Philippine National Standard for Canal Structures
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Questions and Answers

The Philippine Council for Agriculture, Aquaculture and Forestry and Natural Resources Research and Development is not part of the Department of Science and Technology.

False (B)

The Bureau of Agriculture and Fisheries Standards is mandated to develop standard specifications for agricultural machinery and equipment.

True (A)

The Agricultural and Fisheries Mechanization Law is also known as Republic Act 10602.

False (B)

The word 'should' indicates a mandatory requirement within the standard.

<p>False (B)</p> Signup and view all the answers

The Philippine National Standard for the design of canal structures is numbered PNS/BAFS/PAES 222:2017.

<p>False (B)</p> Signup and view all the answers

The formulation of this national standard was initiated by the Bureau of Agriculture and Fisheries Standards.

<p>False (B)</p> Signup and view all the answers

BPS Directives Part 3:2003 provides the rules for the structure and drafting of international standards.

<p>True (A)</p> Signup and view all the answers

This standard provides maximum requirements for hydraulic evaluation and stable design of road crossing, drop, siphon, and elevated flume.

<p>False (B)</p> Signup and view all the answers

The standard covers only design procedures for road crossings and drops.

<p>False (B)</p> Signup and view all the answers

The Bureau of Agriculture and Fisheries Engineering (BAFE) is responsible for the numbering of the standard.

<p>False (B)</p> Signup and view all the answers

Vertical drop is one type of road crossing structure.

<p>False (B)</p> Signup and view all the answers

A baffled apron drop is a type of vertical drop structure.

<p>False (B)</p> Signup and view all the answers

Design equations for drops are not included in this standard.

<p>False (B)</p> Signup and view all the answers

Inverted siphons have components that must be considered in their design.

<p>True (A)</p> Signup and view all the answers

Elevated flumes do not require data regarding the existing channel during the design process.

<p>False (B)</p> Signup and view all the answers

The standard provides design requirements for rectangular inclined drops but not for vertical drops.

<p>False (B)</p> Signup and view all the answers

The symbol for the 'Canal Bed Elevation Upstream' is CBD/S.

<p>False (B)</p> Signup and view all the answers

The unit for 'Canal Discharge' is m3.

<p>False (B)</p> Signup and view all the answers

hLT is the symbol for 'Total Head Loss'.

<p>True (A)</p> Signup and view all the answers

The 'critical depth' is the water flow depth where the energy content is at a maximum.

<p>False (B)</p> Signup and view all the answers

An 'inverted siphon' is a structure that conveys canal water under pressure and in a completely full state, and are used under roads, railroads, drainage channels, and local depressions.

<p>True (A)</p> Signup and view all the answers

A 'drop' is a structure designed to maintain the water level in a canal.

<p>False (B)</p> Signup and view all the answers

The symbol for 'Canal Area' is A, and it is measured in m2.

<p>True (A)</p> Signup and view all the answers

The parameter 'Conduit Cross-Sectional Area' based on the Orifice Formula is represented by the symbol Ap

<p>False (B)</p> Signup and view all the answers

The 'invert' is the top edge of a canal

<p>False (B)</p> Signup and view all the answers

PNS/BAFS/PAES 218:2017 refers to the design of open channels, main canals, laterals and farm ditches.

<p>True (A)</p> Signup and view all the answers

The orifice coefficient 'C' is always exactly 0.75.

<p>False (B)</p> Signup and view all the answers

The area of a Round Concrete Pipe (RCP) is calculated by $Ap = \frac{\pi D_p^2}{4}$, where $D_p$ is the actual diameter.

<p>True (A)</p> Signup and view all the answers

The nominal diameter of a 24-inch RCP is 61 cm.

<p>True (A)</p> Signup and view all the answers

The available head $h_a$ is computed by subtracting the downstream water surface elevation from the upstream water surface elevation.

