Return to index: [Subject] [Thread] [Date] [Author]

RE: aci 318 Seismic provisions

[Subject Prev][Subject Next][Thread Prev][Thread Next]
This is mainly a seismic design issue. The flexural moment due to lateral
loads is additive for beam ends connecting to a column. The intent is to
ensure that column is not going to yield flexurally when subjected to the
full moment capacity of the beams connecting to it. It is also based on the
flexural strength of the beams and columns not the design loads.

Ben Yousefi, SE
San Jose, CA

	-----Original Message-----
	From:	marfra(--nospam--at)opus.co.tt [SMTP:marfra(--nospam--at)opus.co.tt]
	Sent:	Tuesday, February 22, 2000 9:11 PM
	To:	seaint(--nospam--at)seaint.org
	Subject:	Re: aci 318 Seismic provisions


	 I have a concern about ACI 318/318r-296 regarding clause 21.4.2.2.
	Sum Me must be greater than sum Mg

	For most internal columns , dead and live load moments partially
cancel
	each other out. Therefore the design moment capacity of the column
is
	naturally less than that of the girders it supports. If the moment
	capacities of the girders are added without taking into account the
	partial neutralizing effects of their directions, the columns become
	much larger than they need to be without the provision. Did i miss
	something , this provision  does not seem logical for internal
columns.

	mark francois engineer