Podcast
Questions and Answers
What characterizes a shallow foundation in relation to its depth?
What characterizes a shallow foundation in relation to its depth?
Which type of foundation is specifically used to support several rows of columns?
Which type of foundation is specifically used to support several rows of columns?
What is a requirement for determining the design of a foundation?
What is a requirement for determining the design of a foundation?
Which foundation type is analogous to a spread footing but works by distributing loads vertically?
Which foundation type is analogous to a spread footing but works by distributing loads vertically?
Signup and view all the answers
What must be avoided to prevent lateral squeezing of material under a foundation?
What must be avoided to prevent lateral squeezing of material under a foundation?
Signup and view all the answers
Which factor is least likely to influence the design of a foundation?
Which factor is least likely to influence the design of a foundation?
Signup and view all the answers
What construction method must be considered for foundations to prevent excessive environmental degradation?
What construction method must be considered for foundations to prevent excessive environmental degradation?
Signup and view all the answers
Which material is NOT commonly used in the construction of retaining structures?
Which material is NOT commonly used in the construction of retaining structures?
Signup and view all the answers
What is the primary purpose of performing a utility survey before drilling?
What is the primary purpose of performing a utility survey before drilling?
Signup and view all the answers
What is a benefit of using excavations instead of borings when sampling near the surface?
What is a benefit of using excavations instead of borings when sampling near the surface?
Signup and view all the answers
Which type of boring is described as shallow and typically penetrates up to 3-4 m in depth?
Which type of boring is described as shallow and typically penetrates up to 3-4 m in depth?
Signup and view all the answers
Which of the following drilling methods is NOT mentioned as suitable for shallow soil borings?
Which of the following drilling methods is NOT mentioned as suitable for shallow soil borings?
Signup and view all the answers
What key factor may limit the maximum depth for using hand augers and portable motor-driven augers?
What key factor may limit the maximum depth for using hand augers and portable motor-driven augers?
Signup and view all the answers
What should be ensured regarding personnel before commencing drilling activities?
What should be ensured regarding personnel before commencing drilling activities?
Signup and view all the answers
What precaution is advised during drilling to mitigate risks associated with underground utilities?
What precaution is advised during drilling to mitigate risks associated with underground utilities?
Signup and view all the answers
In what scenario are excavations particularly beneficial for soil sampling?
In what scenario are excavations particularly beneficial for soil sampling?
Signup and view all the answers
What is the primary effect of the added load on soil during settlement?
What is the primary effect of the added load on soil during settlement?
Signup and view all the answers
What is a general rule-of-thumb for the depth of borings in foundation engineering?
What is a general rule-of-thumb for the depth of borings in foundation engineering?
Signup and view all the answers
Which of the following parameters is NOT typically treated as elastic in soil settlement analyses?
Which of the following parameters is NOT typically treated as elastic in soil settlement analyses?
Signup and view all the answers
Which of the following structures typically requires borings to extend to bedrock or competent soil?
Which of the following structures typically requires borings to extend to bedrock or competent soil?
Signup and view all the answers
What is one major problem encountered during soil settlement analyses?
What is one major problem encountered during soil settlement analyses?
Signup and view all the answers
What is the range of influence depth (H) typically considered in stress computations under a loaded area?
What is the range of influence depth (H) typically considered in stress computations under a loaded area?
Signup and view all the answers
What primary concern should be investigated regarding the soil under a structure?
What primary concern should be investigated regarding the soil under a structure?
Signup and view all the answers
What typically controls the allowable bearing capacity of a structure?
What typically controls the allowable bearing capacity of a structure?
Signup and view all the answers
How is settlement, denoted as ∆H, primarily defined in relation to applied stress?
How is settlement, denoted as ∆H, primarily defined in relation to applied stress?
Signup and view all the answers
Which factor has contributed to the infrequency of structural collapse from base shear failure?
Which factor has contributed to the infrequency of structural collapse from base shear failure?
Signup and view all the answers
Why is there a tendency to use in situ tests for soil parameters despite their drawbacks?