<p>True (A)</p> Signup and view all the answers

The velocity in a box culvert is calculated by $V_b = \frac{A_b}{Q}$ where $A_b$ is the area of the box culvert and $Q$ is the canal discharge.

<p>False (B)</p> Signup and view all the answers

If the actual diameter of a 30 inch RCP is 76 cm, then the radius is 38 cm.

<p>True (A)</p> Signup and view all the answers

If the upstream water surface elevation is 10 m and the downstream water surface elevation is 8 m, the available head is 18 m.

<p>False (B)</p> Signup and view all the answers

The area of a box culvert is calculated as the average base width multiplied by the culvert's length.

<p>False (B)</p> Signup and view all the answers

A streamlined warp to a rectangular opening has an inlet coefficient of 0.20.

<p>False (B)</p> Signup and view all the answers

A brokenback to a rectangular opening has an outlet coefficient of 0.50.

<p>True (A)</p> Signup and view all the answers

The conduit friction loss, $h_{Lv}$, can be calculated using the formula $h_{Lv} = S_f \times L$, where $S_f$ is the conduit slope and $L$ is the conduit length.

<p>True (A)</p> Signup and view all the answers

The minimum conduit slope for a straight line profile is 0.050.

<p>False (B)</p> Signup and view all the answers

The total head loss is calculated by multiplying 1.20 with the sum of inlet transition loss, conduit friction loss, and outlet transition loss.

<p>False (B)</p> Signup and view all the answers

Outlet transition loss is calculated using the formula $h_{Lo} = k_o (h_{v2} - h_{vp})$, where $k_o$ is the outlet coefficient.

<p>True (A)</p> Signup and view all the answers

An earth canal to RCP opening has an inlet coefficient of 1.00.

<p>False (B)</p> Signup and view all the answers

Drop structures are required for the stability of the canal when there is a minor change in the canal's elevation.

<p>False (B)</p> Signup and view all the answers

The optimal placement and design of drop structures must balance stability and budgetary concerns.

<p>True (A)</p> Signup and view all the answers

When selecting a type of lining for a canal drop, only the materials should be considered, not the flow velocities.

<p>False (B)</p> Signup and view all the answers

If the elevation difference is more than 5 meters, a vertical drop is required rather than an inclined structure.

<p>False (B)</p> Signup and view all the answers

Detailed information about the existing canal structures nearby, is not relevant when designing a new canal drop.

<p>False (B)</p> Signup and view all the answers

The standard requires having data about subsoil water levels and seasonal fluctuations to design canal drops.

<p>True (A)</p> Signup and view all the answers

A vertical drop is unsuitable to use for drops of 2 meters and a discharge up to $5 m^3$.

<p>False (B)</p> Signup and view all the answers

A baffled apron drop uses a water cushion for energy dissipation.

<p>False (B)</p> Signup and view all the answers

In the design procedure of a vertical drop, the basin elevation is determined before determining the basin length.

<p>False (B)</p> Signup and view all the answers

Flashcards

What is a Standard?

A document that outlines the requirements and specifications for a particular product, process, or service.

What is the PNS/BAFS/PAES 221:2017 standard?

This refers to a national standard, specifically for the design of canal structures like road crossings, drops, siphons, and elevated flumes.

Who initiated the development of this standard?

The Agricultural Machinery Testing and Evaluation Center (AMTEC) played a role in developing this standard.

What was the source of funding for the standard development?

It was funded by the Philippine Council for Agriculture, Aquaculture and Forestry and Natural Resources Research and Development under the Department of Science and Technology.

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What is the role of the Bureau of Agriculture and Fisheries Standards (BAFS) in this context?

It outlines the process for developing agricultural and fisheries machinery standards.

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Who approved this standard?

The standard was approved by the DA Secretary through the Bureau of Agricultural and Fisheries Engineering (BAFE).

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What is the purpose of this standard?

This standard provides guidelines to ensure uniformity in the construction of canal structures.

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What is the difference between 'shall' and 'should' in this standard?

