BUILDING CONSTRUCTION 1 ARCH 205 | A is a structure that transfers loads to the ground. Foundations are generally broken into two categories: 1. shallow foundations and 2. deep foundations.

2 3 Shallow foundations of a house versus the deep foundations of a Skyscraper 1- SHALLOW FOUNDATIONS

Shallow foundations are usually dug a meter or so into suitable . One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the or . Another common type is the slab- on- foundation where the weight of the building is transferred to the soil through a concrete slab placed at the surface.

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1. A shallow foundation is a type of foundation which transfers building loads to the earth very near the surface, rather than to a subsurface layer or a range of depths as does a . 2. Shallow foundations include: 1. spread footing foundations, 2. mat-slab foundations, and 3. slab-on-grade foundations

5 1- SHALLOW FOUNDATIONS SPREAD FOOTING FOUNDATION

| Spread footing foundations consists of strips or pads of concrete (or other materials) which transfer the loads from walls and columns to the soil or bedrock. Embedment of spread footings is controlled by several factors, including development of lateral capacity, penetration of soft near-surface layers, and penetration through near-surface layers likely to change volume due to frost heave or expansion and contraction. | These foundations are common in residential construction that includes a basement, and in many small commercial structures.

6 SHALLOW FOUNDATIONS SPREAD FOOTING FOUNDATION

In ground reinforced concrete block perimeter footing

7 SPREAD FOOTING FOUNDATION IN-GROUND-FOUNDATION

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8 Wall-foundation SHALLOW FOUNDATIONS MAT-SLAB FOUNDATIONS

| Mat-slab foundations are used to distribute heavy column and wall loads across the entire building area, to lower the contact pressure compared to conventional spread footings. Mat- slab foundations can be constructed near the ground surface, or at the bottom of basements. In high-rise buildings, mat-slab foundations can be several meters thick, with extensive reinforcing to ensure relatively uniform load transfer.

9 1- SHALLOW FOUNDATIONS SLAB-ON-GRADE FOUNDATION

| Slab-on-grade foundations are a Structural Engineering practice whereby the concrete slab that is to serve as the foundation for the structure is formed from a mold set into the ground. The concrete is then placed into the mold, leaving no space between the ground and the structure. This type of construction is most often seen in warmer climates, where and thawing is less of a concern and where there is no need for heat ducting underneath the floor.

| The advantages of the slab technique are that it is relatively cheap and sturdy, and is considered less vulnerable to termite infestation because there are no hollow spaces or wood channels leading from the ground to the structure (assuming wood siding, etc., is not carried all the way to the ground on the outer walls).

10 1- SHALLOW FOUNDATIONS SLAB-ON-GRADE FOUNDATION

| The disadvantages are: y a very low elevation that may expose the building to flood damage in even moderate rains. y Remodeling or extending such a structure may also be more difficult. y Over the long term, ground settling (or subsidence) may be a problem, as a slab foundation cannot be readily jacked up to compensate;

| proper prior to pour can minimize this.

y the lack of access from below for utility lines, the potential for large heat losses where ground temperatures fall significantly below the interior temperature, and

| The slab can be decoupled from ground temperatures by insulation, with the concrete poured directly over insulation (for example, styrofoam panels), or heating 11 provisions (such as hydronic) can be built into the slab (an expensive installation, with associated running expenses). 1- SHALLOW FOUNDATIONS SLAB-ON-GRADE FOUNDATION

| Slab-on-grade foundations are commonly used in areas with expansive soil, particularly in California and Texas. While elevated structural slabs actually perform better on expansive clays, it is generally accepted by the engineering community that slab-on-grade foundations offer the greatest cost-to-performance ratio for tract and semi-custom homes. Elevated structural slabs are generally only found on large custom homes or homes with basements.

12 SHALLOW FOUNDATIONS SLAB-ON-GRADE FOUNDATION

| Care must be taken with the provision of services through the slab. Copper piping, commonly used to carry water and galvanized steel piping used for natural gas, reacts with concrete over a long period, slowly degrading until the pipe fails. Copper pipes must be run below the slab, run through a conduit, or piped into the building above the slab. Electrical conduits through the slab need to be water-tight, as they extend below ground level and can potentially expose the wiring to groundwater.

