Dave Rogowsky: Good morning. I see Peter.
Dave Rogowsky: Is that Peter from Queens?
Dave Rogowsky: Huh!
peter: Hey!
Marco Carlini: And everything.
Marco Carlini: Body.
peter: It's a lot of echo.
Dave Rogowsky: Yeah.
Dave Rogowsky: Good morning. Peter.
peter: Morning.
Dave Rogowsky: You have a lovely background. Is that fake or real.
peter: It's no, it's actually real. You may be able to see the trees moving. No, it's a Queen's holiday.
peter: you know.
Dave Rogowsky: Oh!
peter: In lieu of in lieu of Monday, being a holiday, we get an extra holiday because queens want to save money.
peter: so they turf us out.
peter: they're into firing people these days.
peter: anyway.
Dave Rogowsky: Up.
Dave Rogowsky: I remember the days
Dave Rogowsky: when in Manitoba, when Gary Filming was the Premier. Yeah, these were called Film and Fridays.
peter: Yes. Well, we had ray days in the past. Okay, and now it's
peter: I don't know. It's Queen stays, I guess. But yeah.
peter: whatever what.
Dave Rogowsky: See.
Dave Rogowsky: I think we looks like we have most of the people who will be able to join us.
Dave Rogowsky: so 1st thing on the agenda was a presentation, or at least a discussion, on the factors of safety and some related issues and thinking about preparing this presentation.
Dave Rogowsky: The audience that that we have, I believe, are going to be mostly mechanical engineers
Dave Rogowsky: and some scientists.
Dave Rogowsky: and only one or 2 structural engineers.
Dave Rogowsky: So I've tried to keep it, use a vocabulary, and and I present the ideas with that audience in mind.
Dave Rogowsky: The
Dave Rogowsky: outline for the presentations really to talk about what a safety factor is
Dave Rogowsky: some typical values that are used. Now, ways of selecting a factor of safety
Dave Rogowsky: issues with the factor of safety approach to design.
Dave Rogowsky: And we'll talk about limit States design, which is the current.
Dave Rogowsky: procedure for structural design, and has been for at least the last 4 decades.
Dave Rogowsky: And then, finally, we'll end up with some insights on what we learn from the history of failures.
Dave Rogowsky: and and how that may or may not relate to the selection of factors of safety.
Dave Rogowsky: and it'll
Dave Rogowsky: so
Dave Rogowsky: And this I'm entirely interruptible. So if you have any questions.
Dave Rogowsky: Could you please raise your hand? And Anson, if you could just watch to see if there's a hand raised
Dave Rogowsky: or just speak up.
Dave Rogowsky: Yeah. So the factor of safety.
Dave Rogowsky: Well.
Dave Rogowsky: as a structural engineer. I'm often asked by nonstructural engineers, what factor factor of safety do we need?
Dave Rogowsky: And the glib answer is that it depends on your definition and your risk tolerance.
Dave Rogowsky: Dan.
Dave Rogowsky: the factor of safety that we choose, because we we can select that if we, if we want to go, that route
Dave Rogowsky: should be at least as great as that required in the any of the applicable design, codes and standards.
Dave Rogowsky: so that
Dave Rogowsky: definition for a factor of safety according to Wikipedia, and it
Dave Rogowsky: in simple layman's languages
Dave Rogowsky: that the factor of safety expresses how much stronger a system is
Dave Rogowsky: than it needs to be for the intended use.
Dave Rogowsky: The factor of safety is also known as a safety factor
Dave Rogowsky: and in equation form, the safety factor is basically the ratio of capacity to demand.
Dave Rogowsky: And that's the ratio of the structure's absolute strength
Dave Rogowsky: to the actual applied forces
Dave Rogowsky: or loads.
Dave Rogowsky: it's non-dimensional.
Dave Rogowsky: which is good.
Dave Rogowsky: so
Dave Rogowsky: some people refer to the factor of safety as really a factor of ignorance. The the factor of safety is really can be thought of as a measure of the designer's uncertainty
Dave Rogowsky: in the loading scenarios, the loads that are applied, how they're applied, the analytical models that we use for the analysis failure, theories.
Dave Rogowsky: the material property data
Dave Rogowsky: that we use.
Dave Rogowsky: and we take that into account in choosing a factor of of safety that recognizes our degree of uncertainty
Dave Rogowsky: about these things. Now many systems are intentionally built with much stronger
Dave Rogowsky: than needed for the normal use.
Dave Rogowsky: and that's to improve reliability. It allows for emergency situations, unexpected loads, misuse and degradation.
Dave Rogowsky: Then a factor of safety is a good thing to have in your back pocket
Dave Rogowsky: up
Dave Rogowsky: this slide shows, some indicative values to to put things in perspective.
Dave Rogowsky: Norton, who's a mechanical engineering professor and author. All
Dave Rogowsky: we have. The reference will be on the next slide.
Dave Rogowsky: He he says that
Dave Rogowsky: commercial aircraft
Dave Rogowsky: have a factor of safety, of about 1.2 to 1.5 typically. And he says you should think about that next time you go on a flight.
Dave Rogowsky: Do you want them? Have a bigger factor of safety than that?
Dave Rogowsky: Well, I think the success with the aircraft, industry and and airlines is that we don't crash too many planes.
Dave Rogowsky: Because the the factor of safety is too low.
Dave Rogowsky: Norton points out that military aircraft are designed with a factor of safety less than 1.1,
Dave Rogowsky: but he points out that the crew wear parachutes.
Dave Rogowsky: and that test pilots get paid very well to prove that confirm that the factor of safety is actually greater than one.
Dave Rogowsky: Missiles are apparently designed with a factor of safety of one
Dave Rogowsky: point 0.
Dave Rogowsky: They don't have a crew, and they're really not expected to return.
Dave Rogowsky: So you can get by with some some very low factors of safety and those types of applications.
Dave Rogowsky: I went into an old steel code
Dave Rogowsky: where factors of safety were
Dave Rogowsky: who are the basis for the allowable stresses.
Dave Rogowsky: And in the Canadian code for steel buildings it ranges from about 1.6 7 to 2.5
Dave Rogowsky: is a typical factor of safety that was used for the design of steel buildings in Canada.
Dave Rogowsky: We go to lifting devices.
Dave Rogowsky: They're a little bit.
Dave Rogowsky: I'm more serious, because if you drop something while you're lifting it, the consequences can be large. So the factors of safety are typically between 2 and 6,
Dave Rogowsky: and it can be as high as 10 if you're lifting people.
Dave Rogowsky: And
Dave Rogowsky: the last item are aquariums. I thought that was interesting.
Dave Rogowsky: because they're made out of acrylic or pmma.
Dave Rogowsky: And
Dave Rogowsky: like, according to the literature, aquariums typically are designed with a nominal factor, safety of 12,
Dave Rogowsky: and that includes the aquarium that failed in Berlin a few years ago.
Dave Rogowsky: So, even though a factor of safety of 12 looks very generous.
Dave Rogowsky: that aquarium in in Berlin failed, for whatever reason
Dave Rogowsky: that's not yet made public. Apparently.
Dave Rogowsky: So those are typical values.
Dave Rogowsky: this slide is from Norton, and there's a reference. It's actually on a
Dave Rogowsky: a really good reference for machine design.
Dave Rogowsky: And
Dave Rogowsky: what Norton does is he has a short section on on Factors of safety, and this is taken from there.
Dave Rogowsky: and he reckons that you base it on.
Dave Rogowsky: the type of information you have and the quality of the information like I refer to that as uncertainty.
Dave Rogowsky: So
Dave Rogowsky: he ends up with, and the final right hand column.
Dave Rogowsky: a. A typical factor of safety. And there's a factor f, 1 f. 2 and F. 3
Dave Rogowsky: for the 3 different primary sources of information.
