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Basics of Concrete Barriers (2000)

137 点作者 quotha超过 2 年前

14 条评论

at_a_remove超过 2 年前
So, that little slope probably saved my life once.<p>I was trucking up 44 at a fairly moderate pace (I&#x27;m not a big speeder) around a curve when there was suddenly a car in my lane, so I jerked the wheel to the right lane ... where there was <i>another</i> car, I twitch back to the other lane and begin, well, hydroplaning or whatever it is when you have just a touch of rain to bring up the oil from the road. Brakes were not effective and I was headed right for the highway divider at somewhere between forty to fifty miles per hour, at a forty-five degree angle. In this flimsy little car, that corner impact is going to hit me pretty hard.<p>That&#x27;s when I looked at the little slope at the base of the highway dividers and reasoned that if I could get my car <i>parallel</i> to the divider, the impact would be taken on the left wheels and the left side of the suspension, areas designed to bear some weight from that particular direction already. I managed to get the car aligned by tweaking the wheel direction, hit, slid for about ten or fifteen feet. I was so nearly perfect to parallel that I only lost the rubber covering to about an inch of bumper. Ended up replacing the tires a few weeks later just out of an abundance of caution, but otherwise fine.<p>(It turned out that there was a big wreck up around the curve and various drivers had decided to just sort of stop where they were, hence my surprise obstacles)
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ortusdux超过 2 年前
I&#x27;ve been wondering if the new Korean style rolling barriers would gain acceptance in the US and other countries.<p><a href="https:&#x2F;&#x2F;interestingengineering.com&#x2F;innovation&#x2F;this-new-korean-rolling-barrier-system-could-save-millions-of-lives" rel="nofollow">https:&#x2F;&#x2F;interestingengineering.com&#x2F;innovation&#x2F;this-new-korea...</a>
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ggm超过 2 年前
Amazingly well thought out design. If you want something as impactful (hah) think about the fluid related mechanics of urinal and toilet design, and how much thought has to go into splashback.<p>Jersey kerb has become ubiquitous worldwide.<p>Interestingly, the alternate designs often used (guyed wires, steel barrier) have good and bad points, for survivability if an impact is unavoidable. They &quot;give&quot; -and in some circumstances, thats exactly what you want. Jersey Kerb is for the &quot;nope: no giving here: wear the decelleration, hard&quot; situations where giving (eg. into the oncoming traffic flow) would be worse overall.
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abestic9超过 2 年前
If you&#x27;re having trouble reading the diagrams, several barrier types are available in this New Zealand Transport Agency publication [1]. The F-shape barrier is detailed on page 10.<p>[1] <a href="https:&#x2F;&#x2F;arco.co.nz&#x2F;wp-content&#x2F;uploads&#x2F;2017&#x2F;12&#x2F;m23-road-safety-barrier-systems-appendix-a.pdf" rel="nofollow">https:&#x2F;&#x2F;arco.co.nz&#x2F;wp-content&#x2F;uploads&#x2F;2017&#x2F;12&#x2F;m23-road-safet...</a>
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defrost超过 2 年前
I started in engineering before moving into applied math backend numerical engineering .. I still appreciate the quiet understatement of phyical testing results such as:<p>&gt; To contain and redirect a 36,000-kg gasoline tanker after impacts at high angles and speeds, a 2290-mm (90-in) concrete barrier is required.<p>[ picture of hard impact big truck side humping and sliding into said barrier ]
w10-1超过 2 年前
These have been lifesavers. Highway 101 in South San Jose used to be called &quot;Blood Alley&quot; for lack of effective separators. The biggest reduction in traffic fatalities historically accompanied their adoption.<p>However the US improvement is 3-5X less than other similar countries. For details on that and links to some data sources, see <a href="https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC4103211&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC4103211&#x2F;</a>
rocketflumes超过 2 年前
saw a fascinating video on this topic awhile ago:<p><a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=w6CKltZfToY" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=w6CKltZfToY</a>
mooneater超过 2 年前
I&#x27;m glad they are thinking through the details on barrier design.<p>Lets not forget that is only necessary because the automotive industry is barbaric to begin with. Let&#x27;s recall why trains dont require advanced crash barrier design like this.
