I am assisting an industrial client reviewing cracking distress in an 8-inch thick elevated slab. Visual petrography suggests that there is evidence of external sulfate attack limited to crack surfaces, likely a result of the chemicals to which the slab is exposed. The slab is reinforced with...
I have been tasked with enlarging existing roll-up door openings and am in a very preliminary phase of the design. The current 7 1/4" thick panels are approximately 28' wide by 25' high and currently contain two 10' wide by 10' high doors. The client needs to enlarge these doors to 12' wide by...
I was recently on a project observing test cuts in a strand-wound shotcrete tank structure (~50 yrs old) with an embedded steel diaphragm. The diaphragm is severely corroded at the vertical diaphragm joints adjacent to what was reported to be polysulfide sealant. The corrosion decreases with...
Does anyone have any resources or recommendations for material to use in guardrail post pockets? We are working on concrete balcony repairs. The aluminum rail posts were originally embedded. I am considering blocking out pockets at the rail bases in the repair areas and filling the pockets...
Ron is correct, the motor is coupled to a gearbox (ratio 70.32) with a 15 tooth sprocket at the box connected by a chain to a 52 tooth sprocket at the shaft in question. I was told 7 RPM, but field measurement and the above info suggests 5 RPM. Beach marks on the shaft (from a stress riser at...
I am a structural engineer assisting a client in determining the cause of a shaft failure. We normally strain gage components, but this is an inaccessible rotating shaft. I can analyze the shaft and key, but need to determine the shaft torque. I have limited motor info so far (25 HP...
Not being a design engineer, I have a question on standard terminology. I know how to evaluate and use live load reductions; however, we have been asked to interpret drawings that indicate the design live load is "80 psf Reduced". How can this be stated for the entire floor when various...
Here is a typical formula for calculating strength based on time for "normal" concrete. You have to know the design or expected f'c. t is time in days since the concrete was cast.
f'ci= f'c*(t/(4.00+0.85t))
If you don't know the f'c, back into it using the 7-day break value. Then...
In the US, towers are generally analyzed using software. There are some out there specifically designed for towers such as ERI Tower. A free standing tower like yours can also be modeled in most structural analysis software accurately. For the latter case you will have to do more hand calcs...
We rent a seismograph from a company called Geosonics of Warrendale, Pennsylvania. They have different models and a few regional offices. The SSU2000DK is what I use and is very easy to learn.
"Damage" to the structure usually won't be a problem unless you are right on top of it...
You might try posting in the "Foundation Engineering" Forum if you haven't already. It might yield more responses.
I imagine they will ask you for more info, such as soil information (boring logs) for bearing and other soil parameters. You will also need to consider the effects of...
You could put the casters on some type of custom wood(2x4)or other type of track to spread the load. The floor manufacturer probably has recs. for this type of application.
Is the support system for the raised floor adequate to support the new additional loads?
I recently performed a general evaluation of a large concrete parking lot (xp joints at 40' 1-way, control joints at 20' e.w.)to determine the cause of cracking/ spalling near expansion joints.
An ~2 sq.ft. collapsed section near (~20') the lot's earth drainage swale revealed an approximate...
Regarding the stresses in the plate, a simple Curved Beam Analysis assuming a 1-inch thick constant section could be in order. Look it up in a "Mechanics of Materials" book, the calculations are pretty simple once you have the section properties and this would give you a good...
MGO,
I am taking the Structural I exam in April. All I have found so far is one study guide from NCEES (www.ncees.org). However, you cannot download it, you have to order it. Gonna have to open up that wallet.
