Steel rebar, the world’s favorite reinforcement material for concrete, greatly increases tensile strength in concrete. Due to concrete’s rigidness and tendency to shrink and expand, reinforcement is necessary in many cases to reduce cracking and slow structural failure. This material is elementary to most of throughout the construction industry, but what you may not be familiar with is how much stress steel rebar must be under before it completely snaps in half.
Gav and Dan, also known as The Slow Mo Guys, have amassed a huge youtube audience simply by filming awesome things, mostly exploding, in super slow motion. Their most recent video shows what it looks like when a piece of #11 grade 60 steel rebar, which measures 1.41 in (35.81mm) in diameter, is put under enough force to completely snap it in half. The force is measured in kips, which the guys called “pulling apart force” (technical term), one of which equals 1000 pounds-force.
The experiment, which was filmed at the University of Purdue’s College of Engineering, showed that it took 157.401 kip of force, or 157,401 pounds of force, before the rebar broke. Watching the footage slowed down to 28,000 frames per second (fps) and again at 148,000fps allows you to see the millions of steel particles that explode into the air as the steel breaks.
Demolitions by implosion seems like the easiest way to knock down a structure, but there is so much preparation that goes into it that even the slightest mistake can have a huge impact. When smokestacks are demolished correctly, it can be a thing of beauty, like when these two silos in Scotland hit each other midair or when this asbestos filled stack was precisely demolished to fall into a pool of water. Things didn’t go so smoothly for demolition crews in Denmark last week, however.
Crane collapses on construction jobsites are usually pretty terrifying, especially when the jobsite is full of workers. A construction site in St. Petersburg, Florida got extremely lucky when a large construction crane collapsed and narrowly missed several running workers.
This video is a bit of a throwback, but I recently came across it on the interwebs for the first time and thought it was worth a share.
It’s been a while since we have shared a demolition video on Construction Junkie. We recently discussed a very high profile demolition project, the tallest voluntary demolition on record, which is schedule to start next year and how it is expected to happen, but no videos. Between the cold weather in most of the country and the general lack of interesting demolitions happening, it’s good to finally be back to feeling normal around here.
Last Thursday, every construction professional’s worst nightmare happened. Lives were lost, both construction workers and civilians, by way of the catastrophic collapse of FIU’s under construction pedestrian bridge. We shared what we knew as of late Thursday night, but since this is not only a tragedy directly related to construction, but also a huge learning opportunity for the entire industry, I wanted to make sure we continued to follow and update on the story as it develops.
Terrible tragedy struck Florida International University’s (FIU) campus yesterday when a newly installed pedestrian bridge collapsed onto the road below, killing at least 4 and severely injuring many more.
It’s pretty amazing the work that can get done when a lot of resources and money are thrown at one project. Past examples of this include a gigantic sinkhole that was repaired in Japan in just under a week, the complete emergency rebuild of Atlanta’s I-85 overpass that was completed a month ahead of schedule, and this video of 116 excavators working side by side to demolish a 1,640 foot long overpass overnight.
When anyone sees a hard hat, they typically immediate associate it with construction. It’s the ultimate symbol of safety on the job site. We all know we should wear them, but it’s easy to get annoyed with the minor inconvenience that they cause and forget about the extreme consequences that could result if a falling object catches us when we aren’t wearing one.
Cameras are EVERYWHERE these days. They’re on sites documenting the full construction process of your project, they’re on projects taking 360 degree progress footage, and most importantly, they’re in your pocket on your smartphone. Having a camera in your pocket at all times can be a good or bad thing, especially for employers, because not only can it make lives much easier for communication and documentation purposes, but it also gives people the chance to show the world when things go absolutely terribly.
With cranes being on many construction sites, it’s easy for workers to get complacent. Hundreds or thousands of construction materials can be lifted by cranes throughout the project, but all it takes is one time for a disaster to occur.