Soil Loading

[Godfrey]

Hello to everyone; There are a few issues I would like to get your opinion on about soil loading; 1. We should define 4 combinations out of 2x2 for H in 1.4G+1.6Q+1.6H and 0.9G+1.6H combinations, the first of which is specified in TS500, considering the effects in earthquake and non-seismic conditions, right? 2. Why is it optional to use H-loaded combinations in soil tension controls in ideCAD? Wouldn't it be wrong not to put these effects into ground stress control? Because soil loads are not very rare like earthquake loading, but are a constant load that acts statically on the structural elements. Thirdly, although it is required by the regulation, I think the 1.6 coefficient of H is very brutal in the absence of surcharge loads ))

 

[sereze]

Moments due to vertical loads in the 2nd side columns inward. Soil loading can act in the direction of reducing these moments, thus reducing the soil stresses in that area.

 

[Godfrey]

Mr. Sereze, you may be right about the internal forces, but this depends on many parameters such as floor height, static and dynamic active ground pressure coefficient and so on. Let me give an example, in my last project the basement floor height is 6.97 m. When I use the H-loaded combinations only in the reinforcement design, the project continues without any problems, but when I use the H-loaded combinations for soil safety stress control, the safety stress is exceeded with significant differences in 21 of 35 foundation beams. So why ? Soil safety stresses cannot be increased by 50% in combinations with H loading, because these combinations do not include earthquake loading. In this case, it becomes impossible to provide the ground safety stresses in the foundation beams (maybe raft foundation) unless the dimensions are large. So what? As a result, not using H-loaded combinations for soil safety stress control in structures where soil loads are effective becomes a necessity rather than an option, and I think the designers of ideCAD left this option to the user's choice for this reason. But it is not a necessity to consider the effects of a load that is included in the static load class, such as the soil loads that I am stuck with.

 

[sereze]

I've thought about it some more and I take it back. In the side columns, both the effect of vertical loads and the effect of soil load are inward. If there is a soil load, it means that there is a basement, a raft foundation is needed for bundling waterproofing in a basement building. In addition, if you make a continuous foundation, padding and 15 cm. The ground concrete needs to be poured, you can finish the job with 8 cm screed on the raft (If there is a lot of installation and a filling area is not required for the installation). Of course, the decision is not exactly related to the subject you asked, but my humble opinion is to make a raft foundation. Adjacent regulations, those who prepare the ground studies are on the overly safe side, etc. etc. Ninety percent of the foundations in our environment come out as rafts due to reasons such as: Even if it is 4-5 floors.