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University of New HavenUniversity of New HavenID 218 Interior Systems, Materials and CodesID 218 Interior Systems, Materials and Codesby: Denis R. Ouimette AIA, OAQ, NCARBby: Denis R. Ouimette AIA, OAQ, NCARB

Lecture 002:Lecture 002:Chapter 2 FoundationsChapter 2 FoundationsReview Chapter 1Review Chapter 1Questions 1-5 on page 17Questions 1-5 on page 17

Reading assignment:Reading assignment:““Fundamental of Building Construction” Fundamental of Building Construction” Chapter 3, WoodChapter 3, WoodQuestion: 1 – 7 page 112Question: 1 – 7 page 112

ID 218 Interior System, Materials and CodesID 218 Interior System, Materials and CodesChapter 2, Foundations:Chapter 2, Foundations:

In this chapter, you will learn:In this chapter, you will learn: What a building foundation doesWhat a building foundation does The types of soils on which buildings are The types of soils on which buildings are

founded, and their characteristicsfounded, and their characteristics How soil is excavated for a buildingHow soil is excavated for a building How soil is kept from sliding back into an How soil is kept from sliding back into an

excavationexcavation How water is kept out of an excavationHow water is kept out of an excavation The various types of shallow and deep The various types of shallow and deep

foundations, and the conditions under which foundations, and the conditions under which each is appropriateeach is appropriate


2.1 Waterproofing and Drainage 1. For each condition below, indicate whether

dampproofing or waterproofing is most appropriate:Basic concepts of waterproofing and drainage are discussed starting on page 59 of the text. a. Below-grade space for housing library stacks



dampproofing or waterproofing is most appropriate:Basic concepts of waterproofing and drainage are discussed starting on page 59 of the text. a. Below-grade space for housing library stacks

Waterproofing



dampproofing or waterproofing is most appropriate:Basic concepts of waterproofing and drainage are discussed starting on page 59 of the text.

b. Crawlspace in well-drained soil




b. Crawlspace in well-drained soil

Dampproofing



dampproofing or waterproofing is most appropriate:Basic concepts of waterproofing and drainage are discussed starting on page 59 of the text. c. Below-grade utility room, in normally-drained

soil




c. Below-grade utility room, in normally-drained soil

Dampproofing, as long as drainage conditions are good. Waterproofing is also an option where drainage conditions are poor, or where tolerance for moisture in the utility room is especially low.



dampproofing or waterproofing is most appropriate:

Basic concepts of waterproofing and drainage are discussed starting on page 59 of the text.

d. Finished basement, in normally-drained soil, where owner has expressed particular concerns regarding moisture damage and mold growth



dampproofing or waterproofing is most appropriate:

Basic concepts of waterproofing and drainage are discussed starting on page 59 of the text.

d. Finished basement, in normally-drained soil, where owner has expressed particular concerns regarding moisture damage and mold growth

Waterproofing


2. For each of the following, propose a waterproofing system and comment briefly on the reason for your choice:

a. A concrete basement poured in the winter, which is likely to remain damp for many months.



a. A concrete basement poured in the winter, which is likely to remain damp for many months.

Bentonite (suitable for application over damp concrete)



b. A concrete foundation carrying a prestressed concrete deck. The deck is likely to creep and cause significant cracking in the foundation wall over an extended period.



b. A concrete foundation carrying a prestressed concrete deck. The deck is likely to creep and cause significant cracking in the foundation wall over an extended period.

Loosely laid membrane (less sensitive to stresses caused by movement in the substrate)



c. A concrete elevator pit below grade. The exterior sides of the pit are cast directly against the excavation and will never be accessible for application of waterproofing.



c. A concrete elevator pit below grade. The exterior sides of the pit are cast directly against the excavation and will never be accessible for application of waterproofing.

Cementitious waterproofing (may be applied to the interior, negative side of the wall)



d. A foundation for an underground mechanical room. The foundation is geometrically complex, and is penetrated in many places to permit the passage of pipes and wiring conduits.



d. A foundation for an underground mechanical room. The foundation is geometrically complex, and is penetrated in many places to permit the passage of pipes and wiring conduits.

