ACI 318-19, Tables 20.2.1.3 (a). (b), and (c) list what seem to be additional ductility-related properties for reinforcing steel. Are these supplemental requirements in addition to what is already in ASTM 615 and ASTM 706? If they are not already in the ASTM specifications, then I would think...
I have some old 1963 concrete flat plate drawings. They use bar designations I am not familiar with.
See the attached image.
18BC6: (18) bottom bars, column strip #6 bar?
26TC6: (26) top bars, column strip #6 bar?
Is anyone familiar with this reinforcing steel nomenclature?
Thank you in...
Can someone tell me if ACI 318-14 (or -19) requires the use of an encapsulated system for all unbonded PT construction for all slabs regardless of whether the slab is exposed to weather? We always use encapsulated tendons in garages; however, someone recently told me an encapsulated system is...
When load testing piles (pipe piles and auger-cast piles), what vertical settlement defines pile failure?
I seem to remember an older version of the IBC Code used to specfically define failure load as the load corresponding to 1” of vertical settlement - but I can’t find this anywhere. The...
I am looking for the requirement in ACI 318 that prohibits the pouring of columns and slabs together in single pour. This practice is not recommended because it can lead to shrinkage cracks at the interface between the top of the column and underside of the floor slab.
I seem to remember a...
One of our flat plate projects is out for bid. The reinforcing steel in the slab consists primarily of #5 bars. One of the concrete bidders wants to use fiberglass reinforcing bars instead of A615 Grade 60 bars. (Just the straight bars.) This is a new one for me. They claim the limited...
For many years we have required standees supporting top reinforcing steel located more than 4’ above the bottom of a member to be designed by an engineer hired by the contractor. Someone in our office asked me where this requirement came from – and I can’t remember. I know I did not arbitrarily...
What is an acceptable value to use for strength level bond stress between 4 ksi grout and smooth concrete?
I am designing floor framing comprised of hollowcore plank supported on steel. For reasons I will not get into, we cannot put longitudinal integrity steel in the plank joints at the beams...
Question: ACI 318-14 has an equation for computing tension development lengths of hooked bars. Factors are listed in Table 25.4.3.2 (attached) that are applied to the equation. “Psi e” is an adjustment factor for spacing and cover. A factor 0.70 can be used when side cover (normal to the plane...
Concrete exposed to freeze/thaw is air entrained. We do not air entrain concrete in floor slabs that are not exposed to freeze/thaw. A question came up in our office about what precautions, if any, need to be taken during construction to protect non-air entrained floor slabs that have achieved...
Does anyone have ACI 318-19? I have a question about the ACI 318-19 requirements for development of headed deformed bars in tension. ACI 318-14 has numerous restrictions on the conditions for using headed anchors on reinforcing steel. Two of those restrictions are,
60 ksi upper limit on Fy...
ASCE 7-05 Section 4.7.2 required that hangers supporting floors or balconies be designed for 1.33 x hanger load.
ASCE 7-10 Section 4.6 deleted the requirement that hanger loads be automatically increased by 1.33. (Section 4.6.1 still requires that impact forces be considered.)
Am I missing...
What do joist manufacturers do to deal with bar joists tilted about their longitudinal axis? I know that additional bridging is required to restrain the joists, but is the additional bridging automatically designed and provided by the joist manufacturer, or does the EOR have to add a note on the...
A contractor on one of our projects accidently poured a cantilevered site retaining wall (retaining 5’ of soil) using 5,000 psi lightweight concrete (115 pcf)– and now we need to tell them whether or not it needs to be ripped out and rebuilt with the proper concrete. I never heard of lightweight...
When computing the water/cement ratio in concrete mixes we are required to include water in admixtures as part of the total water content in the mix. Does anyone know the approximate water content in admixtures?
When computing the development length of 90-degree hooked bars in tension, ACI 318-14 permits a 0.70 reduction factor on the development length when there is at least 2.5” of cover measured normal to the plane of the hook (i.e, side cover) and when there is at least 2” of cover “…on the bar...
I am detailing joist connections to W shape beams. (see attached) In some cases I have joists on only one side of the beam and I am concerned about torsion on the beam. But even where I have joists with equal spans on both sides of the beam there might be live load on only one side. These are...
We are designing a multi-family residential structure using floor sheathing over cold-formed steel joists. The sheathing will be screwed to the joists. When we use wood joists, we require the sheathing to be glued and nailed to the joists. Can floor sheathing be glued to cold-formed steel...
We are framing a roof screen with HSS sections and are connecting the members with blind bolts (also known as Box Bolts or Hollo-bolts). Is there a need to be concerned about water seeping into the HSS's through the bolt holes? If the bolts are properly tightened and connection plates are...
