Dik, heres a link that provides some info of buckling of the stringers https://files.engineering.com/download.aspx?folder=a2fa6dff-3227-4afa-af19-04f93ad0ce21&file=AD_310_-_Staircases_With_Flat_Stringers.pdf
I ran in to this issue when reviewing a project a couple of years ago. The original designer had ignored eccentricities. Some of the gusset plates were very long as they were picking up 2 incoming members that were at shallow angles to each other. The reduction in capacity of the connection when...
I agree with varying the stiffness parameter to get a range of design values.
If getting guidance from a geotech make sure that they are considering all of the soil layers that will be affected by the stress bulb under the mat foundation. I've had goetechs provide a subgrade modulus based on a...
When doing hand calcs are you assuming that the upper column loads get transferred directly down though the bottom column which is adjacent to the retaining wall?
In your etabs model is the lower column connected to the retaining wall? If so load will be transferred from the column and in to...
dccd, it's due to the stiffness of the torsional support and the amount of rotational restraint it provides. For example if you had a single span with different rotational support stiffnesses at either end then the distribution of torsion in the beam won't be symmetric, there will be higher...
I think this benefit of cladding is often used when checking floor vibrations. Similar to assuming that the connections act as fixed rather than pinned for vibration checks.
For a 2 span beam with both spans subject to an eccentric udl causing torsion and 3 fully fixed torsional supports, then each beam will have the same torsion moment each end of the 2 spans (+/-). If the inner support is pinned then the 2 span beam will act as if it were a single span w.r.t the...
For a mid-terrace house you are correct that it wont sway as the houses at each end will take the lateral wind loads. However you shouldnt rely on these other houses, thus should treat the mid-terrace as a separate building that is able to look after its self.
Sorry Rod for late response just seeing your comment now. Yes S355 can be used instead of S275.
Bear in mind that additional properties of the S355 (impact toughness, etc.) will need to be at least as good as that of the specified S275 product.
Fynch,
In the UK S355 is now the norm for beam and column sections. It will be more expensive to buy the same sections in S275, as these are not rolled regularly.
For plates S275 is the norm.
This may be why 2 different grades have be shown by the designer.
Link to youtube playlist which has a few videos on elastic and inelastic buckling
https://www.youtube.com/watch?v=jNwvub87l8o&list=PLXdvc710ImyKoCSALYq0XLAmb9cmPoZy0
I use SCIA Engineer, but dont get involved in scaffolding design. They have a module specifically for the design of scaffolding which is meant to simulate the behavior of the couplers, etc., to get a more accurate analysis. Dont know how good it is or if other software packages have similar bolt...
Eurocodes recommend to base leeward pressures based on qz at the top of the building (same as US code).
I think that it depends on the aspect ratio of the structure, and how the wind moves around/over the building.
For a (tall) slender building the majority of the wind will pass around the...
Dave,
Please find a couple of links below that discusses soil/structure interaction. The way that most software programs apply spring supports to a ground bearing slab is known as the winkler spring method. Whilst this is simple for engineers to use, it can be highly inaccurate. For example...
DaveAtkins,
In an analysis package your statement is correct, assuming that there is a uniform spring stiffness under the slab.
Using a uniform spring stiffness does not reflect reality and isn't appropriate, due to the soil continuum beyond the edges of the slab.
This results in the slab...
