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  1. LittleWheels

    Pilaster minimum reinforcement

    It is fairly common in the marine industry for large diameter steel tube piles to be connected to RC capping beams without any shear connectors, relying on the bond and particularly friction between the steel tube and concrete pile plug.
  2. LittleWheels

    Concrete hinge or pin

    I have seen such sliding joint details used in circular post-tensioned concrete tanks within municipal potable water and wastewater networks. Sikadur Combiflex is a commonly specified membrane...
  3. LittleWheels

    Concrete hinge or pin

    Just for completeness, below is the specific Highways England guidance for deck hinges, as opposed to concrete hinges that are in permanent compression. https://www.standardsforhighways.co.uk/tses/attachments/a5411e11-d9af-4c13-8566-9f96d6716e69?inline=true I suspect the fairly brief popularity...
  4. LittleWheels

    Concrete hinge or pin

    I've not designed concrete hinges in frames or tanks but about two decades ago, I had some intensive investigation and analysis work with reinforced concrete deck hinges in bridges built in the 1960-70s. They are known as Freyssinet hinges, which is not strictly correct. Freyssinet hinges rely...
  5. LittleWheels

    Questions about Rebar Anomalies and Maintenance in Concrete Structures

    I mostly want to know how much rebar is within a RC wall and at what spacing. Ferroscan surveys or GPR are the most common methods. Detailing (lap length, multiple rebar layers) can be a issue but can more difficult to determine non-destructively. I also want to know if corrosion is occurring...
  6. LittleWheels

    Trimmer bars to reentrant corner in suspended slabs

    Reinforcement doesn't have to be perpendicular to expected crack direction; it is just the most efficient reinforcement orientation. There does need to be enough steel crossing the crack to achieve the required max. crack width. Just increase your steel cross-section to account for the less...
  7. LittleWheels

    Deep foundation Recomendation

    Increased cover and crack width limitations. Stainless is too expensive for most of our clients.
  8. LittleWheels

    Strand Pattern in Historic Double Tee

    I have done betatron radiography on T-beams about two decades ago. That was more detailed than GPR but more cost and hassle.
  9. LittleWheels

    Deep foundation Recomendation

    We ban epoxy-coated rebar on our designs. Too much opportunity for corrosion initiating at coating defects or coating damage, which is then localised and intense. Most of our work is marine or coastal.
  10. LittleWheels

    How to verify plumbness of a drilled hole

    Can't you just use a rod and the angle measure app on your smartphone? Checking at 0, 45 and 90 degrees around the rod would be plenty.
  11. LittleWheels

    Left vs right thread

    Precession is the behaviour that drives left-hand threads in some applications. https://blog.everydayscientist.com/why-is-the-left-bike-pedal-left-hand-threaded/ As EdStainless noted, a chamfered interface overcomes precession. This solution was promoted by Jobst Brandt back in the day...
  12. LittleWheels

    When is Lamellar Tearing a concern?

    https://www.twi-global.com/technical-knowledge/job-knowledge/defects-lamellar-tearing-047 The Welding Institute has a good basic reference and guide. The threshold for 'problematic thickness' will vary depending on the degree of restraint, the type and size of weld and even whether preheat is...
  13. LittleWheels

    riveting alu to titanium

    There are several builders who fillet brazed stainless steel tubing (not just Reynolds 953, when it was available). https://www.moultonbicycles.co.uk/features.html scroll down to the seat post clamp for an example of eutectic silver fillet brazing of stainless tubing...
  14. LittleWheels

    riveting alu to titanium

    Generally <50% silver, otherwise it is almost impossible to build up a fillet i.e. lugged only. https://www.ceeway.com/Framesaver.htm https://framebuildersupply.com/collections/rods-wire https://www.bikefabsupply.com/filler-rod-1
  15. LittleWheels

    Jersey Barrier Anchoring Advantage

    30 degrees is a really steep approach angle for most vehicle barriers alongside a road. Is it practical for a vehicle to approach your pipeline at 30 degrees at full speed (outside of a curve = probably, inside of a curve = unlikely)? There are national and other codes/ guides available that...
  16. LittleWheels

    Jersey Barrier Anchoring Advantage

    It isn't necessarily a problem if a flexible barrier allows a vehicle to go partially over a bridge edge. CC, a large part of solving your problem is defining how large a vehicle you are intending to stop, how fast is the vehicle travelling and at what angle does the vehicle impact the barrier.
  17. LittleWheels

    Jersey Barrier Anchoring Advantage

    How much space do you have available between the barrier location and the pipeline? Concrete traffic barriers can be individually pinned to a bridge deck or highway but some can also be linked longitudinally but allowed to slide laterally. By linking them longitudinally, the barriers behave...
  18. LittleWheels

    riveting alu to titanium

    Eutectic silver-soldered 953 frames from several builders fell apart from the same intergranular corrosion cause. You need very good torch control to fillet braze in eutectic silver, otherwise you just get expensive puddles on the floor.
  19. LittleWheels

    riveting alu to titanium

    Colour me impressed, EdS. Reynolds kept telling frame builders and riders with broken frames that they had never heard of intergranular corrosion of 953. Regluing an Alan is a lot harder than doing a Vitus. Didn't Alan have threaded tubes (opposite at each end) and had to be dismantled/...
  20. LittleWheels

    riveting alu to titanium

    I have cracked a few steel frames, presumably from fatigue, mostly at stress risers (e.g. dropouts, downtube shifter bosses) and tube ends (e.g. just above BB) and a Cannondale 2.8 (typical failure at the cantilevered dropout). I've not spent enough time on a Ti or carbon frame to fatigue them...

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