wait, TLHS, are you implying (as maybe the previous thread did) that after your load combo wHEN USING .9D in LFRD, you need to also add in a 1.5 factor of safety for "overturning" .... that actually is part of my initial question -- 250 yds vd 160 yards. the previous post i referenced talked...
yes, TLHS, that is true, that is for ASD... in a way, I am getting confused by the old LFRD vs ASD and the fact that anchorage bolts design now have to use LFRD ultimate loads (right?!), so, all things being equal the .9D in LFRD should end up being equivolently as big of a footing as the ASD...
ALSO... anybody employ the skin friction of the footing against the soil at .25 of dead load to help out with uplift? specifically, the values in the cbc for soils are desscribing allowable friction as a percentage of DEAD LOAD, which, by the nature of the load UPLIFT, probably should not be...
JAE! THANKS, now this is exactly what i expect from this forum!!!! i appreciate it. I was aware of the "Chissel" weld, it seems that the certified welder should also know how to do this weld, but ofcourse, everyone wants the engineer to be responsible for the universe. Another aside, i...
thread507-352021
so, ya.. kinda clear as mud as far the application i need clarity on (unless ofcourse im reading it wrong again)....
when you are doing footing designs for METAL Building frames with no slab to count for contributory weight, it is a BIG DEAL to have to reduce your required...
I SEE that there are numerous threads about this problem already on this site, and once again, as expected, there is still some grey areas in opinion on whether its a good 'idea' to weld bolt extensions as opposed to core drilling (really?) and install new anchors or some other method. If...
Please comment as to the methods for extension of wet set anchor bolts that are sunk and too low to extend above the baseplate for the nut for metal frame building. discuss coupler vs weld please! we have opted for weld, in which case the welder is asking for details ofcourse (request comment...
i called the local WQCB official with the question : "can i use a FTU meter instead of a NTU portable "turbidity" meter? He KINDA said yes, but now i am not sure because he also said the "new" protocol actually has a TSS requirement not a "ntu". So, when i google something for a half hour and...
this particular job is for outside stairs adjacent to a big (11 foot) retaining wall......still beating dead horse... =) but, if you route out the shape of whatever steel member section you are going to use for the "slot" to slide it into, and then use posts at far cantilever end and other...
well, the client is barely paying us, so there will very unlikely be any input from an architect... why is wet setting a "disaster" waiting to happen? what about an embbedded C channel, weld a gusset for transverse skewage . you get plenty of depth for the cantilever and reduced thickness...
yes, indeed, the deflection of L/240 will create issues - im gettin a 1 3/4" vs say .2" allowed..no good.... i swear i have seen countless architectural digest fancy pants buildings with these floating stairs, with no signs of alternate attachment, just the pretty lines of the actual tread...
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it seems to me that if you got an 8 inch concrete (outside retaining wall say), carve a slot in the form and wet set embed 6.5" a full 10 inch wide (say 1/2" thick) steel stair tread, 300# pt load say at the end of the 3.5' wide stair cantilever, maybe a bolt for "dynamic load"...
and then there is the problem of the anchorage into concrete ... in seismic zone E... i got an omega'd load (1.25x) of say 5000 lbs on top of a 9 foot "ordinary" (or maybe its special?) cantilevered column system, proving rediculous.
and this post is getting no love...
aisc 341-10 specifically states under E5 "ordinary cantilever column systems".. that they are allowed in seis des cat B and C only. Currently in in 05 they are allowed. ASCE 7-05 also allowed in D and E with some load restrictions... which are not hard to satisfy.
clear as mud
excerpt from 341-05
Structural steel systems in seismic regions are generally expected to dissipate
seismic input energy through controlled inelastic deformations of the structure.
These Provisions supplement ANSI/AISC 360 for such applications. The seismic
design loads specified in the...