I have a residential project that includes a concrete driveway. The minimum thickness for a slab-on-grade according to the Florida Building Code is 3.50” and most residential slabs are 4” thick. Welded wire fabric (e.g., 6x6-W2.9xW2.9) is often used for crack control. According to ACI 318...
My question pertains to wood plates that are loaded in weak-axis bending, such as double top plates in a wood bearing wall. I have a case where the nailing is excessive in order for the plies to act compositely, but works with minimal nailing if I assume the plies share the load equally. Just...
In order for multi-ply wood plates (oriented flat-wise) to behave as a single unit, they must be sufficiently fastened in order to transfer the stress across the shear plane (a shear flow calculation). However, sometimes the amount of fasteners required can be problematic. Is it acceptable to...
I have a wood-framed apartment project where the framer wants to construct the shear walls in segments, and sheath them on the ground before lifting them in place. This introduces vertical seams into the shear wall. I understand that each wall segment will require an end stud and that the...
For wood shear walls sheathed with wood panels, does it matter which direction the panels span over the wall studs, or if adjoining edges are staggered? The SDPWS differentiates between different cases for wood diaphragms, but I cannot find anything for shear walls.
I am looking for the minimum bend radius in the VERTICAL plane of a 1/2" diameter unbonded tendon using a parabolic profile. The available literature discusses the minimum radius of sweeps in the horizontal plane, but I cannot find anything for the vertical plane. The following is what I have...
I agree with the previous responders that I have never seen a two-anchor connection into concrete meet Code. Just because that's the way it was done, doesn't mean it works. You can run the numbers using DG1 (with large moments) and it will tell you that you need to use a much larger base plate...
This question is specifically for structural engineers in Miami-Dade County, Florida:
I have always put the following wind load information on my structural drawings: Design Wind Speed, Risk Category, Exposure Category, the C&C Design Pressures (positive and negative pressures for Zones 1-5)...
The Thermal program by Tomanovich is what I used, but my understanding is that it pertains to all-steel buildings only. I am still baffled as to how the Walmart Superstore down the street is the same size building and has no expansion joint.
We have a single-story “big box” project in Florida that is 480’ x 160’. It was originally an all-steel building, with steel stud exterior walls, and using the Thermal Program (steeltools.org) it shows that an expansion joint is not required (Delta-T = 55 degrees). The project has changed to...
We have been asked to design a large shipping container warehouse where the floor live load is 2,500 psf (specified by the user client). The SOG will be supported on soil that will be improved by stone columns (subgrade modulus = 100 pci after improvement). That design load is off the charts of...
Thank you phamENG,
I have reviewed the drawings of three other projects (3-5 stories) by other engineers, and they all used a double top plate with trusses at 24" o.c. and studs at 16" o.c. I just wanted to make sure that I am not missing something.
Continuous beam over multiple supports. Here is an example for discussion purposes:
20’-0” long floor trusses @ 24” o.c. bearing on a 2x6 demising wall studs at 16" o.c. Truss Reaction = 75 psf x (2’ x 20’) = 3,000 lbs.
Forces in top plates (modeled as continuous beam over multiple supports at...
For multi-story wood buildings, I have very often seen the wall studs spaced at 16” o.c. and the trusses spaced at 24” o.c. The trusses bear on a double top plate across the top of the wall studs. This typical configuration will result in every other truss bearing at midspan between the wall...
I have a project with numerous concrete columns that are cast within the plane of concrete masonry walls (a/k/a concrete “tie columns”). The walls and columns are supported only at the floors above and below. The column and walls are 7-5/8” thick and the column widths range from 16”-32”. Does...
We are designing a concrete high-rise building that includes post-tensioned transfer girders supporting multiple levels. Our standard is to design PT beams with a maximum precompression of 350 psi and as Class U (ft <= 7.5sqrt[f'c]). Is this too conservative for a transfer girder? In particular...