Dave Rogowsky: So on material side.
Dave Rogowsky: the factor of safety can be, he says, 1.1.
Dave Rogowsky: If you actually
Dave Rogowsky: test the material that's being used.
Dave Rogowsky: That's not often the case. You have to design it beforehand.
Dave Rogowsky: You buy the material, and then.
Dave Rogowsky: if you're lucky, you can get what are called mill test certificates
Dave Rogowsky: when it was manufactured to show you the material strengths. For let's say, the steel products that you're getting.
Dave Rogowsky: It would be rare to buy the product and then do the material testing on it to find what you actually have.
Dave Rogowsky: Then you get representative testing of the material
Dave Rogowsky: that could be product data sheets.
Dave Rogowsky: Fairly representative, that could be textbook values
Dave Rogowsky: and poorly represented.
Dave Rogowsky: You know how bad is the information? Well, you might need a factor of safety 5 or larger
Dave Rogowsky: in
Dave Rogowsky: Norton's work with machines the environmental conditions are apparently important.
Dave Rogowsky: so are the best case is that the environmental conditions and use are identical to the material test conditions.
Dave Rogowsky: we don't have that for the components that are in the detector. Because in general we don't test our materials at cryogenic temperatures. We don't have that data usually.
Dave Rogowsky: The next best situation is we're essentially ambient environmental
Dave Rogowsky: conditions, and that would apply to things like all of the assembly tools.
Dave Rogowsky: And then we go on to more and more extreme conditions. And again, if it's really extreme
Dave Rogowsky: factors of safety bigger than 5 might be required.
Dave Rogowsky: And then the final consideration, when you're
Dave Rogowsky: according to Norton, it is what he calls analytical models for loading and stress.
Dave Rogowsky: and the model
Dave Rogowsky: is not
Dave Rogowsky: strictly the finite element
Dave Rogowsky: model.
Dave Rogowsky: but it also includes the modeling of the loads
Dave Rogowsky: in in that. And that's where most of the uncertainty is. Today. Most engineers with experience can do a pretty good job of doing the analysis.
Dave Rogowsky: If they know what loads to put in, and in particular, what load combinations we have.
Dave Rogowsky: So you can see again, there's a wide range there from 1.1 to 5.
Dave Rogowsky: So what
Dave Rogowsky: Norton says that these are his typical values for a ductile material, and you use the largest of f, 1 f. 2, or f. 3.
Dave Rogowsky: And then, if the materials are brittle, you double it.
Dave Rogowsky: Are there any questions or comments?
Dave Rogowsky: be a good place to stop. If anybody's awake.
Dave Rogowsky: I'd I'd be interested in feedback from the mechanical engineers to
Dave Rogowsky: if if on on. If this is the way you do it.
peter: So sorry. Okay, so so these factors, you use the product of them as the final safety factor or.
Dave Rogowsky: No, the the large, the largest.
peter: The large.
Dave Rogowsky: The largest
Dave Rogowsky: that way.
peter: In a funny way, though, doesn't it? Oh, okay, whatever, never, never mind.
Dave Rogowsky: Yeah, I know what you're saying.
Dave Rogowsky: but, John, can I pick on you?
Dave Rogowsky: I think you're a mechanical.
John Brandt: Technically, yeah.
Dave Rogowsky: Yeah, technically, okay,
Dave Rogowsky: is this sort of in line with the way mechanical engineers approach the factor of safety.
John Brandt: Generally. Yeah. It depends somewhat on the application. There are means of using combined or average safety factors
John Brandt: in mechanical design. I've I've done that in the past, but it depends on the end use and how much you really are willing to.
John Brandt: How much you're really willing to trust your materials and your design to
John Brandt: actual loading. It's
John Brandt: as it is says in the the name. It's a safety factor. So it's it's a little bit of buffer depending on how sure of your calculations for your material strength and your design, you are.
Dave Rogowsky: Yup, I boy, nothing.
Dave Rogowsky: Okay. I see Marco has a hand up.
marco carlini: Yeah,
marco carlini: I, I can. I can say my knowledge of the European codes for buildings, for civil engineering structures normally for a material resistance. So let's say the for example, the stress.
marco carlini: the we, we use 1 point O 5 safety factor on the material. And this is somehow, let's say, justified by the fact that the steel, for example, used in civil engineering construction must follow, you know, dedicated rules, and these somehow allows us to use lower values. But
marco carlini: but I think this is somehow different from the 1st batch of the let's say, factors, you are using.
Dave Rogowsky: Yup, absolutely. You're absolutely correct. And you're a civil or structural engineer, right?
marco carlini: Actually, I am a process engineer. But with some, yeah, with with some with some yeah, good. Yeah.
Dave Rogowsky: So the next the next slides will will lead into the the limit States design approach eventually with load and resistance factors. So I I
Dave Rogowsky: I thank you for that.
Dave Rogowsky: and it's a good introduction to the next slide.
Dave Rogowsky: Because Norton points out that
Dave Rogowsky: you have
Dave Rogowsky: I
Dave Rogowsky: guidance, and maybe obligatory rules in the codes and standards that we design to. So we can select the factor of safety, which is bigger, but should not be less than
Dave Rogowsky: what is in the governing Co host for the item that we're designing.
Dave Rogowsky: And
Dave Rogowsky: this little table
Dave Rogowsky: basically shows you where the rules are in different parts of the world, Canada and specifically Alberta, Europe and the Us.
Dave Rogowsky: And
Dave Rogowsky: the way loads are defined in the design standards
Dave Rogowsky: and candidates in the building code
Dave Rogowsky: part 4
Dave Rogowsky: in Europe. It's Eurocode one. If if I'm correct, Marco.
Dave Rogowsky: and in the US it'll be asce. 7. That's American society for civil engineering 7.
Dave Rogowsky: And all of those documents have a good description
Dave Rogowsky: of what loads minimum load should be applied, and that covers
Dave Rogowsky: everything from estimating itself weight to live loads due to use and occupancy, like people moving around or equipment moving around. Wind loads.
Dave Rogowsky: thermal load cases where the temperature changes and earthquakes. So that's there's a
Dave Rogowsky: a set of standards for determining the loads.
Dave Rogowsky: The next thing you need to do is you need to have a way of determining the cup
Dave Rogowsky: you're gonna let back. So you got the loads and you could put those into a finite element package.
Dave Rogowsky: The next thing you need are a way of estimating the capacity of the members
Dave Rogowsky: and for steel structures.
Dave Rogowsky: In Canada it's a Canadian Standard Association, s. 1620, 19 version in Europe. It's euro Code 3,
Dave Rogowsky: which when I looked it up and started going through it, it's actually apparently 20 different documents
Dave Rogowsky: depending on what type of steel structure you've got and what problem you have.
Dave Rogowsky: And in the Us.
Dave Rogowsky: It's a
Dave Rogowsky: American Institute of Steel Construction, Aisc
Dave Rogowsky: 3, 6, 0.
Dave Rogowsky: And these are all comparable in the way they approach the computing the capacity of a member like a column for buckling or a beam for bending.
Dave Rogowsky: And
Dave Rogowsky: that's that's the capacity of the problem of the
Dave Rogowsky: that you can then check the finite element analysis against the available capacities.
Dave Rogowsky: And then finally, I added a line there for
Dave Rogowsky: lifting situations. And I think it typically call them below the hook, lifting devices. So it's not the crane itself, but everything below the crane hook.
Dave Rogowsky: and those are treated a little differently than steel structures.
Dave Rogowsky: In Canada. In the Us. We use an A. SME. American system
Dave Rogowsky: Society for Mechanical Engineering.
Dave Rogowsky: VHT. 1 which is below the hook.
Dave Rogowsky: And then in Europe.
