23‏/10‏/2011

Deep foundations (1)

Deep foundations


 
1 / 1 provided
This section contains the minimum security requirements to be met in the deep foundations have been taken into account in its development that covers primarily all of the construction of civilian uses normal in the areas of housing, infrastructure, industry, etc. and then these requirements may not cover the requirements of the proper operation or places in the facilities of an private, such as atomic energy facilities, installations fortified military and the like also taken into account in the preparation of these requirements suitability for most kinds of combinations of soil in Egypt and the applicable Arab neighbors as well as the suitability of the levels of comprehension and practice techniques for the implementation of this type of foundation in this area at this time. Requires in the case of addressing the types of facilities with a special character or unusual combinations of soil to take safety measures required by these cases in addition to the requirements of this section.


1/1/1 field
Deep foundations are the foundations of depth the Great, and the mean depth of the foundation a minimum distance between the level of incorporation and attributed to the final of the surface of the ground and in the case of deep foundations the ratio of the depth of the foundation to the long side is smaller than three, so at least the depth of the base of 4 meters, and usually choose the designer this depth the great access to in accordance with establish a strong and non-compressible enough to affect the safety of origin.


1/1/2 definitions
The following are definitions of terms used in the field of deep foundations.
Air Lock lock antenna
Room transmission used in the work of compressed air (see Qaysonat) for this room two doors and one open to the outdoors and the latest online vacuum compressed air may fill the room with air-ROM or reduce this pressure, even similar to normal atmospheric pressure to allow the passage of workers and materials to or from the vacuum howl-ROM with conservative at the value of the vacuum pressure in the latter.


Anvil Anvil
The part that receives the rate Cako managed energy and transfer it to the stake.






Foran (during the implementation of the foundations Alkhazoukah) Boiling
The phenomenon of surge soil particles within the lumen of the drilling pipe down to the declaration as a result of surge water from the soil under the influence of a difference in water levels inside and outside the pipe.


The masters of Dolly, Hammer Cushion
A pad of hardwood or other suitable material placed on or inside the Tarbush tapping "Driving cap" helmet or "helmet" to receive hammer blows knocking.


Tarbush tapping or Driving cap helmet helmet
Iron helmet temporarily placed over the head of the stake or iron pipe or tapping sensation earlier casting for the distribution of tapping and to reduce the damage the incident to the head during the stake or pipe tapping.


Fall or walk Drop or Strock
Distance of the fall of the ileum "ram"


Free fall hammer Drop hammer
Stomach normally contains the weight of a metal crane lift and allows the free falling (under the influence of gravity only).


Evidence Guides
Sectors of iron mounted on an existing machine tapping or drilling to guide the hammer tapping or Auger or the stake during the ticking.


Free weights Kentledge
Weights are used to add units to carry a temporary origin, such as the higher weights that are used to help Qaysonat Nguesa Lamb is dead or in tests Althma usually of iron or concrete blocks .. Etc..


Leader-based machine
Consists of the sectors of iron proved by evidence Cako or pile or auger to determine their path during execution.










Filler Packing, Pile Cushion
A pad of flexible material (able to absorb shocks and return to its original form) content between the helmet "helmet" and the head of the stake to reduce the damage likely to occur to the top of the stake during the ticking.


Penetrate Penetration
Penetrate the distance tool palpation or Qayson or deep foundation .. Etc. measured from the level surface of the earth.


Significant pile or piles Pile Cap
Armed concrete block poured over the head of the stake or a group of piles for the movement of pregnancy from the origin to the stake or a group of piles.


Beats of the hammer ram
Part Alchukosh moving up and down to make efforts to drive a dynamic.


Decline in immunity (break) Set (refuse)
Net distance which penetrate the stake into the ground versus the accuracy of one of the beats Cako.


Shoe heel sensation
A piece of iron, usually made of steel or cast iron, and fastened in the bottom of the pole or pipe tapping to facilitate penetration or pipe pile of the land.


1/1/3 uses deep foundations
Use these types of foundations usually when the classes appropriate to build on the great depth from the surface of the earth and all the layers topped unsuitable for the establishment of them because they Latvian transactions security required in terms of stresses or decline of the origin or equipment that Christoaha also used deep foundations when required by economic studies that As in the case could not be performed foundations shallow for the consequent reduction in water level the ground for great depths and the consequent problems is also to ensure the safety balance of the building in the future at sites prone layers the top of the slaughter or cleansing or drilling may be used deep foundations also to ensure the integrity and balance, neighboring buildings and cases of enterprises that need in their design to compress the soil profile for balanced state.










1/1/4 trade-off between the foundations deep and shallow foundations
Before making a decision to use any of the types of deep foundations must work a comprehensive study to make sure it can not build on any of the types of deep foundations must make a comprehensive study to make sure it can not build on any of the types of foundations shallow because the cost of deep foundations often increase the costs of foundations shallow as well as the difficulties that accompany the implementation of deep foundations.


