Survey Techniques in Civil Engineering

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Questions and Answers

Which factor is NOT typically considered during the trial and error approach to route identification?

Construction material sources (correct)

Sight distances

Grades

Alignment

What is the primary purpose of conducting a reconnaissance survey?

To assess the environmental impact of construction

To examine the general character of the area for route selection (correct)

To finalize the design of the structures

To confirm the overall project budget

Which of the following instruments is commonly used in a reconnaissance survey?

Total station

GPS unit

Abney level (correct)

Theodolite

During a reconnaissance survey, which characteristic is essential to assess regarding alternative routes?

High flood level (HFL) Signup and view all the answers

What type of environmental factors must be considered when proposing sites for stream crossings?

Land use upstream and downstream Signup and view all the answers

What is one objective of preparing a report on different alternative routes after the reconnaissance survey?

To outline pros and cons for further study of few alignments Signup and view all the answers

Which aspect is crucial when deciding the location of a highway crossing a stream?

Hydrologic and hydraulic factors Signup and view all the answers

What impact does crossing a stream near the confluence of two streams have compared to a single stream?

Introduces more complex hydraulic considerations Signup and view all the answers

What is the primary objective of a preliminary survey in road design?

To survey various alternative alignments and collect necessary physical information Signup and view all the answers

Which method involves the use of aerial photographs to gather topographical data?

Modern rapid approach Signup and view all the answers

What type of curve is defined as an arc with a single constant radius connecting two tangents?

Simple Curve Signup and view all the answers

Which factors are incorporated in the design considerations for horizontal alignment?

Cultural development, aesthetics, and vertical alignment Signup and view all the answers

In horizontal alignment, what is the purpose of a transition curve?

To connect circular curves with straight tangents smoothly Signup and view all the answers

What is the minimum exploration depth recommended for subsurface investigation in regions with light cut and fill conditions?

1.5 meters Signup and view all the answers

What is a compound curve in horizontal alignment?

Two or more adjoining circular arcs of different radii Signup and view all the answers

Which of the following methods is NOT used in subgrade investigation?

Radiographic testing Signup and view all the answers

Which of the following is NOT a consideration when finalizing the best alignment in road design?

Public opinion on design aesthetics Signup and view all the answers

What does properly balancing design considerations in horizontal alignment achieve?

An alignment that is safe, cost-effective, and harmonious with land contours Signup and view all the answers

What is the purpose of taking soil samples during subgrade investigation?

For on-site soil classification Signup and view all the answers

In which scenario would deeper borings (>3 m) be required during investigations?

In cases of high embankment or roadside cut sections Signup and view all the answers

Which statement accurately describes the method used for widening existing pavements?

It uses the same method as subsurface investigation. Signup and view all the answers

What governs the formulation of the geotechnical investigation program?

Volume 2C provisions Signup and view all the answers

What type of testing follows AASHTO T 191 standards during subgrade investigation?

In-situ density testing Signup and view all the answers

Which factor is NOT considered when determining exploration depth in subsurface investigation?

Anticipated traffic volume Signup and view all the answers

What is the interval at which cross-sectional levels are taken in built-up areas?

50 m Signup and view all the answers

What is the purpose of performing a detailed soil survey in a highway project?

To determine the CBR value for pavement design Signup and view all the answers

Which map should show the proposed and existing roads and important places to be connected?

Key map Signup and view all the answers

What scale is suggested for preliminary survey plans in a highway project?

10 cm = 1 km to 25 cm = 1 km Signup and view all the answers

At what intervals should contours be shown in a detailed plan for plain terrain?

1 to 2 meters Signup and view all the answers

Which of the following is NOT a document typically produced during the field survey phase of a highway project?

Construction schedules Signup and view all the answers

What should the size of the key map generally not exceed?

22 x 20 cm Signup and view all the answers

What is the primary focus of a reconnaissance survey in highway projects?

Mapping the general topography of the area Signup and view all the answers

Where are boring and test pit locations typically situated?

Beneath the shoulder in the widening area Signup and view all the answers

Which laboratory test assesses the mechanical analysis of soil samples?

