Roof Joist Design Example

Ce 331 spring 2002 joist and frame design example 1 2 1.

Roof joist design example.

Let s consider a basic gable wood roof framing design. Calculate the dead load on a typical purlin. Ij 14 minor flange cuts. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.

The even distribution of weight across a roof joist network is intended to prevent the roof from collapsing. Design criteria and specifications a. 2x joists rafters 2 or better 2. You can earn a ceu by watching the industry version of this webinar then successfully completing the related ceu exam.

Design examples for strengthening joists example 3 1 strengthening a k series joist with crimped angle webs example 3 2 strengthening a k series joist with rod webs example 3 3 strengthening an end diagonal w2 using double angles example 3 4 strengthening of joist girder chords example 3 5 strengthening of a lh series joist with double angle webs. Timber beam design seismic forces wind forces floor shearwall diagram lateral loads roof diaphragm design shearwall design continuous footing design. Draw the purlin and show the dead loading. The allowable ceiling joist span tables in the 2018 version are found in section r802 5.

Example joist design for uplift bottom chord properties llllxx lllzz 24 better partners. Ij 16 bci web stiffener. Ij 8 glue nail floor composite action. For example a 24cj 1400 800 240 composite joist has a steel joist depth of 24 inches 610 mm a total factored composite load carrying capacity of 1 400 plf 20 4 kn m a factored composite live load capacity of 800 plf 11 7 kn m and a factored composite dead load capacity of 240 plf 3 5 kn m.

Example joist design for uplift tension webs must be checked for compression c. Ij 12 design live loads for residential floors. Calculate the moment due to dead load. Design of steel joist roofs to resist uplift quiz.

Ij 5 joist to hip beam connection. Access to the exam is available for purchase. The design and construction of ceiling joists are found in section r802 4 of the irc. Ij 10 rafter cut length table.

Floor beam span tables of residential structural design we will now look at roof rafter and beam design. Design a typical floor joist for the two story office building indicated below. Draw the shape of the moment diagram below. In this post we will cover wood roof framing members specifically ceiling joists.

Here we have a wood framed gable roof. The table references have changed in the 2018 version of the irc. Continuing on from part 3. 4x 6x 8x beams headers 1 orbetter.

Since the weight of a roof is fairly static it is easy to design for but engineers do need to think about issues like the accumulation of snow in cold climates layers of roofing materials added over the lifetime of the structure and changes in roofing materials when they determine. Example joist design for uplift bottom chord lyybraced by bridging y axis lyy better partners. Ij 13 multiple ply bci ajs member.