296.23658.93965.74490.7


3.484.29

5.125.846.547.29

6.377.167.928.719.63

7.628.759.68

10.4711.82

CELLULAR BEAMS®

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Cellular beams® section properties: H-sections


H D=h H

S-1.5D


D=1.05h H

S-1.25D

ROOF (example only)


152x152x23152x152x30152x152x37

203x203x46203x203x52203x203x60203x203x71203x203x86

254x254x73254x254x89

254x254x107254x254x132254x254x167

305x305x97305x305x118305x305x137305x305x158

H(mm)217.4222.6226.8

269.3272.3275.7281.9288.3

362.4368.6375

384.6397.4

437.8444.4450.4457

D(mm)

150150150

200200200200200

250250250250250

300300300300

S(mm)

225225225

350350350350350

375375375375375

450450450450

Iˣˣ(10⁶mm⁴)

25.4135.4344.56

79.0690.98

105.64131.16161.61

234.72393.31356.71454.88598.01

452.98561.63663.58780.01

Zᵉˣˣ(10³mm³)

233.8318.4393.1

587.1668.1766.2930.4

1120.9

1295.51586.21902.72365.83009.9

2069.32527.62946.63413.6


245.5337.3420.2

616.7705.4814.1997.9

1215.4

1364.11683.72037.42562.53309.3

2173.22674.13137.43659.8


2.383.223.98

4.825.486.297.619.17

7.959.73

11.6914.5118.43

20.4612.7814.9

17.25

H(mm)239.5244.7248.9

322325

328.4334.6341

399.3405.5411.9421.5434.3

486492.6498.6505.2

D(mm)

180180180

245245245245245

300300300300300

370370370370

S(mm)

225225225

305305305305305

375375375375375

470470470470

Iˣˣ(10⁶mm⁴)

30.842.9153.89

115.71132.83153.94190.13233.42

285.48355.02432.47550.32721.31

556.87689.54813.8

955.38

Zᵉˣˣ(10³mm³)

257.1350.7433

718.7817.5937.6

1136.61369.1

1429.81750.92099.72611

3321.4

2291.62799.53264.33782.1


267.9368.6458.9

750.4857.1988.5

1207.81468.8

1794.718442229

2801.53613.4

2386.72935.23442.54013.8


2.343.173.92

4.875.546.367.699.27

7.849.6

11.5214.3118.18

10.2512.5214.6

16.91

CELLULAR BEAMS®

7

NOTES

June 2021

Pursuing Reinvention

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Email: [email protected]

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programme design guide may2021

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