Introduction to Materials and Methods
1 Introduction to Materials and Methods
Learning Objectives
Aim to achieve an understanding of key concepts related to design and construction criteria.
Objective 1: Recognize and understand the six design and construction criteria:
Environmental Quality
Aesthetic Characteristics
Non-Mechanical Properties
Mechanical Properties
Production/Construction Considerations
Economic Factors
Objective 2: Understand the pillars of the Circle of Sustainability.
Objective 3: Be able to identify mechanical and non-mechanical properties relevant to design and construction professionals.
Responsibilities of Construction Professionals
Key Roles:
Architects
Engineers
Construction Managers
Core Responsibilities Include:
Selection of appropriate materials
Specification of materials for projects
Quality Control during the construction process
Design and Construction Selection Criteria
The design and construction process adheres to established criteria, which include:
Environmental Quality
Aesthetic Properties
Non-Mechanical Properties
Mechanical Properties
Production/Construction Considerations
Economic Factors
Environmental Quality
Key aspects impacting environmental quality include efforts to:
Reduce depletion of fossil fuels
Preserve land
Minimize material usage and waste
Protect forests and forest ecosystems
Protect water resources
Minimize air pollution
Maximize the healthfulness of the interior building environment
Environmental Quality – Life Cycle Analysis
Environmental Impacts:
Global warming
Acidification
Smog
Ozone depletion
Carbon balance
Definition of Sustainable Development
According to the Brundtland Report:
Sustainable development is defined as: "development that meets the needs of the present without compromising the ability of future generations to meet their own needs."
This definition emphasizes two concepts:
The concept of needs prioritizing essential needs of the world's poor.
Limitations imposed by technology and social organization on the environment's ability to meet present and future needs.
Citation: World Commission on Environment and Development (WCED). Our Common Future. Oxford: Oxford University Press, 1987, p. 43.
Sustainable Development UN Global Compact Cities Programme
Concept Presentation: Initially presented in Melbourne in 2011, it encompasses multiple sectors:
Economics
Production & Resourcing
Exchange & Transfer
Accounting & Regulation
Consumption & Use
Labour & Welfare
Technology & Infrastructure
Wealth & Distribution
Politics
Organization & Governance
Law & Justice
Communication & Movement
Representation & Negotiation
Security & Accord
Dialogue & Reconciliation
Ethics & Accountability
Ecology
Materials & Energy
Water & Air
Flora & Fauna
Habitat & Food
Place & Space
Constructions & Settlements
Emission & Waste
Engagement & Identity
Recreation & Creativity
Memory & Projection
Belief & Meaning
Gender & Generations
Enquiry & Learning
Health & Well-being
Culture
…
Rated on a scale from Highly Unsatisfactory to Highly Satisfactory.
Circle of Sustainability
Relevant aspects in construction include:
Time and Money
Environmental Impact
Building Codes and Specifications
"Know-how"
Aesthetic Characteristics
The appearance of material is primarily the architect's responsibility.
Collaboration between civil engineers and architects ensures satisfaction of structural and aesthetic requirements.
Design outcomes are documented in construction plans and specifications.
Non-Mechanical Properties
Types of Non-Mechanical Properties Include:
Acoustical Properties
Atomic Properties
Chemical Properties
Electrical Properties
Magnetic Properties
Optical Properties
Thermal Properties
Related Issues Include:
Density
Unit Weight
Specific Gravity
Thermal Expansion
Abrasion Resistance
Corrosion Resistance
Color
Material Selection Examples
Materials Chosen for Structural Integrity and Effectiveness in Various Applications:
Snow Guards: Help maintain green roof stability.
Rain Gutter: Directs water flow.
Metal Flashing: Prevents water intrusion at joints.
Peel-n-Stick Membranes: Applied at joints & seams for waterproofing.
Cor-a-Vent™ Vent Strip: Facilitates ventilation.
Spray Foam: Used for cavity insulation.
Various other materials contribute to the building envelope's integrity.
Mechanical Properties
Mechanical Properties Describe the Behavior of a Material Under External Loads, which include:
Stress-Strain Relations
Elastic Behavior: Material returns to its original shape after load removal.
Elastoplastic Behavior: The material exhibits plastic deformation after a certain yield stress.
Viscoelastic Behavior: The material exhibits time-dependent strain.