13 SHALLOW FOUNDATIONS SLAB-ON-GRADE FOUNDATION

Slab on Grade house foundation

14 SHALLOW FOUNDATIONS SLAB-ON-GRADE FOUNDATION

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Example of slab on grade foundation 16 2- DEEP FOUNDATIONS

| Deep foundations are used to transfer a load from a structure through an upper weak layer of soil to a stronger deeper layer of soil or to carry loads to bedrock. | Different types of deep foundations include: y piles, y drilled shafts, y caissons, y piers, and y earth stabilized columns. y The naming conventions for different types of foundations vary between different engineers. Historically, the first piles used were wood, later steel, reinforced concrete, and pre-tensioned concrete were introduced. 17 2- DEEP FOUNDATIONS

| Deep foundations are distinguished from shallow foundations by the depth they are embedded into the ground, by their shape, the level of design engineering required and their much higher .

| There are many reasons a geotechnical engineer would recommend a deep foundation over a shallow foundation, but some of the common reasons are: y very large design loads, y a poor soil at shallow depth, y or site constraints (like property lines).

| There are different terms used to describe different types of deep foundations including piles, drilled shafts, caissons, and piers. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of timber, steel, reinforced concrete and pre-stressed concrete.

| Deep foundations can be installed by either driving them into the ground or drilling a shaft and filling it with concrete, mass or reinforced. 18 DEEP FOUNDATIONS DRIVEN FOUNDATIONS

| Prefabricated piles are driven into the ground using a pile driver. Driven piles are either wood, concrete, or steel. Wooden piles are made from trunks of tall trees. Concrete piles are available in square, octagonal, and round cross-sections. They are reinforced with rebar and are often pre- stressed. Steel piles are either pipe piles or some sort of beam section (like an H-pile). Historically, wood piles were spliced together when the design length was too large for a single pile; today, splicing is only common with steel piles, though concrete piles can be spliced with difficulty. Driving piles, as opposed to drilling shafts, is advantageous because the soil displaced by driving the piles compresses the surrounding soil, causing greater against the sides of the piles, thus increasing their load-bearing capacity. 19 DEEP FOUNDATIONS DRIVEN FOUNDATIONS- PILE FOUNDATION SYSTEMS

| Pile foundation systems: Foundations relying on driven piles often have groups of piles connected by a pile cap (a large concrete block into which the heads of the piles are embedded) to distribute loads which are larger than one pile can bear. Pile caps and isolated piles are typically connected with grade beams to tie the foundation elements together; lighter structural elements bear on the grade beams while heavier elements bear directly on the pile cap.

20 DEEP FOUNDATIONS DRIVEN FOUNDATIONS- PILE FOUNDATION SYSTEMS DEEP FOUNDATIONS DRIVEN FOUNDATIONS- PILE FOUNDATION SYSTEMS

Pile driving operations 22 DEEP FOUNDATIONS DRIVEN FOUNDATIONS- PILE FOUNDATION SYSTEMS

23 Pipe piles being driven into the ground. DEEP FOUNDATIONS DRILLED PILES - PILE FOUNDATION SYSTEMS

24 DEEP FOUNDATIONS DRILLED PILES

| Also called drilled piers or Cast-in-drilled-hole piles (CIDH piles) or Cast-in-Situ piles. Rotary boring techniques offer larger diameter piles than any other piling method and permit pile construction through particularly dense or hard strata. Construction methods depend on the of the site. In particular, whether boring is to be undertaken in 'dry' ground conditions or through water- logged but stable strata - i.e. 'wet boring'. | 'Dry' boring methods employ the use of a temporary casing to seal the pile bore through water-bearing or unstable strata overlying the suitable stable material. Upon reaching the design depth, a reinforcing cage is introduced, concrete is poured in the bore and brought up to the required level. The casing can be withdrawn or left in situ.

25 DEEP FOUNDATIONS DRILLED PILES

26 zA pile machine DEEP FOUNDATIONS DRILLED PILES

| 'Wet' boring also employs a temporary casing through unstable ground and is used when the pile bore cannot be sealed against water ingress. Boring is then undertaken using a bucket to drill through the underlying soils to design depth. The reinforcing cage is lowered into the bore and concrete is placed by tremmie pipe, during which, extraction of the temporary casing takes place.

