Whoops

[juddian]

Fair points.

If it comes to it 90% of us could safely move these things from one end of the country to another without so much as a cable tie restraining them, and no doubt the two straps holding it back combined with the others aiding friction grip are fine for most eventualities, but fate is a fickle thing.

Even if many here actually think they are driving gods, sooner or later, especially in urban areas, that steady speed panic stop will happen no matter how careful you are, it might not happen for 10 years or a million miles of driving but one day we all have no option but to chuck the anchors on hard as we can, when that time comes its natural to stop dead, and thats where the weight of the object overcomes friction, and once its done that it is only the restraints placed purely to stop the shift forward that will prevent the very scene in the OP’s pic.

My two unintended (some lower speed ones deliberate in order to re-distribute load) panic stops of the last 15 years from memory have both been for loose dogs suddenly appearing literally under the wheels, in both instances in 30 limits and in both cases (early morning) my speed probably 25mph ish…one dog straight went under the beam axle and even though it appeared ok at the time had suffered internal injuries and was later destroyed, the other i do not know how i missed the bloody thing with my nsf wheels cos it literally appeared around a hedge and went to cross the road…i suppose the DG’s here would have instantly calculated that being dogs instead of people that they wouldn’t have braked so violently, trust me there isn’t time to process such stuff the reaction is instantaneous.

I can tell you without fear of contradiction that a loaded dead stop at low speed is far more violent than we imagine it is until it happens, luckily i always strapped cars on properly with such an eventuality in mind (others have had cars shoot forward and several i know have had them come of the peak, either hanging down in front of the screen or shot off completely), and once in a powder tanker which shot so much weight forward it took hours to tip the body enough to fully offload.

[dimlaith]

The health and safety ■■■■■■■■ is a direct result of the sub standard driving and training rife in this industry, like it or not we have to obey these draconian rules. If some bod says strap it this way then that’s the way it’s done, if the ■■■■ hits the fan then I’ve done what’s required of me I believe.

[robroy]

Dimlaith:
The health and safety ■■■■■■■■ is a direct result of the sub standard driving and training rife in this industry, like it or not we have to obey these draconian rules. If some bod says strap it this way then that’s the way it’s done, if the [zb] hits the fan then I’ve done what’s required of me I believe.

Agreed.
So yeh, we have to do all this ridiculous ott crap as an arse covering excercise, since thinking for yourself and using driver initiative was virtually out lawed by those ‘‘More intelligent’’ types, who run this industry today.

[kjw21]

Dimlaith:
The health and safety ■■■■■■■■ is a direct result of the sub standard driving and training rife in this industry, like it or not we have to obey these draconian rules. If some bod says strap it this way then that’s the way it’s done, if the [zb] hits the fan then I’ve done what’s required of me I believe.

I only partly agree with what you say there.

Some of the rules are no doubt due to driver error.

I’d also add that many are due to errors from others I.e despatch/goods in staff.

I’d also say that some rules are there due to a lack of thought by individual sites as to what rules/guidelines are required at specific sites - instead it’s a case of Joe Bloggs Steel Inc use these guidelines and therefore Bob Smith Cotton Wool Ltd just copies the guidelines with no thought as to how it relates to them and their site.

Of course there is a certain amount of empire building and making rules up to keep the people who make such rules employed as well.

[grumpy_dad]

Sub standard drivers are the result of penny pinching employers not providing adequate training, employers failing to to do employment history and the over use of agencies who will place a driver in a position wether they are trained or not just to secure a client.
But it’s not always sub standard drivers that are the route of the fault, pressure from traffic offices and planners who know little of what driving is all about guaranteeing deliveries will be made often without taking into consideration delays caused by loading, traffic, accidents, peak time traffic, and the overhanging threat of not having a job the following days it’s not there on time because drivers a ten a penny or so the rumour goes.

[santa]

Remember those boring science lessons where the teacher was wittering on about those old geezers like Hook and Newton? Probably not for many of you, so here is (part of) Newton’s first (there are three) law of motion. He showed that “an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force”. Objects tend to “keep on doing what they’re doing.” In fact, it is the natural tendency of objects to resist changes in their state of motion. This tendency to resist changes in their state of motion is described as inertia.