Dave Rogowsky: Marco sent us this standard. It's a euro norm. 13, 1, 5, 5.
Dave Rogowsky: And when I've looked at them they're they're basically comparable.
Dave Rogowsky: there are a little bit of differences, but
Dave Rogowsky: you can go into these standards.
Dave Rogowsky: and you won't find an explicit factor of safety. But they have a way of
Dave Rogowsky: dove.
Dave Rogowsky: because it's embedded in the in the rules.
Dave Rogowsky: So the
Dave Rogowsky: when when we get into the codes. So this is a slide from
Dave Rogowsky: the last Canadian steel code that actually had
Dave Rogowsky: a clear, unambiguous statement about assume factors of safety.
Dave Rogowsky: It dates to 1969. That was the last code that used a
Dave Rogowsky: what we call allowable stress design, where we take the
Dave Rogowsky: material strength and divide by a factor of safety
Dave Rogowsky: and then get allowable stress. And we compare that to the applied stress. So
Dave Rogowsky: there's quite a bit of variation
Dave Rogowsky: in
Dave Rogowsky: the stress that's used
Dave Rogowsky: and this factor of safety on it.
Dave Rogowsky: So if we look at
Dave Rogowsky: axial tension members
Dave Rogowsky: and parts.
Dave Rogowsky: the factor of safety is about 1.7 on the yield stress
Dave Rogowsky: on the net section.
Dave Rogowsky: so we've got a
Dave Rogowsky: factor of safety 1.7 or thereabouts. But it's a factor of safety, of 2 on the 10 cell strength.
Dave Rogowsky: and the difference between yield and tensile is yield is is basically where the material starts to stretch uncontrollably
Dave Rogowsky: as it stretches, its strain hardens, and eventually it ruptures, and the rupture. Strength is the tensile strength.
Dave Rogowsky: So we have a factor of safety, of 1.6 7 on yield and 2 on
Dave Rogowsky: on rupture.
Dave Rogowsky: and the way the code rules are formulated.
Dave Rogowsky: we. The growth section, should be capable of attaining the yield stress
Dave Rogowsky: on the growth section before the next section.
Dave Rogowsky: Change achieves the tensile strength.
Dave Rogowsky: and the net section is where the the cross section is reduced. So if we have a threaded rod at the ends, you've got threads that are cut in. There's less cross sectional area that's called the net section. We want to make sure that
Dave Rogowsky: the overall rod can yield before the net section fails
Dave Rogowsky: in at the tensile strength. So there's some subtleties in how you apply the the factor of safety for bolts in axial tension. It's a factor of safety of 1.5 on the specified tensile strength.
Dave Rogowsky: Then, when we go to
Dave Rogowsky: axial compression, numbers and parts.
Dave Rogowsky: the factor of safety depends on the slenderness.
Dave Rogowsky: If we have stocky column short members stocky where
Dave Rogowsky: buckling doesn't occur.
Dave Rogowsky: then we have a factor of safety of 1.6 7 on the yield stress.
Dave Rogowsky: That's as good as it gets if we go to this
Dave Rogowsky: far-end, most slender member at the bottom.
Dave Rogowsky: and with a kale over our
Dave Rogowsky: that puts us into an oiler buckling range.
Dave Rogowsky: Then we have a factor of safety of 1.9 2,
Dave Rogowsky: and that's on the Euler buckling stress, not the yield stress.
Dave Rogowsky: because buckling can occur
Dave Rogowsky: that stress is well below yield.
Dave Rogowsky: And then finally, we get into bending situations for beams. It's the same situation, and in this case. If the beams have the compression plans braced.
Dave Rogowsky: it's 1.6 7
Dave Rogowsky: and then for unbrace sections where a beam can fail by lateral torsional buckling.
Dave Rogowsky: It's a stability failure similar to column buckling, and it has a factor of safety of 1.9 2, and then finally for shear 1.6, 7, and bolts again, or have a higher factor. Safety of 2.5
Dave Rogowsky: of
Dave Rogowsky: and those are
Dave Rogowsky: these are all against
Dave Rogowsky: normal working loads, like the nominal loads.
marco carlini: So. So when you say nominal, you mean you don't apply any safety factor on the load.
Dave Rogowsky: No factor safety on the load. This is the old way of doing it.
marco carlini: Okay. Okay.
Dave Rogowsky: And
Dave Rogowsky: so this is the old way. And so some of the issues with the old way. The factor of safety concept
Dave Rogowsky: was that while a factor of safety can provide a relative comparison between 2 designs.
Dave Rogowsky: you can compare the factor of safety as a number. It doesn't provide any indication of the probability of failure.
Dave Rogowsky: It doesn't consider, does not consider the risk
Dave Rogowsky: and risk is defined as the probability of failure. Times the consequences of failure
Dave Rogowsky: the consequences can be measured in dollars or people killed.
Dave Rogowsky: So
Dave Rogowsky: the
Dave Rogowsky: the fact safety factor approach actually doesn't
Dave Rogowsky: address this. You would think that high risk members should have a higher factor of safety than low risk members.
Dave Rogowsky: A 3rd observation is that
Dave Rogowsky: it doesn't recognize that loads with high uncertainty should have a higher factor of safety than loads that are well known.
Dave Rogowsky: We'd have the same factor of safety, whether it was a dead load or a live load, and that
Dave Rogowsky: it doesn't.
Dave Rogowsky: That doesn't make statistical sense.
Dave Rogowsky: And then, finally.
Dave Rogowsky: when loads are counteracting, you can actually produce unsafe situations.
Dave Rogowsky: And I'll explain what that is
Dave Rogowsky: in the next slide.
Dave Rogowsky: Okay, so
Dave Rogowsky: can you see the slide.
John Brandt: Yep.
marco carlini: Yup! Yup!
Dave Rogowsky: Okay, yeah. So this is my
Dave Rogowsky: Hello, Professor Blackboard, whiteboard type sketching. The situation on the left is where we have the nominal working loads with no load factors. We have an object.
Dave Rogowsky: It could be a piece of equipment or a structure and then keep it simple. We have. It only has dead load acting down.
Dave Rogowsky: and in this case there's a horizontal load from wind.
Dave Rogowsky: and
Dave Rogowsky: the wind wants to tip the the object over. It creates more compression, on the left side.
Dave Rogowsky: on the support, and less on the right side.
Dave Rogowsky: So
Dave Rogowsky: the object that has anchored down with anchor bolts.
Dave Rogowsky: And we see this pressure distribution on the underside.
Dave Rogowsky: And what you find out is that the support reactions from below in this
Dave Rogowsky: example, or all compressive.
Dave Rogowsky: there's no design force for the anchor bolt, so small bolts are used.
Dave Rogowsky: what actually happens in what we call the ultimate load case
Dave Rogowsky: where the real
Dave Rogowsky: is not the average wind on a windy day, but it's the extreme value. In a wind event it could be 50 higher.
Dave Rogowsky: so we increase the the wind load by a factor of 1.5.
Dave Rogowsky: And then, when you actually
Dave Rogowsky: look at the statistics quite often, members are underweight.
Dave Rogowsky: so you can't rely on the full deadlon
Dave Rogowsky: to resist overturning.
Dave Rogowsky: And if it's 90%,
Dave Rogowsky: the dead load 0 point 9, that's a typical load factor for an overturning
Dave Rogowsky: load case.
Dave Rogowsky: The distribution of support reactions.
Dave Rogowsky: Changes dramatically from this trapezoid to a couple of triangular distributions. We got large compression on the left side. We get some large tensions. Over on the right
Dave Rogowsky: the anchor bolt, see large forces, and they fail.
Dave Rogowsky: and
Dave Rogowsky: this is a simplification of the ferry bridge. Cooling tower collapse
Dave Rogowsky: furry bridge power generating station in the Uk.