Why is there a tendency to use in situ tests for soil parameters despite their drawbacks?
Signup and view all the answers
What adjustment must be made when using elastic theory to compute soil stress in relation to anisotropy?
What adjustment must be made when using elastic theory to compute soil stress in relation to anisotropy?
Signup and view all the answers
Why is it important for borings not to terminate in soft strata for significant structures?
Why is it important for borings not to terminate in soft strata for significant structures?
Signup and view all the answers
When determining the allowable bearing capacity for foundations, what should also be considered aside from settlement?
When determining the allowable bearing capacity for foundations, what should also be considered aside from settlement?
Signup and view all the answers
What does the shear stress-strain modulus (G’) represent in soil analysis?
What does the shear stress-strain modulus (G’) represent in soil analysis?
Signup and view all the answers
What implication does the lack of binding rules on the number and depth of borings have on foundation engineering?
What implication does the lack of binding rules on the number and depth of borings have on foundation engineering?
Signup and view all the answers
What should be done to estimate the elastic soil parameters for a flexible foundation?
What should be done to estimate the elastic soil parameters for a flexible foundation?
Signup and view all the answers
When reducing the Is factor for a rigid base foundation, how much should it be reduced?
When reducing the Is factor for a rigid base foundation, how much should it be reduced?
Signup and view all the answers
What is the significance of the depth 'z' in settlement calculations?
What is the significance of the depth 'z' in settlement calculations?
Signup and view all the answers
What is one of the main aims of soil improvement techniques?
What is one of the main aims of soil improvement techniques?
Signup and view all the answers
Why may soil improvement be more economical than other methods for dealing with marginal soil?
Why may soil improvement be more economical than other methods for dealing with marginal soil?
Signup and view all the answers
What should be divided to compute the point of settlement for a flexible base?
What should be divided to compute the point of settlement for a flexible base?
Signup and view all the answers
In the context of soil improvement, which technique is primarily used to reduce void ratio?
In the context of soil improvement, which technique is primarily used to reduce void ratio?
Signup and view all the answers
For a corner of a foundation with a lateral dimension B, what is the H/B' ratio when H = 5B?
For a corner of a foundation with a lateral dimension B, what is the H/B' ratio when H = 5B?
Signup and view all the answers
What is the preferable outcome when estimating settlement values?
What is the preferable outcome when estimating settlement values?
Signup and view all the answers
How long does immediate settlement typically take to occur after load application?
How long does immediate settlement typically take to occur after load application?
Signup and view all the answers
Which type of settlement is related to saturated fine-grained soils?
Which type of settlement is related to saturated fine-grained soils?
Signup and view all the answers
What is the ratio range of measured versus computed ∆H typically observed?
What is the ratio range of measured versus computed ∆H typically observed?
Signup and view all the answers
Which of the following is NOT a factor in immediate settlement analyses?
Which of the following is NOT a factor in immediate settlement analyses?
Signup and view all the answers
In calculating settlement, what does 'qo' represent?
In calculating settlement, what does 'qo' represent?
Signup and view all the answers
What is the essential function of the Ii influence factors in settlement equations?
What is the essential function of the Ii influence factors in settlement equations?
Signup and view all the answers
Which of the following is cited as an extreme case of uneven settlement?
Which of the following is cited as an extreme case of uneven settlement?
Signup and view all the answers
Study Notes
Foundation Engineering
- Foundation: Part of an engineered system that transmits loads from the superstructure to the underlying soil or rock.
- Superstructure: The engineered part of the system that applies loads to the foundation.
- Foundation Engineer: A person with the training and experience necessary to design foundations. This involves understanding soil mechanics, geology, and foundation engineering, as well as structural aspects like reinforced concrete and steel design.
Steps in Foundation Design
- Site Location and Load: Locate the site and the position of the loads to be supported.
- Site Inspection: Physically inspect the site for geological or other potential problems, and supplement with existing data if available.
- Field Exploration: Develop a program to collect necessary soil data through field and laboratory testing.