So - your ten tonnes of steel sitting on a trailer doesn’t go anywhere because the trailer bed is pushing up as hard as the steel is pushing down. Once the trailer moves, all sorts of other forces come into play: Turn and the steel wants to keep going straight on, but friction keeps it where it is on the bed. Turn too fast and inertia will overcome the friction and the steel exits sideways. Brake, and the steel wants to keep going - again friction keeps it from sliding to the headboard or joining you in the cab. Now; suppose that you go over a bump which pushed the steel upwards, and at the same time, you brake hard? The push-up reduces the friction and the hard braking may well cause the steel to overcome resistance of all the straps

Most drivers know all this instinctively, without worrying about the science, but next time you strap a load, just think what it’s like in the back of a bus when it goes round a corner or brakes sharply, and multiply that by 100.

Oh - Hook found a law that determines how springs work and it’s that law that makes lorries fall over on roundabouts.

[reef]

Dimlaith:
I’m no expert but I know how to respect the load on the trailer. TATA wants it done that way or it does not leave site. I would think that the combined force of 5 straps per coil pulling down onto anti slip matting is sufficient to secure the load under normal driving conditions. Like I said earlier, drive like a [zb] and nothing will stop it moving. People way above my intelligence and pay grade have come up with this system, the firm I work for does a hell of a lot of steel from Port Talbot and Llanelli and since this system has been introduced I am unaware of us losing a load of steel.

Do you work for the boys in blue then mate?

[dimlaith]

[quote=“Reef”

Do you work for the boys in blue then mate?[/quote]
What gave it away lol.

[reef]

Dimlaith:

Reef:
Do you work for the boys in blue then mate?

What gave it away lol.

It’s easy to assume it’s them running out of Tata but I also know there are lots of smaller hauliers that do too so it was a percentages based guess

[franglais]

Santa:
Remember those boring science lessons where the teacher was wittering on about those old geezers like Hook and Newton? Probably not for many of you, so here is (part of) Newton’s first (there are three) law of motion. He showed that “an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force”. Objects tend to “keep on doing what they’re doing.” In fact, it is the natural tendency of objects to resist changes in their state of motion. This tendency to resist changes in their state of motion is described as inertia.

So - your ten tonnes of steel sitting on a trailer doesn’t go anywhere because the trailer bed is pushing up as hard as the steel is pushing down. Once the trailer moves, all sorts of other forces come into play: Turn and the steel wants to keep going straight on, but friction keeps it where it is on the bed. Turn too fast and inertia will overcome the friction and the steel exits sideways. Brake, and the steel wants to keep going - again friction keeps it from sliding to the headboard or joining you in the cab. Now; suppose that you go over a bump which pushed the steel upwards, and at the same time, you brake hard? The push-up reduces the friction and the hard braking may well cause the steel to overcome resistance of all the straps

Most drivers know all this instinctively, without worrying about the science, but next time you strap a load, just think what it’s like in the back of a bus when it goes round a corner or brakes sharply, and multiply that by 100.

Oh - Hook found a law that determines how springs work and it’s that law that makes lorries fall over on roundabouts.

Where does Hooke’s Law come into trucks tipping over please?
And why the comment about multiplying the forces we feel when in a bus by a hundred? Isn’t that a red herring?

Sent from my GT-S7275R using Tapatalk

[carryfast]

Santa:
Remember those boring science lessons where the teacher was wittering on about those old geezers like Hook and Newton? Probably not for many of you, so here is (part of) Newton’s first (there are three) law of motion. He showed that “an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force”. Objects tend to “keep on doing what they’re doing.” In fact, it is the natural tendency of objects to resist changes in their state of motion. This tendency to resist changes in their state of motion is described as inertia.

So - your ten tonnes of steel sitting on a trailer doesn’t go anywhere because the trailer bed is pushing up as hard as the steel is pushing down. Once the trailer moves, all sorts of other forces come into play: Turn and the steel wants to keep going straight on, but friction keeps it where it is on the bed. Turn too fast and inertia will overcome the friction and the steel exits sideways. Brake, and the steel wants to keep going - again friction keeps it from sliding to the headboard or joining you in the cab. Now; suppose that you go over a bump which pushed the steel upwards, and at the same time, you brake hard? The push-up reduces the friction and the hard braking may well cause the steel to overcome resistance of all the straps

Most drivers know all this instinctively, without worrying about the science, but next time you strap a load, just think what it’s like in the back of a bus when it goes round a corner or brakes sharply, and multiply that by 100.

