Help with a dam problem and pressure

  • Thread starter rishid
  • Start date
  • Tags
    Pressure
In summary: So the pressure at the face of the dam is just static pressure from the water. The coefficient of static friction is 0.42, so the factor of safety against sliding is 0.68.
  • #1
rishid
9
0
Figure 15-34 shows a dam and part of the freshwater reservoir backed up behind it. The dam is made of concrete of density 3.38 g/cm3 and has the dimensions shown on the figure.

http://www.webassign.net/hrw/15_34.gif

(a) The force exerted by the water pushes horizontally on the dam face, and this is resisted by the force of static friction between the dam and the bedrock foundation on which it rests. The coefficient of friction is 0.42. Calculate the factor of safety against sliding, that is, the ratio of the maximum possible friction force to the force exerted by the water.

(b) The water also tries to rotate the dam about a line running along the base of the dam through point A; see Problem 23. The torque resulting from the weight of the dam acts in the opposite sense. Calculate the factor of safety against rotation, that is, the ratio of the torque owing to the weight of the dam to the torque exerted by the water.

Anyone have any idea how to do that? Do you think pressure of air
 
Physics news on Phys.org
  • #2
The horizontal force acting on the dam is the integral of the water pressure over the area of the dam in contact with the water. Be sure to account for the fact that the pressure varies with the depth of the water.
 
  • #3
Think I would need to use air pressure of the water?
 
  • #4
I'm not sure what that means. If you calculate the pressure of the water properly then you know that the water pressure at the water's surface will match that of the atmosphere. Also, air pressure opposes the pressure of the water on the opposite side of the dam.
 
  • #5
water pressure varies linearly with depth

pressure head of water at a given depth = (water density) x (gravity) x (height of water column)

As Tide said, atmospheric pressure on the water is canceled out by the atmospheric pressure around the dam.
 

1. How do dams help with flood control?

Dams can help with flood control by holding back water during heavy rainfall or snowmelt. This prevents the water from flowing downstream too quickly and causing flooding in surrounding areas. Dams also have the ability to release water in a controlled manner, which can help mitigate the impact of flooding.

2. What is the role of pressure in dam construction?

Pressure plays a crucial role in dam construction as it helps to keep the dam stable and secure. Dams are designed to withstand the weight of the water they are holding back, as well as any additional pressure from strong currents or seismic activity. The way pressure is distributed and managed within the dam is essential for its structural integrity.

3. How do engineers monitor pressure in dams?

Engineers use a variety of methods to monitor pressure in dams, such as installing pressure sensors and gauges throughout the structure. These sensors measure the force exerted by the water against the dam and provide real-time data for engineers to analyze. They also use visual inspections and advanced technologies like satellite imagery to monitor any changes in pressure over time.

4. What are some common problems with dams and pressure?

Some common problems with dams and pressure include leaks or cracks in the dam structure, which can lead to a decrease in pressure and stability. Changes in water levels, such as droughts or heavy rainfall, can also affect the pressure on the dam and potentially cause damage. Poorly designed or maintained dams can also be susceptible to pressure-related issues.

5. How can pressure-related issues with dams be addressed?

To address pressure-related issues with dams, engineers may need to make repairs or modifications to the structure to improve its stability. This could involve reinforcing the dam with additional materials or implementing new technologies to monitor and manage pressure more effectively. In some cases, it may be necessary to decommission or remove a dam if the pressure issues are too severe or cannot be resolved.

Similar threads

  • Introductory Physics Homework Help
Replies
7
Views
14K
  • Introductory Physics Homework Help
Replies
29
Views
2K
  • Introductory Physics Homework Help
Replies
18
Views
23K
  • Introductory Physics Homework Help
Replies
1
Views
4K
  • Introductory Physics Homework Help
Replies
4
Views
7K
  • Introductory Physics Homework Help
Replies
2
Views
4K
  • Introductory Physics Homework Help
Replies
17
Views
4K
  • Introductory Physics Homework Help
Replies
2
Views
13K
  • Introductory Physics Homework Help
Replies
1
Views
7K
  • Introductory Physics Homework Help
Replies
4
Views
1K
Back
Top