RMEYou're getting carried away.
Really? You choose the joint spacing so that the tensions from hampered temperature contraction don't exceed the tensile strength. And yes the spacing is about 25''. That is what I meant in my last post. In a foreign language you always what you want to say but never can be sure if you really wrote it.
The tensile strength of a good composed concrete can reach 10% of the compressive strength.
RMEWhat MC is discussing is not so much a tendency for the slabs to 'pull apart' as for the structure as a whole to stringline.
How shall slabs with grouted joints stringline? Or do I understand stringlining differently than you? In the Boegl drawing you see #8 GEWI steel. That is a threaded reinforment steel similar to Lenton steel. GEWI has a cylindrical coarse thread, Lenton a conical fine thread. The corresponding GEWI steel of two slabs are coupled with turnbuckles and nuts (#10) according to the drawing on page 7.
The two grouted recesses act as dowels for transverse forces. Prestressing is only in transversal direction.
The subgrade is a hydraulically bound layer upon a compacted frost protection layer. The slab are erected with a 3cm (1.2'') wide joint which is poured from above with a bitumen-cement grout. When pouring the concrete only the dowels for the rail fasteners are inserted into the steel formwork (page 15, picture top left). The fasterner seats are digitally CNC processed for the required rail fastener and the fastener assembled on the slab. The slabs are stored with the rail fasteners assembled.
On page 5 you can see that the rail seat is already profiled in the formwork. There are only last adjustments necessary.
Boegl only gives the requirements for the subroadbed not the measures.
By the way Boegl designed and produced the precast concrete elements including the Guideways for the maglev train from Shanghai to the airport.Regards, Volker
Paul_D_North_JrVolker Landwehr said (above): "To avoid misalignment at joints dowels or tongue and groove constructions can be used."
This comment was directed ar the concrete highway problems.
Paul_D_North_JrThose methods address only the deflection/ displacement (i.e., in the Y and Z directions) at the joint, and not the slopes or angles approaching and leaving the joint.
As already said, Boegl addresses this topic. Thr rail seats are about 13'' from the joint. The rail will compensate for some of this angles.
Paul_D_North_JrI'd still like to know what the average and maximum 'normal' axle loads are used for the design and actual operation of such slab-track systems, as well as the speeds.
For Europe the axle load is 25 tons. The ICE trains have axle loads of 20 tons and speeds of up to 200 mph. The Chinese high speed trains have axle loads of 19 tons and speeds up to 220 mph.
If I read the diagram on page 4 correctly, axle loads of 42 tons at 68 mph are possible.Regards, Volker
Volker -
Thanks for your comprehensive and informative response.
For comparison, US freight car and locomotive axle loads are routinely from 33 to 36 tons, and occasionally 39.4 tons (263,000 lbs. gross weight per car to 286,000 lbs, and 315,000 lbs. respectively) on close axle spacings. Speeds vary, but 40 to 70 MPH are typical for the upper end of the speed range.
- PDN.
RMEThere is an interesting discussion on the conversion of a 100mph line which needed rebuilding due to what I understood as being subgrade instability -- the specific details on how the subgrade was remediated here would be highly interesting.
I have looked into their German language broschure of their China projects. The soft soil in place was improved with all kind of piles, mostly CFG-piles with 24'' geo-grid reinforced cushion. I think that won't help to improve soil with track in place.www.bbri.be/index.cfm?dtype=services&doc=tc17_Ground_improvement_in_China_by_Zheng.pdf&lang=en
To improve existing rail lines jet grouting may be useful:http://www.kellerholding.com/soilfrac-compensation-grouting.htmhttp://www.kellerholding.com/soilcrete-jet-grouting.html
Perhaps vibro compacting or vibro replacement may be possible depending on soil type, non-cohesive or conhesive.Regards, Volker
Paul, I had a mistake in some axle loads. I found Boegl's German language broschore today and both version show metric tons. Here are the correct axle loads:
For Europe 27.5 tons, ICE-train 20 tons, Chinese high speed train 19 tons. For heavy freight traffic 46 tons at 68 mph are possible.Regards, Volker
Tons vs Tonnes. Long tons; Short tons. Just plain old tuns. Life can get confusing. Welcome to the English language.
