STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

Abbas_S · SEFI Member Joined: 24 Oct 2016 Posts: 1

Hello Sefians.

I am just a beginner in str. design. The beam is designed to carry the lift machine weight which is point load of 160kN assuming the beam is exactly below the Lift machine loading point. However now the beam location is casted wrong. So the point load is coming out 100mm from the beam edge . The slab is not designed to carry the machine weight. What will be the impact now and how to rectify it.

es_jayakumar · Posted: Tue Oct 29, 2019 4:11 am Post subject:

The point load from lift machine (160kN) looks exorbitant. Please check it.

E S Jayakumar

kawshik9 · General Sponsor Joined: 28 Oct 2009 Posts: 16

Following things are to be done in this situation:

1) Calculate the torsional moment in the beam due to eccentric point load

2) Check the design for additional moment and shear induced due to eccentric load.

3) If it fails while designing as a rectangular beam. Try to design it as T-beam.

4)If it fails in both cases. Try to think of additional strengthening measures to be taken.

K.Ramakanth.

es_jayakumar · Posted: Tue Oct 29, 2019 4:48 pm Post subject:

I feel the load of 160 kN (16 MT) is erroneous for passenger lifts from the payload, car weight, counter weight and machine weight. Please specify if it is a heavy-duty goods lift.
As the point load from the system is only marginally eccentric, it will not induce much extra BM in the slab. However you have to check its adequacy for shear stress at the appropriate point in the slab. Your 250 mm thick slab is likely to cater to this requirement, for a moderate point load. As suggested by Er. Ramakanth, you have to check the adequacy of the beam with the extra torsional moment.

E S Jayakumar