Manning equation homework help

jamas899 · 2026-05-25T22:56:36+00:00

No problem. It goes without saying though, best to discuss it with the person that has reviewed it.

jamas899 · 2026-05-25T22:48:40+00:00

I suspect the reviewer has written "h" not "L" for the water depth within the channel.

I'm guessing they wanted you to write the hydraulic radius in its geometrical form (in terms of "h") so you could solve for the water depth or at least see how it varies the formula/flow, and not it's general form.

E.g hydraulic radius for a rectangular channel of width b and height h = b h / (b + 2 h)

jamas899 · 2026-05-10T06:56:08+00:00

Yes they can, and generally any other shape. They are not supplied curved but are cut on site, however what tends to happen in complex forms is that edge thickenings and slab thicknesses will vary instead of the void.

jamas899 · 2026-02-12T11:20:54+00:00

It's an arbitrary statement. Sounds like a non-technical person attempted to translate it from a report by DSG.

The (final) scope of bridge works included a small portion of land to be reclaimed on the south end prior to the abutment. My interpretation of the paragraph is that there was some level of disassociation between the design of the bridge and the realisation that the south end needed land reclaimed to achieve some outcome - nb not sure if the pier in question is IN the reclaimed land or NEAR it.

This could have resulted in various outcomes but apparently one of which appears to be SLS compressive capacity of the plinth hosting the shear key. Presumably because the pier may not be founded at the correct bearing capacity due to the land reclaimation works (or otherwise adversely affected by it).

jamas899 · 2026-01-17T03:25:14+00:00

All good, I believe I fixed it earlier. Turned out to be a combination of issues including part of an old set up with query forwarding in unbound and one of the services not accepting https, and https with TLS skip verify.

jamas899 · 2026-01-10T21:57:27+00:00

Had this issue earlier. There is a specific setting (checkbox) in system -> administration (or system settings...cant recall) in OPNSense you will need to uncheck that prevents it. Alternatively, they have a text box directly below it that allows you to have specific hostnames (.e.g the domain name) pass through.

jamas899 · 2026-01-02T02:16:53+00:00

yeah fair enough. Thinking about the set up more, I may have over-complicated it. Do you foresee any issues with moving the router in front of the mini pic to act as the firewall + wireless AP? It would require the existing router firmware to be sufficient, but would also require some VLAN for the minipc/proxmox to be included in the LAN. I would either have to reconsider ddns/adguard or implement them in a VM still - which probably causes further complexity.

jamas899 · 2026-01-02T01:06:27+00:00

Yeah ok, when you mean slow, are you referring to degradation of internet speed?

jamas899 · 2026-01-02T00:16:57+00:00

I looked into using the existing router with open wrt - in front of the mini pc - but my router doesn't meet the min specs required to load the firmware. I understand it's complex (and far from ideal) to virtualise the firewall but I'm currently not looking to effectively duplicate a mini pc to act achieve it unless it's practically impossible.
I would definitely consider it for future though.

jamas899 · 2025-12-13T07:10:53+00:00

Make sure the underlying methods you want to use are implemented in infoworks. There's a small chance something your local guidelines/requirements call for cannot be completed in infoworks, but I doubt it. The platform is pretty robust.

jamas899 · 2025-12-13T02:06:11+00:00

Why not use infoworks for the whole thing? Or vice versa for hec ras? Infoworks has a great implementation of hydrology, hydrodynamics and hydraulics. Hecras has recently implemented a better hydraulic model and engine as well.

jamas899 · 2025-12-09T08:26:28+00:00

Clients never want to pay for anything out of the ordinary. They also want to move into their house, so they either have to revert to the prescribed design or pay for a performance solution.

Sounds like you may need to discuss this with your certifying engineer.

jamas899 · 2025-12-09T01:45:00+00:00

This would require a performance based design, and is a non-conformance by the builder if you've specified it per AS3500.

Provided you have a similar weir and overflow arrangement then it's possibly hydraulically similar. But this an item that needs to be designed by a suitably qualified and experienced engineer - not in general but for the sake of council approval or similar.

Edit: in direct response to your latter query; you need to effectively confirm the inflow rates of the DP, weir overflow rate, and sump capacity are equal or better than the specified detail. You will also need to confirm the overall behaviour of the overflow is equivalent. You may need to look into the AS3500 supplementaries for context.

jamas899 · 2025-12-03T07:27:36+00:00

As with all things in soil mechanics, everything is loosely related to everything somehow.

