EXAM1-Solution-Fall-2023-10-23
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Mathematics
Date
Jan 9, 2024
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22
Uploaded by butterball587
10/23/2023
1
Online Distributed
Midterm Exam Kurt McMullin
CE164 – Fall 2023
A
15 ft
The only load on the beam is a Dead Load which is the three point loads of 10 kips each.
The two point loads are halfway between Point A and Point B and halfway between Point B and Point C.
There is no Live Load on the frame.
Determinant Continuous Beam
P
15 ft
B
C
The internal hinges are 3 feet from Points B and C
Points A and B are pin supports. Point C is a fixed support.
Calculate three things.
The Reaction at B.
The Shear 1’ to the right of B.
The Moment at B.
P
P
Engr Fundamentals
RB = (1/15){10*7.5 + 10*15 + 5*18} = 21 kips
VB = 5 kips
MB = 5*3 = 15 kip-ft.
10/23/2023
2
A
15 ft
The only load on the beam is a Dead Load which is the three point loads of 5 kips each.
The two point loads are halfway between Point A and Point B and halfway between Point B and Point C.
There is no Live Load on the frame.
Determinant Continuous Beam
P
15 ft
B
C
The internal hinges are 3 feet from Points B and C
Points A and B are pin supports. Point C is a fixed support.
Calculate three things.
The Reaction at B.
The Shear 1’ to the right of B.
The Moment at B.
P
P
Engr Fundamentals
RB = (1/15){5*7.5 + 5*15 + 2.5*18} = 10.5 kips
VB = 2.5 kips
MB = 2.5*3 = 7.5 kip-ft.
A
15 ft
The only load on the beam is a Dead Load which is the three point loads of 5 kips each.
The two point loads are halfway between Point A and Point B and halfway between Point B and Point C.
There is no Live Load on the frame.
Determinant Continuous Beam
P
15 ft
B
C
The internal hinges are 3 feet from Points B and C
Points A and B are pin supports. Point C is a fixed support.
Calculate three things.
The Reaction at B.
The Shear 1’ to the left of B.
The Moment at B.
P
P
Engr Fundamentals
RB = (1/15){5*7.5 + 2.5*18} = 5.5 kips
VB = 2.5 kips
MB = 2.5*3 = 7.5 kip-ft.
10/23/2023
3
A
15 ft
The only load on the beam is a Dead Load which is the three point loads of 10 kips each.
The two point loads are halfway between Point A and Point B and halfway between Point B and Point C.
There is no Live Load on the frame.
Determinant Continuous Beam
P
15 ft
B
C
The internal hinges are 3 feet from Points B and C
Points A and B are pin supports. Point C is a fixed support.
Calculate three things.
The Reaction at B.
The Shear 1’ to the right of B.
The Moment at B.
P
P
Engr Fundamentals
RB = (1/15){10*7.5 + 5*18} = 11.0 kips
VB = 5 kips
MB = 5*3 = 15.0 kip-ft.
TOP VIEW
BOLTED CONNECTION
3x8
2x10
SIDE VIEW
The Dead Load force applied to the assembly is 8 kips. Each bolt can resist 2.5 kips parallel to the grain and 1 kip perpendicular to the grain.
Calculate the net area of the 2x10.
Calculate the tension stress on the 2x10.
Calculate the strength, Z’, of the assembly if we only consider the bolt strength of the 2x10.
SAWN LUMBER – All bolts are 7/8” diameter
DEAD LOAD
30 degrees
Anet = 13.88 – 2(7/8 + 1/8)(1.5) = 10.88 sq inch
ft = 8000 / 10.88 = 735 psi
Z’ = 0.9(6)(2.5) = 13.5 kips
10/23/2023
4
TOP VIEW
BOLTED CONNECTION
3x8
2x10
SIDE VIEW
The Dead Load force applied to the assembly is 6 kips. Each bolt can resist 2 kips parallel to the grain and 1.5 kips perpendicular to the grain.
Calculate the net area of the 2x10.
Calculate the tension stress on the 2x10.
Calculate the strength, Z’, of the assembly if we only consider the bolt strength of the 2x10.