Norm
Norm48327Tons vs Tonnes. Long tons; Short tons. Just plain old tuns. Life can get confusing. Welcome to the English language.
Tums
Never too old to have a happy childhood!
BaltACDTums
Only after eating my late MIL's cooking. She could ruin boiling water.
Norm48327 BaltACD Only after eating my late MIL's cooking. She could ruin boiling water.
BaltACD
Saw a clip on Facebook about how to cook water!
BaltACDSaw a clip on Facebook about how to cook water!
One of the Home Ec classes when I was in Jr High managed to burn water (or rather, they melted the pan...)
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Paul_D_North_Jr Volker Landwehr said (above): "To avoid misalignment at joints dowels or tongue and groove constructions can be used." Those methods address only the deflection/ displacement (i.e., in the Y and Z directions) at the joint, and not the slopes or angles approaching and leaving the joint. That only guarantees that at any dip at a joint, both sides will be equally far down. Such a loss of support is not good for the ride on the rail above, depending on the depth and length. I'd still like to know what the average and maximum 'normal' axle loads are used for the design and actual operation of such slab-track systems, as well as the speeds. - PDN.
Volker Landwehr said (above): "To avoid misalignment at joints dowels or tongue and groove constructions can be used."
Those methods address only the deflection/ displacement (i.e., in the Y and Z directions) at the joint, and not the slopes or angles approaching and leaving the joint. That only guarantees that at any dip at a joint, both sides will be equally far down. Such a loss of support is not good for the ride on the rail above, depending on the depth and length.
I'd still like to know what the average and maximum 'normal' axle loads are used for the design and actual operation of such slab-track systems, as well as the speeds.
What do yopu mean by "Z" and "Y" directions? If you arer trying to apply the cartesian coordinate system used in machine tools to rail roadway then it cannot be done.
tdmidget If you arer trying to apply the cartesian coordinate system used in machine tools to rail roadway then it cannot be done.
Why not? (Apply x-y-z Cartesian axes to civil structure, that is...)
WGS-84 and the ephemeris algorithm alone disprove that stupidity. But three axes for 3D track structure (which PDN's discussion of slab-end displacement clearly concerns) are also perfectly admissible, whether we define z as vertical or use some other standard for reference plane.
What would you suggest be used for the axis orthogonal to the x-y plane for 3D structure?
Since numerous international conventtions define "Z" as the axis of spindle rotation then it looks like there won't be a "Z" as their is no spindle. Why do you need to indulge such fantasies? The roadway is well defined now. Your Cartesian sytem won't even tell you whether or not it is on railway property.
Against stupidity the gods themselves contend in vain.
Fortunately there are things like Wikipedia articles that can disprove stupid allegations -- except, I suppose, wilfully stupid ones.
While we are on the subject of international 'conventtions', I am unable to find a spindle-axis reference in either WGS84 or DIN 9300, or, say, in IERS note 36 4.2.6 regarding ITRF conventions. Mr. midget needs to send some authoritative-sounding e-mail to the appropriate standards bodies quick to set 'em straight!
Try a search of "Denavit-Hartenberg Parameters", which is a system for specifying the sequence of link-local Cartesian frames associated with a robot or a CNC machine. The local z-axis is always parallel to the joint axis, same as the "spindle" for the last rotating joint on a milling machine. The x-axis is always parallel to the common normal to the pair of joint axis lines. The common normal is a unique line, that is, unless the joints are parallel. The y-axis is "just along for the ride", defined by the Right Hand Rule for axes in the sequence z-x-y or x-y-z.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Oh, good grief - I was trying to make this easier to understand, not harder - although for the local coordinate system, I could have used the X direction as across the track instead of along it. Let me try again:
. . . deflection/ displacement (i.e., in the vertical and lateral [across the track] directions at the joint, . . . [with the understanding that the longitudinal direction is the direction in which the track is aligned, and likely will not move in that direction]
Otherwise, some of us here with a surveying background (mudchicken comes to mind) are most accustomed to using North, East, and elevation conventions.
