I am one of the structural engineers working on a project where we need to create a perforated steel plate. The plate is nominally going to be 1" thick, grade 50 structural steel (ASTM A572). We need to create thousands of 1/8" diameter holes through the plate. Some of the holes are...
So I have a project where we need to thread some rebar, to create an M20 metric thread on a US standard size bar. I am wondering if we need to spec out that they start with #7 or #8 bars. I dont know what the max shaft diameter will be, after the ribs are removed. I am leaning to the #8 bars...
A question has come up on how to design nailing patterns for roof plywoood, considering combined interaction of uplift loads and diaphragm shear. I have typically done a linear interaction of tension/shear for fasteners, but can't find any direct language to this interaction for engineered...
Hi all.
We are working on an elevated, outdoor hotel pool deck per 2010 Florida Building Code, using a 2-way slab. The deck is over ground level parking, connects to the hotel lobby, and also has direct egress to the ground. We are having a debate on the appropriate live load, as the Code is...
Hi all. We are doing a design of a large PT slab building where several walls butt up against adjacent walls. The slab spans are long enough to require stressing from both ends, but because of the walls, we don't have access on one side to stress the tendons. So our first thought was to...
Hi all. We are working on a project which is located in an area where there is no coarse aggregate at all, only sand. We had desired to create a 4000 psi sand-cement mix to use for structural foundations, slab on grade, 8" thick 2-story high walls, CIP stairs, and infill on composite metal...
So I was at a job site visit the other day, and when reviewing the photos I took, I noticed that some of the Tapcons used to install wood straps (Simpson straps and buckets) had countersink heads (Phillips flat head), instead of standard hex heads. I don't know overall how many are affected...
So I am working on a cantilever steel tower where I need to accurately calculate the natural frequency of the tower. Current design is round pipe, 12 feet diameter, 80 feet tall. Base of pipe is assumed rigidly attached to infinitely stiff foundation. So it will behave as a cantilever column...
I know the standard Canadian rebar designations (M10, M15, etc) but I am wondering about what is typically available for use in Canada. Do you strictly use rebar with these designations, or do you also use soft metric equivalent of US bar sizes? For instance, a #6 US bar is 19mm and a #5 US...
Ok, so I need to calculate the capacity of wood framed shear walls clad in 2 plies of 1/2" gypsum board on each side of the wall. These are interior shear walls between condo units. I had specified 5/8" plywood on one side. The architect wants me to consider the capacity of the 4 plies...
OK, so I am looking at a PEMB fire station where the original drawings are 1974. We have no info on the metal building itself, so I went out and measured everything. I am running the calcs now, but I need to know what grade of steel was commonly used in 1974 for cold formed C and Z...
I am working on an evaluation and renovation of a wood framed hotel in Cape Cod, Massachusets that was built in 1955. It has prefab wood trusses (like metal plate, but with plywood plates), 2x12 floor framing, and 2x4/2x6 walls with plywood sheathing. The owner sent me lots of pictures showing...
They introduced a new provision in ASCE 7-05 that adds a 1.9x wind pressure multiplier for "Rooftop Structures and Equipment", section 6.5.15.1. My question is "what is the definition of a roof top structure?". If I have a small pop-up roof area, say elevator overtravel or something similar...
I am working with an architect on a project that will have lots of exposed structural concrete. It is a high end project, and the architect is very concerned about the quality of the concrete finish. I have spec'd a grout cleaned finish for exposed areas, to fill any voids and provide a nice...
We are considering buying staad foundation. We do a lot of combined footings and mats, as well as pile caps. It looks great. Just wondering how other users like it, after using it a while.
Thanks
I am designing a 70 foot tall glass atrium, which is basically the shape of a football in plan view, with straight vertical walls and flat roof. The "football" passes through an office building, with 5 stories on one side, and 2 stories on the other. The framing sizes are all preliminary right...
A pedestrian bridge in Atlanta collapsed during construction, killing one worker and injuring 18 others. No indication of what went wrong yet.
http://news.yahoo.com/s/ap/20081219/ap_on_re_us/pedestrian_bridge_collapse_7
We have a job where the contractor and testing agency is telling us that the A490 bolts are loosening all by themselves. The bolts in question are 7/8" diameter x 2-3" long, and are being used in top & bottom plate moment connections on floor beams, so loaded primarily in shear. (non-seismic...
Hi all.
I am designing an office floor over a very large conference room, where the span is almost 80 feet. I would like to use composite beams for this span, but I am concerned about some of the sizes and deflections I am seeing. Using various calculations and tools, like the AISC bay...
HI all. I am starting schematic design concepts on a building which has a "football" shaped glass atrium, about 90 feet tall, 185 long and 75 wide. By this I mean if you took a section cut long ways through a football, you end up with a section which curves at constant radius (about 135')...
