Truss Technician Training - Level I Sample Exam ANSWERS

Truss Technician Training - Level I Sample Exam
ANSWERS
This exam has been developed by the Wood Truss Council of America (WTCA) to
prepare you for the types of questions that will be asked in the proctored TTT Level I
Exam. A separate Answer Sheet is also available. The exam will cover the following five
basic categories of information.
Truss Math
The use of geometry, trigonometry, and algebra in the design of trusses.
Truss Standards
Standards and documents pertaining to the design, manufacturing, and
use of metal plate connected wood trusses.
Structural Design
Basic engineering principles, statics, strength of materials, load
development, and load paths.
Building Codes
Design load and performance requirements applicable to wood trusses
as specified by building codes and engineering standards.
Wood Technology
Basics understanding of lumber grades and the natural and in-service
factors affecting the strength and performance of wood and wood
trusses.
This sample exam will present at least one question from each category. The proctored
TTT Level I Exam will be much longer and you will be given a 4 hour time limit to
complete it.
Things to remember for the proctored TTT Level I Exam:
ƒ
Bring a calculator and any books, binders or notes you have used while taking the
course. These will be allowed.
ƒ
Computers are NOT allowed.
ƒ
Use the space provided on the exam to show all work or include additional paper
as necessary. Partial credit can be given. Numerical answers not accompanied by
the calculations will be considered incorrect.
ƒ
You must do your own work without assistance from anyone else.
1 of 4
Truss Math
Sample Question #1: Fill in the chart below:
PITCH
RISE
RUN
HYP
TAN
SIN
COS
Angle
9.8
103.15″
126.3″
163.07″
0.8167
0.6325
0.7745
39.23º
Sample Question #2: A truss has a 8/12 pitch, a 1/4″ butt cut, and a 2x4 top chord.
a) What is the plumb cut height of the 2x4?
Ө = Tan-1 (Pitch/12) = Tan-1 (8/12) = 33.69º
Plumb = (lumber/cos Ө) = (3.5 in./ cos (33.69º) = 4.206 in.
b) What is the heel height of the truss?
4.206 in. + 0.25 in. = 4.456 in.
2 of 4
Truss Standards
Sample Question #3: Who is responsible for communicating the design criteria from the
construction documents to the Truss Designer?
a) Truss Manufacturer
c) Contractor
b) Owner
d) Building Official
Structural Design
Sample Question #4: For the loading diagram shown, find the reactions R1 and R2.
R1 = 3,666.7 lbs. / R2 = 2,833.3 lbs.
3 of 4
Building Codes
Sample Question #5: What is the total weight (in pounds) of a 10-ft by 10-ft floor area
consisting of one layer of 20 lb. felt, 3/4 in. plywood sheathing, and 1/2 in. interior gypsum
board? (Use Table C3-1a of ANSI/ASCE 7-98)
Area = 10-ft x 10-ft = 100 ft2
ƒ
1 layer of 20 lb. felt = 0.2 psf
20 lb./100 ft2
ƒ
3/4 in. plywood sheathing = 2.4 psf
0.4 psf per 1/8 in. thickness
(0.4) x (6) = 2.4 psf
ƒ
1/2 in. interior gypsum board = 2.2 psf
0.55 psf per 1/8 in. thickness
(0.55) x (4) = 2.2 psf
Total Dead Load in psf = 0.2 + 2.4 + 2.2 = 4.8 psf
Total Weight = 100 ft2 x 4.8 psf = 480 pounds
Wood Technology
Sample Question #6:
a) What happens to the strength of wood as the temperature increases?
Strength of Wood Decreases
b) What is used to “adjust” for the strength properties for lumber used in high
temperature conditions?
Ct
4 of 4