No, you don't use negative masses.
----- Original Message -----
From: "Gobo, Gina" <ggobo(--nospam--at)DLRGROUP.com>
To: "'seaint'" <seaint(--nospam--at)seaint.org>
Sent: Friday, February 04, 2000 12:21 PM
> In SAP2000, when adding joint mass loads converted from the structure dead
> loads (gravity loads), do you add them as negative mass loads (downward
> direction)? I was not sure if mass loads have a positive or negative
> As dead weight, the loads are acting in the downward direction (gravity).
> But when you convert them to a mass, do you still use the negative sign to
> indicate a downward direction?
> Gina T. Gobo, E.I.T.
> Structural Engineering
> DLR Group
> Ph. 206.461.6000
> Fax 206.461.6049