TomG2 wrote:
blt2ski wrote:
I was asked to build an engineered design wall of concrete blocks.
Marty
I built an engineered concrete block retaining wall at Lincoln's Tomb in Springfield, Illinois. 15,000 blocks, 12,000 tons of sand backfill. I built it per Illinois Department of Transportation (IDOT) design and specs. We make a pot full of money and it looks great twenty two years later.
Bituminous asphalt concrete, commonly called asphalt is not usually designed only for compressive strength. Portland Cement Concrete, often called simply cement, is designed for many qualities including compressive and flexural strenth. Asphalt is the bituminous material that binds the hot mix asphalt (HMA) together while Portland cement is what binds the aggregates together in concrete. Both have their place in modern pavement designs. Nothing to do with trucks but I felt like some more educating might be in order. Have fun with that my haters.
Actually Tom,
These materials DO have something to do with truck design! As I have stated MANY times, we drive our trucks on these materials, they will wear based on how heavy our trucks are. As such, roads need to be designed accordingly to handle the wear and tear on them. If we used my example earlier, a million lbs on a 10" wide tire! It would cut thru the asphalt, along with concrete like a pizza cutter in a cooked pizza! Hence why police enforce that design limit, not the Ford engineer limits!
DOT spec on a wall.....yep, built those too. Including the one with the engineer spec that had no geo grid, 6' tall, with top to blocks filled with concrete to hold the poles for a guard rail and rebar to hold the 5' wide concret sidewalk literally on top of it. at the 6' mark behind this wall, was asphalt, and where some of out local double length 50K lb metro buses parked as this was the beginning end of a route. Did I mention NO geo grid in the wall!?!?!?
built on a 1-1 slope, base soil is a silty clay loam. No pipe at bottom for drainage, and 6" of crushed clear rock behind it! No geogrid designed into the wall too!
How long do you the engineer think this wall would last? me the contractor with a basic landscape design degree and a build certification from the wall block manufacture knew this wall was in trouble before it was built! Went to builder/developer and said you're screwed if you build a wall like this. Went to the city of Bellevue, they agreed that said wall was a basic 6' tall, flat top, flat base, no design factor for active and inactive loads above and behind the wall.
I'm not an engineer, but I do have some brains to know, not ALL design engineer architect designed things are always correct for the end result of what someone wants to do.
Also why, I will not follow the new tow specs. 12% minimum grade in low gear at max GCWR! I needed to go up an 18% grade to get to where this wall I described above was built at! I may not have gotten there at full load pulling a trailer, a load in the truck etc.....BUT! I'm under design spec weight wise! OH, I did not look up the 12% max grade at that weight! OOPS!
same as the concret pavers I have installed. If it is a walk way, I can use 4" of crushed rock below the pavers, If a lighter car truck driveway, 6-8", maybe as much as a 12" rock base. If these heavy metro buses are in the mix. 24-36" of compacted crushed rock is needed......
I'll assume you may know these types of specs if you work in this environment. More than likely, more than me! I know enough to get me in trouble, not enough to get out! Hence why I hire the correct design engineers to make sure I build this stuff correctly! I usually need a structural and soils engineers at a minimum for some sites.
Many ways to look at things, as you should know!
Marty