Oh - Hook found a law that determines how springs work and it’s that law that makes lorries fall over on roundabouts.

It’s my guess that there are numerous different forces in numerous different directions acting on a load and its securing ties which the ‘academics’ haven’t taken account of.IE the force of shear against the fastenings being just one in addition to the difference between a shock/■■■■■■ loading,such as in the case of an emergency stop,as opposed to a static or sustained one.

Which is why they don’t generally secure a truck axle,or its engine,or its body,to the chassis,using ratchet straps.IE it takes the correct grade of bolts in terms of tension and shear and resistance to shock loadings and enough of them set at numerous critical angles to hold the thing together.

In which case why do they think that ratchet straps are the right way to secure a unit weight,which weighs more than the truck,to the body of it when they wouldn’t dream of doing that in the case of its engine,axles and body to chassis interface/connections.

As for the laws of spring it’s obvious that a lateral force can be transferred into a vertical force especially in the case of a high centre of gravity.Which is why a bus load of passengers will literally be thrown off their feet not slide along the floor in an emergency stop and it’s also why centrifugal lateral force can turn into a roll over.In just the same way that a load can literally fly,not slide,off the side of a truck or through the cab and therefore obviously makes the idea of anti slip mats a bit dubious.

As said previously steel loads like this need chains to hold them not straps and also ideally need to sit in a well to locate them better.Thereby reducing the potential directions and types of forces acting on the securing ties.

[carryfast]

Franglais:
And why the comment about multiplying the forces we feel when in a bus by a hundred? Isn’t that a red herring?

Maybe not a case of multiplying the same force literally by a hundred.More like a violent change in ‘direction’ of force from the sustained normal vertical force of gravity that’s allowing you to stand normally.To the vertical force that lifts you off your feet together with the lateral force that throws you to the front or sides of the bus without your feet touching the floor.

On that note I speak from experience in that there was a driver on the old 65/71 route during the 1970’s who was the nearest I’d ever seen in being able to drive an RT double deck bus like an F1 car.

[captain_caveman_76]

Santa:
Remember those boring science lessons where the teacher was wittering on about those old geezers like Hook and Newton? Probably not for many of you, so here is (part of) Newton’s first (there are three) law of motion. He showed that “an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force”. Objects tend to “keep on doing what they’re doing.” In fact, it is the natural tendency of objects to resist changes in their state of motion. This tendency to resist changes in their state of motion is described as inertia.

So - your ten tonnes of steel sitting on a trailer doesn’t go anywhere because the trailer bed is pushing up as hard as the steel is pushing down. Once the trailer moves, all sorts of other forces come into play: Turn and the steel wants to keep going straight on, but friction keeps it where it is on the bed. Turn too fast and inertia will overcome the friction and the steel exits sideways. Brake, and the steel wants to keep going - again friction keeps it from sliding to the headboard or joining you in the cab. Now; suppose that you go over a bump which pushed the steel upwards, and at the same time, you brake hard? The push-up reduces the friction and the hard braking may well cause the steel to overcome resistance of all the straps

Most drivers know all this instinctively, without worrying about the science, but next time you strap a load, just think what it’s like in the back of a bus when it goes round a corner or brakes sharply, and multiply that by 100.

Oh - Hook found a law that determines how springs work and it’s that law that makes lorries fall over on roundabouts.

This is where Newtons second law comes into play. Normally the acceleration of an object is proportional to the force but inversely proportional to the mass. By looking at this from the point of view of the forces, they are equal to the mass multiplied by the acceleration. The fact that in this case the acceleration is negative doesn’t matter, it simply shows the direction of force. All units must be S.I. so 20 mph is about 10 metres per second. Going from 10 m/s to 0m/s in one second gives us an acceleration of -10m/s/s
A coil weighing 20 tonne would have a mass of about 2000 newton.

Since force =mass x acceleration we have 2000 x 10 which gives us a forward force of 20000 kg. Which makes sense, since these numbers are exactly the same as we’d use to find its weight.

Hooke’s law tells us that the more we compress a spring, the more force we need to compress it further. Unless I’m missing something, I don’t know where that fits in with lorries rolling over.

