Lately it seems like I'm either involved with or hear about a lot of projects where it is necessary to jack a bridge superstructure off its bearings. This is generally to replace bearings or repair the substructure. So far, these have all been steel bridges, and the bearing types have varied...
I'm working on a project where it would be helpful to know the temperature forces on an existing bridge pier. The bridge bearings consist of pots with a stainless steel plate sliding on Teflon with a center guide bar. The bridge was built in the mid 80's. The stainless steel surface appears...
I'm currently looking at a highway bridge with a longitudinal slope of as much as 14%, which is more than I--or anyone else in my office--can ever recall seeing. I think I generally have my head wrapped around it with the exception of the deck. I'm concerned that it could be difficult to...
I have a client who is going to be on a project in Croatia and wants to build a rectangular concrete settling tank at what I guess is a temporary industrial process water treatment plant. I am wondering what the common form dimensions are for concrete forms in that area. Here in the eastern...
At the David Lawrence Convention Center in Pittsburgh, PA. I saw this on the news and thought it would get a good discussion going. A section of the 2nd floor collapsed under a truck at the loading dock, leaving the front of the truck hanging over the street below. I think this is steel...
I find myself working on repair plans for a series of structural problems at a recently completed building containing a certain big box retailer. Neither the original designer nor the original contractor is available to me (in case something goes to court), but—at least to my eye—the plans look...
I’m looking at some existing 2x4 wood floor trusses. I need to come up with an allowable load for a client that wants a change of use (which will require a larger load.) Now I already know the answer: the trusses aren’t gong to have the extra capacity (125% of what the original should have...
I've noticed that a lot of reviewing agencies (I work in Pennsylvania and surrounding states, USA) are now accepting the use of the National Flood Frequency Program for determining peak stream flows. (For designing a bridge into a residential development, for example.) Depending on where you...
I'm looking at a residential structure where the contractor used a few ACQ treated 2x8's for joists in an interior application. (He did this because the treated lumber was immediately at hand, rather than getting more untreated 2x8's to finish that run of joists.) Naturally, all the fasteners...
For a private road underpass below a public road in Pennsylvania, I am considering an arch structure with footings located 12' to 15' above the elevation of the lower road. These footings would have very little lateral load, would be poured against the neat excavated rock, and would be about 5...
I recently saw a laminated veneer lumber beam being used in an outdoor application (header on a deck). This made my engineer sense tingle, because I'm pretty sure that ALL LVL's are only for moisture content <16% applications. (Literature on LP's web site has a note to this effect.) Can...
This question has bothered me for some time, and it seems to be coming up more often, so I guess it's time to delurk.
In almost any residential construction code or publication, (I'm thinking of the IRC, specifically) there are rafter span tables. These list the maximum horizontal span for a...