PDN: I got it. Made perfect sense here. Why TDM wanted to convert to some little used, totally off the wall convention was strange. ( Guess his car speedometer is gradated in some weird nomograph like furlongs per fortnight? We could all start speaking FRA213 language and lose most of the readers.)
Almost sounds like another modeller trying to act like a railroader and he ain't got a clue
mudchicken PDN: I got it. Made perfect sense here. Why TDM wanted to convert to some little used, totally off the wall convention was strange. ( Guess his car speedometer is gradated in some weird nomograph like furlongs per fortnight? We could all start speaking FRA213 language and lose most of the readers.) Almost sounds like another modeller trying to act like a railroader and he ain't got a clue
Personally I use light-nanoseconds for measuring things.
1 foot = distance light travels in 1.0167033621639674471063578257196 nanoseconds.
(With thanks to the late Admiral Grace Hopper)
IslandManPersonally I use light-nanoseconds for measuring things. 1 foot = distance light travels in 1.0167033621639674471063578257196 nanoseconds. (With thanks to the late Admiral Grace Hopper)
A similar approach to human-scale units is the attoparsec (and its associated measure, attoparsecs per microfortnight).
Note that the latter metric is also very close to a nanocentury / pi.
I first found a couple of these when, in disgust, I first looked at studying Corb's Modulor system, which purported to define architectural proportions in human scale - if the humans involved are dyspeptic inmates of an orphanage for dwarfs [sic].
Yes, we should all remember Grace better.)
(MC, has this demonstrated your original point dramatically enough yet?? )
I rest my case.
Next!
RME . . . Yes, we should all remember Grace better.
Concur. From a Google Search - "Grace Hopper/Quotes":
Back to the topic, kind/ sorta:
The late great model railroad track planner John Armstrong (among his numerous other skills) devised a system of measurement that he designated as "squares". A "square" has sides which have a length = radius of a curve plus (2 time the minimum track center). As he said, it's a real quick and easy way to determine what'll fit, and most other dimensions of a model railroad can be related to it - e.g., a 180 deg. curve will be 2 squares 'across' and 1 square 'deep', a turntable takes up about 1-1/4 squares IIRC, etc.
RME IslandMan Personally I use light-nanoseconds for measuring things. 1 foot = distance light travels in 1.0167033621639674471063578257196 nanoseconds. (With thanks to the late Admiral Grace Hopper) A similar approach to human-scale units is the attoparsec (and its associated measure, attoparsecs per microfortnight). Note that the latter metric is also very close to a nanocentury / pi. I first found a couple of these when, in disgust, I first looked at studying Corb's Modulor system, which purported to define architectural proportions in human scale - if the humans involved are dyspeptic inmates of an orphanage for dwarfs [sic]. Yes, we should all remember Grace better.) (MC, has this demonstrated your original point dramatically enough yet?? )
IslandMan Personally I use light-nanoseconds for measuring things. 1 foot = distance light travels in 1.0167033621639674471063578257196 nanoseconds. (With thanks to the late Admiral Grace Hopper)
I measure time taken in business meetings in nanoyawns ( 1 yawn = 31.796 years).