Liquid-applied waterproofing (easy to detail around complex shapes)


3. Complete the following foundation section to include a waterproof membrane on the exterior of the wall, insulation, a drainage system, backfill, and finish grade. Label all features contributing to waterproofing. For guidance, refer to Figures 2.55, 2.57, and 2.60 of the text.


3. Complete the following foundation section to include a waterproof membrane on the exterior of the wall, insulation, a drainage system, backfill, and finish grade. Label all features contributing to waterproofing. For guidance, refer to Figures 2.55, 2.57, and 2.60 of the text.


2.2 Soil Types and Bearing Capacities 1. Give one or two possible identifications for each of the

following. Provide a Group Symbol and descriptive name for each. It is not necessary to distinguish well-graded from poorly-graded soils:

See Figure 2.2 in the text for soil classifications. a. All of the soil particles are visible. Some of the

particles are large enough to be picked up individually, but most cannot.

b. When dry, the soil seems to be a dusty sand. When wetted it is still gritty like sand, but the soil sticks together in a ball if compressed in the hand.

c. No individual soil particles are discernible by eye, but the soil came out of the ground in hard chunks. When a small sample is wetted it becomes a sticky paste that can easily be molded into shapes.


2.2 Soil Types and Bearing Capacities d. The smallest particles in the soil can be

individually lifted between two fingers, the largest with the whole hand.

e. No soil particles are discernible by eye, yet the soil, even when wet, falls apart when an attempt is made to mold it into a shape.

f. The soil smells musty and is very dark in color. It seems to spring back slightly after being compressed in the hand.

3. Which of the above soils would you expect to drain freely?


4. How large does a square column footing need to be to support a load of 85,000 pounds (39,000 kg) on a compact sandy gravel soil? Show calculations. Make a sketch of the footing, assuming that it is 12” (300 mm) thick.


4. How large does a square column footing need to be to support a load of 85,000 pounds (39,000 kg) on a compact sandy gravel soil? Show calculations. Make a sketch of the footing, assuming that it is 12” (300 mm) thick. a) From Figure 2.5, assume an allowable bearing

pressure of 3000 lb/sf. b) Stress = force/area; f = P/A; Solve for Area A = P/f

= 85,000/3000 = 28.33 sf c) 28.33 = 5.33 x 5.33, say 5.5’ x 5.5’


5. How wide must a wall footing be if the load is 3,200 lb (21,000 kg) per foot of wall length, and the footing rests on a sandy clay soil? Show calculations and make a sketch.

Assume the footing is 12” (300 mm) thick.


5. How wide must a wall footing be if the load is 3,200 lb (21,000 kg) per foot of wall length, and the footing rests on a sandy clay soil? Show calculations and make a sketch.

Assume the footing is 12” (300 mm) thick.

a) From Figure 2.5, assume an allowable bearing pressure of 1500 lb/sf.

b) Area A = P/f = 3,200/1500 = 2.13 sf, or 2.13 ft wide, per foot of length

c) 2.13 ft x 12 in/ft = 25.6”, say 26”


2.3 Foundation and Slope Support Systems

1. Three excavations are shown below in cross section. Draw a slope support system for each as indicated. a. Steel sheet piling supported by cross-lot bracing

made of steel wide-flange shapes.


2.3 Foundation and Slope Support Systems

1. Three excavations are shown below in cross section. Draw a slope support system for each as indicated. a. Steel sheet piling supported by cross-lot bracing

made of steel wide-flange shapes.


b. Soldier beams and wood plank lagging supported by heavy timber rakers


b. Soldier beams and wood plank lagging supported by heavy timber rakers


c. Slurry wall supported by tiebacks


c. Slurry wall supported by tiebacks


On the section below, draw foundation elements as indicated. Caisson, End Bearing Pile, Shallow Foundation,

Pile Cap.


On the section below, draw foundation elements as indicated. Caisson, End Bearing Pile, Shallow Foundation,

Pile Cap.


Review Questions:1. What is the nature of the most common type of foundation failure?


Review Questions:1. What is the nature of the most common type of foundation failure?

The most common type of failure in foundations is differential settlement, in which overall settlement of the building is not excessive, but differences in the amount of settlement between different areas of the building cause failure of structural, cladding, or finish components of the building.


