Bottom Chord Attic Not Connected

Plating o do not reduce minimum plating defaults.

Bottom chord attic not connected.

Given that this section of the bottom chord is likely where one of the connector plates that hold the truss together is located you may need to nail through a metal plate on one side of the truss. D sketch the loading diagram and calculate the reactions. O no top chord splices in haunch of attic room as shown below. In other words the attic truss had no bottom chord.

B the top chord live include snow load as a live load and bottom chord live load. C determine the total load and proper load duration. This anomaly did not make it into the 3rd printing of asce 7 10 in 2013 but did create a discrepancy in the 2012 2015 irc. See table r301 5 for the above and then this note below the table.

The design was 2 mono trusses sistered together at a ridge girder over the attic space. Where ceiling joists are not parallel to rafters rafter ties shall be installed. About the bottom chord. It s okay to do this.

Lay a 2 by 4 across the truss with its bottom end on the top edge of the lower cord and centered on the mark you made between the end of the truss and its center. The remaining portions of the bottom chords shall be designed for a uniformly distributed concurrent live load of not less than 10 lb ft2 0 48 kn m2. A triangle is the simplest form of a truss and the bottom chord is the base piece. A the top and bottom chord dead load.

Center the 2 by 4 on the mark on the upper cord as well so that it extends from the lower cord at a 90 degree angle. Attic with storage is 20 psf versus 10 psf for attic with no storage. Metal plate connected mpc splice joints were tested in combined tension and bending to generate data that were used in the development of a design procedure for determining the steel net section strength of bottom chord splice joints of mpc wood trusses. Where ceiling joists are not connected to the rafters at the top wall plate joists connected higher in the attic shall be installed as rafter ties or a continuous tie should be provided.

The bottom chord therefore carries combined stress of both tension and bending of the truss. A rafter tie forms the bottom chord of a simple triangular roof truss. Toenail a truss into the top of the wall plate by nailing through the sides of the bottom chord at a 30 degree angle. The horizontal beam of the triangle of a bottom chord is used in this simple triangle truss construction.

Several common wood truss splice joint configurations were tested at varying levels of. The attic space is considered uninhabitable but will be used for storage. O limit attic room bottom chord l d to max 23 for example attic truss with 2x10 bottom chord lumber in the room should not have room wider than 17 9. Recently a project came across our desk that was an unusual attic design.