BIZOMAT MAKEOS · Mechanics
Wall Jib Crane Check (Tie Tension, Beam Bending and Axial Stress, Deflection, Wall Bolts)
For a wall-mounted jib with a tie rod, how much tension is in the tie, are the beam stress and deflection within limits, and can the top wall bolts take the pull?
Check of a wall jib crane with a pinned I-section jib supported at its outer end by a tie: the section area, second moment and section modulus of the jib (as the section shapes tool), the tie tension and beam compression with the load at the end, the bending moment and deflection with the load at mid-reach (as the beam cases tool for a central point load), the combined bending and axial stress, the tie rod stress, and the wall pull shared by the top bolts, against your allowable stresses, deflection limit and bolt capacity.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Load including hoist and trolley | N | Rated load plus hoist, trolley and an allowance for dynamic effects. |
| Reach (wall pin to tie point) | mm | Distance from the wall pin to where the tie meets the jib. |
| Tie angle from the jib | ° | Angle between the tie and the jib. |
| Jib section (I) | ||
| Overall depth | mm | Overall depth of the jib section. |
| Flange width | mm | Flange width. |
| Flange thickness | mm | Flange thickness. |
| Web thickness | mm | Web thickness. |
| Modulus of elasticity | GPa | Modulus of elasticity. |
| Allowable combined stress | MPa | Allowable combined bending and axial stress. |
| Deflection limit (reach ÷) | Largest deflection as a fraction of the reach. | |
| Tie and wall | ||
| Tie rod diameter (at the thread root) | mm | Tie rod diameter at its weakest section (thread root). |
| Allowable tie stress | MPa | Allowable tensile stress in the tie. |
| Top bracket bolts in tension | bolts | Bolts at the top wall bracket that take the tie’s horizontal pull. |
| Allowable tension per bolt | N | Allowable tension in each wall bolt or anchor. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Load including hoist and trolley
- What it is
- The total load hanging from the jib: the rated load plus the hoist and trolley, with any allowance for dynamic effects you add.
- Units and format
- Enter a number in N: newtons. The form accepts 0.000001 N to 100000000 N. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 10000 N as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Every stress, the deflection and the bolt load rise in proportion to it.
- Get it right
- Enter it in newtons; include the hoist and trolley and add the dynamic allowance your crane standard requires.
What this means: Reach (wall pin to tie point)
- What it is
- The reach of the jib: the distance from the wall pin to the point where the tie meets the jib.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 100000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 3000 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Bending moment rises in proportion to the reach and deflection with its cube.
- Get it right
- Measure between the pin centres, not to the end of the beam if it overhangs.
What this means: Tie angle from the jib
- What it is
- The angle between the tie rod and the jib beam at the tie point.
- Units and format
- Enter a number in °: degrees of angle. The form accepts 5° to 85°. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 30° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- A smaller angle raises the tie tension, the beam compression and the wall pull.
- Get it right
- Measure it between the tie and the jib, not between the tie and the wall.
Jib section (I)
What this means: Overall depth
- What it is
- The overall depth of the I-section jib, from the top of the top flange to the bottom of the bottom flange.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 10000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 200 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Bending stress and deflection fall steeply as depth increases.
- Get it right
- Take it from the section tables for the actual beam size.
What this means: Flange width
- What it is
- The width of the flanges of the I-section jib.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 10000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 100 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Take it from the section tables; both flanges are taken as equal.
What this means: Flange thickness
- What it is
- The thickness of each flange of the I-section jib.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 1000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 8.5 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Use the flange thickness from the tables; tapered flanges are treated as parallel.
What this means: Web thickness
- What it is
- The thickness of the web joining the two flanges of the I-section jib.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 1000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 5.6 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Take it from the section tables for the actual beam.
What this means: Modulus of elasticity
- What it is
- The modulus of elasticity of the jib material, used for the deflection.
- Units and format
- Enter a number in GPa: gigapascals (1 GPa = 1000 MPa). The form accepts 0.000001 GPa to 1000 GPa. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 200 GPa as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Deflection falls in proportion to it.
- Get it right
- Enter it in GPa, not MPa; take it from material data.
What this means: Allowable combined stress
- What it is
- The highest combined bending and axial stress you allow in the jib, compared with the larger of the mid-reach and end-load stresses.
- Units and format
- Enter a number in MPa: megapascals (1 MPa = 1 N/mm²). The form accepts 0.000001 MPa to 10000 MPa. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 160 MPa as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Take it from your crane or structural design standard; the tool applies no factor of its own.
What this means: Deflection limit (reach ÷)
- What it is
- The deflection limit written as the reach divided by a number: the tool allows a deflection of reach ÷ this number.
- Units and format
- Enter a plain number with no unit. The form accepts 10 to 100000. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 250 as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Raising the number lowers the deflection allowed.
- Get it right
- A larger number is a stricter limit; take it from your crane standard.
Tie and wall
What this means: Tie rod diameter (at the thread root)
- What it is
- The diameter of the tie rod at its weakest section, normally the root of the thread at its end fittings.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 1000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 20 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Tie stress falls with the square of the diameter.
- Get it right
- Use the thread root (minor) diameter, not the plain rod diameter.
What this means: Allowable tie stress
- What it is
- The highest tensile stress you allow in the tie rod, compared with the tie stress at its root diameter.
- Units and format
- Enter a number in MPa: megapascals (1 MPa = 1 N/mm²). The form accepts 0.000001 MPa to 10000 MPa. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 140 MPa as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Take it from your design standard for the rod material, including your safety factor.
What this means: Top bracket bolts in tension
- What it is
- The number of bolts or anchors at the top wall bracket that share the horizontal pull of the tie.
- Units and format
- Enter a number in bolts: bolts. The form accepts 1 bolts to 100 bolts. Use a whole number. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 4 bolts as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- The load on each bolt falls in proportion as bolts are added.
- Get it right
- Count only bolts loaded in tension by the tie pull, not those at the lower pin bracket.
What this means: Allowable tension per bolt
- What it is
- The allowable tension in one wall bolt or anchor, compared with the wall pull divided by the bolts.
- Units and format
- Enter a number in N: newtons. The form accepts 0.000001 N to 100000000 N. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 20000 N as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Use the anchor maker’s allowable load for your wall material and edge distances, per bolt.
Method and formulas
- A, I and Z of the I-section (as the section shapes tool).
- Load at the end: tie T = W ÷ sin θ; wall pull = T cos θ. Load at mid-reach: M = W L ÷ 4 and deflection W L³ ÷ 48EI (as the beam cases tool), with axial compression W cos θ ÷ (2 sin θ).
- Combined stress = M ÷ Z + N ÷ A; tie stress = T ÷ (π d² ÷ 4); bolt load = wall pull ÷ bolts.
- Example: tie 20 kN; jib 43.816 MPa and 1.5239 mm deflection; 4,330.1 N per wall bolt.
Limitations
- Pinned jib and tie, load on the jib centre line; lateral-torsional buckling of the jib and trolley wheel loads on the flange are not checked.
- Static load including the dynamic allowance you add to it.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check a workshop wall jib
- Size the tie rod and wall bolts
- Check a jib for a heavier hoist
Who it is for
- Design engineers
- Maintenance engineers
- Structural detailers
What you get
- Jib section properties
- Tie tension, beam moment, stresses and deflection
- Tie rod and wall bolt checks
Interpreting the result
- A steeper tie (larger angle) cuts the tie tension and the jib compression sharply.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 234–246, 257–277, 153–163. Topic reference; no source tables or recommended settings are reproduced.
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