Are there any restrictions on the slenderness ratio of non-standard lug bearing stiffeners?
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Recently, I saw the AD2000 support-type bearing and ear-type bearing calculations. For stability considerations, this specification limits the slenderness ratio of the ribs. However, domestic specifications do not seem to have this provision. I wonder if everyone who makes non-standard bearings has noticed this problem?
This should consider the load! I have not seen it in China, but our company uses non-standard leg supports. Basically in accordance with the standards
The maximum size of the standard C-type ear bearing has a slenderness ratio of about 260. Generally, the maximum slenderness ratio of axial compression members of steel structures does not exceed 250. The coefficient k of the ear bearing must also be determined according to the steel structure. It seems to be the coefficient φ in GB50017.
I agree with your point of view. In the steel structure standards, the corresponding stability coefficient can be found if the slenderness ratio is within 250, but it is usually stipulated that the slenderness ratio should not be greater than 150.
This post was last edited by FMSD at 2019-6-26 09:28 NB/T47065-2018 Ear Bearing Preparation Instructions: The coefficient k is determined according to the steel structure specification 50017. It should be the coefficient φ in GB50017, right?
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Found a new problem today: formula: The allowable stress c of the rib plate has taken into account the stability factor and is reduced a lot based on the allowable stress of the material. Generally, it is only a few tens of MPa. ； It doesn’t make sense that the allowable load determined by the ribs should also consider the influence of the stability coefficient k again. ； If k is the pressure bar stability coefficient φ in GB50017, the allowable load will be very small. I think that since the allowable stress has already considered the stability of the ribs, there is no need to consider the stability coefficient k again in the allowable load calculation.
Haven't looked into this formula in detail yet. However, I personally think there are several reasons:: 1. What is considered in the allowable stress is the safety factor, not the stability factor. ； 2. The calculation of the rib plate is based on the calculation of the maximum "compressive stress", that is, the calculation based on the "compression bar" principle. Usually the allowable compressive stress of a long compression bar is far less than the allowable stress (that is, the strength is already unstable before the strength is destroyed). So this stability coefficient (reduction coefficient) is no problem. You can look at it this way: Bending moment/(Bending resistance coefficient * (stability coefficient) < allowable stress, the right side of the equation becomes the allowable stress multiplied by the stability coefficient.