Temperature and Time Effects on Material Behavior
Notable Earthquakes:
1989 Loma Prieta Earthquake (Magnitude 6.9) - Note documented damage and responses.
2010 Haiti Earthquake (Magnitude 7.0) - Notable structural failure with reference to the Hotel Montana collapse.
Production and Construction Considerations
Factors influencing material selection based on:
Material availability
Fabrication capabilities
Equipment availability
Construction considerations
Workforce availability and competence
An engineer's competence in handling materials
Economic Factors
Considerations Regarding Cost, Including:
Materials Cost
Labor Costs
Equipment Costs
Time Factors:
Means: Refers to tools, labor, equipment, and resources.
Methods: Refers to construction techniques and sequencing
Economic Factors - Material Choices
Comparison of selected materials, such as:
Steel
Reinforced Concrete
Investigation into why differences in material choices exist based on performance and cost assessment.
Risks of Incorrect Material Choices
Consider implications and consequences associated with poor material selection:
Environmental challenges
Service life challenges
Engineering, construction, and repair challenges
Structural failures
Conclusion
Decisions made in the materials and methods selection process profoundly affect overall project sustainability, safety, and functionality.
Ongoing assessment of environmental impact is essential for sustainable development in construction.
2 Properties of Soils
Properties of Soils Fundamentals of Building Construction, Materials & Methods
This document covers the properties of soils as they relate to building construction.
Learning Objectives
Identify earth materials and describe their properties in relation to design and construction parameters.
Understand the Unified Soil Classification System (ASTM D2487).
Comprehend the subsurface exploration and soil testing process.
Classifying Earth Materials
Types of Earth Materials:
Rock:
Definition: A continuous mass of solid mineral material.
Characteristics: Generally, the strongest and most stable of earth materials.
Variability: Strength varies with mineral content and physical structure.
Soil:
Definition: Particulate material composed of fine particles.
Characteristics: Properties vary with particle size and shape, mineral content, and sensitivity to moisture content.
Standards of Classification: ASTM D2487
Boulder:
Size: Greater than 12 inches in diameter.
Characteristic: Requires two hands to lift.
Cobble:
Size: Smaller than boulders but larger than 3 inches in diameter.
Characteristic: Can be lifted with one hand.
Gravel:
Size: Ranges from 3 inches to 0.187 inches in diameter.
Characteristics: Individual particles can be lifted between two fingers.
Sand:
Size: Ranges from 0.187 inches to 0.003 inches in diameter.
Characteristics: Particles are visible but generally too small to be picked up singly.
Silt:
Size: Smaller than 0.0029 inches in diameter and approximately spherical.
Characteristics: Too small to see with the naked eye.
Clay:
Size: Smaller than 0.0029 inches in diameter, typically 10 times or more smaller than silt.
Characteristics: Particles are flat or plate-shaped.
Organic Soils
Comprises materials such as peat and topsoil that contain organic content.
Characteristics: Generally weak, unstable, and not suitable for supporting building foundations.
Note: Topsoil is often removed from the building site for later use in landscaping and lawns.
Unified Soil Classification System
Soil Types:
Coarse-Grained Soils:
Types: Sands and gravels.
Suitability: Better suited for use as a foundation material.
Fine-Grained Soils:
Types: Silts, clays, and organic soils.
Suitability: Not a good choice for foundations due to instability and moisture sensitivity.
Soil Properties: Coarse-Grained Soils
Types: Boulder, cobble, gravel, sand.
Characteristics:
Cohesionless, strength depends on friction and interlocking of adjacent particles (shear strength).
Little strength when unconfined; good for foundations when compacted.
Properties are minimally affected by moisture content, allowing for efficient water drainage away from foundations and substructures.
Density Testing Video:
A resource for additional understanding: Density Testing Video.
Soil Gradation Types
Well Graded Soil:
Feature: Wide distribution of particle sizes, minimizing void spaces.
Well-Sorted Soil:
Feature: Limited range of particle sizes resulting in more void space and increased drainage.
Soil Properties: Fine-Grained Soils
Types: Silts and clays.
Characteristics:
A smaller particle size leads to less effective drainage.
Properties and strength are highly sensitive to moisture content.
Optimum Moisture Content:
Achieves optimum strength at a specific moisture level: Too dry results in dust (weak), too wet results in mud (weak).
Soil Properties: Clay Specifics
Characteristics:
Very small particles that stick together due to electrostatic forces (cohesion).
Properties vary with moisture content and mineral composition.
Some clay types can be highly expansive when wetted, while others can be virtually impermeable to water.
Some clays undergo consolidation, a gradual compression process over time.
Foundation Problems
Reference: David Brown, "Top 5 Causes of Foundation Problems" (2019). Common Problems, Foundation Professionals of Florida.
Exploration & Testing
Geotechnical Reports:
Describe soils and their properties derived from:
Test pit samples.