The standard uses the word 'shall' to indicate mandatory requirements and 'should' to suggest recommendations.

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What is the purpose of PNS/BAFS/PAES 221:2017?

This standard sets the minimum requirements and methods for evaluating and designing road crossings, drops, siphons, and elevated flumes, ensuring hydraulic stability.

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What's the key principle behind designing canal structures?

Components of a canal structure, such as a road crossing or drop, are designed to manage water flow efficiently while ensuring the structure's stability.

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What's the purpose of a road crossing in a canal?

Road crossings in canals are designed to allow vehicles to safely pass over while maintaining water flow without disruptions.

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What is the function of a drop in a canal system?

Drops are structures designed to control water flow and manage elevation changes in a canal, ensuring a smooth and controlled transition.

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What is an inverted siphon in a canal and how does it work?

A siphon is a curved pipe that allows water to flow uphill, crossing a barrier or obstacle, such as a road, while maintaining a continuous flow of water.

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What is an elevated flume and how does it function?

An elevated flume is a raised channel that carries water over an obstacle or a change in elevation, allowing the canal to continue its course.

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What factors are considered when designing canal structures?

The design of canal structures involves numerous factors, including water flow, soil conditions, and expected load, ensuring both structural integrity and efficient operation.

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What does it mean to design canal structures for both stability and efficiency?

This standard ensures that canal structures are designed not only for strength and stability but also for efficient water flow, preventing waste and promoting sustainability.

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Canal Discharge (Q)

The rate at which water flows through a canal.

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Orifice

The opening in a structure that regulates water flow, like a pipe or culvert.

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Orifice Coefficient (C)

A coefficient reflecting the efficiency of the orifice in controlling water flow.

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Available Head (ha)

The vertical difference in water levels between the upstream and downstream sides of a structure.

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Conduit Cross-Sectional Area

The cross-sectional area of a conduit, such as a circular pipe or square-shaped culvert.

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RCP Diameter (Dp)

The diameter of a circular pipe or culvert used to transport water.

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Box Culvert Height (hb)

The length of a rectangular-shaped culvert that carries water.

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Conduit Velocity

The speed at which water flows through a conduit.

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Critical Depth

The depth of water flow where the energy content is at its lowest, meaning there are no additional backwater forces affecting it.

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Drop

A canal structure designed to move water from a higher elevation to a lower elevation, safely dissipating the extra energy caused by the drop in height.

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Elevated Flume

A water-carrying channel or conduit supported by piers, positioned above ground level.

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Equipment Crossing

A passageway made in a canal for equipment and small machinery to cross over.

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Invert

The lowest inside point of a conduit, often referred to as the sill.

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Inverted Siphon

A closed conduit that carries canal water under pressure, allowing it to pass beneath roads, railways, drainage channels, or low-lying areas.

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Road Crossing

A section of a canal designed to safely carry water underneath roads or railroads.

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Canal Area

The area inside a canal's open channel.

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Canal Bottom Width

The width of the bottom of a canal's channel.

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Drop Structure Selection Criteria

The choice of drop structure type and placement should be based on a comparison of structural stability and construction costs.

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Lining Material and Flow Velocities

The type of lining material for the canal and the flow velocities need to be considered when selecting the drop structure type to prevent erosion.

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Inclined Drops for Large Elevations

For significant elevation changes (above 5 meters), an inclined drop or chute is required for safe water flow.

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Contour Plan Requirement

A detailed map showing the contours and elevations of the area where the drop structure will be built.

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Profile Sheet Requirement

A drawing that shows the vertical profile of the canal and positions of existing structures, to consider potential combinations with the drop.

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Canal Flow Data Requirements

Information on the cross-sectional area of the canal, water flow speed, water volume, and critical elevation points upstream and downstream of the drop.

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Lining Details Requirement

Details about the lining material used on the canal sections both before and after the drop structure.

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Drop Structure Height Requirement

The proposed height of the drop structure as indicated in the profile sheet.