Righto, time to get out the bath.

[the_nodding_donkey]

pete smith:
ND,
There must be a god or you had the “MOT” trailer for a few weeks?

yes, with the set of MOT tyres fitted that week…

Should I know you? When did you drive for Andrew?
(Or should that be his mother. We all know who was in charge… ).

[buckstones]

Assuming a coefficient of friction between tyres and road of 1.0 and highly efficient brakes, the best deceleration (without hitting something) is 1g, which applies the same force rearward as gravity does downward.

This suggests a 10 ton object will exert 10 tons of force forward and any restraint has to be strong enough to hold that object up in the air - same effect as the trailer being tilted up to a vertical position.

( Friction between the object and the surface its sitting on helps, and if there is a fixed bolster in front, it may not slide but will tend to tip with the bolster as a pivot if its centre of gravity is above that level.)

I may have missed something here, if so, please correct me.

[juddian]

Buckstones:
This suggests a 10 ton object will exert 10 tons of force forward and any restraint has to be strong enough to hold that object up in the air - same effect as the trailer being tilted up to a vertical position.

Which just goes to show i remember bugger all from Physics, sorry Mr Braithwaite, for i would have expected a 10 ton weight to have exerted far higher relative weight during a rapid stop.

Back to school

[pete_smith]

the nodding donkey:

pete smith:
ND,
There must be a god or you had the “MOT” trailer for a few weeks?

yes, with the set of MOT tyres fitted that week…

Should I know you? When did you drive for Andrew?
(Or should that be his mother. We all know who was in charge… ).

Sent you PM mate.

[captain_caveman_76]

Buckstones:
Assuming a coefficient of friction between tyres and road of 1.0 and highly efficient brakes, the best deceleration (without hitting something) is 1g, which applies the same force rearward as gravity does downward. No, acceleration is measured in metres per second per second. Deceleration is measured the same way, but with a negative value. The force an object (person ) feels is also relative to their mass. This is why racing drivers and fighter pilots feel such high negative g’s during maneuvers. There is of course a limit to the ground force that a human body can withstand.

This suggests a 10 ton object will exert 10 tons of force forward and any restraint has to be strong enough to hold that object up in the air - same effect as the trailer being tilted up to a vertical position.Assuming a deceleration of 10ms^2, spot on.

( Friction between the object and the surface its sitting on helps, and if there is a fixed bolster in front, it may not slide but will tend to tip with the bolster as a pivot if its centre of gravity is above that level.) Friction (and resistance of the fluid the object is in) are all opposing forces, but fairly insignificant when the masses become large as in this case. Lever theory, spot on.

I may have missed something here, if so, please correct me.

[dimlaith]

Carryfast, a ratchet strap is designed for a specific use,i.e. to secure a load. A bolt is designed for a specific use also. The two are totally sperate things as I think you well know.

[carryfast]

Buckstones:
Assuming a coefficient of friction between tyres and road of 1.0 and highly efficient brakes, the best deceleration (without hitting something) is 1g, which applies the same force rearward as gravity does downward.

This suggests a 10 ton object will exert 10 tons of force forward and any restraint has to be strong enough to hold that object up in the air - same effect as the trailer being tilted up to a vertical position.

( Friction between the object and the surface its sitting on helps, and if there is a fixed bolster in front, it may not slide but will tend to tip with the bolster as a pivot if its centre of gravity is above that level.)

I may have missed something here, if so, please correct me.

It’s never a case of just a change from the vertical force of gravity to lateral forces of inertia.Which is why the rear of the vehicle lifts under braking and the offside lifts during a right hand turn in answer to the left hand lateral centrifugal force and vice versa.IE just like the bolts securing the engine and axles and body to the chassis the restraint has to stop the load from effectively being thrown from the truck forwards or sideways at numerous angles including it lifting from the opposite side to the direction of travel.Not just sliding along the floor laterally.In this case ideally a well will obviously contain most/all of the lateral forces leaving the lashings to get on with cancelling out the vertical ones.

Which then just leaves that question of what’s best for resistance of shear and other loading regardless,chains or straps.Bearing in mind that high grade steel bolts are rightly the tool of choice to hold the vehicle together in that regard.So why would anyone then want to use straps to hold a lump of steel,weighing as much as the truck or more,to the body ?.