AASHTO T 88 or T 27 Signup and view all the answers

What type of samples are taken from test pits for soil classification?

Small and large samples Signup and view all the answers

Which of these is NOT a requirement for logging pits and boreholes?

Color of construction equipment Signup and view all the answers

Which AASHTO test would you use to determine the California Bearing Ratio (CBR%)?

AASHTO T 193 Signup and view all the answers

Study Notes

Trial and Error Approach

Involves identifying the optimal route for projects by evaluating factors such as alignment, grades, sight distances, and necessary compensations.
Takes into account constraints like curves, slopes, and visibility to ensure safe travel.

Field Survey Information and Investigation

Reconnaissance Survey

Confirms features on maps and assesses the area's general character for route feasibility.
Utilizes simple instruments (e.g., abney level, tangent clinometer, barometer) for field investigations.
Collects additional data on alternative routes, including valleys, ponds, marshy lands, gradients, and obstructions like permanent structures.

Data Collection Details

Records the number and type of cross drainage structures.
Identifies high flood levels (HFL), soil properties, geological aspects, and sources of construction materials (stone quarries, water sources).
Prepares reports evaluating the pros and cons of different alternative routes to select viable alignments for further study.

Stream Crossing Considerations

Highway location for stream crossings is crucial, impacted by hydrologic and hydraulic factors.
Urban areas have less tolerance for backwater than rural settings.
Tidal zones introduce specific hydraulic considerations.
Design type (bridge vs culvert) affects hydraulic analysis alongside environmental factors like land use and debris control.

Preliminary Survey

Objectives

Surveys alternative alignments identified during reconnaissance to gather essential physical information about topography, drainage, and soil.
Compares different proposals to meet alignment requirements and estimate construction costs.

Methods of Survey

Conventional approach involves field surveys using equipment for measurements and data collection.
Modern aerial surveys facilitate rapid data collection and mapping.

Horizontal Alignment

Consists of circular curves and transition curves, ensuring safe travel at consistent speeds.
Design considerations include safety, functional classification, desired speed, topography, costs, and aesthetics.
Balancing these factors results in a safe, cost-effective alignment that aligns with natural landscapes.

Types of Curves

Circular curves can be simple (fixed radius connecting tangents) or compound (multiple adjoining arcs with different radii).

Final Location Survey

Temporary benchmarks are set at intervals for accurate level measurements related to earthwork and drainage.
Cross-sectional levels recorded vary in frequency depending on terrain type (plane, rolling, built-up, hilly).
Detailed soil surveys and California Bearing Ratio (CBR) testing are critical for pavement design.

Drawings and Reports for Highway Projects

Key maps include existing/existing roads and vital connection points, typically not exceeding 22x20 cm in size.
Index maps display general topography and should be at a suitable scale.
Plans from preliminary surveys show alternative alignments with collected data.

Soil Investigations

Subsurface Investigation

Analyzes subsurface conditions and depth depending on geological and historical factors along the road.
Basic exploration reaches 1.5 meters below planned subgrade; deeper for complex conditions.

Subgrade Investigation

Involves evaluating the soil layer beneath pavement through boreholes and test pits along the centerline.
Detailed logging of bore profiles is essential for determining material conditions and pavement thickness.

Widening of Existing Pavements

Follow subsurface investigation methods; additional boreholes and test pits assess existing conditions for paving.

Sampling and Testing

In-Situ Testing

Pits and boreholes must properly document layer characteristics and moisture levels, following prescribed standards.
Soil samples taken for classification and density testing.

Laboratory Tests

Various tests including Mechanical Analysis, Specific Gravity, and CBR conduct on collected subgrade samples as per AASHTO standards.
Laboratory results guide in determining soil behavior and suitability for the proposed construction.

These notes encompass critical aspects of highway project planning and soil investigation methods essential for efficient and effective transportation infrastructure development.

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Description

This quiz focuses on the trial and error approach used to identify optimal routes in civil engineering. It considers various factors such as alignment, grades, sight distances, and compensation while addressing constraints like curves and slopes. Gain insights into reconnaissance surveys and field investigations essential for ensuring good visibility in route planning.