I am designing a bridge pier with columns and a cap at the top. The system works as a moment frame during an EQ. I perform an elastic seismic analysis based on the response spectrum to get axial, moment, and shear. Time to design the rebar...
The column rebar will be governed by the moment at...
I have seen a few things to worry about w/ highly skewed bridges (over 30 degrees). One is increased shear on some of the girders, and I can understand that since the load path can be kind of odd given the geometry of the loading relative to the abutment. The other is uplift at the bearings...
I have a simply supported W27x281, 10ft long, 100kip/ft. Basic beam equations give a displacement of 0.065in.
I model the beam in STAAD (single element), and get 0.065in. However, once I model the beam as ten 1ft long elements, I get a deflection of 0.109in.
Anyone else have this sort of...
There is guidance for development lengths of black bars and epoxy coated bars, but what about galvanized and solid stainless steel?
Anyone have any thoughts? Is the stainless surface just as slick as the epoxy? or even more smooth?
I have modeled a simply supported beam 10' long, 5kip point/line load at midspan. Midspan moment = 12.5k-ft. For a 1ft thick concrete slab (and assuming no cracking), there should be ~500psi compression on top, ~500psi tension on the bottom.
I run the model and good results for principal...
I have modeled a simply supported beam 10' long, 5kip point/line load at midspan. Midspan moment = 12.5k-ft. For a 1ft thick concrete slab (and assuming no cracking), there should be ~500psi compression on top, ~500psi tension on the bottom.
I run the model and good results for principal...
I've read several of the topics on the overstrength factor, but they mostly refer to steel (brittle bolted connections vs ductile connections).
How about if I am designing a concrete moment frame for gravity and seismic forces? Overall I divide my seismic forces by R. Given those forces, I...
I am reading "Structural Steel Design: LRFD 3rd Ed" by A. Williams. For design of Plate Girders, Ch 8.4 says intermediate stiffeners (when required, with or without tension field action) must be connected to webs to resist shear given by
f_vs = 1.67h(Fy/340)^1.5
Could someone help tell me...
I'm detailing anchor bolts for column base plates. I've got a threaded rod embeded in the concrete footing. For anchorage of the rod, I do not want to bend or hook the rod. 2 questions for everyone...
1 - I've seen an embeded nut, a nut and washer, 2 nuts sandwiching a plate, and 2 nuts with...
I'm trying to design a fairly deep basement and I am not quite sure how to design for seismic soil pressure. People have told me Monoabe-Okabe does not apply and I should look at ASCE 4-98 Seismic Analysis of Safety-Related Nuclear Structures, where they use the Wood Elastic Method.
The Wood...
I have an outdoor 30' tall canopy made of a HSS members, architecturally exposed steel. There is a welded cap plate on the columns, and the welded base plates are embedded in 2' of concrete (architectural curb). Do you usually put a vent hole in the column?
I am afraid that the column will...
I am designing an ordinary moment frame as defined by AISC 341-05. All beams and braces are pin connections. Please see the attached.
Frame A - just an example of a perfectly acceptable moment frame using knee braces.
Frame B - Is this allowed to be qualified as an ordinary moment frame? I...
I am designing an ordinary moment frame as defined by AISC 341-05. All beams and braces are pin connections. Please see the attached.
Frame A - just an example of a perfectly acceptable moment frame using knee braces.
Frame B - Is this allowed to be qualified as an ordinary moment frame? I...
2 different questions on same topic
Lets say I have a typical 2 story building, 4 columns (1 at each corner). There are floor stringers from column to column, floor beams from floor stringer to floor stringer.
1) Is a typical shear connection w/ clip angles of the beam to the stringer enough...
I am designing a bldg according to IBC 2006. I have designed everything up to the foundation using LRFD. Now I am at the foundation, and Section 1804 only allows ASD to check the soil capacity. Is this right? Any ideas how I can move forward besides doing a separate ASD analysis just for the...
