hello, how should the snow load be calculated on multi span roofs? I couldn't find anything about it in asce7-16. Should it be calculated by the Sawtooth Roof division?
I'm not sure exactly what roof geometry you're referring to when you say "multi span roofs", but I can point you to some cases that require special attention. If your roof surface is supported by continuous, multi-span beams, you'll need to consider multiple load patterns with full and partial loading on different spans per ASCE 7-16, Section 7.5.1. If your roof consists of different slopes that merge together, then the sections on Multiple Folded Plate, Sawtooth, and Barrel Vault Roofs may apply. (You can do a Google Image search for these terms to see exactly what they are.) Section 7.4.4 requires you to use Cs = 1.0 and Section 7.6.3 requires you to use unbalanced snow loads with higher loads in the valleys and lower loads in the ridges. I hope that this helps!
@@StructuralCentral First of all, thank you for answering my question. I'm sorry for my bad english. The roof type I mentioned is referred to as "Multi span roof" on page 24 of EN 1991-1-3 in Eurocode. there is also this type of roof at the bottom of page 33. How should the snow load calculation of the roof type formed by combining two or more roofs like this be done side by side? Snow will accumulate at the junction of the two roofs due to snow drift and how should this be calculated? thanks
The Eurocode examples of "multi span roofs" that you mentioned appear to be referring to the same thing that ASCE 7-16 calls "sawtooth roofs". Take a look at ASCE 7-16, Figure 7.6-3 to see the design load cases. They account for the additional snow that accumulates in the valleys.
I have seen your presentation before ~ year an add notes. As you have said snowfall and drifting of snow on roofs as well as in roads, harbors, ports, dams, karst buildings, airpots snd railways must be removed. You give me path to see how to start research existing method and combine in a model for wind and snow simulation. Many researchs use FLOW-3D with general purpose for transient fluid flow phenomenon that runs under UNIX on workstation computers. To make real case we must imply geometry from both CAD models and digital terrain models must be converted to an appropriate format. Meteorological and hydrological data for boundary conditions as the sources usually field measurements at specific places. With this data we figure vector plot of wind speed and direction for horizontal cladding with different placings of gaps as well as a three-dimensional simulation of snowdrifs by numerical discrezization of two phase problems for a simplified drift-flux model and solutions similar to real measurements. Like you content as well as The Method called SNOW - SIM.😊
Understanding the intricacies of simulating wind and snow dynamics is no small feat. Wishing you the best in your endeavors as you navigate this complex analytical terrain!
@@StructuralCentral I should like to express immediately my deep gratitude to yours support and helpful sugestions which intrigated me before and contributed increasing this topic. Snowdrift and snow deposition have always been major problems and it will be. Numerical simulation of snowdrift with aspects on snowdrift experiments and process need to consider the diffusion theory and The finite - volumen solution as snow represents phase. Like you have said it is quite task to find solution or a further approach to the basic drift-snowflux rutine as well as investigation into complex geometry of the simulation where the snow will deposit, not as a exact quantity calculation. Mixture density, velocity, dispersed phese mass conversation, i.c. is BIG TOPIC and I am so truly delighted to give me INPUT BEFORE ONE YEAR. Yours topic is brilliant for researching energy efficiency in the enviroment also with quantum dinamics. I wish you all the best in further topics and "snowing", as well, again THANKS. 😊
Making the interface simple and straightforward without options hidden in menus was one of the design goals for the software. More calculations are being developed now.
To use the metric system, you would just have to do the proper unit conversions for each of the equations and limits. If you're in Canada, though, it's likely that you're required to follow the National Building Code of Canada. It contains its own method for determining snow loads. (See Section 4.1.6 of the 2015 Edition.)
How do we calculate the snow drift if the roof is flat but there is a air vent or a chimney etc. on the roof just like in the 'Drift Snow Load' part of the video?
Take a look at the "Roof Projections" section of ASCE 7 (Section 7.8 in ASCE 7-16). Projections on the roof get designed as windward drifts (0.75 factor on hd) using the length of the roof upwind or downwind of the projection. Also, note that for projections less than 15 feet long, drift loads are not required. Hope this helps!
There's several more videos in the works now. A video on ASCE 7-16 wind loads is likely a future addition. Subscribe to be notified when they are released.
