Practical Questions for Transportation and Highway Engineering

84問 • 1年前

Mea Jane Ramos

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This is the application of scientific principles to the planning, operation, and management of transportation systems.

Transportation Engineering

Also known as carriers, are primarily concerned with operating fleets to provide transportation services.

Operating Organization

If viewed in transportation system functional terms, the includes the following components: I. Physical Facilities II. Fleets of vehicles III. Operating bases and facilities IV. Organizations V. Operating Strategies

All of the above

Most civil engineering activity related to the provision of physical facilities is what might be called as.

Physical civil engineering

These are primarily involved in planning, designing, constructing, maintaining, and operating fixed facilities.

Facility-oriented Organizations

This is a highly specialized mode of transportation. It includes traditional mass transit modes such as buses, streetcars, and light rail and rail rapid transit, as well as paratransit modes such as jitneys and dial-a-ride services.

Urban transit

This exists wherever demand exceeds the capacity of the transportation system.

Traffic congestion

Is the distance required to see an oncoming vehicle of a certain minimum size.

Passing sight distance

Is a major challenge to the transportation system and the transportation engineering profession because it undermines the effectiveness and efficiency of the system.

Traffic congestion

Is defined as the maximum safe speed that can be maintained over a specified section of highway when conditions are so favorable that the design features of the highway govern.

Design Speed

Is a continuing challenge for the transportation engineering profession because of public expectations that safety will continue to improve.

Traffic safety

Is the distance required to see an object 150 mm high on the roadway.

Stopping sight distance

What are the two components in stopping sight distance?

Reaction and braking distance

The components of passing sight distance includes: I. Distance traversed during perception and reaction time II. Distance traveled while the passing vehicle occupies left lII. Distance between the passing vehicle at the end of its maneuver IV. Distance traversed by opposing vehicle for two-thirds of the time the passing vehicles occupies the left lane

All of the above

These are written instructions detailing how the facility is to be constructed.

Specifications

These include cost estimates for various parts of the project and are used to evaluate the acceptability of bids and financial feasibility of the project.

Estimates

Bid documents are often spoken of as including: I. Plans II. Specifications III. Estimates

All of the above

The four basic elements of standard plans include: I. Plan view II. Profile III. Geometric cross-section IV. Superelevation diagram

All of the above

There refer to drawings, usually accompanied by notes, of various aspects or components of the design.

Plans

This is a drawing of the facility as it would look to an observer directly above it.

Plan view

This drawing has elevation as its vertical axis, and horizontal distance as measured along the centerline of the facility (or other reference line), as its horizontal axis.

Profile

The line representing the facility on the profile.

Profile grade

These are in meters above some datum; usually this datum is mean sea level, but it may be any arbitrary scale.

Elevation

This view has elevation as its vertical axis and horizontal distance, measured perpendicular to the centerline, as its horizontal axis.

Geometric cross-section

These are normally specified in m/m or in percentages. In railway practice, cross- slopes may be expressed in millimeters (or inches) that the high rail is above the low rail, since there is a standard horizontal distance maintained between rails.

Cross-slope

This applies to curved facilities, such as highways or railways, only. It consists of a graph with roadway or railway cross slope versus horizontal distance.

Superelevation diagram

Are expressed as decimal fractions (m/m) or as percentages (m/station).

Grade

Geometric design for transportation facilities includes the design of the following elements. I. Geometric cross sections II. Horizontal alignment III. Vertical alignment IV. Intersections V. Various design details

All of the above

These may consist of ditches (usually graded swales) or of paved shoulders with berns or curbs and gutters.

Drainage

The vertical alignment of a transportation facility consists of the following:

Tangent grades and vertical curve

The primary consideration in the design of geometric cross sections for highways, runways, and taxiways is _____.

Drainage

These are normally parabolas centered about the point of intersection (P.I) of the vertical tangents they join.

Vertical curve

These are intended primarily as a safety feature. They provide for accommodation of stopped vehicles, emergency use, and lateral support of the pavement.

Shoulders

For highways, minimum length of vertical curve may be based on the following: I. Sight distance II. Comfort standards involving vertical acceleration III. Apperance criteria

All of the above

For crest vertical curve, the minimum length depends on the following: I. Sight distance II. Height of the driver's eye III. Height of the objects

All of the above

These are usually laid out in the field by occupying the tangent-to-curve point TC with a transit and then establishing successive points by turning deflection angles and measuring chords.

Circular Curves

Horizontal alignment for linear transportation facilities such as highways and railways consist of the following: I. Horizontal Tangents II. Circular Curve III. Transition Curves

All of the above

These are used to connect tangents to circular curves.

Transition curves

The purpose of this is to counteract the centripetal acceleration produced as a vehicle round a curve.

Superelevation or banking of curves

These are described in terms of their lengths (as expressed in the stationing of the job) and their directions.

Horizontal tangents

This involve modification of the roadway cross section from normal crown to full superelevation, at which point the entire roadway width has a cross-slope of e.

