Skewed Joint Lines in Conc Pavt
Skewed Joint Lines in Conc Pavt
(OP)
I reside in Michigan; therefore, I am not entirely sure whether this is localized to MDOT or if it's similar in other places.
Specifically in the MDOT Road Design Manual it discusses skewed joint lines shortly and states that skewing the joint lines helps dampen resonant responses to traffic traveling over the pavement. It then discusses randomly spacing these joint lines @ intervals of 12'-13'-16'-15' etc.
My question is: What is the significance of randomly spacing the joint lines in this manner, and specifically is this aforementioned spacing the "best" or does it really matter as long as they are randomly spaced?
Thanks for any thoughts.
~Chris
Specifically in the MDOT Road Design Manual it discusses skewed joint lines shortly and states that skewing the joint lines helps dampen resonant responses to traffic traveling over the pavement. It then discusses randomly spacing these joint lines @ intervals of 12'-13'-16'-15' etc.
My question is: What is the significance of randomly spacing the joint lines in this manner, and specifically is this aforementioned spacing the "best" or does it really matter as long as they are randomly spaced?
Thanks for any thoughts.
~Chris





RE: Skewed Joint Lines in Conc Pavt
RE: Skewed Joint Lines in Conc Pavt
Hence, my need to understand it's origins in order to understand whether this is a mistake or whether it really doesn't matter as long as you don't exceed maximum joint spacing.
Thanks.
RE: Skewed Joint Lines in Conc Pavt
I would suspect that randomizing the slab length might reduce the probability of that occurring, since the shocks would have more time to damp out the motion before the vehicle hit the next slab of the 'wrong' length.
"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928
"I'm searching for the questions, so my answers will make sense." - Stephen Brust
RE: Skewed Joint Lines in Conc Pavt
If you have poor shocks or struts the creep and uniform pier spacing effects are greatly magnified.
When it hit me,it took a while to get to the right speed to a avoid the porpoising (pun) since it could have caused accidents and some cars joining the rare dolphins below.
There might be something to the harmonics in a slab, but there is a lot of variable dampening. Also, michigan has some of the most unique heavy trucks and load limits.
Dick
RE: Skewed Joint Lines in Conc Pavt
Teddy
RE: Skewed Joint Lines in Conc Pavt
Thanks for all your help.
RE: Skewed Joint Lines in Conc Pavt
The joints are skewed so that heavy loads do not encounter the joint all at once, i.e. each wheel crosses the joint at a different time.
THere have been several studies done, not all of them find a benifit. However, how hard is it to skew the joint and change the spacing. Just remember to mark the dowel bar locations so the joints are sawed in the correct loctaions.