- Soil Design Parameters: Establish the required soil design parameters using test data, scientific principles, and engineering judgment.
- Foundation Design: Design the foundation using the soil parameters, considering cost effectiveness, construction personnel, and practical tolerances.
- Collaboration and Oversight: Maintain close communication with the client, other engineers, architects, and contractors to prevent overdesign and ensure risk is managed appropriately.
Foundation Classification
-
Shallow Foundations: Include bases, footings, spread footings, or mats. Generally, their depth is approximately less than the building width or breadth (D/B < 1).
- Spread Footings: Support a single column
- Mat Foundations: Support multiple columns, potentially the entire building structure.
- Bases: Support machinery.
- Deep Foundations: Include piles, drilled piers, or drilled caissons. Their depth is greater than the building width or breadth (D/B > 4).
Retaining Structures
- Retaining Structures: Structures that hold back soil or material in a shape different from that given by gravity. Constructed from materials like wood, metal sheeting, concrete, and earth.
Soil Exploration/Sampling
- Soil exploration is an essential step for economical substructure design and is needed to determine foundation type, load capacity, settlemet predictions, and groundwater table depth.
- Economic evaluations of site exploration should be made in the early stages of a project to assess costs.
- The main objective of site investigation is to ascertain adequate information to help in foundation type determination, calculate allowable load capacity, make accurate predictions of settlement, and locate groundwater.
Soil Boring Methods
- Hand Tools: Backhoes and hand tools can be used to excavate test pits for obtaining undisturbed soil samples or obtaining samples for testing in non-vertical orientation.
- Mounted Power Drills: Used for numerous borings to deeper depths. Includes methods like wash boring and rotary drilling. Continuous-flight augers, especially common in North America and Europe are now the most often used method for soil exploration.
Additional Considerations
- Foundation Depth: Sufficient depth is required to avoid seasonal ground shifts (freezing/thawing), lateral squeezing beneath the foundation, and possible disturbances to adjacent properties.
- Expansive Soils: Conditions in soil can cause swelling during moisture changes.
- Corrosion: Potential for materials within the foundation to be affected by corrosive components in the soil.
- Future Changes: The foundation should accommodate possible future changes in superstructure design or loading.
- Environmental Concerns: The foundation design must meet environmental standards.
Bearing Capacity of Foundations
- The soil must have the capacity to support loads from the structure without failure. This often involves considering shear failure and settlement.
- Settlements are time-dependent and often cause structural problems, in which case intervention must occur
- Bearing capacity of rocks may be much higher than that of soils, but the structure or material properties of the rock must be considered.
- Water tables can significantly impact bearing capacity calculations, utilizing the effective unit weight of the soil.
Soil Improvement Techniques
- Consolidation: Preloading (surcharge fill) or the installation of vertical drains can be used as methods to increase consolidation of soil.
- Compaction: Methods such as excavation and recompaction, vibrocompaction, deep dynamic compaction, and vibro-replacement.
- Adhesion: Chemical stabilization, slurry grouting, jet grouting, and thermal stabilization.
- Reinforcement: Soil and rock anchors, mini-piles, soil nailing and soil mixing
- Physical alteration: Electro-osmosis, lime columns, and vitrification.
- Biological transformation: Soil mixing.
Additional Considerations
- Grouting methods involve injecting grout into the soil to control displacement, increase strength, and prevent settling.
- Stabilization using admixtures involves mixing material like Portland cement or lime to improve soil properties
- Soil inclusion refers to methods designed to prevent subsidence and to give structure support on compressible soils, including excavation with or without displacement, driving, vibrating the ground, and using various fillings for the creation of superficial foundations
- The choice and application of soil improvement methods depends on many factors; environmental characteristics, soil type and condition, economic constraints, technical feasibility, required bearing capacities, and time scales are some important factors to consider.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the fundamental concepts of foundation engineering, including the roles of different components like foundations and superstructures. It also outlines the essential steps involved in designing a foundation, from site location to soil design parameters. Test your knowledge on the critical aspects necessary for effective foundation engineering.
