My naive opinion would lead me to believe that using a crane would cost less, be quicker. Without doubt, there are factors I am ignorant of. That probably surprises you. Not that there are factors I am ignorant of, but that I would confess to ignorance. One factor could be access.
Yep. This basic design was taken from the Bailey Bridge system used in World War Two by the Allies. If you have good landings, you can launch a bridge a hundred feet across any gap. They could do it in hours during the war, and the pieces were designed to be moved and assembled with troops, not equipment.
I'd forgotten that where water is more plentiful, this counts as a mere creek and not a river. Here in the western USA, where water is scarce, this would be a river. Where I grew up, where there are lots of navigable rivers with barge traffic on them, this would be a creek. Anyway, nifty looking bridge. Would have been nice to see more of the site /footing prep.
@Southeastern777 This is a tidal creek, located less than 3ks from the coast.. I'm sure from time to time it does see flood water.. but the rise and fall in this video is from the tides..
The bottom of the beam is very near to the level of the normal level of the water,,,considering if there is a flood or typhoon which is the river is caring logs or volume of water,,,just a thought,,,good job though
everyone's on there cell phones, funny thing, since its a time-lapse, when you see someone texting on there cell phone for a split second, they were actually there for a couple hours texting
When you're driving, it takes less than one second to go over a bridge like this, and you never give a thought to how it was built or how long it took.
Hebneh, I appreciate that comment. We are surrounded by infrastructure and technology that everyone takes for granted. This tiny project is the culmination of people who have coordinated centuries of skill and thought. Designers, engineers, workers and even the accountants have probably planned, discussed, argued, collaborated and maybe even had headaches about every aspect of this little project. We don’t even notice.
Why did they bring the yellow "needle" back to the far side for each beam instead of going back and forth like a shoelace? It would have saved all that transportation cost.
This method rules out the conventional supports at midspan to launch the girders and omits heavy lifting cranework of installing it in place.Not only enormous savings in cost of resources s evident,workability is simplified hence the pace of work advances with speed resulting to early completion of project.
It does NOT look like the concrete was kept damp/wet for at least 28 days for proper curing. Good Luck with that bridge lasting more than a few years without the concrete deteriorating and eventually needing an early replacement. I am not an expert on doing concrete work. I read up a lot on whatever job skill I need when starting a project. Then, I do what I have read to do. See the following: "Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (chemically-cures) over days/time. In the past lime-based cement binders were often used, such as a lime-putty; but, sometimes with other hydraulic cements, such as a calcium-aluminate cement or with Portland cement to form Portland cement concrete (called “Portland” for its visual resemblance to Portland stone). When aggregate is mixed with dry Portland cement and water, the mixture forms a fluid slurry that is easily poured and then molded into shape. The cement reacts with the water and other ingredients to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. Often, additives (such as pozzolans or super-plasticizers) are included in the mixture to improve the physical properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials (such as steel rebar) embedded to provide tensile strength, yielding a re-inforced concrete. Because concrete cures (which is not the same as drying such as with paint), how concrete is handled after it is poured is just as important as before. Concrete must be kept moist during curing in order to achieve optimal strength and durability. During curing, hydration occurs, allowing calcium-silicate hydrate (C-S-H) to form. Over 90% of a concrete mix's final strength is typically reached within four weeks, with the remaining 10% achieved over years or even decades." NOTE: During this process, the concrete heats up because of the curing chemical-reaction. NOTE: Hoover Dam heated up so much that cooling pipes were laid in each section of concrete pour so that cooling water could be pumped through them. Later the pipes were filled with concrete grout. Some concrete engineers that I know say that properly cured concrete will continue to cure for 100+ years then slowly deteriorate for the next several hundred years. There is a building in Rome that attests to this: [“The Roman Pantheon: The Triumph of Concrete”, 6 October 2014, at the Wayback Machine. Romanconcrete.com. Retrieved 19 February 2013. - WikiPedia, ref. #1]. "Hydration and hardening of concrete during the first three or four days is critical. Any abnormally fast drying and shrinkage due to factors such as evaporation from wind during placement may lead to increased surface tensile stresses at a time when the concrete has not yet gained sufficient overall strength, resulting in greater shrinkage cracking. Properly curing concrete leads to increased overall strength and lower water permeability (resistance to water penetration the surface) and this also avoids cracking where the surface dries out prematurely. Care must also be taken to avoid freezing or over-heating due to curing chemical- reaction, exothermic result (giving off heat) in the setting of the cement. During the curing period, concrete is ideally maintained at controlled temperature and humidity. To ensure full hydration during curing, concrete slabs are often sprayed with "curing compounds" that create a water-retaining film over the concrete. Typical films are made of wax or related hydrophobic compounds. After the concrete is sufficiently cured, the film is allowed to abrade from the concrete through normal use. Traditional conditions for curing evolved into spraying or ponding the concrete surface with water - submerging setting concrete in water and wrapping in plastic to prevent dehydration. Additional common curing methods include using wet burlap and plastic sheeting in covering the freshly-poured concrete. Then, keeping the burlap wet for 28 - 30 days. For higher-strength applications, accelerated curing techniques may be applied to the concrete. A common technique involves heating the poured concrete with steam, which serves to both keep it damp and raise the temperature, so that the hydration process proceeds more quickly and more thoroughly.” - Source WikiPedia! NOTE: In order for the chemical-reaction of curing to occur, the concrete MUST BE KEPT WET for at least three or four days and ideally 30+ days! A rule of thumb that I use is "Keep concrete wet one day for each year that you want it to last." Footers for my woodworking shop were kept wet 100+ days through the winter while I worked on other parts of shop construction. I wet them down each morning and covered them with plastic sheets. The water never froze! The chemical-reaction kept it warm enough to keep the water from freezing. The footers and walls above should last 100+ years!