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Inlet Coefficient

A coefficient that accounts for energy losses occurring at the transition from an open canal to a closed conduit, representing the efficiency of the transition.

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Outlet Coefficient

A coefficient that accounts for energy losses occurring when water flows out from a closed conduit to an open canal. It represents the efficiency of this outflow.

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Conduit Friction Loss

The head loss due to friction within a conduit, calculated as the product of a friction factor, the conduit length, and a function of velocity and cross-sectional area.

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Outlet Transition Loss

The head loss occurring at the transition from a closed conduit back to an open canal, calculated using the outlet coefficient and the difference in velocity heads.

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Total Head Loss

The total energy loss in a system, calculated as the sum of the inlet transition loss, conduit friction loss, and outlet transition loss.

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Drop Structure

A structure built to prevent erosion and instability in a canal when there is a significant change in elevation.

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Drop Structure Criteria

Criteria outlining the need for drop structures in canals, emphasizing the importance of maintaining canal stability.

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Minimum Conduit Slope

The minimum slope required for a straight-line canal profile to ensure proper flow and prevent sediment buildup.

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Study Notes

Philippine National Standard - Design of Canal Structures

  • Standard Number: PNS/BAFS/PAES 221:2017
  • ICS Number: 65.060.35
  • Subject Matter: Design of canal structures (road crossings, drops, siphons, and elevated flumes).
  • Initiated by: Agricultural Machinery Testing and Evaluation Center (AMTEC) under a project.
  • Funding Source: Philippine Council for Agriculture, Aquaculture, and Forestry.
  • Developed by: Bureau of Agriculture and Fisheries Standards (BAFS).
  • Mandate: To develop standard specifications and test procedures for agricultural and fisheries machinery and equipment (per AFMech Law of 2013, Republic Act 10601).
  • Standard Development Process: Endorsed for DA Secretary's approval through the Bureau of Agricultural and Fisheries Engineering (BAFE) and the Bureau of Philippine Standards (BPS) for inclusion in Philippine National Standard (PNS).
  • Document Structure: Covers scope, references, symbols, definitions, road crossings, drops, inverted siphons, elevated flumes, design procedure, design equations, and bibliography.

Road Crossing

  • General Criteria: Right-angle intersection preferred.
  • Data Requirements: Canal hydraulic elements (discharge, velocity, area, width, depth, etc.), levels upstream and downstream of the structure.
  • Design Procedure: Determine conduit size, available head, conduit velocity, and invert elevation. Account for total head loss (inlet, friction, and outlet transition losses).

Drops

  • General Criteria: For significant elevation changes. Selection by cost and stability.
  • Data Requirements: Contour plan, profile sheet, canal structure locations, cross-section, types of drop, velocity information, upstream & downstream levels and relevant details.

Inverted Siphon

  • Components: Inlet and outlet transitions, conduit, blowoff structure and manhole.
  • Design Criteria: The siphon should be short and intersecting angles to be as close as possible to 90 degrees. Minimum cover requirements for different types. The slope of the conduit should follow certain parameters, and velocity needs to follow specific patterns depending on the location.
  • Data Requirements: Accurate contour plan and cross-section of the river.

Elevated Flume

  • Design Criteria: Suitable if canal bed is high enough, with sufficient freeboard (clearance). Velocity and slope need to meet specific parameters to prevent undesirable water surface undulations.
  • Data Requirements: Details of the relevant hydraulic elements, upstream and downstream levels, with sufficient specifics.

Design Procedure

  • Follows defined formulas and equations for each type of structure to derive calculated values for each component of different aspects of the canal systems.
  • Comprehensive procedures ensure accuracy and proper implementation of design principles throughout the process.

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Explore the Philippine National Standard PNS/BAFS/PAES 221:2017 dedicated to the design of canal structures including road crossings, drops, and siphons. This standard aims to establish specifications and test procedures critical for agricultural and fisheries machinery. Test your knowledge on the development process and key components outlined in this standard.

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