Too bad that the speed of light wasn't more accurately measured in Thomas Jefferson's time, the light-nanosecond would have made for a dandy decimal measurement system that could be established in any well-enough equipped laboratory. (Of course there were no such laboratories in existence at tha time.)
erikem IslandMan Personally I use light-nanoseconds for measuring things. 1 foot = distance light travels in 1.0167033621639674471063578257196 nanoseconds. (With thanks to the late Admiral Grace Hopper) Too bad that the speed of light wasn't more accurately measured in Thomas Jefferson's time, the light-nanosecond would have made for a dandy decimal measurement system that could be established in any well-enough equipped laboratory. (Of course there were no such laboratories in existence at tha time.)
One of the arguments put forward for decimalisation is that it is somehow more 'rational' than feet, miles etc. In fact the kilometre was originally defined as a proportion of the Earth's circumference - too bad that that neat definition was neither accurate nor constant! I think linking the foot to the distance light travels in a vacuum is about as constant as it's possible to be.
IslandManOne of the arguments put forward for decimalisation is that it is somehow more 'rational' than feet, miles etc. In fact the kilometre was originally defined as a proportion of the Earth's circumference - too bad that that neat definition was neither accurate nor constant!
One of the problems was that the kilometre referenced to geodesy was originally defined as 1/4 of a defective measure of the Earth's circumference longitudinally measured at Paris, France. It went downhill from there.
The original "rational" measure, before the French (we might gainfully remember this was the same French who 'gamed' the phlogiston discussions at around this same era) started overthinking it by wanting wack decimal time, was the length of a pendulum beating exactly 1sec at sea level on the Equator, which has the immediate and powerful advantage of being quickly and easily replicatable by anyone with access to standard equipment at the Equator, and with reasonable ease derived from relatively straightforward period calculations elsewhere on Earth's surface.
I think linking the foot to the distance light travels in a vacuum is about as constant as it's possible to be.
In fact, the current definition of the meter has come 'full circle' and is now related to ... the distance light travels in a particular time. (The fact that the 'time' involved does not fit into the groups-of-three SI framework applied to time in seconds, and would hence be deprecated, is a mere intellectual bagatelle compared to other frank inconsistencies in SI)
The first proposal for the meter was the described pendulum in about 1668. But the French Academy of Science decided to choose the form of the earth as a base in 1791. The meter was the one ten-millionth part of the longitudinal length North-Pole to Equator through Paris.
They built prototype meter bars that were used as definition. Sometime the realization set in that aging might change the prototype meter and duplicating might be faulty. So a definition was looked for which described the length of the prototype meter bar with firm physical characteristics, in the end the speed of light.
But it is still the same length.
RMEThe fact that the 'time' involved does not fit into the groups-of-three SI framework applied to time in seconds, and would hence be deprecated, is a mere intellectual bagatelle
Could you please elabotate? I understand that there are currently seven basic SI dimensions that can not be deviated by multiplication of other SI-dimensions:meter, kilogram, second, ampere, kelvin, mole, candela.Regards, Volker
RME if the humans involved are dyspeptic inmates of an orphanage for dwarfs [sic].
if the humans involved are dyspeptic inmates of an orphanage for dwarfs [sic].
I find you guilty of spending too much time reading Lucius Beebe.
Volker,
I suspect the dialogue and dissention over measurement systems will last a long time. I once had a phone call with someone in Canda after they made the switch to Celsius. She asked me the temperature where I was and I gave he Farenheit temperatuer. She asked why we weres still using that "old scale" and I replied that it was a better indicator of comfort than Celsius.
Norm,
the discussion will go on until the last country switches to SI-unit. Having had a decimal system before the switch was quite easy for us.
I started as an civil engineer in the pre-SI-unit era. I'm in model railroading following American prototypes since the early 1980s. So I'm quite used to imperial measures.
For industry and trade one single system might be better. But I think humans would find measures to erect new hindrances.
I get along with both systems, for sure better with the decimal system.
Perhaps I didn't understand RME's post correctly. So I posted some details about the meter definition and its history.
I don't understand RME's statement "The fact that the 'time' involved does not fit into the groups-of-three SI framework applied to time in seconds". Therefore the list of basic SI-units.
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