Hi, I have concrete that is spalling from a wall in an industrial yard. I don't know what caused it. There appears to be no leak from the roof or impact. I am left guessing it is just spalling due to moisture from the environment getting in over time and causing the rebar to rust and concrete to...
Hi, I am designing a pipe rack. The geotech says the soil has a high risk of liquefaction and hence the foundation will have piles going more than 50 ft deep. For the purpose of designing the piles, should the weight of the pile cap/foundation be considered as part of the seismic weight? For...
For welds in bending, should we use the plastic section modulus or the elastic section modulus? I understand welds are more brittle in nature but per the AISC, we are already applying a 0.6 reduction factor. Does this already account for the brittle/shear nature of welds and hence we can use the...
Hi I am a structural engineer designing a structure made of aluminum. The aluminum needs to be welded in field. Does anyone know if it can be heat treated in field at the weld points to recoup some of the yield strength loss during the welding? Also, I plan on specifying to the welder to weld...
Hi, what risk category should I use for a canopy, industrial equipment, and pipe rack all located at a winery. I am leaning towards risk category II for all three since I do not think anything at the winery poses a risk to the public even when there is an accidental release.
Regards,
Hi, I am building a canopy over what used to be just a dirt area. The canopy is next to an existing road that drains to the city drains. Is there an issue if the canopy's gutters direct to the street? I look up the city municipal codes but couldn't fine anything.
Regards,
Hi, I have two new pads. One very large 100'x25' and one smaller square shape pad about 15'x15'. Both are 18" thick. The way they are oriented (see below), I am sure they would crack along their connected edge if they were poured together. Should I pour them as separate pads? I planned for it to...
Hi,
I am installing a new concrete pad for heavy industrial equipment. Upon doing exploratory excavation, we discovered two 8" buried pipes at the location that spans across the entire future pad. One is made of plastic and the other is concrete. They are about 1 ft below the bottom of the...
Hi, has anyone used a trench drain in lieu of a buried pipe to transport chemicals? I have to connect some new drainage to an existing shallow drainage system. I was planning on using buried pipes but customer asked why not just use trench drains along the entire route (200 ft). Both can...
Hi, I have a 120'x20' mat foundation designed for a bunch of equipment. I need to develop a localized drainage plan for various equipment. Having a drainage pipe go below the 2' thick foundation isn't feasible since I don't have the necessary slope to pull that off. Hence, I plan on adding...
Has anyone ever put design load assumptions on their structural drawings? I am analyzing an existing pipe rack for additional loading and the client suggests the original loading is 20 psf. This seems reasonable as the pipes here are no more than 4". This is not a refinery where 40 psf is the...
Hi,
Is there any issues with pouring a new foundation next to an old one? I don't think so but I was wondering if doing so would add a surcharge to the existing foundation causing it to potentially fail in soil bearing. I also found this excerpt in the building code but it is open to...
Hi,
I am working on a nonbuilding structure and I need to install a new column/post onto an existing beam. The new column/post will be supporting some panels. I have been looking for some design guides but they are all for beam to column instead of column to beam (E.g. AISC design guide 4). Can...
Hello all,
I have a flexible sign that will go on top of a building. I need to determine the wind force on the sign to design the sign supports and anchorage. Please correct me if I am wrong but in such a case, I would compute the gust effect factor of the sign structure and not that of the...
Hello all,
Please see the attached photo. I am analyzing an existing multistory pipe rack. My question is; should the beam (pointed at with the arrow) be designed with diaphragm forces (assuming forces acting in the longitudinal Z direction)? These piperack do not have a diaphragm or horizontal...
Hello all,
I designed a drilled pier that is 5' deep with 6" above ground. Upon doing a structural observation, it is found that the contractor used a sonotube for the full length of the drilled pier (from bottom of embedment to top). It is my view that the sonotube can rot since it is made of...
Hi, I am trying to figure out how pole crossarms work. Please see the attached images. The way I see it, if there is an imbalanced longitudinal(horizontal) load due to one wire failing on one side, the crossarm would twist about the pole's vertical since there is only one pin connecting the...
Hello all,
I am wondering which is worst for a wooden pole in terms of rot, embedding it in concrete or soil. The client wants to encase to the wooden pole in concrete so we can increase its diameter in the ground and reduce the required embedment but I feel like encasing it in concrete will be...
Hello all,
Should the seismic forces on directional anchors be combined with thermal forces if there are loops that allows the pipes to expand in the direction away from the anchor?
Per PIP STC01015 "Friction loads shall be considered temporary and shall not be combined with wind or...
