Increasing existing portal frame
Increasing existing portal frame
(OP)
Has anyone sucessfully extended a steel portal frame upwards to provide additional height?
A client has an existing portal frame building, and is looking to increase its height.
Conceptually, this would seem simple:
- Remove existing rafters
- Designing moment resisting splices at the existing column heads
- Bolt in new extension pieces to raise column height
- Re-fix the existing portal rafters at the higher level
Of course, the moments at the hanuches (and based if moment rsisting) will increase, and the columns\rafters may well now be undersized and require strengthening. There are plenty of ways to achieve this, and whilst I can advise the client that it's conceptually possible, I can't predict (without spending quite a lot of their money on design) if it can be economically achieved.
Has anyone successfully completed this sort of operation in practice, and could they share their practical experience or offer suggestions as to what methods would be most economic.
Thanks in advance for any comments.
A client has an existing portal frame building, and is looking to increase its height.
Conceptually, this would seem simple:
- Remove existing rafters
- Designing moment resisting splices at the existing column heads
- Bolt in new extension pieces to raise column height
- Re-fix the existing portal rafters at the higher level
Of course, the moments at the hanuches (and based if moment rsisting) will increase, and the columns\rafters may well now be undersized and require strengthening. There are plenty of ways to achieve this, and whilst I can advise the client that it's conceptually possible, I can't predict (without spending quite a lot of their money on design) if it can be economically achieved.
Has anyone successfully completed this sort of operation in practice, and could they share their practical experience or offer suggestions as to what methods would be most economic.
Thanks in advance for any comments.