SAWN LUMBER
DEAD LOAD
30 degrees
Anet = 13.88 – 2(7/8 + 1/8)(1.5) = 10.88 sq inch
ft = 6000 / 10.88 = 551 psi
Z’ = 0.9(6)(2) = 10.8 kips
7/8” Diameter Bolts
TOP VIEW
BOLTED CONNECTION
3x8
2x10
SIDE VIEW
The Dead Load force applied to the assembly is 8 kips. Each bolt can resist 2.5 kips parallel to the grain and 1 kip perpendicular to the grain.
Calculate the net area of the 2x10.
Calculate the tension stress on the 2x10.
Calculate the strength, Z’, of the assembly if we only consider the bolt strength of the 2x10.
SAWN LUMBER – All bolts are 3/4” diameter
DEAD LOAD
30 degrees
Anet = 13.88 – 2(3/4 + 1/8)(1.5) = 11.23 sq inch
ft = 8000 / 11.23 = 712 psi
Z’ = 0.9(6)(2.5) = 13.5 kips
10/23/2023
5
TOP VIEW
BOLTED CONNECTION
3x8
2x10
SIDE VIEW
The Dead Load force applied to the assembly is 8 kips. Each bolt can resist 2.5 kips parallel to the grain and 1 kip perpendicular to the grain.
Calculate the net area of the 2x10.
Calculate the tension stress on the 2x10.
Calculate the strength, Z’, of the assembly if we only consider the bolt strength of the 2x10.
SAWN LUMBER – All bolts are 1/2” diameter
DEAD LOAD
30 degrees
Anet = 13.88 – 2(1/2 + 1/8)(1.5) = 12.01 sq inch
ft = 8000 / 12.01 = 666 psi
Z’ = 0.9(6)(2.5) = 13.5 kips
TOP VIEW
NAILED CONNECTION
2x8
4x10
SIDE VIEW
SAWN LUMBER
The stars represent 16d nails. The nails are 0.22 inch diameter and 3.5 inches long. The yield stress is 90 ksi.
DEAD LOAD
Calculate the strength of a single nail (Z) considering the bearing strength of both wood pieces is 3000 psi. Consider only modes I and IV.
Rd = KD = 10(0.22) + 0.5 = 2.7
Mode I Main = (0.22)(2)(3000)/2.7 = 489 lbs.
Side = (0.22)(1.5)(3000)/2.7 = 367 lbs.
Mode IV - for Re = 1
Z = (0.22)^2/2.7 * sqrt{2*3000*90000/(3*2)} = 170 lbs
Z = 170 lbs
.
10/23/2023
6
TOP VIEW
NAILED CONNECTION
2x8
4x10
SIDE VIEW
SAWN LUMBER
The stars represent 16d nails. The nails are 0.22 inch diameter and 4.0 inches long. The yield stress is 90 ksi.
DEAD LOAD
Calculate the strength of a single nail (Z) considering the bearing strength of both wood pieces is 2000 psi. Consider only modes I and IV.
Rd = KD = 10(0.22) + 0.5 = 2.7
Mode I Main = (0.22)(2.5)(2000)/2.7 = 407 lbs.
Side = (0.22)(1.5)(2000)/2.7 = 244 lbs.
Mode IV - for Re = 1
Z = (0.22)^2/2.7 * sqrt{2*2000*90000/(3*2)} = 140 lbs
Z = 140 lbs
.
TOP VIEW
NAILED CONNECTION
2x8
4x10
SIDE VIEW
SAWN LUMBER
The stars represent 16d nails. The nails are 0.20 inch diameter and 4.0 inches long. The yield stress is 90 ksi.
DEAD LOAD
Calculate the strength of a single nail (Z) considering the bearing strength of both wood pieces is 2000 psi. Consider only modes I and IV.
Rd = KD = 10(0.20) + 0.5 = 2.5
Mode I Main = (0.20)(2.5)(2000)/2.5 = 400 lbs.
Side = (0.20)(1.5)(2000)/2.5 = 240 lbs.
Mode IV - for Re = 1
Z = (0.20)^2/2.5 * sqrt{2*2000*90000/(3*2)} = 125 lbs
Z = 125 lbs
.
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