INTRO TO FOUNDATION ENG. Flashcards
New methods of building construction began to appear in the late ____ century.
19
The introduction of steel and reinforced concrete led to transition away from ___________________ structures to more ___________________ structures.
rigid masonry, flexible rigid frame
Eiffel tower in Paris was built in _______ - _______
1887 - 1889
It is an excellent example of a new type of structure in which old rules for foundation no longer applies.
Eiffel tower in Paris
Where is Eiffel tower adjacent and what is the soil condition in there?
Seine River, uncompacted fill and soft alluvial soils
In the Eiffel tower, piers for the nearby Alma bridge had already settled by ___ meter/s.
1
Eiffel devised a new way of exploring the soils, which consisted of driving ______ mm diameter pipe filled with ___________________,
200 , compressed air
Eiffel placed the foundations for the two legs farthest from the river on the SHALLOW but firm ________ soils. The bottom of these foundations were above _____________.
Alluvial Soils
Ground Water Table
Eiffel made the foundations for the other two legs much DEEPER on firm soils. This required ____ m excavation below the ground surface ( ____ below GWT)
12, 6
The angular distortion is defined as
change in height over length
Engineers instead of simply developing new empirical rules, they began to investigate the __________ of foundations and developed more rational methods of design thus establishing the discipline of ___________ engineering.
behavior, foundation
Design methods includes a mixture of _________ and _________ techniques.
rational, empirical
these are those developed from the principles of physics and engineering sciences
rational techniques
are based primarily on experimental data
empirical techniques
In spite of many uncertainties in foundation design and analysis, the public expects the engineers to develop reliable and economical designs in a timely and efficient manner.
We compensate these uncertainties by using _________________________ in our designs.
factor of safety
Railway bridges
Warehouses
Blast furnaces
Retaining walls
Silos
Maximum design load likely to occur often
disastrous consequences
thorough 3
limited 4
Highway Bridges
Light industrial and public buildings
Maximum design load may occur occasionally
serious consequences
thorough 2.5
limited 3.5
Apartment Buildings
Office Buildings
Maximum design load unlikely to occur often
thorough 2
limited 3
UBC
Uniform Building Code
ACI
AISC
American Concrete Institute
American Institute of Steel Construction
AASHTO
American Association of State Highway and Transportation Officials
What are the two types of shallow foundations
spread footings and mats
Give 3 examples of deep foundation
Pile, Anchor, Caisson, Pressure Injected Footings
What are the performance requirements
- design loads
- methods of expression
- strength requirements
- serviceability requirements
What are the strength requirements
geotechnical and structural strength requirements
are caused by the weight and lateral pressures from soil or rock, such as those acting on a retained wall.
Earth Pressure Loads
are those caused by intended use and occupancy
Live Loads
these are those cause by temperature changes, shrinkage, moisture changes, creep, differential settlement, and other similar processes.
self straining loads (T)
are the result of vibratory, dynamic, and impact effects.
impact loads (I)
_____________ and ____________ are caused by the action of WATER and ICE in bodies of water, and are especially important in bridges, offshore drilling platforms, and port facilities.
Stream flow loads (SF), ice loads (ICE)
_____________ and ___________ are caused by the motion of vehicles moving on the structure.
Centrifugal loads (CF), Braking loads (B)
this is intended to avoid catastrophic failures
strength requirements
intended to produce foundations that PERFORM WELL when subjected so service loads
serviceability requirements
address the ability of the soil or rock to accept the loads imparted by the foundation without failing
it is satisfied by comparing SHEAR STRESSES with SHEAR STRENGTHS and designing accordingly
geotechnical strength requirements
for spread footing foundations, geotechnical strength is expressed as the ________________ of the soil
bearing capacity
____________ are intended to produce foundations that PERFORM well when subjected to service loads.
These include
Serviceability requirements
lateral movement
heave
tilt
settlement
vibration
durability
the vertical downward movement of foundations
settlement
the change in foundation elevation from the original UNLOADED position to the final LOADED position
Total Settelement
Typical Allowable Settlements
OFFICE BUILDINGS
0.5 - 1 in
Typical Allowable Settlements
Heavy Industrial Buildings
1 - 3 inches
Typical Allowable Settlements
Bridges
2 inches
If the predicted settlement is greater than the allowable settlement, the following measures can be considered
- adjust foundation design
- use a more elaborate foundation
- improve the properties of soil
- redesign the structure so it is more tolerant to settlements
the difference in total settlements between two foundations or between two points in a single foundation
Differential Settlement
What settlement produces cracks in walls, jamming in doors and windows, poor aesthetics, and if allowed to progress, can threaten the integrity of the structure
Differential Settlement
Allowable Differential Settlement can be calculated by
allowable angular distortion * column spacing
Foundation designs are usually more conservative than those in the _______________.
superstructure
T/F
Foundations are built with the same degree of precision as the superstructure
F
not built
A type of failure, the failure to produce economical design
over - conservatism
It is often the most important serviceability requirement
settlement
Design loads may be expressed using the __________ or ____________
LRFD, ASD/WSD
