Design Wind Loads on Enclosed and Partially Enclosed Buildings. .. Society of Civil Engineers (ASCE) ASCE Wind Loads, as the basic reference. Assignment No.2 (Wind load analysis By ASCE ) Data on Design Problem ( Wind load analysis) My Serial No = 33 Nature of Building: Typical Office Building . The design wind loads for buildings and other structures, including the Main. Wind-Force Resisting System (MWFRS) and component and cladding elements.
|Published (Last):||11 November 2007|
|PDF File Size:||19.84 Mb|
|ePub File Size:||17.21 Mb|
|Price:||Free* [*Free Regsitration Required]|
Loafs ASCE wind loads ultimate or service level? Hey everybody – launching off of what Winnd just said – what do you consider “transient” loads in terms of the IBC?
I know we’ve had these discussions before in Eng-tips – the IBC doesn’t seem to define what the word transient means – I know its wind and seismic, but the context of the code seems to imply that there are “other” transient loads that may be combined with wind or seismic. So is Live load a transient load? The only other transient loads would be soil, flood, etc.
They only reduce wind or earthquake when applied with other loads. Also in my IBC Yes live load is a transient load. Essentially all loads with the exception of 7-002 load and superimposed dead load can be classified as “transient” and therefore come under the umbrella of the 0.
ASCE 7 Windspeed
Rather it is intended to account for the reduced probability that the transient load will occur simultaneously – it is doubtful you would have a full live load during a hurricane for instance. Back on the wind load issue, I believe it is helpful to think of the wind loads provided by ASCE in terms of their recurrence intervals rather than stamping them with a “service” or “ultimate” level.
This can be verified using the velocity recurrence interval multiplier in the commentary: Keep in mind this is a velocity multiplier and force levels are equal to velocity levels squared. In this case, 1. Therefore if you used a 1. As demonstrated in the commentary, you can back calculate the return period for a certain load factor by plugging in the square root of the load factor as Fc and solving for T.
So by removing the directionality factor from the typical 1.
ASCE Wind Loads – definition for enclosed structure – ASCE (civil) Code Issues – Eng-Tips
And taking the square root of this to make it in terms of force: Back solving 77-02 T results in a return period of approximately years. Therefore using a 1. As an end note, the code recommends using 0. This is based on bringing the 50 year map speeds down to 10 year speeds.
Fc is the wind speed multiplier so to get the force multiplier you must square 0. Sorry for the novel, hope it helps.
WillisV – appreciate your comments – but in the first paragraph you assert that live load is a transient load per the IBC I would really like to know what the ICC intent was so if I’m challenged in the future, I have a source. I’m not trying to diminish your statement, its just that I can’t say “WillisV told me so”.
Also, I’m not sure I’d say: How about snow loading? In some cases snow sits on a roof for weeks. JAE, I agree that the statement was a bit broad – certainly permanent earth pressures etc. User judgement is certainly in order. The assertation that live load is a transient load is based upon two things. First, code wise, is section Also, if this did not apply to live load, then you would rarely if ever get to use the 0.
Second, common sense wise, is that live load is not always there and is therefore transient. Also the majority of “canned” engineering software out there such as RAM follows this logic and applies the 0. WillisV – sounds right to me. On your question about snow, I asked somebody at the Southern Building Code a few years ago about it and he said that snow is a live load and therfore a transient load.
Transient by dictionary definition is “passing with time” or “remaining in a place only a brief time”.
So I don’t think transient is the best term to apply to snow load if a reduction is implied to be used by the code. What is the limit on time that can pass? I would still hesitate to apply the 0.
Download Wind Loading Calculator Sheet (Per ASCE 7-02 Building Code) (FREE!)
This suggests that the snow load is transient in terms of the logic in the code. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.
The Eng-Tips staff will check this out and take appropriate action. Click Here to join Eng-Tips and talk with other members! Join your peers on the Internet’s largest technical engineering professional community. It’s easy to join and it’s free. Register now while it’s still free!
Close this window and log in. Are you an Engineering professional? By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Are the wind loads in ASCE at ultimate or service level. But ASCE 7 indicates ultimate strength level forces for seismic load.
Am I correct in this assessment, that they are in fact allowable stress level loads? Wind loads in ASCE 7 are service level. Seismic loads are ultimate. I believe ASCE-7 also gives recommended load factors in the first part of the book- check if that helps any. I believe the load combinations in ASCE wind loads are not written to take this into effect which is why you are required to increase the wind load by 1. So you can either use the equations from So you increase This doesn’t seem right.
Or alternatively, if you have some other design code that allows stress increases for wind, you’d use the calculated loads without the reduction factor. It has to do with the calibration of the load combinations. The load combinations of The combination equations of Note that the ASCE wind loads utilize a wind directionality factor Kd which are not to be utilized without using there load combinations.
You can calculate wind loads per ASCE without the Kd factor and use whatever load combinations you think are appropriate. The ASCE commentary and your responses have been very helpful.
Thank you all for your contributions. I’m glad to see that the way I interpret the Code is essentially in line with most of you. Red Flag This Post Please let us know here why this post is inappropriate. Digital Transformation may be defined in a number of different ways by analysts or enterprise software vendors.
Defense manufacturing is all about project manufacturing and project accounting. Students Click Here Join Us! Posting Guidelines Promoting, selling, recruiting, coursework and thesis posting is forbidden. Resources Digital Transformation may be defined in a number of different ways by analysts or enterprise software vendors. Download Now Defense manufacturing is all about project manufacturing and project accounting.
Download Now White Paper: