Yes, this change is going to facilitate some interesting designs.
For example, I decided to add single-leg shear stirrups in the lower portion of my basement wall rather than double the thickness of the wall or add absurd amounts of vertical reinforcement. The wall thickness is sized for Vc...
This document is very helpful. Thanks.
The example on page 309 is similar to the example I posted above. The example confirms that the one-way shear calculated using ACI 318-19 is indeed significantly reduced. I was certainly hoping there was something in the code that would exempt footings...
Good to know, but even after excluding the size effect factor, footing shear capacity is dramatically reduced. Consider a 12" thick footing (f'c=3000 psi) reinforced with #5 at 12"o.c. with d = 8".
ACI 318-14
Vc = 2*√(f'c)*b*d = 10516 lbs per ft
ACI 318-19
Vc = 8*(λs)*(ρw)(1/3)*√(f'c)*b*d
Vc...
Local jurisdictions in my area recently started to adopt IBC 2021, so we are implementing ACI 318-19 on our projects for the first time. I have concerns about the new shear provisions. Updated equations are included in ACI 318-19, Table 22.5.5.1. At first glance it looks like the familiar...
I think I answered my own question. Section 907.4.4 allows "Limited structural alterations" to be reviewed in accordance with section 807.5. The 10% allowance applies to these situations.
Please refer to IEBC 2015 section 907.4.1 regarding existing structural elements resisting lateral loads:
"An engineering evaluation and analysis that establishes the structural adequacy of the altered structure shall be prepared by a registered design professional and submitted to the code...
I always thought that the limitations set by some of our clients are a little extreme. In some cases we are able to convince them that connections are required; but sometimes the architect is adament in limiting connections to the stairs.
The architect's argument has always been:
If a beam...
I'm not sure that the architects are being pushy. I think there are some legitimate fire safety concerns when you are dealing with stair walls as a means of egress. Unfortnately, I think that each architect interprets the code differently.
This is exactly what I would like to do. Have you...
There are many reasons engineers are interested in connecting masonry stair walls to the primary structure. For shear wall applications a connection is needed to transfer forces out of the floor diaphragm and into the masonry. Sometimes it would be nice to brace masonry walls to the floor to...
@msquared48 - The overstress does not include any time-dependent factors. I was not aware that IBC allows a 15% increase on snow loads. Can you reference this section?
@dcarr82775 - The unit is located away from the drift. I always include the base snow load in addition to the unti because i...
Thanks for the response Ron. I probably need to do more research into the codes applicable in the early 1960's, but my general understanding is that drfiting snow was not a code consideration at the time. Therefore, the original joist design was sufficient to meet code at the time of...
We have a difference of opinion in our office, and I am hoping to get clarification from some other colleagues. IBC 3403.2 permits an increase in gravity load on the existing structure, provided the stresses in the member do not increase by more than 5%. The language varies slightly between...
