That's the term these days. We used to speak of "live loads", but for the layman, at least, that became confusing because people tended to think of live loads as the people on an office floor and dead loads as the furniture, typewriters, grand pianos, etc. In fact, both static and dynamic "moveable" loads are "imposed loads" - imposed on the loadbearing structure which has its own dead loads - now known as permanent loads -, including selfweight.

imposed load ( im′pōzd ′lōd ) ( civil engineering ) Any load which a structure must sustain, other than the weight of the structure.
www.answers.com/topic/imposed-load

Imposed Load
A load that can be moved; for example, boxes or vehicles
http://www.interconstruction.co.uk/glossary/i/imposed-load.h...

Live Load
The weight of people, things and materials that are not always present at the same place in a building. A live load is assumed to provide lateral pressure but not vertical pressure
http://www.interconstruction.co.uk/glossary/l/live-load.html

Dead Load
The weight of materials that are always present at the same place in a building. The dead load can provide lateral pressure against the wall as well as vertical force downward on the wall mass.
http://www.interconstruction.co.uk/glossary/d/dead-load.html

IMPOSED LOAD The load produced by occupancy and use including storage, inhabitants ... LIVE LOAD term sometimes used for IMPOSED LOADS. LONGITUDINAL BRACING ...
www.wolf-system.co.uk/glossary.asp

LIVE LOAD, a term often used instead of IMPOSED LOAD. ...
www.gte-uk.com/glossary.php


I've never seen surcharge vive. However, Kiwipedia has made a note of a surcharge libre which apparently translated as "live load", though I suspect it's a redundancy born out of confusion.

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Note added at 2 hrs (2010-04-27 20:45:09 GMT)
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SURCHARGE (n.f.) Se distingue de la charge par le fait que son application n'est pas permanente. Toutefois, dans le cas d'une longue durée d'application (plus de trois mois consécutifs ou 50 % du temps), la surcharge doit être considérée comme permanente.
http://www.crit.archi.fr/Web Folder/bois/Bois/9.Glossaire/s....

However, it would appear not everyone is ready to drop "live load" and so have come up with "superimposed load" ... but that's Canada for you.

SURCHARGE: charge appliquée à un élément de charpente en raison de son utilisation prévue. La surcharge peut être due à la circulation, l'usage, l'entreposage des matériaux, la neige, le vent, les séismes ou autres charges transitoires
http://www.cssbi.ca/Fra/lexique.shtml#s

LOAD - LIVE: Is the load on a structural member resulting from its intended use. This load could be the result of traffic, occupancy, storage of materials, snow, wind, earthquake, or other transient loads.
LOAD - SUPERIMPOSED: This is the sum of the live load plus the dead load minus the self-weight of the structural member. (Often used for composite slab load tables).
http://www.cssbi.ca/Eng/glossary.shtml#i