27 DEEP FOUNDATIONS DRILLED PILES

| In some cases there may be a need to employ drilling fluids (such as bentonite suspension) in order to maintain a stable shaft. Rotary auger piles are available in diameters from 350 mm to 2400 mm or even larger and using these techniques, pile lengths of beyond 50 metres can be achieved.

28 DEEP FOUNDATIONS DRILLED PILES

Underreamed piles | Underream piles have mechanically formed enlarged bases that have been as much as 6 m in diameter. The form is that of an inverted cone and can only be formed in stable soils. In such conditions they allow very high load bearing capacities.

29 DEEP FOUNDATIONS DRILLED PILES- AUGER CAST PILE Auger cast pile | An auger cast pile is formed by drilling into the ground with a hollow stemmed continuous flight auger to the required depth or degree of resistance. No casing is required. A high slump concrete mix is then pumped down the stem of the auger. While the concrete is pumped, the auger is slowly withdrawn, lifting the spoil on the flights. A shaft of fluid concrete is formed to ground level. Reinforcement placed by hand is normally limited to 6 metres in depth. Longer reinforcement cages can be installed by a

vibrator, or placed prior to pouring concrete if 30 appropriate specialized drilling equipment is used. DEEP FOUNDATIONS DRILLED PILES- AUGER CAST PILE

| Auger cast piles cause minimal disturbance, and are often used for noise and environmentally sensitive sites. Auger cast piles are not generally suited for use in contaminated soils, due to expensive waste disposal costs. In ground containing obstructions or cobbles and boulders, auger-cast piles are less suitable as damage can occur to the auger

31 DEEP FOUNDATIONS DRILLED PILES- PIER AND GRADE BEAM FOUNDATION

| Pier and grade beam foundation | In most drilled pier foundations, the piers are connected with grade beams - concrete beams at grade (also referred to as 'ground' beams) - and the structure is constructed to bear on the grade beams, sometimes with heavy column loads bearing directly on the piers. In some residential construction, the piers are extended above the ground level and wood beams bearing on the piers are used to support the structure.

32 DEEP FOUNDATIONS DRILLED PILES- PIER AND GRADE BEAM FOUNDATION

| This type of foundation results in a crawl space underneath the building in which wiring and duct work can be laid during construction or remodeling.

33 DEEP FOUNDATIONS DRILLED PILES- C. PIER AND GRADE BEAM FOUNDATION

34 2- DEEP FOUNDATIONS 2-3- SPECIALTY PILES

| 2-3-1- Micropiles | Micropiles, also called mini piles, are used for underpinning. Micropiles are normally made of steel with diameters of 60 to 200 mm. Installation of micropiles can be achieved using drilling, impact driving, jacking, vibrating or screwing machinery. | Where the demands of the job require piles in low headroom or otherwise restricted areas and for specialty or smaller scale projects, micropiles can be ideal. Micropiles are often grouted as shaft bearing piles but non-grouted micropiles are also common as end-bearing piles. 35 zA micropile installation. DEEP FOUNDATIONS SPECIALTY PILES - TRIPOD PILES

| The use of a tripod rig to install piles is one of the more traditional ways of forming piles, and although unit costs are generally higher than with most other forms of piling, it has several advantages which have ensured its continued use through to the present day. The tripod system is easy and inexpensive to bring to site, making it ideal for jobs with a small number of piles. It can work in restricted sites (particularly where height limits exist), it is reliable, and it is usable in almost all ground 37 conditions. DEEP FOUNDATIONS SPECIALTY PILES - SHEET PILES

| Sheet piling is a form of driven piling using thin interlocking sheets of steel to obtain a continuous barrier in the ground. The main application of steel sheet piles is in retaining walls and cofferdams erected to enable permanent works to proceed.