Boring samples.
Laboratory tests.
Information Provided:
Location of the water table.
Load-bearing capacity of the soil.
Soil stratum data.
Video Resource
Soil Drilling and Sampling:
William A Kitch (2015). "Drilling and Sampling," Introduction to Geotechnical Engineering.
Link: View Video.
Soils For Foundation Design
Table 1804.2: Allowable Foundation and Lateral Pressure
Class of Materials
Allowable Foundation Pressure (psf)
Lateral Bearing (psf/f below natural grade)
Coefficient of Friction (psf)
1. Crystalline bedrock
12,000
1,200
0.70
2. Sedimentary and foliated rock
4,000
400
0.35
3. Sandy gravel and/or gravel (GW and GP)
3,000
200
0.35
4. Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC)
2,000
150
0.25
5. Clay, sandy clay, silty clay, clayey silt, silt and sandy silt (CL, ML, MH and CH)
1,500°
100
-
Important Notes:
(a) Coefficient to be multiplied by the dead load.
(b) Lateral sliding resistance value to be multiplied by the contact area, as per Section 1804.3.
(c) Soils with an allowable bearing capacity of less than 1,500 psf require investigation for determination of allowable capacity.
(d) An increase of one-third is permitted under certain load combinations in Section 1605.3.2 involving wind or earthquake loads.
Soil Properties Lecture
3 Earthwork
Earthwork Notes
Learning Objectives
Understand the basic components of a site plan.
Identify retaining walls, gabions, and earth reinforcement visually.
Recall the procedures for filling and backfilling.
Site Plans
Lot Dimensions: Measured dimensions of the lot where construction takes place.
Building Setbacks: Required distances from property lines to the structure.
Public Utility Easements (PUE): Areas designated for utilities must remain unobstructed.
Building Footprint: The outline of the structure at ground level.
Location of Structure on Lot: Positioning of the building within the lot.
Driveway Location and Width: Design and positioning of access points.
Topography: The arrangement of the natural and artificial physical features of an area (not shown in the current materials).
Retaining Walls - Purpose
Function:
Retaining walls are designed to hold back soil in areas where there is an abrupt change in ground elevation.
They must possess sufficient strength to withstand the forces exerted by the earth and any groundwater present.
Retaining Walls - Failures
Retaining walls are susceptible to several types of failures, including:
Horizontal Sliding: Movement of the entire wall sideways due to pressure from the soil behind.
Overturning: When the wall tips or rotates due to an imbalance of forces, causing it to collapse.
Undermining: Erosion or washout occurs beneath the wall, leading to structural instability.
Retaining Walls - Construction Type
A visual representation of different construction methods may be required here for detailed analysis (not provided).
Foundation Requirements
Gabions:
Define gabions as a form of earth retention using corrosion-resistant wire baskets filled with cobble or boulder-sized rocks.
They are placed in layers to create sturdy walls that hold back soil and resist erosion.
Gabions
In addition to their primary function, gabions may also serve to combat erosion effectively by stabilizing loose ground and preventing soil degradation.
Earth Reinforcement
Definition:
Often referred to as "Mechanically Stabilized Earth (MSE)."
Involves placing reinforcing material between layers of fill or backfill, which is compacted accordingly.
Benefits:
The addition of reinforcement creates tensile strength in the soil, which aids in structural integrity.
It is frequently a more economical alternative compared to traditional retaining walls for soil stabilization.
Filling and Finish Grade
Filling:
A broad term that refers to any process of placing earth material, such as raising the existing grade of a site.
Backfilling:
Specifically pertains to replacing earth material into trenches or excavated areas to restore the ground to its original or desired level.
Lifts:
Both filling and backfilling operations are performed in layers or “lifts.”
Lift thickness can typically range from 4 to 12 inches based on the compaction requirements.
Filling
Large open areas allow for the effective compaction of fill material using heavy construction equipment, ensuring stability and density of the earth used.
Filling and Proper Compaction
In constrained or confined spaces, the compaction of fill or backfill may necessitate the use of smaller, walk-behind equipment to ensure proper density and stability of the material.
Backfilling
Backfill operations often take place in trenches, where each layer, known as a "lift," is critically compacted to ensure firm ground structure and prevent settling or shifting over time.
4 Excavation Support Systems
Fundamentals of Building Construction, Materials & Methods
Learning Objectives
List the steps involved in earthwork and excavation.
Know the parameters influencing the selection of excavation support systems.
Know the types of excavation support and general earth-retaining concepts.
Visually identify and describe means and methods for different excavation support systems.
Understand the differences between the excavation support systems.
