Calculate distance between top and bottom chord of the truss, Civil Engineering

Assignment Help:

A W12x58 member, which comprises a vertical member in a truss span, is subjected to a factored axial compressive force of 163 kips.  The W12x58 section is oriented such that the strong axis is subjected to wind loading.  For a grade 50 specimen, what is the maximum permitted uniformly distributed wind loading on truss vertical member, assuming the distance between top and bottom chord of the truss is 12-ft.?

The section is subjected to a combined loading of axial force and strong axis bending.  Because the member is part of a truss, it is assumed to be pinned at both ends. 

The first thing to determine is what the ratio of applied axial force to allowable is, to determine which interaction equation to use.

We can determine the allowable axial force for a given K and L values.  The problem doesn't explicitly use the term unbraced length.  However, for a vertical member in a truss, it is sufficient to use the vertical distance between the top and bottom chords.  Thus, L = 12 ft.  The k value is set to 1.0.  Therefore, the K*L value is then 12-ft. *1.0 = 12-ft.  From Table 4-1, this results in an allowable axial capacity of 603 kips

φPn = 603 kips

Pr = 163 kips

Pr / φPn = 163 kips / 603 kips = 0.27 which is greater than 0.2.  Therefore the first equation governs the capacity.

Next, the maximum permitted moment and the capacity is estimated at 306 kip*ft.

φMux = 306 kip*ft

Now, the interaction equation can be solved.

163 kip / (603 kip) + 8*Mr / (9*306 kip*ft) = 1.0

Solving for Mr = 251.2 kip*ft.  From this, the required distributed loading can be determined from the equation:

Mmax = wL2 / 8.  Solving for w, we obtain:

W = Mmax * 8 / L2 = 251.2 kip*ft * 8 / (12-ft.)^2 = 13.9 kip / ft. 

 


Related Discussions:- Calculate distance between top and bottom chord of the truss

Trusses, Determine the support reactions for the truss shown below

Determine the support reactions for the truss shown below

Zones of smear around vertical drains, Zones of smear around vertical drain...

Zones of smear around vertical drains Smear zones are produced during the installation of vertical drains in that zone of soils surrounding the band drains are disturbed. Soil

Define the term- erection stresses, Define the term- erection stresses ...

Define the term- erection stresses The creep loss due to live load stress, erection stresses and other stresses of short duration may be ignored. The loss of prestress due to

Road maintenance, Road Maintenance: Importance of Road Maintenance ...

Road Maintenance: Importance of Road Maintenance Roads deteriorate in their condition due to traffic, rain, snowfall and temperature variations. They requirement to b

Survey 1, describe how you would range a surveying line betwen two point wi...

describe how you would range a surveying line betwen two point wich are not entervisible?

Which is stronger solid steel rod or hollow steel pipe, On a per pound basi...

On a per pound basis, steel pipe is stronger in bending and is less likely to buckle in axial compression.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd