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Hi, I am designing an open gantry crane for the first time though I have experience of eot cranes.I need to know the allowable deflection at top of legs under normal operating conditions i.e maximum acceleration with wind load of 25kgf/sq m.Any help in this matter would be highly appreciated.

Bridgebuster, Your notation of box and tub section is same as given in AASHTO bridge design spec 2007 and this was what I meant. However finally I could locate flange proportion for box section.In 6.11.8.2.2.Actually flexure resistance for compression flange is given in terms of flange...

Hi, I was looking for proportions of web and flange for single box section in lrfd bridge spec-2007{SI edition).In 6.10.2 I could get these values for I section.In 6.11.2.2 these values for tub section are given.However proportions for box section could not be found (like ratio of compression...

Thanks for all your replies.I am referring to steel box girder with plate diaphgrams like the ones used in overhead cranes where drive platforms are directly attached to one web.Voyageofdiscovery which manual are you referring to?

Hi I am in need of some good reference book on design of steel box girders.I specifically need the moment of inertia requirements for diaphragms at the point of eccentric loading where torsional moment and a vertical load is applied to only one web(like from cantilever platforms attached to one...

We are in the practice of giving same groove angles(say38degrees)to both the pulleys(having different dia's) of a transmission pair.However since correct groove angle of pulley depends upon ratio of pitch dia to belt thickness,I feel the two pulleys should have different groove angles(say 38 and...

As per the byelaws of AISC the employees of a firm which is eligible for higher level of membership can not become professional members(lowest cost for engineers).I work in a public sector steel plant in india.My company is not an AISC member nor will it sponsor my membership.I am not allowed to...

Thanks apsix for giving requirements of AScode.This information was not available with my code(IS)to the best of my knowledge.Its because of the same reasoning as given by Dinosaur that I have never considered shielding in such cases.Confirmation from both of you have definitely given me...

Thanks to all of you for your thought provoking replies.The 60kw slip ring motor will have double the rated torque(of 30kw motor).Since load is constant,60kw motor will supply the required loadwith less slip.So at full speed it will be exerting the same torque as 30 kw motor was. The running...

What I really want to know(not only with reference to the problem mentioned above)is the effect (on internals of gear box)of using 60kw975rpm motor for a gear box having a rating of 30 kw at 975 rpm.The gear box is used infrequently and has a factor of safety of about 1.5 for static...

A 30kw motor that was supplied along with the original 70mm plate bending m/c has burnt out.Right now we only have a 60 kw motor as a replacement. Both are slip ring 975 rpm motors.Assuming that the factor of safety on various mechanical components like gears ,shafts etc used in the m/c is 1.5...

There are 3 columns in a plane braced frame spaced at 6 m. In order to calculate the total wind force on frame when wind is in the plane of frame,I get the force coefficient for single column(I section) as 2 . This multiplied by depth of column(500)*height(16m)give me the total force on a single...

How does one calculate wind force on bottom of conveyor gallery? Can the pressure coefficients for roof with 0 slope be used for it?

I feel without proper stiffeners 4mm sheet( even if continuously welded to the beam) cannot be taken as a reliable lateral constraint.I would prefer not to consider it .

Jmiec can you please give the details of your code

Jmiec, The code to be used in this case is indian code IS:800-86. It doesn't clearly mention the requirements for box girder in detail. For single web the maximum flange outstand is given as 16t.Doubling it for box girder for flange between two webs , it comes out to be 32t where t is flange...

A junction house of belt conveyors is supported in one of the planes on 3 braced columns in a plane.To calculate wind force on the structure when wind flows along this plane i also need to find udl of wind load on these columns .Columns are 16 m tall and spaced at about 6m each.I get the force...

I need to calculate total uplift on conveyor gallery due to wind load ,in order to calculate tension in bolts connecting gallery end portals to trestle top.I can calculate suction on roof from design pressure and pressure coefficients given in standards for roof.To calculate suction at...

Thanks nutte and twinnell for your helpful response.I am now clear on it. Unfortunately I don't have access to aisc manual.Mukhonov states on page112"The strength of side welds also depend on their size,the ultimate strengthdecreasing somewhatwith anincrease of the size.The size of the weld is...

What is the rationale behind limiting fillet weld size as .8to .9t,where t is plate thickness?Is this also valid for T joints(double fillet)?One of the reasons that appears to me is that there is no point in making weld stronger than the plate. In addition to this,isit also(or only)related to...