Dave Rogowsky: Had these huge hyperbolic, paraboloid cooling towers.
Dave Rogowsky: These are typically what you see when you, when people have. An idea what a picture of a nuclear power plant looks like!
Dave Rogowsky: And the cooling tower
Dave Rogowsky: was anchored with anchor bolts.
Dave Rogowsky: and it was designed by the allowable stress approach on the left.
Dave Rogowsky: and when the extreme wind force develop.
Dave Rogowsky: we and had the case on the right, and it failed.
Dave Rogowsky: And for me. That was, I started out life in the early 70 s.
Dave Rogowsky: As an allowable stress
Dave Rogowsky: safety factor kind of guy.
Dave Rogowsky: In this case history convinced me that
Dave Rogowsky: we need another way. And that way.
Dave Rogowsky: is
Dave Rogowsky: what's what's called limit States design.
Dave Rogowsky: And that's the
Dave Rogowsky: the design methodology. That
Dave Rogowsky: and structural design started in the 1970 S. And all the major codes in the world transition
Dave Rogowsky: to a limit State design philosophy in the Us. It's known as
Dave Rogowsky: load and resistance factor design.
Dave Rogowsky: Lrfd. Because Lsd had a bad connotation in the 70 s.
Dave Rogowsky: So the essence of limit States design is, is, talk about the
Dave Rogowsky: the limiting States.
Dave Rogowsky: A limiting state is a condition
Dave Rogowsky: of a structure beyond which it is no longer, it no longer fulfills
Dave Rogowsky: the relevant design. Criteria
Dave Rogowsky: There are a variety of limit states. The 1st one we talk about is a serviceability limit state
Dave Rogowsky: you wanna make sure that it doesn't deflect or vibrate too much to interfere with use under normal loading.
Dave Rogowsky: The ultimate limit state is a check against structural failure. That's the safety limit state.
Dave Rogowsky: And those are the 2 most common ones that will affect us.
Dave Rogowsky: There's also fatigue, limit, state, and a few others that we don't have to get into
Dave Rogowsky: the
Dave Rogowsky: and what you have to do is you've got to go.
Dave Rogowsky: And
Dave Rogowsky: for all members and connections
Dave Rogowsky: they're checked for all limit states.
Dave Rogowsky: And it's a lot more work than the simple factor of safety approach.
Dave Rogowsky: But that is the the essence of limit states design.
Dave Rogowsky: The yeah.
Dave Rogowsky: Just for serviceability limit, state. We use the nominal loading and nominal material factors with only adjustments for overload or under strength.
Dave Rogowsky: and we compute the deflections or vibrations. If if vibrations an issue.
Dave Rogowsky: I point out that serviceability is really subjective.
Dave Rogowsky: a deflection that's acceptable to one building owner
Dave Rogowsky: may not be acceptable to another building owner.
Dave Rogowsky: and in dark side.
Dave Rogowsky: Our allowable deflections are controlled
Dave Rogowsky: to a large extent by the scientific requirements.
Dave Rogowsky: Our deflection limits are
Dave Rogowsky: at least an order or 2 orders of magnitude more stringent than you would have in a typical building.
Dave Rogowsky: Hello.
Dave Rogowsky: and that's 1 where we'll we have to watch
Dave Rogowsky: very carefully when we analyze something that it doesn't deform excessively because we can ruin the science. Typical example was the deflection of the anode with the creep
Dave Rogowsky: would put it so far out of flat that the science would be compromised.
Dave Rogowsky: The
Dave Rogowsky: most important one for safety is the ultimate limit state
Dave Rogowsky: and the strategy is, we take the nominal capacity
Dave Rogowsky: of the member or the part
Dave Rogowsky: and reduce it
Dave Rogowsky: by a material
Dave Rogowsky: or member resistance factor.
Dave Rogowsky: And this results in a factored resistance.
Dave Rogowsky: And that really represents the capacity.
Dave Rogowsky: So, Marco, I think you pointed out that in Europe
Dave Rogowsky: you have a partial safety factor on the much, on the resistance of
Dave Rogowsky: 1 point. 5
Dave Rogowsky: typically.
marco carlini: That that's correct, let's say between 1.0 5 and 1.1 normally. So if you, for example can justify the fact that you have used the steel from with the meal test certificate showing, that is you? Let's say, complying with European norms. Still that then you can use 1 0 5. Normally.
Dave Rogowsky: Yeah. So in in Europe, y, your factors, you divide the material strength by a factor than bigger than one.
Dave Rogowsky: In North America. We take the materially, and we
Dave Rogowsky: capacity strength, and we multiply it by a factor less than one.
Dave Rogowsky: So it's just a different way of formulating the
Dave Rogowsky: the uncertainty and the material and resistance.
Dave Rogowsky: So the factory resistance is going to be smaller than the nominal resistance of a member.
Dave Rogowsky: So on the
Dave Rogowsky: loading side, we take the nominal loads
Dave Rogowsky: and we increase them by what we'll call load factors.
Dave Rogowsky: The load, the magnitude of the load factor deals with the uncertainty in the loading.
Dave Rogowsky: So a dead load, which is fairly well known will have a small load factor of something like 1.2 or 1.2 5 typically and a live load
Dave Rogowsky: or a wind load or a snow load would have a load factor of about 1.5,
Dave Rogowsky: because they're they're they're less well known.
Dave Rogowsky: So this results in factored loads.
Dave Rogowsky: You take the factored loads and you perform a structural analysis. Let's see with FE.
Dave Rogowsky: And what you get.
Dave Rogowsky: or what we call factored load effects.
Dave Rogowsky: not stresses. They're factored low defects, and they would be member forces like an axial force, a shear force
Dave Rogowsky: bending moment or torsional resistance.
Dave Rogowsky: and you get that for each member or connection in your your structure.
Dave Rogowsky: So these factored load effects
Dave Rogowsky: represent the demand on the members.
Dave Rogowsky: and
Dave Rogowsky: there are really many load combinations that must be considered.
Dave Rogowsky: what I've observed in dark side is that
Dave Rogowsky: there's lots of good finite element analysis being done, but
Dave Rogowsky: not very many different loading scenarios are being considered yet.
Dave Rogowsky: and a loading scenario is is what we call a load combination.
Dave Rogowsky: You know, combination of loads that are applied to our structure.
Dave Rogowsky: and there are a lot
Dave Rogowsky: in general. We have the advantage that we don't have to worry about wind loading because we're indoors. We don't have to worry about rain loading or snow loading.
Dave Rogowsky: but it still leaves
Dave Rogowsky: a lot of situations
Dave Rogowsky: that must be considered, especially during construction.
Dave Rogowsky: So that's the
marco carlini: But state.
marco carlini: Dave, if I can say just one, let's say one curiosity. For example, in Europe we also the deadlock we divide between structural deadlock on which we apply normally 1.2
marco carlini: for the non-structural parts. That loading we apply 1.5. If it's not well known, let's say, or we can go down to 1.2. If the non-structural that loading is very well known or defining the project.
Dave Rogowsky: No, that that that's absolutely correct.
Dave Rogowsky: The current
Dave Rogowsky: formulations and the codes
Dave Rogowsky: recognize the statistics of the of the the loading by their nature, and if dead load is the only load acting, it needs a load factor of 1.4,
Dave Rogowsky: which is higher than when the the dead load is combined with other factors. So there's some
Dave Rogowsky: combine it. Combinatorial statistics that go into that.
Dave Rogowsky: But they end up with
Dave Rogowsky: doing a check with what we call the limit state equation.
Dave Rogowsky: So the the safety check is this one in red. The factored resistance has to be greater than or equal to the factored load effect.
Dave Rogowsky: And
Dave Rogowsky: you've
Dave Rogowsky: so many of the structural engineering analysis packages. The fea programs that are used
Dave Rogowsky: can actually perform a code check
Dave Rogowsky: sometimes called a unity check.
Dave Rogowsky: and it's done member by member and load combination by load combination.
Dave Rogowsky: And
Dave Rogowsky: in a typical
Dave Rogowsky: real world structure there can be between 300 500 load combinations that actually have to be checked.
Anson Wong: Hey!
Dave Rogowsky: And it's good.
Dave Rogowsky: Yep.
Anson Wong: Who has his hands up for a while.
Bruce Vogelaar: Oh, sorry! Just
Bruce Vogelaar: finish your sentence, Dave, so it's fine.
Bruce Vogelaar: So the question was.
Bruce Vogelaar: do we have earthquake things? We have to add to all this as well, and.
Dave Rogowsky: We.
Bruce Vogelaar: Sifts.
Dave Rogowsky: We do?
Dave Rogowsky: that'll be if we have time and get to it, there'll be a short one on construction earthquake during construction.
Dave Rogowsky: because we have a lot of situations where it's not fully braced. And we have to deal with that.
Dave Rogowsky: you know. And ultimately, I believe we have to deal with the earthquake in the experiment itself.
Dave Rogowsky: And, Marco, maybe you can tell us a little bit more because you've been involved with the earthquake assessment for the cryostat
Bruce Vogelaar: And.
marco carlini: Yeah, yeah, that that that's definitely was taken into account for the Graus, that Bruce and the the the. Let's say, I I think we don't have time to go into the details. But the Italian code was followed with the with the most stringent class
marco carlini: which is normally used, for you know, hospitals or bridges, or stuff like that which resulted in a design spectrum which was around 0 point 4 or something. A G
marco carlini: that that was the design. The design spectrum used.
Bruce Vogelaar: And segment? Do they allow us to do our own code check? Or do we need to hire contractor to come in and
Bruce Vogelaar: and confirm all these analysis, because it seems like that would be a big time cost actually to to have it done.
marco carlini: So that's a good question. And
marco carlini: the Dave you want to answer.
Dave Rogowsky: I'm I'm sorry I missed that sound broke up a bit. Could you repeat that.
Bruce Vogelaar: Do we
Bruce Vogelaar: do? They allow us to do our own code checking, or do we have to hire a 3rd party to come in and verify that we've done everything right because that sounds like it could be.
Bruce Vogelaar: Take a lot of time and actually be fairly expensive to do.
Dave Rogowsky: Absolutely correct. And and I'm the wrong person to answer that because I am not they, I think the collaboration senior management have to make a decision on the
Dave Rogowsky: the type of checking that they require.
Dave Rogowsky: said we.
marco carlini: So. What I can say, Dave, if I can interject, is that the the approach I've seen in the past for projects at LNG? Yes, is that for civil engineering structure? we have an official deposit of the documentation to a external authorities.
marco carlini: and these was either done by engineers of LNG. Yes, or by 3, rd the party authorities. But anyhow, these would be checked by 3rd party for a temporary structures or structures which are, for example, support of the of the detectors, which are not meant as engine civil engineering structures.
marco carlini: This was enough to provide
marco carlini: a calculation, not from the collaboration to Lngs. And this does not go to external authorities. This is my experience in the past. So a note from the collaboration is enough.
marco carlini: Yeah.
Dave Rogowsky: Yeah, so it has to, Bruce. I think this summary is. It has to be checked at least internally.
Dave Rogowsky: and it'll be up to the authorities having jurisdiction whether they want a 3rd party check.
Dave Rogowsky: So so the way we do that check structurally today is we don't check a factor of safety. We
Dave Rogowsky: we check, do what's called a code checker unity check. We take the factored load effect by the factored resistance.
Dave Rogowsky: and it should be less than one
Dave Rogowsky: to satisfy the limit. State equation
Dave Rogowsky: it
Dave Rogowsky: that that's the type of check we do. And it's done for what's potentially hundreds of load cases and all the members.
Dave Rogowsky: The
Dave Rogowsky: what you get from
Dave Rogowsky: design codes that are based on limits States design, which are the codes that we're using today.
Dave Rogowsky: You'll get a structure
Dave Rogowsky: that's proportioned to sustain all loads likely to occur during its design life
Dave Rogowsky: and remain fit for use
Dave Rogowsky: with an appropriate level of reliability for each limit State.
Dave Rogowsky: So the reliability levels
Dave Rogowsky: are different for a serviceability limit state than for an ultimate limit state.
Dave Rogowsky: And then finally, building codes and design standards based on limit States design implicitly define the appropriate level of reliability in their prescriptions.
Dave Rogowsky: In this presentation today, a discussion of the prescriptive requirements is really beyond our scope today.
Dave Rogowsky: just about out of time. Here, I've got 2 more slides, I think.
Dave Rogowsky: the looking at the history of failures.
Dave Rogowsky: You can the
Dave Rogowsky: you can learn from them. The the 1st thing is that
Dave Rogowsky: about 75% of failures are human error.
Dave Rogowsky: and their errors can be
Dave Rogowsky: Here's a judgment.
Dave Rogowsky: lack of understanding or simple blunders
Dave Rogowsky: that's responsible for, I think 75% of the failures and about 90% of the consequences.
Dave Rogowsky: Now, when you actually dissect
Dave Rogowsky: the failures.
Dave Rogowsky: Most failures occur under a scenario or or bloat combination that the designer did not envision or check.
Dave Rogowsky: That would be, for example, construction stages
Dave Rogowsky: and accidents.
Dave Rogowsky: second observation is that many of the failures are due to instability.
Dave Rogowsky: and that could be local buckling where
Dave Rogowsky: a thin part of a Member Cross section that's in compression buckles locally.
Dave Rogowsky: But the rest of the member stays there that's called local buckling. We can get column buckling.
Dave Rogowsky: You can get beam lateral torsional buckling, and then you can get overall buckling of the frame, or what's called a frame sway.
Dave Rogowsky: You're overturning.
Dave Rogowsky: and my view is that
Dave Rogowsky: that's in part because we do a poor job at the University
Dave Rogowsky: of Teaching stability
Dave Rogowsky: to students.
Dave Rogowsky: Most engineers are pretty good at
Dave Rogowsky: knowing whether a beam will yield or a member will fail in tension. But when you get into the instability problems it's a bit a bit more challenging for them. So we make more mistakes
Dave Rogowsky: that result in instability. Failures.
Dave Rogowsky: Failures
Dave Rogowsky: often occur at the connections. They're points of weakness. And again, at university. We don't really teach engineers very well
Dave Rogowsky: about connection design.
Dave Rogowsky: So that's typically where you see failures show up.
Dave Rogowsky: not up
Dave Rogowsky: you. Some failures occur because of deviations from the original design drawings and specifications like the design could have been fine.
Dave Rogowsky: but they weren't followed up during construction. Typical cases. There'll be a something will come up during construction, there'll be an issue well, meaning individuals will change things without consulting the original designer.
Dave Rogowsky: or without having a full understanding of the design requirements.
Dave Rogowsky: And there's a blunder made. The classic example of that
Dave Rogowsky: would be the Kansas City Hyatt Regency Hotel collapse
Dave Rogowsky: where someone changed
Dave Rogowsky: the way the tension rods that were holding up the walkway bridges across the atrium.
Dave Rogowsky: They were tension rods, and they
Dave Rogowsky: they change the arrangement of the rods and the bolts of the nuts to make it simpler to construct.
Dave Rogowsky: It was a huge blunder and killed a hundred 14 people.
Dave Rogowsky: So we've got to be careful about changing things.