1 / 2 types of deep foundations
Deep foundations include the following types:
Piles Qaysonat Alexandrian pillars wells.


1.2.1 Piles
Are the elements of structural thin-efficient load axial usually high Matzad the proportion of length to diameter of about ten, and diameters ranging from 0.3 meters to 1.50 meters or more and the lengths of 4 m and above may reach in some special cases to 60.00 meters and necessary for their implementation is usually mechanical equipment different piles the prefabricated prove penetration in the soil (may twirl pressure) or implemented in its place by means of discharge or drilling and tapping.


1/2/2 Qaysonat
Are the foundations of the cylindrical or box-with a single cell or multiple cells are characterized by Bmqasadtha large manufactured partly or wholly outside the place of incorporation and fastened in place Balngues and drilling is based usually below the water table or under the bottom of water bodies Wet drilling and Tnqiv objects such Qaysonat inside the rooms are open or closed may be equipped with the possibility of controlling the air pressure inside.


1/2/3 props
The foundations of her outsize implement manual or mechanical digging, but without submersion and the cover or not, might dry place around and inside the intensities as implemented in the pillars of bridges made of stone blocks or concrete strong regular-efficient private or reinforced concrete.


1/2/4 wells Alexandrian
Are the elements of construction carried out the bottom level of the rules of armed and usually less than a length to diameter or Mikavih for about ten used locally in the Dry Areas (no ground water) drilling of the well executed manually and without the support of the aspects only rarely. Body fills the well using concrete sand is usually poor or installed or Mdcockh layers of sand and gravel and usually less than 1.5 meters in diameter.




1/2/5 choose the type of deep foundation course
When appropriate state soil incorporation of more than one type of the species mentioned in item 1 / 2 of these requirements, the trade-off is usually to select the type most economical in cost and implementation period and generally be a foundation Alkhazoukah diameter normal of any of 300 millimeters to 600 millimeters more appropriate in cases of foundations with loads are relatively light and the many number while building on piles drilling large diameter (diameters greater than 600 mm) or Qaysonat props and more suitable for loads of high-value, low number of facilities such as major bridges big seas.


1 / 3 foundations Alkhazoukah
1/3/1 Introduction
· These requirements apply to all types of piles penetration (pressure tapping twisting) or perforation (drilling discharge) its articles and the different ways to implement multi-listed in these requirements in the case of exposure to the use of other types not mentioned in these requirements must be applied to them as much as Maalaúmha possible.
· Basic function of the piles is to transfer the load to the lower layers are able to load safety factor K, and so to not prejudice the values ​​of land corresponding to working load functions of origin and acquire piles its ability to conceive of the solidarity of the resistance of friction along the sides with resistance to build at the bases of any points Artkazha prevail resistance to friction the piles carried out in accordance with the mud and silt build resistance to prevail while the piles, which ends on or based on a layer as strong as the heavy clay sand gravel rock hard.
· In some cases, otherwise transfer the load to the lower layers are used piles of sand or gravel in order to increase the carrying capacity of the soil for the establishment of the Balosasat shallow or in order to accelerate Bandgatih clay soils or to address some of the damage to the soil viable ruffled and implement these piles usually work a hole into the ground and fill it with sand or pebbles include appropriate for the purpose of the use of piles.


1.3.2 The study and testing and working on the site
Must precede the design and implementation of a comprehensive foundation Alkhazoukah exploration of the site includes the following:
1/3/2/1 examination of the ground
Pending examination of the land allocated for the project in accordance with the recommendations of the special "study site" contained in Part I of this code by specialized and experienced with the preparation of a special report that according to the terminology adopted taking borings at the site of work with the attached tests hack appropriate whenever possible and should include borings sufficient data to explore and identify the nature of the soil around the pile and the bottom of the proposed






Especially for layers that appear to contribute significantly in determining the safe load-bearing capacity in order to provide the following data:
· Geological sections show the path of the main classes and whether there are obstacles buried within the layers.
· The results of tests is sufficient to estimate the coefficients of resistance for maximum cut and mistake is the main layers of the soil.
Identify along the layer anchor pile of potential, if any, in the case of rock layers, it must ensure the continuity of the rock to a sufficient distance below the point fulcrum piles and determine if the surface of the rock flat or tilted or irregular as well as the thickness of the layer the rock is weak cohesion, if any, which must penetrate Piles.
· Estimate the resistance of roller bearings at the base of the stake any point Artkazh and the resistance of friction on the sides of the stake and the singles on the different depths at the site and when soil conditions do not allow the use of hazing on the depth of the economic fulcrum.
· Must set the limits of successive layers with sufficient precision roller bearings in the case of piles, which ends in a thick layer of sand or gravel.
• Identification of ground water levels and the different layers have a bearing and chemical analysis are needed to set the items that are harmful in any of the ground water or soil, which may affect the material for sensation, to the work of the special precautions and appropriate in such circumstances.
· To determine very carefully and there is no mains gas, water or electricity cables or any other type of services that may get hurt or destroy or cause hazards or the presence of any obstacles to the execution of piles such as underground facilities, or the foundations of old, either of the maps for these services be found by following or secure means of drilling.
· Examine the site of where the nearest neighbors Tabowerevih limits available source of electricity or water, which is one of the most important factors that determine the most appropriate pile of the site.
· Check the website in terms of suitability for Choinat required for the proposed types of piles where you should avoid storing heavy equipment on soft soil or use of equipment need to be very high in places covered (limited height).


