Hello,
I am not matching LEAP's operating rating factors for shear (screenshots below) - 0.99 (HL93 Inventory), 1.46 (HL93 Operating), and 0.78 (FL120). I am using the appropriate live load factor for each case. The difference seems to be in the Shear Capacity value used by LEAP as the dead and live loads are consistent between Strength I and Strength II. Does LEAP print the values somewhere that are used in the rating equation? The capacity I use is calculated using the (phi*Vn)/Vu from Print --> Vertical/Horizontal Shear for the governing beam. I did independently verify the moment rating factors and they matched exactly; it is shear I am having trouble with.
Please let me know if you would like the models or the calculation files.
Thanks
Sathvika,
Please make sure you are not using the option of considering the shear reinforcement across the failure plane (see first screen shot below). The shear report does not report Av-provided, and shear capacity for this method. Fort the traditional method of computing Av-provided at location, follow hand calculations for Tutorial 6 (see second screen shot below).
Alex,
This bridge is in Florida and I do have the "Shear rf. across failure plane" selected as allowed by the Florida Load Rating Manual. However, at the governing shear location on this bridge, 0.5*dv*cot(theta) does not take it to the next stirrup zone and the stirrup spacing is consistent for the section. So, even with the option selected, Av should not have increased. I have independently verified Vn at a couple different locations and I am matching LEAP's. When calculating the shear rating factor, however, I am not matching LEAP's rating factors. This step should be just plugging in the capacity, DL, and LL into the rating equation but one of the values used by the program seems to be different (likely the Capacity). Hence, my initial question on where the values for rating equation can be extracted in Conspan. Based on your response, I understand that Conspan does not print the values for each of the parameters in the rating equation at the tenth point locations.
Here is a summary of what I get for the shear rating factors:
1. I am using Beta-Theta Tables procedure for shear capacity per which the strain, beta, theta etc. are load factor dependent. i.e., the variables need to be recalculated for a LL factor of 1.35 vs 1.75. For operating, using a LL factor of 1.35 and going through the full beta-theta procedure, I get a shear rating factor of 1.600 while Conspan reports 1.46 at 0.3L. As mentioned earlier, all the hand-calculated parameters matched LEAP's and the disconnect seems to be when calculating the rating factor. Similar case for Design Inventory where the LL factor is 1.75 and I am not matching LEAP's shear rating factor at 0.2L.
2. I unchecked the "Shear rf. across failure plane" under Parameters and I am getting interesting results. The design operating rating factor for shear at 0.3L went up from 1.46 to 1.57. This shouldn't be the case. At a minimum, it should have been the rating factor of 1.46 that LEAP was reporting earlier.