Earthwork and Excavation Steps
Earthwork is a critical initial phase of virtually every construction project.
Grubbing and Clearing:
This step involves removing vegetation, roots, and debris from the construction site.
Topsoil Management:
The top layer of organic-rich soil is scraped off the pad site and stored for later use, allowing for proper foundation laying in subsequent steps.
Excavation Process:
Excavation is essential for various components, such as basements, shallow footings, and utilities, and for addressing unstable or undesirable soil conditions.
Selection of Excavation Support
The choice of excavation support depends on the following key parameters:
Soil Type: Determines the most appropriate excavation method and support.
Depth of Excavation: Deeper excavations require more robust support mechanisms.
Type of Construction: The nature of the building being constructed may dictate specific excavation techniques.
Proximity of Surrounding Roads/Buildings: Nearby structures may restrict certain excavation methodologies.
Presence of Groundwater: Water levels can impact excavation stability and support needs.
Excavation Support Types
Sloped or Benched Excavation:
More cost-effective than sheeted excavation but necessitates sufficient space away from property lines and adjacent structures.
Sheeted Excavation:
Utilized in confined spaces wherein soil surrounding the excavation must be contained by a support system.
Sloped or Benched Excavation
The geometry of excavation selection is influenced by the soil's natural Angle of Repose, which is the steepest angle at which a sloping surface of loose material remains stable.
Soil Type Stability Classification:
Most Stable: Clay, silty clay, and cemented sands can support steeper angles of benching.
Moderately Stable: Angular gravels, silt, loamy silt, and moist cohesive soils require sloped benches.
Least Stable: Granular soils (gravel, sand, loamy sand), submerged soil, or soils with water seepage can only have sloped benches; benching is not permissible.
Sheeted Excavation
Definition:
Sheeting refers to the solid panel systems used to create walls that hold back soil.
Shoring System:
A structural support system that actively resists loads to prevent collapse during the excavation process.
Methods for Lateral Support of Sheeted Excavation:
Crosslot Bracing: A system that provides support across the width of the excavation.
Rakers: Supports that are angled from the excavation wall to the ground.
Tiebacks: Anchors that provide tension support to keep the sheeting in place.
Bracing Example: Installation of Tiebacks or Ground Anchors
Drilling:
A hole is drilled into stable rock or soil.
Insertion and Grouting:
Steel prestressing tendons or rods are inserted into the hole and grouted to secure.
Post-Grouting Tensioning:
Once the grout has hardened, the steel tendons or rods are put under tension using a hydraulic jack and anchored to a waler or steel plate.
Excavation Shoring Types
Soldier Beams and Lagging:
Construction examples include Berliner wall, which consists of steel H-pile soldiers with wood lagging and raker bracing.
Steel Sheet Piling:
These piles can be hammered or vibrated into place, with placement methods dependent on soil conditions.
Sheet piles are usually made from steel or fiber-reinforced polymers (plastic).
Secant Piles (Von Der Wand Pile Wall):
A type of wall that consists of intersecting piles creating stability and reducing water inflow.
Ground/Earth Improvement Techniques
Soil Mixing:
This technique creates columns of strengthened soil using a chemical binder (such as Portland cement and water) prior to excavation. The mixed soil remains in place post-excavation.
Excavation Shoring Type Example:
Mixed soil support incorporating soldier beams, walers, and tie-backs.
Rammed Aggregate Piers:
Composed of crushed rock which is compacted in lifts, densifying the surrounding soil. Piers can be up to 36 inches in diameter and reach depths of 30 feet.
Shotcrete:
Application example of shotcrete on mixed soil wall for stabilization during underground basement excavation.
5 Foundations
Foundations Learning Objectives
Remember dead load and live load types, and categorize a load by its type.
Define uniform and differential foundation settlement and explain the consequences of settlement.
Describe the purpose of foundations.
Visually identify foundation type and describe its applications.
Describe general construction methods for different foundation types.
Describe and differentiate waterproofing, dampproofing, and drainage for subgrade walls.
Load Types
Dead Loads:
Definition: Dead loads refer to the combined weight of a building's permanent components.
Components: Includes the weight of all building components, which can be determined from volumetric calculations and the known density of materials.
Live Loads:
Definition: Live loads consist of non-permanent loads caused by the weight of the building’s occupants, furnishings, movable equipment, and external influences.
Types of Live Loads:
Rain/Snow Loads: Act primarily downward on building roofs.
Wind Loads: Can act laterally, downward, or upward on a building.
Seismic Loads: Dynamic horizontal and vertical forces caused by motion of the ground relative to a building during an earthquake.