Dave Rogowsky: And and we really do have to follow the
Dave Rogowsky: the design drawings and specifications. And if we're going to make a change, consult the original designer.
Dave Rogowsky: and then the final
Dave Rogowsky: thing B is that occasionally failures are are simply
Dave Rogowsky: that fall into the category of simply blunders like you got conceptual errors, arithmetic mistakes.
Dave Rogowsky: common one is, drawings are missing, information or details are are shown in a manner that leads to construction errors.
Dave Rogowsky: Ian.
Dave Rogowsky: when we think about factors of safety.
Dave Rogowsky: you know it's hard to make up
Dave Rogowsky: for
Dave Rogowsky: blunders
Dave Rogowsky: you just.
Dave Rogowsky: You can't have a factor of safety big enough.
Dave Rogowsky: I think, someone said. It's hard to make things idiot proof because idiots are so ingenious
Dave Rogowsky: and determine.
Dave Rogowsky: So the last slide I've got
Dave Rogowsky: is a
Dave Rogowsky: huh
Dave Rogowsky: is is 5 points to think about, and I call them the designers best friends. The 1st one is critical thinking.
Dave Rogowsky: You always have to ask yourself.
Dave Rogowsky: have I missed a load case, or a load combination
Dave Rogowsky: or a loading scenario that could lead to failure.
Dave Rogowsky: And and have I analyzed it correctly? Is is my analysis sound?
Dave Rogowsky: Or there are flaws in it because I've got
Dave Rogowsky: assumptions that are really not valid.
Dave Rogowsky: then, as you're conceiving a structure and selecting materials, ductility
Dave Rogowsky: helps us a lot
Dave Rogowsky: and but preventing failures that kill people, because if things are doctile they will deform. We'll see the deformations, and people can get out of the way before things collapse.
Dave Rogowsky: Redundancy
Dave Rogowsky: is where you've got multiple load paths.
Dave Rogowsky: So if if you have a way of building redundancy
Dave Rogowsky: and a member fails, if there's a way for the load to
Dave Rogowsky: to be carried through other elements
Dave Rogowsky: that'll also prevent catastrophic collapse.
Dave Rogowsky: Then
Dave Rogowsky: checking and peer review are are probably
Dave Rogowsky: under undervalued, because we never allow enough time in our schedule to do that. But it's essential.
Dave Rogowsky: And then finally, inspection and testing is
Dave Rogowsky: is really
Dave Rogowsky: a very powerful tool
Dave Rogowsky: in trying to get safety, and I think at this point
Dave Rogowsky: I'd throw the floor open to questions or comments
Dave Rogowsky: if anybody's still awake out there.
Bruce Vogelaar: Hello!
Bruce Vogelaar: So, Dave.
Bruce Vogelaar: when you
Bruce Vogelaar: presented the different codes for everything
Bruce Vogelaar: you talked about these new
Bruce Vogelaar: approaches, the new codes incorporate all this
Bruce Vogelaar: this
Bruce Vogelaar: approach that you've just described. Is that correct?
Dave Rogowsky: Yeah. Well, I say, new, that since since about the late seventies, early eighties, yeah.
marco carlini: Yeah in Europe is since a 1993, and in Italy since 2,008.
Dave Rogowsky: Well.
Bruce Vogelaar: Okay.
Dave Rogowsky: Yeah, so I I just introduced it so that those who are not structural engineers under under must understand that.
Dave Rogowsky: Asking
Dave Rogowsky: what a factor of safety is. Isn't really A a very powerful question.
Dave Rogowsky: because it depends on your definition.
Dave Rogowsky: What I see is some fea work where? It's good analysis. It calculates all the stresses
Dave Rogowsky: you get a vonesis
Dave Rogowsky: stress what's called a von misa stress. It's a way of
Dave Rogowsky: of getting the maximum stress in any element in your structure. And then you
Dave Rogowsky: you take the yield stress divided by the Von Mesa stress, and some people call that the factor of safety
Dave Rogowsky: that only applies if it actually fails by yielding.
Dave Rogowsky: But structures can fail by many other methods.
Dave Rogowsky: Buckling
Dave Rogowsky: is a typical example.
Dave Rogowsky: Okay.
Dave Rogowsky: so
marco carlini: Maybe, if I can, also an another comment
marco carlini: they've
marco carlini: so still, we still have time.
Dave Rogowsky: Yes, yup! Yup!
marco carlini: I I think, one one aspect that it is also of interest, for dark side is the the pressure vessel code. We. We don't really.
marco carlini: let's say, in the inner detector we don't really take care about that much. But, for example, in the atmospheric carbon cryogenic system we have some pressure actually, and also there, as you are mentioning.
marco carlini: If you follow, for example, the European code, which I know because I've worked with it some some time ago. There is really a lot of interest, not only in say, making sure your structure doesn't yield, but also your structure doesn't buckle, because, for example, the same code is apply applicable also to the bakum lot case
marco carlini: in which you can have a really dangerous boggling situation. So that's that's also somehow. Let's remember that, for example, in Europe, if we have a a best, precious best a vessel with the 4.5 bargain
marco carlini: pressure design pressure and higher. Then you have to consider to, let's say, to to follow this code. And I think in us is the same.
Dave Rogowsky: Oh!
marco carlini: More or less.
Dave Rogowsky: Yeah, certainly it is. and you're correct. I I've just focused on structures, but the pressure vessel has its own set of codes
Dave Rogowsky: a vacuum chamber that's being used for the coatings.
Dave Rogowsky: it's actually designed to an American society for Mechanical engineering pressure vessel standard
Dave Rogowsky: in. In. They're they're similar. codes. But
Dave Rogowsky: they require a lot of detail calculations to which are today are automated.
Dave Rogowsky: Oh.
Bruce Vogelaar: So
Bruce Vogelaar: one more question about
Bruce Vogelaar: the
Bruce Vogelaar: sociology of physicists versus engineers.
Dave Rogowsky: Yep.
Bruce Vogelaar: And
Bruce Vogelaar: and sometimes.
Bruce Vogelaar: if if you if you're building a bridge, you, you can't be off by a factor of 2 in safety, or whatever, because it costs too much, and you need to go broke
Bruce Vogelaar: and a lot of things until engineer, you know, the cost actually matters.
Bruce Vogelaar: And I had
Bruce Vogelaar: for most of the physics stuff I've done over the years.
Bruce Vogelaar: The idea was, just
Bruce Vogelaar: make it so bloody strong
Bruce Vogelaar: that that that you're past the finesse of getting it.
Bruce Vogelaar: Reason, we say, because
Bruce Vogelaar: it's 1 of a kind you're not trying to sell it commercially.
Bruce Vogelaar: If you have a doubt, just make it
Bruce Vogelaar: just make it stiffer than than what you needed, or stronger than what you needed.
Dave Rogowsky: Yep.
Bruce Vogelaar: Because it's very hard to get all these details actually right? Correct. And because you also don't have
Bruce Vogelaar: 20 years of experience of doing the same thing. It's the 1st time you're doing something.
Bruce Vogelaar: And so just
Bruce Vogelaar: so, so are how do you view us? Are we? Are we in the realm of of.
Bruce Vogelaar: We can just make it so that
Bruce Vogelaar: we're not at the limit of things. We're we're cause.
Dave Rogowsky: Oh!
Bruce Vogelaar: Be part of the goal is
Bruce Vogelaar: just, be safe.
Bruce Vogelaar: As well follow the regulations, but but actually also be safe.
Dave Rogowsky: Yeah. So your your point is is well taken. When I was teaching students.
Dave Rogowsky: I would point out that if you design a structure to the minimum requirements of the code.
Dave Rogowsky: Then, by definition, you've designed a marginal structure.
Dave Rogowsky: and you really don't want to be there.
Dave Rogowsky: In real structures. When we do these unity checks by the code.
