m/d/yyyy string to yyyymmdd decimal in SQL

My input date, from a spreadsheet that comes from the a client, is a string
using the format (m)m/(d)d/yyyy, (m)m represents that there could be one or
two digits and ditto for (d)d, and I need to convert it to a decimal
yyyymmdd.

The following does it, but it seems to me that there should be an easier
way, utilizing less than four functions to do the conversion. Is there?

select BI_DOSA,
Dec( Replace(
Cast( Date(TIMESTAMP_FORMAT( BI_DOSA, 'MM/DD/YYYY'))
as Char(10)),
'-', ''),8)
from CA8560BIP

BI_DOSA DEC
8/21/2017 20,170,821
8/21/2017 20,170,821
9/06/2017 20,170,906
9/06/2017 20,170,906
9/07/2017 20,170,907
1/19/2017 20,170,119
10/31/2017 20,171,031
10/5/2016 20,161,005
2/13/2018 20,180,213
1/05/2018 20,180,105
1/05/2018 20,180,105
3/01/2018 20,180,301
2/21/2018 20,180,221
2/26/2018 20,180,226
2/28/2018 20,180,228
8/10/2016 20,160,810
11/14/2016 20,161,114
3/23/2017 20,170,323
11/9/2016 20,161,109

- Dan