Superelevation transition

The distance which runs from the point at which the outside half of the roadway is at zero cross-slope to the P.I. at full superelevation is called

Superelevation ruoff

This traffic conflict occurs when vehicles enter a traffic stream.

Merging conflicts

This determines the length of the superelevation runoff of transitional curves (spiral curves).

Vehicle dynamic or appearance criteria

These result when two crves of differing radius (or for vertical curves, different rate of change of grade) join one another.

Compound curve

Geometric design of transportation facilities must provide for the resolution of traffic conflicts. In general, these may be classified as: I. Merging conflicts II. Diverging conflicts III. Weaving conflicts IV. Crossing conflicts

All of the above

This traffic conflict occurs when vehicles leave the traffic stream.

Diverging conflicts

These consist of two curves in the same direction separated by a short tangent.

Broken-back curve

This traffic conflict occurs when vehicles cross paths by first merging and the diverging.

Weaving conflicts

These traffic solutions eliminates the crossing conflicts by placing the conflicting traffic streams at different elevations at their point of intersection.

Grade separation

This traffic conflict occurs when they cross paths directly.

Crossing conflicts

These quantities are normally expressed as volumes, in metric units, they are given in cubic meters (cubic yards in traditional units).

Earthwork

The basic ways of resolving crossing conflicts in traffic. I. Time-sharing II. Space-sharing III. Grade-separation

All of the above

Wherever the existing ground is above the constructed section, the construction is said to involve _____.

Cut or excavation

These traffic solution involve assignment of the right-of-way to particular movements for particular time.

Time-sharing

Wherever the existing ground is below the constructed section, the construction is said to invole.

Fill or embankment

The points at which the cut or fill slopes intersect the existing ground are referred to as:

Catch point

The product of a volume of materials times the average distance it is hauled is referered to as a _____, and it is expressed in stations times cubic meters.

Haul

In earthworks, it is defined as the proportional change in volume of the material, relative to the volume it occupied in its natural state.

Shrinkage and swell

The cost of excavation normally includes the cost of removing the material from its existing state, hauling it up to some specified distance referred to as the ____.

Free haul distance

Calculation of optimum haul strategies and earthwork costs is done by means of a _____.

Mass diagram

This is the cost of any material that has to be obtained off the job site in order to make a fill.

Cost of borrow

This is a graph of cumulative volume of earthwork versus distance in stations from the beginning of the job, in which cut is considered to be positive and fill to be negative.

Mass diagram

The longest distance material should ever be hauled is called the _____.

Limit of economic haul

Pavement consists of the following: I.Surface course II. Subbase III. Base course IV. Subgrade V. Base course

All of the above

These are sometimes used in constructing pavements. These are used to add strength, control moisture, and prevent the movement of fine materials into drainage layers.

Geotextiles

This term refers to any material consisting of a mixture of aggregates, such as sand, gravel, or crushed stone, fastened together by cement.

Concrete

For a given service life and performance index value, a _____ is determined based on the traffic loads, soils support, and other design factors.

Structural number

This normally consists of aggregates such as gravel and crushed rock.

Base courses

A series of interconnected or interlaced cracks caused by fatigue failure of the asphalt concrete sureface under repeated traffic loading.

Alligator cracking

These are usually local aggregate materials. They may consist of either unstabilized compacted aggregate stabilized materials.

Subbases

Cracks forming large interconnected polygons, usually with sharp corners or angles. These cracks are generally caused by hardening and shrinkage of the asphalt and/or reflection cracking from underlying layers such as cement-treated base.

Block cracking

Wearing away of the pavement surface caused by the dislodging of aggregate particles and binder.

Raveling

Progressive disintegration of the surface between the heel paths caused by dripping of a gasoline or oil from vehicles.

Drip track raveling

Cracks approximately at right angles to the pavement center-line. These may be caused by shrinkage or differential thermal stress of the asphalt concrete, or may be reflective crack.

Transverse cracking

Cracks approximately at right angles to the pavement center-line. These are caused by poorly constructed construction joints and shrinkage of the asphalt concrete surface; they may also be reflective cracks.

Longitudinal cracking

The exuding of bitumen ono the pavement surface, causing a reduction in skid resistance.

Bleeding or flushing

Type of pavement distress affecting VI. Surface polish Portland cement concrete pavements include the following: I. Faulting II. Settlement Ill. Blowups IV. Joint or crack spalling V. Surface attrition or surface abrasion VI. Surface polish

All of the above

Localized upward buckling and shattering of the slabs at transverse joins or cracks.

Blowups

The breakdown or disintegration of slab edges at joints or cracks, usually resulting in the loss of sound concrete and the progressive widening of the joint or crack.

Joint or crack spalling

Elevation differences between adjacent slabs at transverse joints. This is usually the result of pumping, and is a major source of Portland concrete pavement failure.

Faulting

Abnormal surface wear, usually resulting from poor-quality surface mortar or coarse aggregate.

Surface attrition or surface abrasion

Local sagging in the pavement caused by differential settlement, consolidation, or movement of the underlying earth mass.

Settlement

Loss of the original surface texture due to traffic action.

Surface polish

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