
Ned Pelger's blog on construction, design and other weirdness. Email him at ned@constructionknowledge.net
Please help him win his readership competition against his son Lex at the Construction Phone Apps Blog
These photos came from a forum site about building skyscrapers. I found the photos interesting and the commentary instructive, but just loved the title. Nice Dress, Sorry about the Shoes.
Like so many crane failures, the terra firma was the culprit. In this case, it was an 8″ raised slab concrete floor that some knucklehead assumed would support the crane outrigger loads. Punching shear is the name of the type of slab failure when a load just pushes through.
I’ve included the commentary from the Australian forum below, as well as the photos.
Common Problem, Nice dress, sorry bout the shoes
Seen it so many times.
Engineers put large cranes on slabs and they think with a bit of back propping that’s OK. Tri shores or in some cases only simple across props can hold up the titanic they think.
They forget about point loading only taking into account distributed loads.
Then they think the crane crew has x-ray vision looking through concrete to see where their outriggers and pads are directly over the back propping.
Think again ginger beers.
This a copy of an email sent to me;
Brand new $4,000,000,
250t Mobile Crane
Friday 8:30h – 26.09.08 –
Castle Hill, Sydney Australia,
$8,500 / Day
The mistake was to place the crane on the 8 inch concrete slab
As soon as the jib was all the way out, the slab broke
crane balanced for about one hour before the rest of the slab gave way to the crane
Except for the slightly harmed driver no one was hurt, but no one has seen the site manager since…
The very short video clip below shows a large (maybe 12′ deep) bridge girder being transported by truck.
As you work today, remember we’re in a dangerous business.
The Schoutens came to Lititz from Holland. When I was a youngster, I remember all these little Dutch boys playing at the swimming pool and their pretty mom and funny dad. Years later, when building the Highlands at Warwick apartment buildings in Lititz, we bought pizza and ice cream for the entire crew. As we ate, I began talking with one of the drywallers and realized it was Erik Schouten, who I hadn’t seen for years.
A couple of years later, Erik started his own drywall business and we worked together on the Crest at Elm Tree apartments. During that time, Erik innovated. I’ll let him explain.
So Erik developed this simple clip that prevents drywall stacks from toppling and injuring others. He got it patented, worked to get ASTM to include the clip in regulations (almost competed), and has been selling the clips to various drywall supply yards. As a full disclosure I should note that TBW and I believed in the business enough to invest some of our hard earned shekels. It’s cool to be part of an innovation.
So that’s the back story. A few days ago this video appeared that was produced by Canada’s version of OSHA. Please take the minute to watch it.
httpv://www.youtube.com/watch?v=TW4cBOCt05U
Isn’t that a wonderful promotion from someone who has no ties to the Rock Steady clip? Erik has been getting these kinds of bumps over and over. It’s great to see the progress of a good idea moving forward in these challenging times.
When a carpenter buddy told me about a table saw safety feature that was absolutely fail-safe, I had to check it out. In 10 seconds, the video below will make you a believer.
httpv://www.youtube.com/watch?v=esnQwVZOrUU
Steve Gass loves to work with wood and has a PhD in physics. He conceived the idea and started Saw Stop to make and sell his innovative table saws.
As I watched the video, I thought of another buddy of mine who works in a custom cabinet shop. His boss pushed him into cutting some thin laminate backwards through the saw, even though my pal mentioned how the last time he used that method it grabbed and kicked back. After being upbraided for almost an hour about the need to just get it done, the supervisor ordered him to do as he was told.
With a fear of losing his job, he started cutting and the material bound and pulled his hand into the saw for a nasty gash. The wild part of this story, though, is that the cabinet shop is owned by a physician and he treated my friend for the Workman’s Comp injury. The Doc/Owner told him to go into work the next day, that he’d be fine and certainly didn’t need any time off, even though he has permanent nerve damage in his hand.
In Lancaster County, we tend not to sue people and my buddy just went back to work. Jobs are hard to come by these days.