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jmkd超过 2 年前
There are a group of skateboarders dedicated to only (mostly) riding Jersey barriers: <a href="https:&#x2F;&#x2F;www.instagram.com&#x2F;barrierkult&#x2F;?hl=en" rel="nofollow">https:&#x2F;&#x2F;www.instagram.com&#x2F;barrierkult&#x2F;?hl=en</a>
xrayarx超过 2 年前
From the article:<p>The basic principles of concrete barriers are not generally known or understood. Concrete barriers appear to be simple and uncomplicated, but in reality, they are sophisticated safety devices.
Mistletoe超过 2 年前
I love reading this and seeing just how much science, math, and thought has gone into these. Most people driving by just have dunning-kruger and imagine anyone could throw some concrete barriers up and design them. The deeper I go into most things it seems I always find this to be true.
kazinator超过 2 年前
The concrete barrier industry moves at a fast pace (so to speak).<p>I wonder how much of this stuff from 2000 is still relevant?<p>Back then moor anchor law was still in full swing, for one thing.
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leetrout超过 2 年前
Ah! Always wondered why they called it a Jersey Barrier but had never looked it up.
geocrasher超过 2 年前
I owe my life to these barriers.<p>In 1999 I was driving a &#x27;68 Plymouth Barracuda southbound on US395 in Reno, NV USA, doing 65-70mph in the fast lane (the lane closest to the middle barriers).<p>Being an older car, the &#x27;Cuda had a tendency to drift to the left, toward the barriers. I corrected to the right, as I always did. Nothing happened. The joint connecting the steering column to the steering box, held together by a flimsy piece of sheet metal, had come apart.<p>I was now a passenger, and didn&#x27;t dare not slam on the brakes, lest the all drum brakes send me in some unknown direction as they often did. If you&#x27;re getting the idea this car needed some TLC, you&#x27;d be right.<p>With only a second or two to think about what to do, I simply let off the accelerator. The car started slowing slightly, but by the time the car drifted gently into the barrier, I was still travelling at at least 60mph.<p>My imagination saw me bouncing off the barrier, back into the fairly steady Reno afternoon traffic, where I&#x27;d be bounce like a pinball between other cars, eventually going sideways, flipping, and probably not surviving. I hoped nobody else got seriously hurt.<p>But that wasn&#x27;t what happened.<p>The Cuda&#x27;s front left tire caught the bottom of the barrier- the steepest angle the barrier has- and the front tires immediately slammed hard to the left. Now, both my front tires were at full lock left at 60mph. I expected to flip over.<p>Once again, that wasn&#x27;t what happened.<p>Instead of flipping, the front left corner of the car became airborne for only a moment. Without traction, the front end just came back down, unable to continue its journey past about 40 degrees to the right. I&#x27;m guesstimating here, since at this point I was simply enduring the ride and out of my mind with fear. I didn&#x27;t scream.<p>The cycle repeated itself, and each time the car lurched into the air, it lost speed. After several cycles, I realized that the car had stopped climbing the barrier and was the front tires were just skidding forward against the barrier and the pavement. It was only then that I thought it safe to press the brakes.<p>Finally, the car came to rest. After I stopped shaking internally, I realized the car&#x27;s engine was still running. I turned it off. I was alive, and I realized in a very short time that I owed my life to the engineers who designed the Jersey barrier.<p>After reading this article, my appreciation soars even higher. All of the things that happened to me in my car weren&#x27;t accidental: They were designed.<p>Thanks, Jersey barriers. I owe you one.<p>----<p>As an aside to that story, I was about to horse-trade that car (straight across, no money changing hands) for a 1969 Land Cruiser FJ55 wagon just that week. I was sure that the trade would be a bust, but when I looked out the window, I saw that the only body damage was a bent fender lip! The barrier&#x27;s design really shined even greater in that moment.<p>$100 to a not very friendly tow truck driver got me and the car home, and the very next week I was driving a 1969 FJ55 wagon. <i>That</i> vehicle was actually less safe, but way, way, more fun. And the new owner? He was doing a ground up resto anyway, and didn&#x27;t care about the bent wheel, ruined tire, and broken ball joint. It was all being replaced anyway.