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I'm replacing an existing diaphragm on a bridge, connecting to the existing connection plate on the girder. The iron workers drilled new holes in the connection plate to align with the new diaphragm holes, but one of the holes is too close to the existing hole to meet minimum bolt spacing...

I'm in charge of load rating an existing reinforced concrete arch that has an external carbon fiber wrap along the bottom. I can easily determine the axial-moment interaction curves for the reinforced concrete section, but how do I account for the CFRP? Obviously it won't add any axial capacity...

I have a bridge over a railroad that has limited underclearance, so I'm trying to minimize the structure depth under the road as much as possible. One thought was to use a truss to move the primary structure up above the road. But my truss is roughly square (the width is close to the span)...

For simple span bridges, the state DOT that I'm working for requires in their standard specifications that the deck concrete be placed from the expansion end of the bridge toward the fixed end. Can anyone think of why this may be? I know the reasons for deck sequencing in continuous multi-span...

Are there any references that might give guidance on how to design roadside features to withstand the force of snow thrown up by a passing plow? I have a decorative fence being attached to a bridge parapet, and one of the requirements we included in the spec is that the contractor has to design...

I'm in the process of designing a UHPC beam end repair which requires welding shear studs to the existing beam web and then encasing the beam end in UHPC to create a new load path for the compression in the deteriorated web. If you're unfamiliar, here's a cool little video explaining the...

I find myself disagreeing with our geotechnical engineer's report, but I'd like to get some feedback from others before I bring it up with them. In their report, they give the resistance factors for sliding of abutments as 0.8 and cite Table 10.5.5.2.2-1. They also give the resistance factor for...

I'm designing a bridge superstructure and the client wants to evaluate a "rolled section only" option as well as a "smaller rolled section with bottom cover plate" option. I've determined that by using a cover plate, we can reduce the weight of the rolled beam by 69 plf, but the cover plate is...

I'm designing a multi-column pier cap and the DOT is requiring that we use the strut and tie or other deep beam analysis method. Most software that I can find (ETPier, OpenBridge/RC Pier) doesn't do that, they use elastic beam theory. I found this STM-CAP from the University of Toledo Link that...

I frequently have to detail drilled and grouted reinforcement to be installed into existing concrete structures. Standard Gr. 60 rebar and common non-shrink grout, non-proprietary. It's always been my understanding that the required tension development length for this application would be the...

For bolted steel connections, AASHTO LRFD allows threads to be either included or excluded from the shear plane. Obviously it would be conservative for design to assume that the the threads are included, but is that the standard industry assumption? Or is there some provision somewhere that...

I need to analyze an existing bridge deck overhang to determine its moment capacity. However, the tension bars are not hooked at the deck edge and the overhang width is too short to allow the full AASHTO required development length for the bar size. How much of the tensile capacity of the bars...

This topic came up as the result of a recent Reddit thread on r/StructuralEngineering. As engineers, we are heavily cautioned against giving advice/designs without being fully informed of the whole situation, and against giving advice for free on the internet or in person due to the perceived...

Good morning, I need to specify a stitch weld along the toe of an angle which connects the back of the angle to a plate parallel to that leg (sketch attached). Is this still considered a fillet weld, even though the angle between the plate and toe of the angle if very large, or is it some...

I was hoping someone could help me with a detailing question. I'm designing a reinforced masonry building, but our client has inquired about using internally insulated block. I can't think of any way this would work except to eliminate the insulation in the reinforced/grouted cells. But I'm...

I have a steel plate which is held down by 8 anchor bolts (labeled A-G, see the attached drawing,). The plate is loaded by an upward (out of plane) force which is eccentric to the center of the plate. Can anyone suggest a reference or method to determine the tension that each bolt will resist? I...

I understand deformed WWR is more expensive than smooth, but smooth WWR has a pretty short development length to begin with, so when is the proper to specify deformed?

Hello all, I've been tasked with designing a temporary bridge superstructure to consist 1" thick steel road plates on top of 12" deep timber crane mats. The two materials are not connected in any way, so no composite action. This design is for a state highway, so all calculations have to be in...

Hi everybody, I am in the process of designing a concrete cantilever retaining wall which will have a vehicle barrier attached to the top of it. I was wondering about the method of distributing that point load (AASHTO 10 kip) over the height of the wall to find the moment-per-foot at the...