Subsection 12.14.3.2.1, equation 12.14-9 specifies that Emh = 2.5*Qe. My question is when to use the 2.5 factor and when not to. The Code is unclear. I am designing anchorage forces for a vertical rigid steel storage tank and I use equation 15.4-5 to calculate the lateral seismic force, V...
I am a structural engineer and I have a question: I have a 24" diameter steel pipeline under about 40 feet of hydraulic head with occasional changes in direction of 45 degrees each. The pipes are welded together using groove welds. Do I need to account for thrust forces at the bends even...
We have been tasked to design full height concrete abutments on spread footings subjected to scour. The bridge structure will be an ACROW steel bridge similar to a Bailey bridge. The single span is 110 feet from CL bearing to CL bearing with HL-93 loading. My question concerns scour from...
After determining the depth to fixity for concrete drilled shafts based on ADOT (Arizona DOT) Geotechnical Design Policy DS-3, how does one determine the tip elevation beyond the fixity depth? Is there a good rule of thumb (assuming that even exists) based on the shaft diameter?
After determining the depth to fixity for a concrete drilled shaft, what is the rule of thumb (if such a thing exists) for the increase in depth beyond fixity to the tip elevation?
I am tasked with designing a tank to hold acid (sg = 1.84) and one of the design criteria I have from the owner says: "Tank will be rated for 6" water pressure and -.4 oz vacuum." Can anyone shed some light on what this means? I am a structural engineer, not a mechanical engineer. The tank...
Hello:
We have a bridge here in Tucson that might be scheduled for demolition due to its age and inadequate inventory and operating ratings. The bridge is a 6 span, non composite structure: total length = 363 feet: out to out width = 64 feet. Superstructure is composed of 4 feet wide...
I am designing a narrow concrete trench with proprietary traffic rated grating which spans between the walls. The wall height of the trench is in the order of 5 feet and the wall thickness is tentatively 6 inches. When the wheel load of 16 kips + impact is directly over the wall, how does this...
Gentlemen:
I am analyzing an old 3 span non-continuous, pre-cast box girder bridge, with simple spans of 49.25 feet each. The superstructure is 27 feet wide and consists of 9 voided box sections 3 feet wide and 27" deep. Currently the driving surface is only about 2" of asphalt. Our scope of...
I have a steel storage tank which is required to be anchored because the J factor exceeds the limit for unanchored tanks. I am using the AWWA code. It is 55 feet in diameter, 55 feet high and has an OTM of 14,436 ft-kips. The anchor bolt circle is 55.5 feet in diameter. I want to use a concrete...
I have a steel storage tank which is required to be anchored because the J factor exceeds the limit for unanchored tanks. I am using the AWWA code. It is 55 feet in diameter, 55 feet high and has an OTM of 14,436 ft-kips. The anchor bolt circle is 55.5 feet in diameter. I want to use a concrete...
I have a steel storage tank which is required to be anchored because the J factor exceeds the limit for unanchored tanks. I am using the AWWA code. It is 55 feet in diameter, 55 feet high and has an OTM of 14,436 ft-kips. The anchor bolt circle is 55.5 feet in diameter. I want to use a...
I have an existing wall about 15 feet high and about 30 feet long. The wall is 15 inches thick and any reinforcing is unknown. The owner wants to install a fall protection device at mid length along the wall which will provide a concentrated torsion of 90 in kips. What is a reasonable depth...
I am structural engineer and have been tasked to design a rectangular bin hopper the contents of which is abrasive slurry with a specific gravity of 1.16. Can anyone give me the approximate angle of internal friction?
We are evaluating a 5 span concrete box girder bridge with an existing non-composite asphalt topping. After removal of the existing asphalt topping, can the proposed new 5" concrete deck be made composite with the existing concrete box girders. The bridge is 9 girders wide and the thickness of...
I have designed a 80,000 gallon water steel tank and I need some guidance on how to the anchor the tank to a concrete slab. There will 12 equally spaced anchors around a 20'-6" diameter tank. Seismic forces govern the overturning moment. The max uplift force is about 7 kips. I was thinking of...
I am struggling to understand the provisions of ASCE 7-10 regarding the building enclosure classification. I think this provision of the code is poorly written. I have a rectangular building with both long walls completely open and both short walls solid masonry with no openings in the masonry...
I was reviewing a practice problem in the NCEES study manual about locating the zero movement location along a continuous bridge. The bridge is supported at the ends by expansion bearings at the abutments and by pinned bearings at the two interior piers. The span arrangement is 40'-120'-40'...
I am a structural engineer and I am asking for assistance from the mechanical engineering community relative to the API 650 code. We are tasked with designing a flat roof (steel plate) for an acid reservoir with an internal diameter of 14 feet. When reading section 3.10 of the code, it...