Lateral Soil Pressure Loads: Horizontal pressures of earth and groundwater against basement walls.
Buoyant Uplift Forces: Forces from underground water, analogous to forces that cause a boat to float.
Flood Loads: Lateral forces that occur in flood-prone areas.
Purpose of Foundations
Functionality: Foundations transmit building loads to the rock or soil on which they rest, ensuring stability and integrity.
Foundation Characteristics
Foundations must:
Reliably transfer all structural loads to the ground.
Be economically and technically feasible.
Not adversely affect surrounding structures.
Keep below-grade interior spaces dry.
Foundation Types
Types Include:
Shallow footings
Deep footings
Footing Type
Shallow Footings: Occur close to the bottom of the substructure.
Deep Footings: Extend to deeper, more competent soils.
Shallow Footings Applications
Types of Shallow Footings Include:
Slab On Grade - Less Materials, less Earthwork
Crawlspace - If there is a requirement for flooding, frostline, coastlines (flooding), & central regions (frostline)
Basement - Northern states with snow
Column Footings
Wall (or Strip) Footings
Mat Foundation
Design Requirements
Design Requirements are specified in building codes.
Example - International Residential Code (IRC)
TABLE R402.2: Minimum specified compressive strength of concrete (denoted as fc) varies based on conditions:
Minimum Specified Compressive Strength:
Weathering Potential: Negligible
Basement walls, foundations, and other concrete not exposed to the weather: fc = 2500 psi
Weathering Potential: Moderate
Basement walls, foundations, and other concrete not exposed to the weather: fc = 2500 psi
Basement slabs and interior slabs on grade, except garage floor slabs: fc = 2500 psi
Porches, carport slabs, and steps exposed to the weather, and garage floor slabs: fc = 3000 psi
Weathering Potential: Severe
Basement walls, foundation walls, exterior walls, and other vertical concrete work exposed to the weather: fc = 3500 psi
Other classifications follow similar deteriorations in grades based on conditions.
Slab on Grade
Definition: A foundational technique requiring minimal earthwork.
Mat Footings
Definition: Close to the bottom of the substructure.
Foundation Types Detail
Deep Foundations: Used where the soils directly below the building substructure are weak or unstable.
Deep Foundations Transmit Building Loads to Deeper, More Competent Soils:
Caissons (or Piers): Drilled into the earth with a large auger and belled (flared) at the bottom if necessary. Steel reinforcement is lowered into the drilled hole, followed by pouring concrete.
Belled Caissons: Practical only where the bell can be excavated in cohesive soil that retains its shape until concrete is placed. Used with clay.
Socketed Caissons: Drilled into rock or hard strata without being belled at the bottom. Bearing capacity is achieved through end-bearing and friction between the sides of the caisson and the rock.
Piles: Driven into the earth and may be made of steel, wood, or precast concrete. They can be driven to refusal or depth where determined resistance is achieved.
Pile Cap: Shares loads among clustered piles, providing support for the wall above.
Grade Beam: Spans between the pile caps or piers to provide continuous support for walls above.
Mini-piles (Pin Piles): Made of steel pipe or bar, ranging from 2 to 12 inches in diameter, pressed or rammed into holes and grouted in place. They can be installed in short sections and are suited for limited vertical clearance.
Helical Piles (Screw Piles): Installed without hammering (augered into place) and coupled end-to-end as drilling progresses. They generate no vibration/low noise, making them suitable for work near existing buildings.
Underpinning
Definition: A method in which the superstructure of a building is temporarily supported on cribbing while new footings are built.
Seismic Base Isolation
Used in earthquake-prone areas where base isolators (elastomeric bearings) flex or yield to absorb a significant portion of movement during seismic events.
Waterproofing and Drainage
Typical Section Components:
Drainage fill
Drain mat
Drain piping
Waterproofing membrane
Protection board
Drainage Explained
Drainage mats and free-draining backfill allow groundwater to flow downward to be collected by drain piping (typically 4” or 6” in diameter), which conducts water away from the substructure.
Moisture Proofing:-
Dampproofing: A moisture-resistant layer used where groundwater conditions are mild or where waterproofing is not critical. Liquid-applied (roller or spray).
Waterproofing: Prevents the passage of water in more demanding conditions, even under hydrostatic pressure. It can be liquid-applied or in sheet membrane form (providing more consistent thickness but challenging for intricate shapes).
Foundation Wall Cross-Section
Key Elements:
Protective covering
1" thick rigid insulation
Concrete foundation wall
Foundation damp proofing to the finished grade
3" concrete slab