Review Questions:2. Explain in detail the differences among fine sand, silt, and clay, espacially as they relate to the foundations of buildings.


Review Questions:2. Explain in detail the differences among fine sand, silt, and clay, espacially as they relate to the foundations of buildings.

Fine sand consists of equidimensional particles that are large enough to behave as a particulate soil. Silt particles are also equidimensional but are much smaller, and silts are classified as fine-grained soils. Clay particles are much, much smaller than silt particles and are plate-like rather than equidimensional. Unlike fine sand and silt, clay soils are governed in their properties by surface effects, and are therefore much more strongly affected by water content and the particular arrangement of particles in a given soil.

Sandy soils typically have higher bearing capacity than silts or clays. Sand will drain better than silt, and silt better than clay. Better draining soils generally result in more stable soil characteristics, and less concern for water intrusion through the substructure. Clays can also be particularly problematic due to their expansive behavior when wet.


Review Questions:3. List three different ways of sheeting an excavation. Under what circumstances would sheeting not be required?


Review Questions:3. List three different ways of sheeting an excavation. Under what circumstances would sheeting not be required?

Sheeting may be by means of soldier beams and lagging, sheet piling, or slurry wall. Sheeting is not required when sufficient open space exists around the building to allow excavations to be sloped at less than angle of repose of a cohesionless soil, or where a cohesive soil can support itself in a vertical excavation.


Review Questions:4. Under what conditions would you use a watertight barrier instead of well points when digging below the water table?


Review Questions:4. Under what conditions would you use a watertight barrier instead of well points when digging below the water table?

A watertight barrier is desirable in situations where lowering of the water table would have detrimental effects on neighboring buildings. Such a barrier is possible in situations where the bottom edge of the barrier lies in an impermeable stratum of soil below the water table.


Review Questions:5. If shallow foundations are substantially less costly than deep foundations, why do we use deep foundations?


Review Questions:5. If shallow foundations are substantially less costly than deep foundations, why do we use deep foundations?

We use deep foundations in situations where competent soil lies too far beneath the surface to be reached by shallow foundations.


Review Questions:6. What soil conditions favor the use of belled caissons?


Review Questions:6. What soil conditions favor the use of belled caissons?

Belled caissons are practical only where the bell can be excavated from a cohesive soil, and where the bearing stratum beneath the bottom of the caisson is impervious to the passage of water.


Review Questions:7. Which types of friction piles can carry the heaviest load per pile?


Review Questions:7. Which types of friction piles can carry the heaviest load per pile?

Precast concrete friction piles have the largest potential load carrying capacity, followed by steel pipe piles, steel H-piles, and sitecast concrete piles.


Review Questions:8. List and explain some cost thresholds frequently encountered in foundation design.


Review Questions:8. List and explain some cost thresholds frequently encountered in foundation design.

Some cost thresholds in foundation design include building below the water table, building close to an existing structure, and increasing building loads beyond what can be supported by a shallow foundation.


Chapter 2 Web Links www.ianosbackfill.com/02_foundations/

Author News and Updates Blog on foundations www.calweld.com

Calweld, Inc. www.franki.co.gg

Franki Foundations www.griffindewatering.com

Griffin Dewatering Corporation www.soletanche-bachy.com

Soletanche

http://www.ianosbackfill.com/02_foundations/

http://www.calweld.com/

http://www.franki.co.gg/

http://www.griffindewatering.com/

http://www.soletanche-bachy.com/

University of New HavenUniversity of New HavenID 218 Interior Systems, Materials and CodesID 218 Interior Systems, Materials and Codesby: Denis R. Ouimette AIA, OAQ, NCARBby: Denis R. Ouimette AIA, OAQ, NCARB

To do for next class:To do for next class:

Reading assignment:Reading assignment:““Fundamental of Building Construction” Fundamental of Building Construction” Chapter 3, WoodChapter 3, WoodQuestion: 1 – 7 page 112Question: 1 – 7 page 112

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Documents

waterproofing system

codes chapter

mold growth waterproofing

foundations review chapter

drainage conditions

deep foundations

drained soil dampproofing

interior systems