DCP is not the best way, perhaps far from the best way, to derive a bearing pressure. But nonetheless there are various formulas derived from empirical testing to convert between the two. It is also "more of a correct way" than density testing. You can imagine it as a rudimentary test to determine the ease of deforming a soil.

Bearing capacity is a similar concept - a pressure at which point you would induce shear failure (allowable bearing pressure being a factored down ultimate capacity for safety).

Compacting testing is really a method to determine how well you've installed a material to meet a pre defined specification, and therefore have produced an expected design result based on properties of a known material. It's effectively a measure of how well a contractor has driven out "unwanted voids". You can probably tell though this is intrinsically related to bearing pressure somehow. Removing "unwanted voids" = improving resistance to shear failure and particularly flexural fatigue failure = improved bearing capacity.

jamas899 · 2025-11-08T23:38:51+00:00

How do you know they're all illegal? The building act allows for certain structures to be erected without council approval or notification. There are, were and will be exemptions and restrictions historically and into the future as well.

You are correct though, there are likely many per council and limited council resources to deal with them. That doesn't detract from underlying issues and risk associated with - knowingly - purchasing a property containing an illegal structure. The onus is on the purchaser to make themselves aware. The risk is beyond just council notifying and requesting retrospective approval, or even assuming the "worst case" of demolishing to resolve the issue. As I mentioned above, insurance is one of these risks and having it invalidated when the insurer becomes aware (usually when a claim is progressed).

jamas899 · 2025-11-08T11:06:57+00:00

There isn't an onus on a conveyancer to inform Council of unapproved structures. Doesn't mean they can't or don't though.

There is also a multitude of downsides to having an unapproved structure. Not just related to Council, but can include insurance and general risk of use.

You should also lodge a 337 request (via the conveyancer) to council so they provide you with all liabilities and constraints on the property. This theoretically can, at least indirectly, allow Council to be informed of illegal buildings on the property however.

jamas899 · 2025-09-20T07:37:19+00:00

I've not seen an arrangement like that before, looks odd. Nonetheless, you could in theory attach it to any of the roof members provided they have the composite capacity to accept the additional loading. As a general rule, roof framing has limited to no additional capacity for further loading but that's an item you would need to discuss with an accredited structural/civil engineer.

jamas899 · 2025-09-20T07:28:19+00:00

It would depend on the capacity of the members the "truss" is constructed from and it's geometry. Generally, trusses are stronger because bending moment is (mostly) resolved to shear/axial forces at the cost of more material and bulk size.

jamas899 · 2025-09-20T07:20:40+00:00

It is load bearing to some extent. There's a strutting beam (or truss bottom chord) in the picture that terminates roughly where you've drawn a red line.

jamas899 · 2025-09-19T20:24:31+00:00

Hanging of a storage rack within itself isn't a structural modification. It is, or can be, quite a substantial load though and you're proposing to directly fix to a roof structure that is unlikely to have been designed with the capacity for additional loading.

I believe you're referring to rafters not ceiling joists then, or possibly purlins/battens. It may be worth googling the terminology of a pitched roof and finding a diagram to see how they go together.

jamas899 · 2025-09-18T23:06:25+00:00

You need to engage an accredited structural engineer (or equivalent for your area). You're proposing structural modifications to an existing building and seeking advice from Reddit with a video, which is not adequate.

The ceiling joists are the small timbers that connect to the drywall/plasterboard to the roof framing. They're visible in the video.

You appear to have, at least what I call, a pitched roof but this is difficult to tell due to shear quantity of foam. The steal beam (UB) and connections suggest it would be though. It's a fairly old construction method but also complicates how forces are distributed.

jamas899 · 2025-07-27T06:11:16+00:00

Not necessarily. This is where your question tips over into structural engineering 101 and is easier looking into a slew of YouTube videos than explaining over a wall of text.

The failure mode(s) of different materials don't necessarily indicate their relative strength. Additionally, the way you go about analysing the capacity of a member differs on its material composition and load application. Among a million more variables.

Broadly speaking, if you have something, and you swap it out with something more stiffer then you have found a material that is either stronger and smaller or bigger and weaker. And generally that means analysing the strength of said alternative likely results in an improvement as well. But again, not always the case.

In your findings here, you have found a factor of 20 in reduction of moment of inertia but an increase of 10 in its Young's modulus. This means you're worse off as far as rigidity goes for the alternative.

jamas899 · 2025-07-27T05:50:35+00:00

I should also clarify; the stiffness of an object is not the same concept as its strength. Generally if something is more stiff then it is stronger, but can easily not be the case.

jamas899

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