Dave Rogowsky: we're that unity check is really a utilization ratio. We're not using a hundred percent of the capacity.
Dave Rogowsky: Typically I,
Dave Rogowsky: you will be using probably less than a 3rd
Dave Rogowsky: of the capacity. So you got way. More safety than the than the code would require.
Bruce Vogelaar: So so how do you view us at this point? I mean, you've watched us for a couple of years now.
Bruce Vogelaar: are we?
Bruce Vogelaar: On the hairy edge, or are we
Bruce Vogelaar: doing reasonably well?
Dave Rogowsky: I I think, as a group, you're doing reasonably well.
Dave Rogowsky: What I see the primary weakness is that we're not thinking about all the potential load cases or loading scenarios. We haven't thought through all the construction steps yet
Dave Rogowsky: in enough detail.
Dave Rogowsky: and I think the
Dave Rogowsky: I'm
Dave Rogowsky: yeah and that's all I can say is that you're doing reasonably well. But I'm pretty. We've not considered all the critical cases yet.
Dave Rogowsky: and there could be one that will catch us.
Dave Rogowsky: I see John has a hand.
John Brandt: Yeah, I I think I can maybe add to this question that came up a little bit from
John Brandt: having had the
John Brandt: over a decade of experience, dealing or doing mechanical design for
John Brandt: detectors or scientific instruments like this, and working with physicists closely, and scientists in general.
John Brandt: I think there's almost an analogous relationship to aerospace
John Brandt: safety factors and some of the designs.
John Brandt: That, we're getting toward with larger detectors like this, where you know, a minimization of the safety factor
John Brandt: for either weight concerns or other operational concerns surrounding the amount of material that's present in the support structure. For, you know, radio purity or the experimental concerns is becoming more of a
John Brandt: a requirement as opposed to, you know Bruce's
John Brandt: statement of just make it so bloody
John Brandt: strong that you don't have to worry about. You know a a loading condition where you're taking into account all possible loads by just
John Brandt: over engineering something, so to speak.
John Brandt: So there is some change that I've seen with these these larger scale and much more complex detectors, where
John Brandt: I think we are getting to an overlap of the engineering requirement, for.
John Brandt: you know, more load cases being examined more fully.
John Brandt: And we're maybe getting away from the that
John Brandt: ethos or
John Brandt: mentality of of just over engineering something
John Brandt: for the sake of
John Brandt: safety, and being overly safe.
John Brandt: So
John Brandt: that's that's my 2 cents.
Bruce Vogelaar: So can I just make a comment on that. Just respond to that a little bit.
Bruce Vogelaar: I think there are 2 categories. There's 1 which is the detector itself, and the other is putting the detector together
Bruce Vogelaar: and the scaffolding, the lifting, the cranes, and all that stuff that we can still over engineer that end of things, even if the detector itself has been minimized.
John Brandt: Absolutely. I completely agree with that. There's
John Brandt: no reason to be
John Brandt: over, no reason to not be overly safe when it comes to dealing with devices that people will be close to and operating
John Brandt: in the assembly procedure. Where injury is definitely a major concern. We we absolutely want to take into account all the loading configurations and
John Brandt: you know, information we can to design those
John Brandt: support structures in a way that they'll be
John Brandt: safer than safe.
John Brandt: Yep.
Dave Rogowsky: So the
Dave Rogowsky: you're absolutely right, Bruce, that you differentiate between the experiment itself and the detector
Dave Rogowsky: has one set of requirements, and then, for the all the tools
Dave Rogowsky: they they could be and should be conservatively designed.
Dave Rogowsky: The one thing we have to watch about making things really strong
Dave Rogowsky: is the thermal load cases.
Dave Rogowsky: That's 1 where temperature effects will cause members to grow and clash.
Dave Rogowsky: And if you make the members stiffer and bigger, you just make the forces bigger.
Bruce Vogelaar: Up.
Dave Rogowsky: You can get into problems. And I think right now, that would be the
Dave Rogowsky: the single biggest weakness is that we really haven't thought through the
Dave Rogowsky: all the temperature load cases within the detector during cool down and warm up.
Dave Rogowsky: It's the transient case that I worry about.
Bruce Vogelaar: There is a there's a nice video of a of a roller coaster, one of the big posts supporting it had just cracked in half. Did you see that one?
Bruce Vogelaar: And as the you think of all the places to be really strong, you'd have that strong and cracked.
Dave Rogowsky: Okay, I don't want to cut off the discussion we've now reached the end of our hour.
Dave Rogowsky: A head print.
Dave Rogowsky: Been planning to present an update on the seismic consideration during construction, and it's been on the agenda
Dave Rogowsky: for the last. I think 3 or 4 meetings, and we'll have to shift it on one more time.
Dave Rogowsky: and I,
Dave Rogowsky: unless people want to stay, and when we can chat I I think we can close the
Dave Rogowsky: I'll
Dave Rogowsky: we can close today's meeting, if you like.
Dave Rogowsky: Get on with your work.
Dave Rogowsky: Peter, are you able to to hang on for a minute.
peter: Yeah, yeah, sure.
Dave Rogowsky: Yeah, I just wanted to chat with you one of the things we we'd like is, I think in the engineering forum
Dave Rogowsky: it would be good to discuss annual adjustment system.
peter: Yeah.
Dave Rogowsky: As as as far as the design development goes, I know you guys are are still in er in in design and still developing things, and
Dave Rogowsky: usually it's good to get feedback before you're finished
Dave Rogowsky: or before you go.
peter: So far.
peter: I presume. I mean yeah. So should we schedule
peter: something for next week, then next Friday.
Dave Rogowsky: Oh, well, I chatted with Nick who I didn't see today. And and I said that he could just send us send me an email on when he thinks.
Dave Rogowsky: okay.
peter: Yeah, no, that's that. That's fine. That's fine, or it can be one of these meetings. I don't know.
Dave Rogowsky: Alright, I think we've we've got a bunch of other things that are are, I'd say, a higher priority
Dave Rogowsky: for the next couple of meetings, so if it, if you can do it in in 2 or 3 weeks, or 4 weeks, that would be fine.
peter: No, I think. Well, I think we may even be able to. I'll talk to him. Okay, next week. Okay? And see
peter: yeah. And
peter: sometime next week we can certainly have a meeting. Yeah, absolutely
peter: cause it. You know, he's been working on it, and
peter: we've been discussing things back and forth and stuff like that. So, yeah.
peter: yeah.
peter: Matt.
Dave Rogowsky: And Bruce, you're still there.
Bruce Vogelaar: Oh, yeah.
Dave Rogowsky: Yeah.
Bruce Vogelaar: That, good or bad.
Dave Rogowsky: Thank you for your oh, that's good, that's good. Thank you for your comments, and Marco as well
Dave Rogowsky: You both had a valuable comments. For the collaboration.
Dave Rogowsky: I understand the project office. Has some quality control rules
Dave Rogowsky: or design, and the there may, there may be rules for when we need to go out for 3rd party reviews or 3rd party checks.
Dave Rogowsky: But I.
marco carlini: Is it a question?
Dave Rogowsky: And do me.
marco carlini: Yeah, Dave.
Dave Rogowsky: Well, it's actually to both of you.
marco carlini: So what I know that that there is a a review office, and, for example, I went through
marco carlini: the review of the Stelstill vessel design in which I was in the design team, and in that case there were involved with the a few engineers of the collaboration. I think Ryan was there physicist, but also an external engineer, and I have to say it was really really useful, because, in particular this external engineer was very.
marco carlini: was very expert on the vessels, and he gave a lot of inputs. I think, for the inner director. It will be the same for sure. External engineers, I guess, needs to needs to be involved with. That's my opinion.
