Chapter 79 in Lindeburg
Chapter 79 - Horizontal, Compound, Vertical, and Spiral Curves - 15 Problems
Monday, March 10, 2008
Thursday, March 6, 2008
Surveying - Answers
I marked these pages:
Errors (Survey) - Section 1 ---> - Page 78-1
Elevation corrections - Section 18 - Page 78-9
Today's Answers:
Surveying - Questions
1.
Errors
Four level circuits were run over four different routes. The elevation and error for each circuit is listed below. What is the most probably value of the benchmark’s elevation?
Route 1: 745.07 ± 0.02
Route 2: 745.22 ± 0.03
Route 3: 745.40 ± 0.08
Route 4: 745.16 ± 0.04
2.
Leveling
A level is placed where the height of the instrument above datum is 294.45 ft. The rod is held on a point 4000 ft away. And a reading of 4.65 ft is recorded.
a) Find the effect of the earth’s curvature on the rod reading
b) Find the effect of the atmospheric refraction on the rod reading.
3.
A 5 leg closed traverse is taped and scoped in the field, but obstructions make it impossible to collect all the readings. It is known that the general direction of EA is east west. Complete the field notes:
Leg north azimuth distance
AB 106.22° 1081.3
BC 195.32° 1589.5
CD 247.12° 1293.7
DE 332.37° ______
EA ______° 1081.3
4.
Photogrammetry
A camera with a focal length of 5 inches and a size of 10 in by 10 in is used to photograph an area from an altitude of 4500 ft above sea level.
a) If the average elevation is 600 ft, what is the average scale of the photo?
b) What is the ground area covered by a single photograph?
c) If overlap and sidelap are 50% and 30% respectively, what is the ground spacing between exposures?
d) same as c) what is the ground spacing between flight lines?
e) if the aircraft is moving at 325 mph ground speed, what is the time interval to the nearest 0.1 sec between exposures?
f) two points at elevation 650 ft appear 90 mm apart on the photo, what is the ground distance?
g) what elevation should a plane be flown to get an average scale of 1:10,000 if the elevation is 1100-1300 ft above sea level.
Errors
Four level circuits were run over four different routes. The elevation and error for each circuit is listed below. What is the most probably value of the benchmark’s elevation?
Route 1: 745.07 ± 0.02
Route 2: 745.22 ± 0.03
Route 3: 745.40 ± 0.08
Route 4: 745.16 ± 0.04
2.
Leveling
A level is placed where the height of the instrument above datum is 294.45 ft. The rod is held on a point 4000 ft away. And a reading of 4.65 ft is recorded.
a) Find the effect of the earth’s curvature on the rod reading
b) Find the effect of the atmospheric refraction on the rod reading.
3.
A 5 leg closed traverse is taped and scoped in the field, but obstructions make it impossible to collect all the readings. It is known that the general direction of EA is east west. Complete the field notes:
Leg north azimuth distance
AB 106.22° 1081.3
BC 195.32° 1589.5
CD 247.12° 1293.7
DE 332.37° ______
EA ______° 1081.3
4.
Photogrammetry
A camera with a focal length of 5 inches and a size of 10 in by 10 in is used to photograph an area from an altitude of 4500 ft above sea level.
a) If the average elevation is 600 ft, what is the average scale of the photo?
b) What is the ground area covered by a single photograph?
c) If overlap and sidelap are 50% and 30% respectively, what is the ground spacing between exposures?
d) same as c) what is the ground spacing between flight lines?
e) if the aircraft is moving at 325 mph ground speed, what is the time interval to the nearest 0.1 sec between exposures?
f) two points at elevation 650 ft appear 90 mm apart on the photo, what is the ground distance?
g) what elevation should a plane be flown to get an average scale of 1:10,000 if the elevation is 1100-1300 ft above sea level.
Wednesday, March 5, 2008
Retaining Walls and Deep Foundations - Day 2 - Answers
I marked these pages:
Piles - Section 3 - Page 38-3Today's answers:
Retaining Walls and Deep Foundations - Day 2 - Questions
1. A 10.75 in diameter steel pipe is driven 70 ft into stiff insensitive clay. The clay has an un-drained shear strength of 1250 lbf/ft^2. The clay's specific weight is 120 lbf/ft^3. Water table at ground surface. Entire pile length is effective.
a) Find the end bearing capacity.
b) Find the friction capacity.
c) Find the allowable bearing capacity.
2. Test show that a single pile by itself would have an uplift capacity of 140 tons. And a compressive capacity of 600 tons. 36 piles are installed on a grid with a spacing of 3.5 ft. The pile group is capped and connected at the top by a thick steel-reinforced concrete slab adding it's own axial load of 600 tons. What is the maximum moment that the pile group can take in the x and y directions assuming axial load is applied to permit the moment.
3. A 25 ft deep, 35 ft square excavation in sand is being designed. The sand is dewatered before excavation. The angle of internal friction is 40° and the specific weight of the sand is 120 lbf/ft^3. Bracing is horizontal lagging, supported by 8 in soldier piles separated horizontally by 7 ft.
a) What is the shape of the pressure diagram on the lagging?
b) What is the bending moment on the lagging?
a) Find the end bearing capacity.
b) Find the friction capacity.
c) Find the allowable bearing capacity.
2. Test show that a single pile by itself would have an uplift capacity of 140 tons. And a compressive capacity of 600 tons. 36 piles are installed on a grid with a spacing of 3.5 ft. The pile group is capped and connected at the top by a thick steel-reinforced concrete slab adding it's own axial load of 600 tons. What is the maximum moment that the pile group can take in the x and y directions assuming axial load is applied to permit the moment.
3. A 25 ft deep, 35 ft square excavation in sand is being designed. The sand is dewatered before excavation. The angle of internal friction is 40° and the specific weight of the sand is 120 lbf/ft^3. Bracing is horizontal lagging, supported by 8 in soldier piles separated horizontally by 7 ft.
a) What is the shape of the pressure diagram on the lagging?
b) What is the bending moment on the lagging?
Retaining Walls and Deep Foundations - Day 2
Chapters 38 and 39 in Lindeburg.
These are the chapters in the practice problems book:
Chapter 38 - Piles and Deep Foundations - 2 problems
Chapter 39 - Temporary Excavations - 2 problems
These are the chapters in the practice problems book:
Chapter 38 - Piles and Deep Foundations - 2 problems
Chapter 39 - Temporary Excavations - 2 problems
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