To end on a lighter note, you can’t watch a saw safety video on YouTube without getting some suggestions about not so safe saw work. Here’s a short one that made me laugh…imagining how easily it could happen to me.
httpv://www.youtube.com/watch?v=kHUtp5w3kis&feature=related
We all know we need to be careful around high voltage electrical lines, yet an occasional reminder helps. Watch this 18 second video of what happens to a tree branch that falls onto overhead power lines. It really is wonderful to her the moisture singing and see the eruption of flames.
[youtube=http://www.youtube.com/watch?v=DYktDghfoFM]
If you have a few more minutes, brush up on the helpful concepts on electricity available at ConstructionKnowledge.net.
Last June, I wrote about Why Chinese Buildings are Falling Down? That post showed the some powerful photos of a toppled building.
I later wrote about Contractors Arrested for Lacking Common Sense and tried to explain what actually happened in the collapse. I went on to speculate that the authorities would probably never get to a clear understanding of what occurred.
I was wrong. Today an article announced that 6 people were sentenced in a Shanghai court to prison for 3 to 5 years.
It was interesting to see that the manager of the building’s real estate developer and the person in charge of construction were both sentenced to five years in jail. While the project manager and safety manager, who were deemed directly responsible for the collapse, received four years in jail.
The on site construction supervisor received a three year sentence, partly for dodging checks by the building inspectors.
To my sensibility, it’s appropriate to hold those with higher authority to a higher level of responsibility, even though they probably weren’t involved in the details. We have the tendency to be lenient on everyone involved in a failure, not wanting to do the unpleasant work of holding people accountable for both their tasks and their management.
Remember, this construction and design work we do has dangers: for the public and for us.
Dan Woolley works for Compassion International, a wonderful non-profit that strives to improve the lot of children around the world. I heard their President, Wess Stafford, speak earlier this year about his own horrific childhood experiences and his vow to help other children. To that end, Dan Woolley was in Port-au-Prince hotel working on a film about child poverty.
“Then all of a sudden just all craziness broke loose,” Woolley said. “Convulsions of the ground around us, the walls started rippling and then falling on us.”
As Dan laid there alone in the darkness, he took stock and determined he had blood streaming from his head and his leg. Then he remembered, “I have an app for that!” He took his cell phone and opened the First Aid & CPR phone application from American Heart Association. He used his clothing to make bandages and perform appropriate first aid. Fearing he may be going into shock and knowing he shouldn’t sleep too long, he set his phone alarm to wake himself every 20 minutes.
As he sat in the darkness, he pulled out his journal and wrote the following, bloodstained note to his family, “I was in a big accident, an earthquake. Don’t be upset at God. He always provides for his children even in hard times. I’m still praying that God will get me out, but he may not. But even so he will always take care of you.”
Dan waited about 60 hours until he was rescued. You can read more of the story details at CNN World.
I’ve chosen to invest a fair bit of my time, energy and money into some construction phone apps that should be helpful to many. Reading this article makes me more convinced I’m on the right track.
I think everyone in construction should be able to roughly find the volume of things, have a sense of their density and be able to make a decent calculation of what they weigh. For example, a tree being removed next to a house. Say the tree is about 3′ diameter with 15′ of main trunk and branches that go another 25′.
Just to keep it simple, assume a 3′ x 3′ x 40′ volume x 40 pounds per cubic foot = 14,400 pounds. Everyone involved in this industry that faces us with all sorts of odd challenges should be able to do a similar calculation. We should all know that wood = 40 lbs/cf, soil = 100 lbs/cf, concrete 150 lbs/cf and steel = 500 lbs/cf.
Yesterday in Santa Rosa CA, a crew worked to remove a tree and ended up using the crane boom like a knife to slice the house in half. As in normal in these situations, the workers claimed it was a freak accident. Fortunately no one was hurt. The crane boom missed the worker in the tree by about 4′ and the homeowners were dealing with a car accident they had earlier in the day. A day they won’t forget.
As you work through your day, think about what things weigh. Get adept at volumes, densities and weights and avoid injuries to yourself and others.