Dave Rogowsky: Oh, yeah, I I my view is, we don't have enough internal resources to do all the checking.
Dave Rogowsky: you know various institutions have, you know, a couple of engineers, or maybe more.
Dave Rogowsky: But that's not really enough to handle all the checking that's gonna going to need to be done.
Dave Rogowsky: and in particular
Dave Rogowsky: the Assembly. Tables and things that are being designed in Alberta will be used in Alberta, so they'll have to satisfy
Dave Rogowsky: the Canadian codes
Dave Rogowsky: it, which should be okay for Europe. But someone needs to check it by the European standards.
Dave Rogowsky: and I don't know if that's something that you were in Mckelly could do, or we have to hire a 3rd party to do it.
marco carlini: So I don't know the answer to these. What I know is that normally those
marco carlini: those equipment may be subject to Machinery directive and norm me nor myself, nor Mikael are expert on that, and can can. Let's say, sign off the equivalency. So we I think the the
marco carlini: the approach would be that. If you, for example, design according to your the equivalent of the European machinery equipment you just give us the certificate, or whatever document, and we submit to the lab that normally work it out for other
marco carlini: for other. Let's say equipment. But now, I cannot decide on what I said.
Dave Rogowsky: Yeah, I I guess the other thing that we've got going for us is that with the drive hit
Dave Rogowsky: exercises in Canada the equivalent will have been used and tested once
Dave Rogowsky: least once.
Dave Rogowsky: and and that would
Dave Rogowsky: presumably help
Dave Rogowsky: of
Dave Rogowsky: with its its acceptance in Europe.
Dave Rogowsky: Anyway, that's well.
Dave Rogowsky: a problem that's
Dave Rogowsky: going to come down the road. We got to get things designed 1st
Dave Rogowsky: before they can begin.
marco carlini: Yeah, as a.
Bruce Vogelaar: I mean
Bruce Vogelaar: just
Bruce Vogelaar: just a comment that
Bruce Vogelaar: for me
Bruce Vogelaar: we have a whole bunch of what I would normally call critical lifts and very height, geometries.
Bruce Vogelaar: and more than
Bruce Vogelaar: like a crazy number assembling this thing inside the the cryostat.
Bruce Vogelaar: and that that always has made me very nervous.
Dave Rogowsky: Yeah, we've we've talked about the need for lift studies in. When Marco gave us a presentation on the
Dave Rogowsky: clean room and cranes over the cryostat.
Dave Rogowsky: and there needs to be a series of detailed lift studies.
Dave Rogowsky: because they're all critical lifts.
Bruce Vogelaar: Yeah.
Dave Rogowsky: And normally
Dave Rogowsky: you would involve the the company doing the lifting.
Dave Rogowsky: And is that a 3rd party in Hull C. Or are they going to be our technicians or their technicians, operating the cranes and rigging.
marco carlini: So what I can say is that the the 2 cranes we have in all see are maneuvered by a company which is an external company, but which has a permanent contract with the Lngs, and they are very good. They they did all the work for the Grio set. They are very experienced then, if you need, if we need, and I think it's gonna be the case, external cranes?
marco carlini: Then we have also there are a few external companies in particular, one was already involved for the construction of the cryogenic superstructure, and will be involved also for the installation of the cryogenics itself.
marco carlini: But so we don't have the internal intelligence. Yes, we always ask external companies.
Dave Rogowsky: Okay, so do they. Do they
Dave Rogowsky: design and provide the rigging like the shackles and the slings and spreader beams?
Dave Rogowsky: Or do we have.
marco carlini: They they provide, but they don't provide the the design.
Dave Rogowsky: Oh, okay.
marco carlini: They they provide, based on our design.
Dave Rogowsky: Okay, add.
Dave Rogowsky: because I've
Dave Rogowsky: I've worked with a large, a number of large crane lifting companies.
Dave Rogowsky: And and they
Dave Rogowsky: they provide it. But they also do what's called the lift study, where they design the rigging, and they select all the shackles and the slings, and based on the equipment that they have.
marco carlini: So, Dave, let me say, for example, for the cryosat, we we identified the the products
marco carlini: and they both, and that was all there was.
marco carlini: there was no study from them. Yeah.
Dave Rogowsky: Okay?
Dave Rogowsky: well, that's that's a detail to work through.
Dave Rogowsky: Because.
Dave Rogowsky: yeah, is one of your companies Faggioli.
marco carlini: No that. It's a it's a small company of the train drivers here.
marco carlini: gap.
marco carlini: but they don't, they? They don't design for us.
marco carlini: Yeah, that's that's for sure.
marco carlini: So if we need to do studies, it's either from us or from other companies.
Dave Rogowsky: Yeah, yeah, we're we're experiencing the same sort of issue in Alberta. If you'd got a small company.
Dave Rogowsky: they're not able to do the design they will.
Dave Rogowsky: They'll have the rigging and stuff, but they don't want to do a design
Dave Rogowsky: for the lift.
Dave Rogowsky: But the bigger companies do. And and
Dave Rogowsky: I've worked with. Fagioli is a big international Italian Lifting Company Construction Company.
Dave Rogowsky: and they did that as part of their work on on projects I've worked on.
Dave Rogowsky: We have to tell them here's the object. Here are the lifting points and the lifting lugs.
Dave Rogowsky: and then
Dave Rogowsky: they have to come up with their own rigging, design and and crane selection and component selection.
marco carlini: Yeah, thanks for this information. I will keep in mind that it could be useful.
Dave Rogowsky: Ye, yeah. And and they might be able to to find a local engineering company that specializes in the in the design of the lifts
Dave Rogowsky: for the contractors.
marco carlini: Yeah, I see Fat Joel is in the center north of Italy.
Dave Rogowsky: Well, they work around the world. They work up here in Northern Alberta.
Dave Rogowsky: It
Dave Rogowsky: of.
Dave Rogowsky: But they have, they. They're they're certainly a world-class company.
Dave Rogowsky: I'll.
Bruce Vogelaar: Just can't.
Dave Rogowsky: I.
Bruce Vogelaar: I heard them.
Dave Rogowsky: Sorry.
Bruce Vogelaar: You just can't afford to hire them.
Dave Rogowsky: Well, the problem is, it's it's
Dave Rogowsky: if you try and and
Dave Rogowsky: do everything yourself.
Dave Rogowsky: You got to learn everything yourself
Dave Rogowsky: that these companies have learned the hard way.
Bruce Vogelaar: Yep.
Dave Rogowsky: And
Dave Rogowsky: I don't think
Dave Rogowsky: dark side is an experiment that
Dave Rogowsky: we should be learning on.
Dave Rogowsky: It would be nice, but intellectually, but
Dave Rogowsky: from a practical perspective. You got to get some experts.
Bruce Vogelaar: Oh, yeah, no. It's just budget.
Bruce Vogelaar: Yeah, just budget.
Dave Rogowsky: Yep.
Dave Rogowsky: and the budget.
Dave Rogowsky: yeah, anyway.
marco carlini: David
marco carlini: just to if I can make a very last comment. Just to be, for example, go to a practical example
marco carlini: when we need, we need to lift the fully assembled Tpc. With the, with the, with the top dome of the vessel. I think we really need to go to one company like Fajoli and the, and ask both design and manufacturing. That was our plan, anyhow.
Bruce Vogelaar: Oh, Nope.
Bruce Vogelaar: Ok.
Dave Rogowsky: I I fully concur. I see Bruce is waving goodbye, and I'm gonna have to have to wave goodbye, too.
Dave Rogowsky: I think everybody for
Dave Rogowsky: participating, and
Dave Rogowsky: those who hung on to listen. Thank you.
Dave Rogowsky: Really.
Ben Freeman: Thank you, Dave.
marco carlini: Bye, bye, have a great hand today.