I have a single 42' span one lane (13' wide) bridge located on private property. It has a concrete deck supported by wide flange stringers.
The requirements are to design for a 20T truck. I want to design for tandem axles (akin to HL-93). Since this is a private bridge, low volume low speed...
I have an owner who wants to suspend equipment from a thin shell concrete roof (Monoclastic shell). The shell varies from 4" to 2 1/2" thick. The arch is 80 feet wide. Knowing I can't get proper embedment with an epoxy anchor, I would penetrate through the shell and anchor from the top...
We have an existing beam to column connection that we now have to weld the shear plate to the beam web.
The existing connection has been painted.
The welders can grind most of the paint away, but cant grind all the paint at the joint.
Please, all the CWI's respond, anyone else with experience...
I am designing a bridge on private property that the owner would like to be wood. However, due to the span and clearance limitations, I will be using timber planks over steel stringers. I was comparing load distribution between AASHTO 9.9.3.1 and table 4.6.2.2.2a-1. The 36" spacing or 6x...
I understand that the 6th edition of the AASHTO LRFD bridge design specifications are the most current. How often to the specifications change between editions? I don't want to spend $400 bucks if the code changes in January.
I have a situation where I would like to strengthen an existing girder, simple span. I want to add a cover plate to the bottom flange and fasten it to the flange by intermittent fillet welds. Any concerns with this?
I have a situation regarding a +/- 22'tall cantilevered retaining wall. The wall is approx. 40 years old and that the wall appeared to be "leaning". (that's what we were told)
Current design criteria(i.e. active pressures)provided by the Geotech exceed the original design criteria used. A...
Does any one know what the Live Load Distribution Factor is (ASD)for open steel grid deck on steel beams? I have the LRFD specs, but not the ASD specs.
We have a project where the specifications call for 4%-5% air entrainment for an underground concrete water tank. Testing during the pour showed air content greater than 12% for some of the batches. The site isn't subject to freeze/thaw. Based on my research, other than the concrete looses...
I've checked around looking for a way to calculate the bearing life of a sleeve bearing without luck. Basically, I have a cold rolled steel axle, a bronze alloy sleeve pressed into a steel wheel which will fit around the axle. The velocity is +/- 45 feet per second. Can someone suggest a...
Eq. 4.6.2.2.2a-1 requires that for undistributed wheel loads, one line of wheels is assumed to be carried by one bending member. If I have a condition where stringer spacing is 12" o.c., it doesn't make any sense that the load couldn't be shared by 2 bending members when calculating VsubLU...
I am designing a concrete top for a roadway box. The span is 6'. I am designing the slab based on a 1'-0" strip. Based on my research, AASHTO(1992 edition) gives a distribution width of 4+.06S.(Reinforcement paralell to traffic) This gives 4.36', therefore, I assume that for a 16k wheel load...
Hello all, I would like to get an opinion on the use of Helical piers . We have soft soils over bedrock to a depth of +/- 30'. Soils report recommends caissons. Contractor has suggested Helical piers due to depth to ground water(10') since he says the cost to case the holes are significant...
I have been asked by several masonry contractors to "wet" set the first course of hollow unit block for a retaining wall. According to the code we use(2001 Calif. BC), this is not permitted. I get the usual "we do this all the time" response from the contractor. However, what would be the...
Can anyone give me a reference for lateral stability of unbraced ceiling beams? I have two horizontal beams with king posts @ the one third points. I plan on spacing the beams 3 1/2" apart and providing a spacer block sandwiched between the clg beams below the king posts. Spacer block will be...
I've designed a 75' simple span steel bridge with concrete deck.(Bridge is a private access bridge to a residence) Bridge is supported on grade beam and caissons. One end was detailed with base plate with slotted holes to allow for expansion. Contractor did not use slotted hole bearing plate...
I've been asked several times about cutting holes in steel beams(Fy=36 ksi), 2"-3" diameter for plumbing lines. We usually don't allow flame cutting, however the fabricator says he can apply a compound to minimize the impact on the steel. Has anyone ever heard of this? We usually...
