rbudiman: Thanks for the responses. Do you have a code reference that indicates the overstrength factor requirement for the foundation design? It is clearly noted for battered pile systems in ASCE 7-10 but I could not find that requirement for typical pile systems.
I don't know what is...
I am designing a pile foundation for a new building based on information provided by the geotechnical engineer for the project. The pile foundation is required due to the high probability of liquefaction of the underlying soil during a seismic event. The pile system proposed consists of 8"...
jdgengineer:
What you laid out is the same way I was reading the code. In my case we will be decreasing the capacity of the existing shear walls by more than 10% by cutting in new windows and doors and/or adding load to the walls by a new sprinkler system and mechanical units.
If it is an...
I have a project that is a remodel of an existing one-story masonry building with wood rafter roof framing. The building is located in seismic design category D region. The existing masonry walls have horizontal reinforcing consisting of ladder joint reinforcing only and vertical rebar spacing...
I have designed at least two canopies in different jurisdictions where they required a fire rated wall to be constructed along property line where the canopy roof was closer than 10 feet from the property line. The justification was that if combustible items were stored under the canopy then...
stookeyfpe: do you have a code reference for an exception for canopies? I haven't been able to find anything and most jurisdictions that we deal with treat any structure with a roof as a building.
I have designed several roof structures that are open canopies (no walls) near property lines. Every jurisdiction seems to have a different interpretation of fire rating requirements for these structures. Does anybody have any code sections or ideas on if fire rating is required, fire...
I have been using the newer version of Enercalc (version 6) for a variety of designs. I noticed when using the masonry wall design module that some of the results didn't look correct. The axial stress and calculated deflections look much higher than calculated using rough hand calcs. Has...
...18 psf roof dead weight. The Sds value for the site is 0.70. If you use R = 1.5 then Cs = 0.70/1.5 = 0.47. The total lateral load would be 0.47 * 1040 * 18 = 8,800 lb. The resulting moment at the base is 8,800 lb * 12 ft = 105.6 k-ft. Then if the overstrength factor is required that...
a2mfk: Using a HSS column wrapped with CMU was an alternate I thought of. However due to the added cost and the inefficient use of not being able to use the existing masonry columns to resist lateral I have been looking for an alternate solution.
Sandman: Thanks for that code reference. I am...
I am having trouble in the design of a cantilevered masonry column system. These systems seem to be pretty typical for support of entry canopies or even larger canopy systems (I am picturing bank drive throughs). The basic system is a light roof deck (metal deck or plywood) with light framing...
Thanks for all of the input. I thought it wasn't an air entrainment problem but wanted to see if anyone else has had that problem.
I agree that using a coating may work at the time of construction but you don't have any guarantee it will be maintained.
The admixture being used is Rheomac. Lots of local contractors are using concrete sealant or admixtures similar to Rheomac in place of air entrainment. The thought being that water won't be able to get into the concrete so it is not considered an exterior surface. I was looking for a code...
Yes, the air entrainment is for frost/freeze exposure as required for severe exposure with 3/4" aggregrate by ACI 318 section 4.4.1. The air entrainment used is approx 6%.
I have not seen the surface in question personally but the pictures indicate and the contractor is saying that the air...
Many building departments are switching to electronic plan review programs to reduce paper and hopefully to make the review process more efficient. My question is how this works with requirements for orginal stamps on the construction drawings. How are design professionals insuring that their...
I have an exterior concrete wall that is specified to have a waterproofing admixture in the mix design. The contractor built a mock wall and with the air entrainment added they can't get a finish that the owner will accept. Does anyone know of an alternate method of waterproofing (either with...
ARKeng:
The 2.5 factor is in the IBC portion of our code (1908.1.16)that deals with concrete. I don't know if this is a state specific revision or general IBC revision. To resist the uplift forces I have been including a portion of the slab above which helps. You are right though that...
If you use hairpins and supplementary reinforcement to develop forces in your footings does the ductile steel failure requirement of ACI 318 D3.3.4 still apply? I know this appendix only deals with un-reinforced concrete anchorage but it doesn't seem like adding hairpins or additional steel...
...3" o.c.
using hef = 11"
(0.75)(0.75)Nsa=119.03k
(0.70)(0.75)Ncbg=31.92k f'c=2500 psi, Nb=43.53k Anco=1089in^2, Anc=1521in^2 (no edge within 1.5*hef)
(0.70)(0.75)Npn=259.78k
governing strength = 31.92k > 31.0 (factored uplift force)
however the steel does not govern so IBC requires you to...
