Seven Wonders of the Ancient World Pyramid of Meidum shed 250,000 tons of limestone outer casings
Typical Pyramid Pyramid at Meidum
Mexico Alameda buildings Palace of Fine Arts National Theater Lake Texcoco
Design Decisions location size and shape of building weight of building flexibility of construction shallow or deep foundation
Foundation Location and Design
Why get a Soil Test? location of good bearing soils for foundation design liquid or plastic limits of soil percolation rate of soils location of underground water frost susceptibility bottom of footing is 12 below Average Frost Depth data for frost is localized Saint Paul average frost depth is 4-0 problems from underground surprises
Soil test information layers of soils load-bearing capacity of the soil stability (clay may swell with water) drainage characteristics
Soil Classification and Grading Frictional Soils grain size grain shape G=gravel bulky coarse/silica S=sand sands M=silt flake loams Cohesive Soils grain size grain shape C=clay plate-like larger smaller O to PT organic peat
Soils Test liquid limit the water-content point at which the soil passes from a plastic state to a liquid state plastic limit the water-content point when soil loses its plasticity and begins to behave as solid.
Foundation Types SHALLOW FOUNDATIONS Slab on Grade Grade Beam Perimeter Foundation Wall / Spread Footing Column Pads Raft or Mat DEEP FOUNDATIONS Piles (driven) Caisson (bored and poured)
bigger buildings
deep foundations caissons (drilled piles or piers) cast-in-place concrete 2-6 minimum diameter base bearing condition
deep foundations pile foundation end-bearing or friction piles pile caps tie beams
DEEP FOUNDATIONS Piles (driven) Caisson (bored and poured)
DEEP FOUNDATIONS Piles (driven) Caisson (bored and poured)
Photograph taken ca. 1897 Recent Photograph
The Problem
The Problem
Differential Settlement
Foundation Types SHALLOW FOUNDATIONS Slab on Grade Grade Beam Perimeter Foundation Wall / Spread Footing Column Pads Raft or Mat DEEP FOUNDATIONS Piles (driven) Caisson (bored and poured)
isolated footing strip footings continuous footing grade beam cantilever, strap footing (tie beam) or combined footings mat or raft foundations (also floating foundations)
Simple shuttering for pad foundations is made up on site.
The reinforcing cage and some of the formwork for a foundation
This is one of two reinforced concrete bases which will carry the building's main shear frame.
Steel columns in the building's frame are fixed to their foundations by bolts which have been precast into the foundations.
This is the base of one of the legs of the shear frame The bottom of the leg is bolted onto the top half of the bearing assembly The bottom half of the bearing is fixed to the concrete foundation
Here's a view of the main shear frame. The two inner 'legs' of this massive frame are mounted on bearings.
Steel shims are used to get the steel columns to the correct level - the gap will eventually be filled with a high strength grout.
Portland Square After just two days work the steel frame for the ground floor of Building C is taking shape. The eastern and southern sides of the frame are almost complete while the north west corner is still to be erected.
SHALLOW FOUNDATIONS Slab on Grade Grade Beam Perimeter Foundation Wall / Spread Footing Column Pads Raft or Mat
SHALLOW FOUNDATIONS Perimeter Foundation Wall / Spread Footing Column Pads
Foundation Types rule of thumb for sizes Column Pads size for preliminary design is 3 X 3 X 12 with #5 bars and anchor plates s connect to bars Perimeter Foundation Wall / Spread Footing footing depth is equal to thickness of wall (varies with building load, soils) frost line footing width is twice thickness of wall stepped footing for change in ground s slope to remain below frost
Masonry Wall Stud Wall Thickened Edge Slab Not a frost footing wall footing column footing
Strip Foundations The foundation runs under all the loadbearing walls. In this example this includes the external walls A typical modern detached house will, where possible, sit on strip foundations. Providing the ground is suitable, this is the simplest and cheapest form of foundation. and the internal walls
The foundation supports all the loadbearing walls. This includes the external cavity walls (275mm wide), and the internal walls (100mm wide). The internal walls are loadbearing because they help support the 1st floor joists.
The line of the foundations can be highlighted using hydrated lime - here the trench centre line is being marked.
On some sites you will find both sides of the trench marked. Digger buckets are available in various widths to suit specific trenches.
Correct depth can be checked with a Level and staff. Site rail Boning rod Site rail
When trenches have been excavated they should be checked for square etc - mistakes can be expensive once the concrete has been poured. The trenches should be cleaned out and bottomedup (cleaned out and loose material removed), ready for inspection. In traditional strip foundations the services cross the trench above the concrete - in trench fill they cross through it. duct
Traditional strip Trench fill
Trench fill
Foundation footers for this basement have been completed and the rebar are in place.
The wall frames have been erected and carefully pinned securely into place. The concrete has been poured and the walls are curing.
Poured walls have cured so that the frame panels may be removed. The wall frames are being unpinned and the panels taken away.
Removal of the poured wall frame panels is complete and the walls are allowed to finish curing.
Balance Assoc. Cabin at Elbow Coulee, Washington State
D o w n h i l l
Warehouse: 15 th Ave and 8 th St Lucas Deslauriers. Christopher Farrar. Rachel Hilvert. Ryan O Malley. Stephanie Wichner Group 7
Fault Genesis A B A B A C B A C B
Existing Structure Photos C B A C
Existing Structure Photos B A
Existing Structure Photos B C
Existing Wall Elevation
Existing Wall Elevation
wood cast iron