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Recent studies suggest that battered piles do not perform well in liquefiable soils during a seismic event, and that piers and wharves supported by battered piles have historically not done so well in past earthquakes because they attract significant loads and typically fail the deck, pile or...

Have a contractor that would like to use API 5L X-60 (60 ksi) steel spiral welded pipe in lieu of A252 Gr. 3 spiral welded pipe for marine structural piles. Anyone ever use API 5L pipe for structural piles? Other than the higher yield strength, I don't see much difference. API 5L is typically...

Here in the Portland area we have quite a few floating home communities. I've done some design work for pier replacements and home anchorage. Current can definitely influence the design if you're in a river. Around here if you design for a 100 year flood event, current velocity can be on the...

Hi All - hypothetical question: Let's say we have a pipeline that carries a pressurized petroleum gas product for a distance near the shoreline, and the area is subject to liquefaction and lateral spreading. Let's also say the pipeline is only full of product 5% to 10% of the time, empty the...

We're designing some pretty substantial conveyor galleries (25' wide x 100' long intermediate span) for an industrial project, in which the galleries are supported by bents every 100' and anchored for longitudinal seismic load about every 600' at a transfer tower (pinned at one tower, allowed to...

Is your wharf really flexible enough you have to account for its deck stiffness in your analysis? I am not too familiar with a structural module, but assume it's some type of modularized process equipment or similar. What is the construction of your wharf like, pile supported concrete deck? I...

Foam filled piles?? I can't imagine foam would add much structural strength to the pile as a composite section - what kind of foam are we talking about? There is a section in AISC 13th edition which addresses composite properties of concrete filled steel piles. I imagine you could modify the...

Hi Holly - I do this type of calculation quite frequently when analyzing fender piles for marine terminals. I typically do an iterative approach for impacts at different heights based on the MLLW and MHHW elevations. In short, you apply a trial static load to your fender pile or fender pile...

While I haven't had much experience with site class F, I've designed conveyor transfer towers on offshore pile foundations before. In that case, we performed dynamic analysis of the tower, piles and pile cap together as one structure since the dynamic behavior of the tower itself would be...

Yeah seems like pretty strange evaluation criteria to me - and where in the world did they come up with 1900K? Let's assume its a solid cross section, for a 16" pile that load equates to a stress of roughly 9.45 ksi. Good luck finding any concrete or timber pile that's going to handle that. A...

I agree that it seems to be an out of place spec for a fender pile - I've never designed a fender pile to take ANY axial load, but 1900K is very significant and would overload any 16" pile regardless of unbraced length I would think. Although its rare, I've seen prestressed piles used as fender...

Just passed the California civil PE w/ seismic and surveying - I personally thought that both seismic and surveying were harder than the main 8hr PE exam. However, there are probably just as many folks out there who would say the opposite. I agree with westheimer above, that the Hiner workbook...

Did you check to ensure that you assigned A572 50 ksi steel for your W8 in RISA? It typically defaults to A36 for everything unless you change it manually.

While I'm not familiar with the Canadian code, the ACI shear friction capacity is directly related to the amount of reinforcing steel crossing the shear plane. The new concrete / existing concrete interface is used to factor up or down the calculated strength up or down, depending on the...

Not to worry my friend - I killed my fair share of brain cells back in college at WSU... go Cougs! It took the threat of being booted from university and academic probation for me to realize that homework took priority over the bar - and even then it was tough! When I titled the thread "Kids...

OP here.... I see there is quite a bit of opinion out there on this one! I guess I shouldn't generalize the current generation of grads as a whole - I too am aware that there are plenty of hard working and competent young engineers out there. Heck, at 30 years old I'm still considered a kid by...

I don't know what others have experienced lately, but it seems like a lot of fresh graduates looking for work just don't want to put in the effort to set themselves apart from their peers. In the past couple weeks we've had a few engineering graduates stop by our office to inquire about open...

I would think if you're trying to simulate the adjoining tank wall as a boundary condition, it's a bit more complicated than just the cantilever equation you speak of. A cylindrical tank will have hoop stresses for example that wouldn't be accounted for using that stiffness equation. You...

Something else to consider: You should probably account for a plugged condition as well and assume that the rotating mass will be significant if this is a rotary screen. Either way, a plugged condition will have a higher operating weight, thus your fundamental frequency for the supporting...

Hi eit, is this an aggregate screen for a concrete plant? We've designed support structures for these in the past, and we typically design our structure so that there is at least a 25% difference between the operating frequency of the screen and the nearest structural modal participation based...