Nuts

[Ian PParticipant @ianp]

Posted by old mart on 05/12/2019 22:00:01:

If I am right about the studs passing from one side of the bridge to the other, it would also explain the nut length and sequence. The nuts would have to be extremely tight, and would cause a large amount of tension stretching of the studs. This could be measured in inches rather than fractions of an inch. A long nut of three diameters or more would be safer to tension than the standard length of nut, and the short nut is probably just there to use up the remaining length of thread, and not as a serious lock nut. It also looks the part to casual onlookers.

If you are right about the studs passing through the whole structure then I think they would have to be put in position when the bridge was built.

How on earth could a 1" or so hole be so accurately drilled (guided) over that length and end up in line with

the holes in the bracket?

Ian P

[JasonBModerator @jasonb]

I remember looking at this one while sat in traffic that would tend to indicate studs that don't go all the way through though they may be bonded into middle earth.

Same long nuts but no locknut and a smaller diameter fixing at the bottom.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by old mart on 05/12/2019 22:00:01:

If I am right about the studs passing from one side of the bridge to the other […]

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More later … I’m off to the Dentist

MichaelG.

[Ian PParticipant @ianp]

Posted by Michael Gilligan on 06/12/2019 07:23:05:

Posted by old mart on 05/12/2019 22:00:01:

If I am right about the studs passing from one side of the bridge to the other […]

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More later … I’m off to the Dentist

MichaelG.

The dentist should be knowledgeable on the subject of drilling, maybe discuss (not easy when your mouth is otherwise occupied)

Ian P

[old martParticipant @oldmart]

Not knowing whether drilling a horizontal hole that long is possible without a large error at the other side, lets now assume the holes are blind. They would have to be at least 2 feet deep in the brickwork, and bonded in using one of the modern glues, or the self mixing glass tubes of epoxy. The studs are a good 40mm diameter, judging from the adjacent brickwork. A bonded in threaded stud will probably break before pulling out. The extra length of stud sticking out is insurance against damage, and allows a long screwed on fitting while driving them home with the hole partially filled with glue.

[Michael GilliganParticipant @michaelgilligan61133]

The dentist was not a lot of help [he's better with canals] … so I took a few more photos

Here are the four corners:

Observant viewers will note that the upper 'studs' are horizontal at the high end of the bridge, but all the others are perpendicular to the buttresses.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

And here's the 'product shot' of the nuts:

MichaelG.

[MeunierParticipant @meunier]

Posted by Michael Gilligan on 06/12/2019 20:01:45:

The dentist was not a lot of help [he's better with canals] …

MichaelG.

Oh, I don't know, MichaelG, mine is good at bridgework also
DaveD

[Tim StevensParticipant @timstevens64731]

It is possible, I suppose, that the deep 'nuts' are in fact spacers , or nuts with the thread bored out. This would allow for a longer section of the bolt to be involved, allowing for greater elasticity, and better fatigue resistance. But I expect that this is just 'how grandad did it' in modern terms, even though grandad never went to college.

Cheers, Tim

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, I see, tapered washers on the two bolts into the concrete section, as you wouldn't want a long bolt at an angle with such a slim section, relatively. As far as rebar is concerned, there are drills that will cut through rebar especially water cooled diamond core drills. When I worked in my old job as a maintenance engineer, several machines had the thin nut on top fitted by the manufacturers, one in particular I remember was a vibrating screen, which was about 1.5 M wide by 5M long and it had two vibratory boxes attached to a very heavy cross I beam, each box had four 1-1/4" UNF bolts holding it onto the beam. When we had to transfer the boxes onto a new screen frame, these bolts had to be replaced and tightened up with a slogging spanner and the thin nut went on top, all as per manufactures instructions.

For those who haven't heard of a slogging spanner, it is one that you use with a dirty great big hammer and in the case above, it was a long handled lump hammer.

Good clear photos by the way Michael.

Regards Nick.

Edited By Nicholas Farr on 07/12/2019 12:06:03

[John MCParticipant @johnmc39344]

Theres been some mention of bolts passing through the width of the bridge. The large "washers" on this bridge are fitted to through bolts to repair and strengthen the structure. The bridge is on the London/Bristol main line. I remember it well, this bridge was on my daily commute and the road closure and traffic lights caused chaos. I felt very smug as it made little or no difference to me as I cruised by the long, long queue of traffic on my bicycle!

[old martParticipant @oldmart]

Now the side view puts things into perspective, it is obvious that the bolts do not pass through. I did notice that the bolts into the concrete are not the same from side to side. I expect the threads were lubricated, as they look like stainless steel rather than galvanised.

I remember Fred Dibner feeding long studs through his house from front to back to prevent further bulging of the brickwork.

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