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

Bridge engineering, How to calculate economic span of ss bridge

How to calculate economic span of ss bridge

Float or slack of an activity is positive or negetive, 1. What take place w...

1. What take place when float or slack of an activity is positive Ans: It represents a situation where extra resources are available and the completion of the project is not de

Unloaded propped, Ask questa) In an unloaded propped cantilever, the proppe...

Ask questa) In an unloaded propped cantilever, the propped end sinks vertically relative to the fixed end by an amount ? due to poor construction of the foundation of the prop. Wha

Timber, structure of exogenous trees

structure of exogenous trees

Aslar masonry, different types of ashlar masonry

different types of ashlar masonry

What is assisted siding, Q. What is Assisted Siding? An Assisted Siding...

Q. What is Assisted Siding? An Assisted Siding is a siding to serve a factory, mill or other industrial premises other than colliery or mining are because such siding is antici

Calculate the pressure on the other end, Q. 50 liters per sec of water flow...

Q. 50 liters per sec of water flow in a horizontal pipeline which is 200m long and the centerline of which is 3 m above the datum line. The pipe tapers from 30 cm diameter to 20 cm

Explain the statements about the critical path method, 1. Determine a netwo...

1. Determine a network diagram method that uses only finish-to-start relationships and may use dummy activities to define logical relationships.  2.  Precedence diagr

Rebound hammer.., rebound hammer working mechanism with detailed specificat...

rebound hammer working mechanism with detailed specifications of the images

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