38 DEEP FOUNDATIONS SPECIALTY PILES - SOLDIER PILES

| Soldier piles, also known as king piles or Berlin walls, are constructed of wide flange steel H sections spaced about 2 to 3 m apart and are driven prior to excavation. As the excavation proceeds, horizontal timber sheeting (lagging) is inserted behind the H pile flanges. | The horizontal earth pressures are concentrated on the soldier piles because of their relative rigidity compared to the lagging. Soil movement and subsidence is minimized by maintaining the lagging in firm contact with the soil. 39 40 A soldier pile wall using reclaimed railway sleepers as lagging. DEEP FOUNDATIONS SPECIALTY PILES - SOLDIER PILES

| Soldier piles are most suitable in conditions where well constructed walls will not result in subsidence such as over- consolidated clays, soils above the water table if they have some , and free draining soils which can be effectively dewatered, like . | Unsuitable soils include soft clays and weak running soils that allow large movements such as loose sands. It is also not possible to extend the wall beyond the bottom of the excavation and dewatering 41 is often required. DEEP FOUNDATIONS SPECIALTY PILES - ADFREEZE PILES

| In extreme latitudes where the ground is continuously frozen, adfreeze piles are used as the primary structural foundation method. | Adfreeze piles derive their strength from the bond of the frozen ground around them to the surface of the pile. Typically the pile is installed in a pre-drilled hole 6"-12" larger then the diameter of the pile. A slurry mixture of and water is then pumped into the hole to fill the space between the pile and the frozen ground. Once this slurry mixture freezes it is the between the frozen ground and the pile, or the adfreeze strength, which support the 42 applied loads Adfreeze piles in a building in Barrow, Alaska DEEP FOUNDATIONS SPECIALTY PILES - ADFREEZE PILES

| Adfreeze pile foundations are particularly sensitive in conditions which cause the to melt. If a building is constructed improperly, it will heat the ground below resulting in a failure of the foundation system. | Another ongoing concern for adfreeze pile foundations is climate change. As the climate warms, these foundations lose their strength and will eventually fail.

44 DEEP FOUNDATIONS PILE WALLS

| These methods of construction employ bored piling techniques - normally CFA or rotary. They provide special advantages where available working space dictates that basement excavation faces be vertical. Both methods offer technically effective and cost efficient temporary or permanent means of retaining the sides of bulk excavations even in water bearing strata. | When used in permanent works, these walls can be designed to accommodate vertical loads in addition to moments and horizontal forces. | Construction of both methods is the same as for foundation bearing piles. Contiguous walls are constructed with small gaps between adjacent piles. The size of this space is determined by the nature of the soils.

45 Sheet piling, by a bridge, was used to block a canal in New Orleans after Hurricane Katrina damaged it

46 DEEP FOUNDATIONS PILE WALLS

| Secant piled walls are constructed such that space is left between alternate 'female' piles for the subsequent construction of 'male' piles. Construction of 'male' piles involves boring through the concrete in the 'female' piles in order to key 'male' piles between them. The male pile is the one where steel reinforcement cages are installed, though in some cases the female piles are also reinforced. | Secant piled walls can either be true hard/hard, hard/intermediate (firm), or hard/soft, depending on design requirements. Hard refers to structural concrete and firm or soft is usually a weaker 47 grout mix containing bentonite. DEEP FOUNDATIONS PILED WALLS

| All types of wall can be constructed as free standing cantilevers, or may be propped if space and sub-structure design permit. Where party wall agreements allow, ground anchors can be used as tie backs.

48 DESIGN of FOUNDATIONS

| Foundations are designed to have an adequate load capacity with limited settlement by a geotechnical engineer, and the foundation itself is designed by a structural engineer. | The primary design concerns are settlement and bearing capacity. When considering settlement, total settlement and differential settlement is normally considered. Differential settlement is when one part of a foundation settles more than another part. This can cause problems to the structure the foundation is supporting. It is necessary that a foundation is not loaded beyond its bearing capacity or the foundation will "fail". 49 | Other design considerations include scour and frost heave. Scour is when flowing water removes supporting soil from around a foundation (like a pier supporting a bridge over a river). Frost heave occurs when water in the ground freezes to form ice lenses. | Additionally, uplift from wind forces and liquefaction from must be considered.

50 | Changes in soil moisture can cause expansive clay to swell and shrink. This swelling can vary across the footing due to seasonal changes or the effects of vegetation removing moisture. The variation in swell can cause the soil to distort, cracking the structure over it.

| This is a particular problem for house footings in semi-arid climates such as South Australia, Southwestern US, Turkey, Israel, Iran and South Africa where wet winters are followed by hot dry summers and expansive soils exist

| Clay soils are also a concern for foundation drainage

| Raft slabs with inherent stiffness have been developed in Australia with capabilities to resist this movement.

51 | When structures are built in areas of permafrost, special consideration must be given to the thermal effect the structure will have on the permafrost. Generally, the structure is designed in a way that tries to prevent the permafrost from melting.

52 | Soil material is a critical component in the mining and construction industries. Soil serves as a foundation for most construction projects. Massive volumes of soil can be involved in surface mining, building, and dam construction. Earth sheltering is the architectural practice of using soil for external thermal mass against building walls.

53 In , bearing capacity is the capacity of soil to support the loads applied to the ground. The bearing capacity of soil is the maximum average contact pressure between the foundation and the soil which should not produce shear failure in the soil. Ultimate bearing capacity is the theoretical maximum pressure which can be supported without failure; while allowable bearing capacity is the ultimate bearing capacity divided by a factor of safety. Sometimes, on soft soil sites, large settlements may occur under loaded foundations without actual shear failure occurring; in such cases, the allowable bearing capacity is based on the maximum allowable settlement.

There are three modes of failure that limit bearing capacity: •general shear failure, •local shear failure, and •punching shear failure. 54 | General shear failure

| The general shear failure case is the one normally analyzed. Prevention against other failure modes is accounted for implicitly in settlement calculations. There are many different methods for computing when this failure will occur.

| Local Shear Failure – Failure in a single specific location, like a single beam shearing of from its column junction.

| Punching Shear Failure – when a column punches thru a footing due to excessive point loading.

55 DYNAMIC

| Dynamic load testing of piles is a fast and effective method of assessing foundation bearing capacity that requires instrumenting a deep foundation with accelerometers and strain transducers and analyzing data collected by these sensors. | The procedure is standardized by ASTM D4945-00 Standard Test Method for High Strain Dynamic Testing of Piles. It may be performed on driven piles, drilled shafts and other cast in place foundations. In addition to bearing capacity, Dynamic Load Testing gives information on resistance distribution (shaft resistance and end bearing) and evaluates the shape and integrity of the foundation element. | The foundation bearing capacity results obtained with dynamic load tests correlate well with the results of static load tests performed on the same foundation element

56 SEMESTER PROJECT BUILDING CONSTRUCTION 1 SPRING 2010 SEMESTER PROJECT y Design A House y Program: { 2 stories – 200 square meters per floor plus roof access { 2 story entry hall, courtyard, roof access stair, 3 bedrooms, living room, kitchen, dining area, office, carport area, closets and storage, 3 bathrooms, outdoor patio, area wall around site. { Site is hypothetical – 50 meter by 50 meter SEMESTER PROJECT | Entry gate | Driveway in and gate | Rooftop patio space with shaded area | Landscaped areas CONSTRUCTION TYPE

| You choose the construction type y Heavy Timber y Concrete frame y Steel Frame

y OR

y Bearing Wall Designs y Lots of Windows CLADDING SYSTEM

| The cladding Materials y Glass y Masonry y Stone or Tile facing on Major Elevation y Concrete floors and roof SCHEDULE FOR SEMESTER PROJECT BUILDING CONSTRUCTION 2 - S2010

| Concept Sketches due Week 6 y Scale 1 to 100 or 1 to 200

| Ground floor plan, typical upper floor, elevation(s)

| Drawn Free Hand in pencil or ink. (Color is good)

| Floor Plans due Week 8 y Ground Floor includes site information y Hard line SCHEDULE FOR SEMESTER PROJECT BUILDING CONSTRUCTION 2 - S2010

| Elevations and Sections and Wall Section due Week 10 y Minimum 2 elevations – front and rear y 2 Building Sections – longitudinal and transverse y Typical Wall Section

| Exterior Details by Week 13 y Window – head, jamb and sill y Door detail y A roof detail y A stair Detail SCHEDULE FOR SEMESTER PROJECT BUILDING CONSTRUCTION 2 - S2010 | Submit all drawings end of Week 15 for final