Bridge Design punditry
I made a homework problem where I wanted students to compare suggest moments and shear from the American Concrete Institute (ACI) code against a quick analysis with STAAD. I have never used the ACI coefficients in real life and I wonder who does?
(Looks best at 720p.)
Denis Andrews was kind enough to send me some pictures of his recent accelerated bridge construction project over the Arrow River near Miniota, Manitoba.
It replaced this high abutment “Heritage” bridge.
The bridge is 16.5 meters long with a precast pretensioned voided slab deck. Denis said the project had a few hitches but overall it was a great success.
He thought it has the potential to be placed in a few more sites around the province. Denis thanks for the photos!
For victims and survivors of the Interstate 35W bridge collapse in Minneapolis, the legal odyssey ended Monday with the announcement that engineering giant URS Corp. agreed to pay $52.4 million to settle claims from the 2007 disaster that claimed 13 lives and injured 145.
I am giving a short talk on Tuesday about designing pier columns to meet the AASHTO 400 kip collision load.
I found this new paper, “ANALYSIS OF LARGE TRUCK COLLISIONS WITH BRIDGE PIERS: PHASE 1. REPORT OF GUIDELINES FOR DESIGNING BRIDGE PIERS AND ABUTMENTS FOR VEHICLE COLLISIONS” FHWA/TX-10-4973-1, online from the Texas Transportation Institute, which gives an overview of the design process.
The paper has Mathcad examples in the back but I think there are some inconsistencies in their use of beta /theta and tensile strain factors.
I think the most important point in the paper was the discussion of the shear failure mechanism due to an impact force. Two shear planes should be used in an analysis, which boils down to multiplying the column shear strength by a factor of two. This really boosts the shear capacity of our typical pier columns and helps them meet the AASHTO requirements. I will post some of my talk later…..
Closing a bridge is always a concern for local businesses, so it is important that all aspects of the rehabilitation is carefully planned out.
Oregon City has already adapted to a 14-ton load limit imposed in March 2009 after inspectors found cracked concrete that had allowed water to penetrate and degrade the internal steel girders holding up the bridge. The original concept of a $3 million project expanded to $10 million, while a nine-to-12-month bridge closure expanded to the current expected closure of two years.
I just found out I will be teaching concrete design, at our local University, starting on Monday! Talk about a short time frame to get ready…
I’m sure the class will be well over a hundred students and I will have to shove them into groups of 3-4 for homework assignments. I think this semester I am going to make them develop spreadsheets for major topics, such as single reinforced beam, double reinforced beam, interaction diagrams for square columns, etc.
The biggest headache for me (its all about me) is grading exams. It takes about eight hours to grade an exam and I have four of them this fall, yikes!
On a side note, does anyone know a good free image site I can use to add interesting photos to my blog?
Not much there yet but it is rare for a DOT to have a blog…
You have to dig through the amsterdamny.gov blog to see what is going on but some interesting pedestrian bridge concepts have been posted.
I’m not sure they are feasible…..
