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68問 • 4ヶ月前

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Is defined as the means of collecting, transporting and disposing of surface water originating in or near the right of way, or flowing in stream crossing or bordering the right of way.

Drainage

It is the artificial removal of water, both surface and subsurface.

Drainage

Is often a major element in construction projects and is necessary to avoid flooding and other damage.

Drainage

Is that branch of physical geography that deals with water of the earth.

Hydrology

Deals with estimating the highest rate of run-off to be handled.

Hydraulic Design

Deals with the selection of the kinds and sizes of the drainage facilities that is most economical to accommodate the estimated water flow.

Hydraulic Design

is to ascertain the design will not create the erosion or other unacceptable environmental conditions.

Erosion Control

Item 501

Underdrains

Item 501.3.2

Underdrain Outlets

Item 501.3.3

Blind Drain

Is categorized under item 502 of DPWH Standard Specifications

Underdrain

“This item shall consist of constructing underdrain, using pipes and granular filter material underdrain pipe outlets and blind drains using granular material in accordance with the specification and in reasonably close comfomity with the lines and gradess hown on the plans or as established by the engineer.”

Underdrain

shall be permeable meeting the requirements of AASHTO M-6 specification except that soundness tests will not be required and minor variations in grading and content of deleterious substances may be approved by the engineer. All materials are subject to inspection before acceptance.

Granular Backfill Filter Materials

Trench are excavated to the depth and width as planned.

Underdrain Outlet

Pipes are laid in the trench with all ends firmly joined and backfilled after inspection and approval of the pipe installation.

Underdrain Outlet

Flood water usually carries objectionable objects like brushes, banana trunks, tree branches etc. This floating debris clog culverts entrances and raises the headwater elevation over-flowing the road and damaging adjoining properties.

Debris Control

Trenches for this shall be excavated to the width and depth shown on the plans, the trench shall be filled with granular backfill material to the depth required by the plans.

Blind Drain

Any remaining upper portion of trench shall be filled with either granular or impervious material in accordance with item 103-Structure Escalation.

Blind Drain

Problems usually encountered in the design and constructions of roadways are:

Stability of Fill and Slope, Drainage, Permafrost, Elasticity and Rutting

Run-off Predicted Based on the following Method:

By the Rational Methods, By the Empirical Formula, By the Unit Hydrograph, By Statistical Approach, By Simulation

are under item __ of the DPWH standard specification which includes construction or adjustment of manholes, inlets, and catch basin.

Manhole, Inlets, Catch Basin, 502

Also known as an inspection chamber.

Manhole

Provides access to underground utilities, most commonly sewer system.

Manhole

Usually consist of a chamber or ring.

Manhole

a vertical circular pipe of carrying sizes and depths, which is used to access inspection points.

Manhole

-Test Load 10 km

CLASS A

-Test Load 80 kN

CLASS B

-Test Load 150 kN

CLASS C

-Test Load 210 kN

CLASS D

- Test Load 400 kN, 600 KN and 900 kN

CLASS E,F,G

Its purpose is to determine the cross-section of the canal that will accommodate water flow smoothly and cheapest to construct and maintain.

Designing a Channel

Water flowing down a mild slope in an open canal.

Sub-Critical Flow

Water flow on steep slope.

Super Critical Flow

exist when the depth of water in the channel is greater than the critical depth.

Sub-Critical Flow

exists when the depth is less than the critical level.

Super Critical Flow

occurs when the velocity head is one half the average depths.

Critical Depth

is the cross-sectional area of the flow divided by its width at the liquid surface.

Average Depth or Mean Depth

Is the tendency of water to seek its own level as if in an open channels flows trough the pores and fine channel of the soil.

Capillarity

With the exception of storm drain, it includes all closed conduits with standard design repeated used.

Culverts

ITEM 519

Concrete Slope Protection

ITEM 511

Gabions and Matresses

An existing earth slope that have been stable can experience significant movement called.

Slope Failure or Landslide

Slope Failure or Landslide due to the following changes:

Changes in Natural Conditions, Changes Induced by Man

Changes in natural conditions may be the result from:

Occurrence of Earthquake, Subsidence of Underground Cavern, Erosion, Slope weakening due to the development of cracks or shrinkage cracks that are followed by water intrusions, Variations in the elevations of ground water or changes in the slope subsurface flow that create new seepage forces, Weakening of buried soils or rock seems due to ground water flow or chemical leaching

Changes induced by Man.

Slide

refers to the occurrence where the moving mass is defined and separated from the underlying and adjacent earth by plane, comprising a number of adjacent planes were seepage result.

Slide

Slides is classified into four:

Rotation Slide, Translational Slide, Block or Wedge Failure, Flows and Spread

Types of retaining wall:

Gravity Walls, Cantilevered Retaining Wall, Sheet Pile Retaining Wall, Bored Pile Retaining Wall, Anchored Retaining Wall

Is constructed with high-strength concrete (usually PCC) and behaves like a beam or slab thi spans and distributes loads over a wider area.

Rigid Pavement

Rigid Pavement Characteristics:

High flexural strength, Requires joints to accommodate expansion, contraction, and warping, Less deformation under loads, High initial cost but low maintenance

Rigid Pavement Types:

JPCP - Jointed Plain Concrete Pavement, JRCP - Jointed Reinforced Concrete Pavement, CRCP - Continuously Reinforced Concrete Pavement

consists of multiple layers that bend (or flex) under loads.

Flexible Pavement

Load distribution occurs layer by layer until it reaches the subgrade.

Flexible Pavement

Flexible Pavement Characteristics:

Low flexural strength, Deforms under loading, Easier and cheaper to construct, Requires more frequent maintenance

Typical Structure Flexible Pavement:

Surface Course (Asphalt), Base Course, Sub-Base, Subgrade

An empirical method based on CBR (California Bearing Ratio).

McLeod's Method

CBR

California Bearing Ratio

Used primarily for military and high-traffic pavements.

U.S. Corps of Engineers Method

Based on R-value obtained from lab tests.

California Resistance Value (R-Value) Method

Used to determine subgrade support.

California Resistance Value (R-Value) Method

Charts or empirical equations relate R-value with thickness required for various traffic loads.

California Resistance Value (R-Value) Method

Used when subgrade contains expansive clays.

Expansion Pressure Method

Laboratory tests determine __.

Expansion Pressure Method, Expansion Pressure

__ is designed to resist uplift caused by soil swelling.

Expansion Pressure Method, Pavement

Required thickness increases with expansion pressure.

Expansion Pressure Method

Used to calculate tensile stress at the corner of a rigid concrete slab due to wheel load.

Goldbeck's Formula (Stress at Corner of Rigid Pavement)

To accommodate vehicle off-tracking and ensure safety, extra width is added on curves.

Widening of Road on Curves

To design the base course thickness based on the soil's shear strength from __.

Triaxial Test Method

Enumeration

Sabrina Mikhaela Canindo · 42問 · 1年前

Enumeration