In Florida we have a widget called a pile nibbler, that basically shears concete piling by crushing. The problem here would be excavating down enough to get the hydraulic shears into place.
Why couldn't you excavate down to the point a chain saw could be used to lop away the piling?
Two...
The various formulae and materials data will also be in SI. The exam is probably in english UOM. So ... the answers you get will be near but not exact, due to rounding of coefficients, etc.
When I sat for the exam, I used my AASHTO code to work out a glulam problem. I needed the manual just...
If this is for building design, the lateral wind loading forces tend to be much larger than the gravity loads. You'll get quite an uplift load on the windward size (and slack cables on the leeward side).
Regarding the bearing capacity, the prepared wearing + base courses should be much denser...
On Florida DOT projects, we have gone almost exclusively with drilled shafts (caissons). Given the overturning forces, I would think socketing the caisson into the rock would give you a good design. You mentioned weathered rock, so the socket would need to be in competent material.
Is this a...
Thanks for the comments.
Minerk -- This particular jurisdiction of the DOT has had bad experience with field welding, and will generally reject repair plans calling for it. The real issue is having the government low bidder using the lowest paid welders he can get. Some of this work is...
Thanks for the suggestions from everyone.
"Minerk" is correct that the scab plates extend well beyond the damaged sections, to where solid connections are made (normal practice for this type of repair).
"Prost" summarizes the key issue - the voids are too large for any fasteners. Given the...
Thanks to all for the comments and input.
One aspect I must not have made clear is these holes (from corrosion of the beam flanges) are VERY irregular in shape -- more of an ink splat than a uniform, bushing-ready hole.
Regards, RAF
Thanks for the suggestions, eromliGnoD & Hydtools.
The condition is a thin flange plate with irregular corrosion around the original rivet hole. The repair consists of grinding the hole back to clean, sound metal then adding scab plates to restore section.
The proposed bolts are ~3/4"...
Hi, CivilPerson:
Thanks for your input, but no joy on doing this. These are main girders on a bridge. Florida prohibits field welding; HAZ is an issue; punching not practical in-situ. RAF
We are working on a bridge repair project, replacing rivets in deteriorated structural steel with high-strength bolts.
In some locations, the hole is several times the replacement bolt diametre. The concern when the bolts are torqued to provide a slip-critical connection, the scab plates...
The dimensional issues have been discussed throughly; what about the stresses and strengths? I'm not so sure about the dual-plans approach. I would stick to dual units on one plan for measures and capacities.
If you're the engineer, shop drawings have to be prepared to your satisfaction. It...
For bridge repairs in Florida, we often use reinforced concrete jackets (6" to 9" thick). This is because of severe section loss, though. Also, sesmic resistance is not a consideration.
If your goal is just increasing axial capacity, concrete alone might work (compression only). Surface prep...
The AASHTO LRFD design code uses a notional vehicle, which is a three axle truck, along with a uniform lane load. The design vehicles also include a tandem truck and the military loading. All these add extra axles to the loading.
So ... I think MotorCity's opinion of the design load is correct...
Please see thread794-119271 "Openings in cylindrical shells". Also visit http://www.dot.state.fl.us/structures/proglib.htm and look at the reference files for the Mastarm program. MathCAD is required, but I can send you a PDF if that would help.
My application was also for traffic and overhead...
I am designing a 3-span continuous, reinforced concrete flat slab bridge using LRFD methods. The fatigue loads do not seem to be influencing the design! What is your experience on this?
In my past experience with LFD / AWS slab design methods, the flexural reinforcing, then the fatigue reinf...
I have a prestressed flat slab design that exceeds the older c/d limits.
In the latest edition of the AASHTO LRFD Bridge Design specs, the check for "c/d < 0.42" has been dropped [§5.7.3.3]. The code appears to address this by applying a reduction to the phi factor when the section is...
