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Hello, I'm unsure of how to interpret the design forces for the bridge deck overhang. It says to design for the transverse or vertical forces from the impact table (Design Cases 1 and 2). But it also has a section about calculating the forces based off of the railpost capacity (but it also says...

Hello, AASHTO has a clause where you consider 2 design trucks at 90% weight with a spacing of 50 feet between them for negative moment and reaction at interior piers. When they say reaction at interior piers do they mean to include the bearing in this case as well? It just mentions the piers...

Hi, I'm unsure how to calculate the area enclosed by the shear flow path for a concrete I-girder. Would this just be the area of the girder itself?

Hi Everyone, For determining the forces in a steel girder section with a concrete deck from a modelling program under different conditions, is my interpretation below correct? Before the deck hardens, all these forces are assumed taken by the girder only and is modelled as just the girder...

Hi Everyone, If I have a connection at a gusset plate as shown below, where the entire connection is welded, would the unbraced length of the bottom member be Unbraced Length 1 or 2? I would assume the connection would help prevent some out of plane buckling. Thanks

If I am designing a retaining like shown below, how far should I extend the upper layer of rebar into bottom section to ensure adequate development and load transfer between the tension steel in the two sections? Would 2 times the development length be required? Thanks

Hi Everyone, Design Codes allow a non-contact lap splice of up to 6". Would there be any issue by having a non-contact splice take place vertically instead of transversely like shown below? Provided that the section capacity is calculated assuming the steel is of the lower depth/

Hi Everyone, Due to the existing conditions the reinforcement needs to be spliced as shown below. Is there any issue with the splices looking like this. I don't think so, since all the lap lengths are adequate for full development, but just wanted an outside opinion. Thanks

Hi Everyone, When using skewed reinforcing to calculate flexural capacity the codes don't really give a guideline about taking into effect the skew of bars. I'm assuming you can look at the problem using basic Trigonometry in the example below. Would the assumption be correct that if I am...

Hi Everyone, If I have a longitudinal layer and a transverse layer of bars that are not 90 degrees to one another, does it affect the required splice length. In the first picture below any affect of the bars 90 degrees to one another is ignored, but what about the situation in the second...

Hi Everyone, Is there a minimum recommended distance that a splice should be staggered away from a developing bar in a beam so that they don't interact with each other. The development length is based off the center to center distance between developing bars, so maximizing this number is ideal...

Hello Everyone, I'm looking for clarification on the clause below. From what I take is that this clause only applies if my ultimate shear exceeds my concrete shear resistance. The only thing that threw me off is that the clause provides a maximum value for Vc. If you calculate the shear...

Hello, In AASHTO under service loads, the reinforcement is required to be spaced less than that calculated using the following equation. When using two layers of tension reinforcement, both reinforcing layers will contribute to the resistance of the section as shown below. From what I...

Hi Everyone, AASHTO doesn't seem to specify the allowable fatigue stress range on a lap spliced section. They only provide information for straight reinforcing bars, prestress tendons, and welded or mechanical splices. See screengrabs below. So my assumption is that a section with lap splices...

Hi Everyone, When using high strength steel reinforcing bars (100ksi yield strength), the compression splice length will actually be larger than the tension splice length. My question is, if I have a situation like shown below, where the region of a slab will cycle through positive and negative...

Hi Everyone, Is anyone here familiar with AASHTO's provision for the calculation of shear capacity for box culvert slab when under more than 2ft of fill? I've attached the relevant parts below. The wording in Section 5.12.7.3 isn't explicit, but my assumption is that this equation can be...

Hi Everyone, When analyzing a box culvert I know the trend is to apply an equal but opposite upwards force on the bottom slab to model the reaction of the downwards forces and to place a pin support below the walls. (The assumption is that the soil below provides a uniform reaction force). For...

Hi Everyone, Is the fatigue resistance of a contact lap splice the same as that of a continuous bar? I've only seen any differences for a splice fatigue resistance with respect to welded or mechanical splices, which leads me to believe it is the same, but am not 100% sure about the contact lap...

Hi Everyone, When calculating the stress range for fatigue under live loading I've seen different ways that people do this when the section goes from positive bending to negative bending under passage of the load. For this example, lets say the bottom layer of steel is the one under...

Hi Everyone, I'm not sure which coefficient of lateral earth pressure to use when I have a situation like the one shown below. When you have a live load near a wall, we have to include a horizontal live load surcharge on the wall. If I had the case like shown above where the live load is on...