As you probably know, strokes can be brutal. They are the leading cause of adult disability in the US. What you may not have known is that prompt treatment (within 3 hours) can usually reverse the effects of a stroke. Wikipedia says, “It was found that sudden-onset face weakness, arm drift, and abnormal speech are the findings most likely to lead to the correct identification of a case of stroke.” So if you notice these symptoms on the job site or anywhere else, be prepared.
I received a valuable email forward and decided to share with you below:
STROKE IDENTIFICATION:
During a BBQ, a friend stumbled and took a little fall – she assured everyone that she was fine (they offered to call paramedics) .she said she had just tripped over a brick because of her new shoes.
They got her cleaned up and got her a new plate of food. While she appeared a bit shaken up, Ingrid went about enjoying herself the rest of the evening
Ingrid’s husband called later telling everyone that his wife had been taken to the hospital – (at 6:00 pm Ingrid passed away.) She had suffered a stroke at the BBQ. Had they known how to identify the signs of a stroke, perhaps Ingrid would be with us today. Some don’t die, they end up in a helpless, hopeless condition instead.
It only takes a minute to read this…
A neurologist says that if he can get to a stroke victim within 3 hours he can totally reverse the effects of a stroke..totally. He said the trick was getting a stroke recognized, diagnosed, and then getting the patient medically cared for within 3 hours, which is tough…
RECOGNIZING A STROKE
Thank God for the sense to remember the ‘3’ steps, STR . Read and Learn!
Sometimes symptoms of a stroke are difficult to identify. Unfortunately, the lack of awareness spells disaster. The stroke victim may suffer severe brain damage when people nearby fail to recognize the symptoms of a stroke.
Now doctors say a bystander can recognize a stroke by asking three simple questions:
S *Ask the individual to SMILE.
T *Ask the person to TALK and SPEAK A SIMPLE SENTENCE (Coherently)
(i.e. It is sunny out today)
R * Ask him or her to RAISE BOTH ARMS.
If he or she has trouble with ANY ONE of these tasks, call emergency number immediately and describe the symptoms to the dispatcher.
New Sign of a Stroke ——– Stick out Your Tongue
NOTE: Another ‘sign’ of a stroke is this: Ask the person to ‘stick’ out his tongue.. If the tongue is ‘crooked’, if it goes to one side or the other,that is also an indication of a stroke.
We just took a long weekend at the beach and I rode bike from Ocean City NJ to Cape May with my 14 year old nephew. It’s about a 40 mile ride and he doesn’t ride bike much. He’s on the junior high track team, though, and I figured he’d be fine.
As we rode, he seemed fine, never complaining and not falling behind. We kept a reasonable pace and stopped a couple times to buy bottles of Gatorade. So imagine my surprise when we get back to the house and he starts acting disoriented and spikes a fever. When his temperature hit 102.5, we decided to take a trip to the Emergency Room. Since our youngest daughter had just gashed her foot on the a screen door
and had the bone showing on the top of her foot, we decided to try to negotiate a two-for-one offer.
Tessa’s foot got stitched, as shown below.
Which truly is an amazing process, by the way. I’m so glad some people decide they love healing and fixing people as much as I love building things. Also, cell phone cameras are fun and useful for hospital visits.
Anyway, my nephew, well grand-nephew, actually, had to stay a few hours and get some IV fluids till he started feeling better.
With summer upon us, what should we all know about Heat Exhaustion vs Heat Stroke?
Both come from strenuous activity in hot, usually humid conditions where substantial sweating occurs. Heat Exhaustion has the temperature rising up to 104 F, if it’s over that, it’s Heat Stroke (which can be fatal).
It’s time to take a trip to the Emergency Room with any of the following conditions below:
If you’re not quite ready for that drive to the ER, try to rest in a cool place, drink plenty of fluids with Electrolytes (like Gatoraid), take a cool shower and avoid alcohol and caffeine (which are further dehydrating).
With Heat Exhaustion, avoid strenuous exercise for a few days and let your body re-boot.
Pay attention to these conditions on the jobsite as the summer heats up.