1/3/2/2 examination of the neighboring establishments
Must include the initial screening of the site assessment and adequate to the situation surrounding buildings as the selection of any type of piles may be determined effects that can be bounded on the implementation of this type to adjacent buildings, is this assessment usually examines the neighboring facilities and know the quality of their foundations and may study the records and it may require is the work of drilling a pilot to explore the nature and quality of these foundations with the registration of any indication of a decline or collapse of the former or sliding may have occurred or have any of them of the importance in assessing the situation.




1/3/2/3 piles initial tests
In all the important facilities built on piles must be planned program of preliminary tests of piles include penetration resistance tests and load tests (item 4/3/6) based on data to explore and examine the site of the former carried out.
Must be made piles initial tests of the same material and same dimensions Piling operation to be used the same methods and equipment implementation, the possibility of finding the behavior of piles operating as follows in the load tests Piles initial the same steps used in the tests, load piles of operation and mentioned in item (4/3/9 ) and in some cases may be required to protect the piles until the pregnancy test the initial collapse.


Active work 1/3/2/4
Must set up a spatial map of the preferred site in the early stages showing the various obstacles above or below the surface of the Earth (such as: the foundations of an old water pipes electric cables, etc. ..) in addition to that is a topographic map of the site when there is great variation in the levels of the ground and in the case of there are no obstacles interfere with the work should be removed if not avoided.
Before starting the actual implementation of the foundations must be done to test the carrying capacity of the surface layer of soil where the surface layer must strengthen weak or replaced with a layer of appropriate thickness enough (from Adakkhom for example) so not to cause problems during the operation of the equipment.


1/3/3 types of Piles
Make piles often of concrete, iron or wood and may contain sectors or length of more than material from the previous articles and the movement of pile loads transmitted to it from the origin to the soil by friction on the body of the stake or the focal below or in most cases by a combination of both, and there are two ways Tflidetan for implementation.
A method of penetration displacement (percussion clicking Agreement), including the removal piles (piles solid or hollow and of blocking or closed heel) and partial displacement piles (rolled steel sections or segments of hollow tubes, open sides), which allows the soil to enter freely within the cavity of the stake during the process of the breach.
By way of drilling (discharge) that I am talking in most cases remove any soil and is usually divided into types of piles from the reality of how to implement them.


1/3/3/1 displacement piles executing penetration (percussion or pressure or Balbrm)
Piles of wood 1/3/3/1/1
Rarely use the piles of wood footings of buildings in Egypt, but may be used in the work of Damsat Kdaamat or for the protection of water facilities and usually manufactured in the sectors of the square or round and may be regular or despoiled sector.




It must be the body of the stake free from all defects that can affect the strength of the stake and bear depends Omar pile on the center, which crossed in, case of a breakout to the soil and the entire length of the stake under the level of fresh water it lives for many years in the case of extension of the stake above the surface of the water it be susceptible to corrosion and must be treated until at least the age of the age or origin, who carried it protects.
In the case of the use of piles in the water facilities, the body of the stake will be vulnerable to damage as a result of being attacked aquaculture or fire and therefore must be protected treatment appropriate paint or injection if was treated well, the life of the stake to increase to tens of years and must examine the pile of wood in the selection and pre-processed and the exclusion of Piles which shows the defects, and preferably not less than the rate of moisture by 20% and not more than 50% and in case of difficulty in tapping the solid land, the work can be pre-drilled to facilitate the process of tapping. And may not be used under the piles of wood plants emit excessive heat such as furnaces, where piles of wood that the age is sensitive to heat.
And taken into account in the implementation of the following piles:
1 that the estimated dimensions of the sectors from 150 millimeters to 500 millimeters (diameter or side of the square) The length of the pile of them to 20 meters and the sector regular or usurped if the piles circular section shall not be less than a diameter of 150 millimeters at the bottom and 280 mm, 600 mm from its peak after removing excess parts of it after accuracy. If the square section piles shall not be less sectional for 250 × 250 mm in full length.


2 that the wood piles of good quality wood such as Azizi and so resist the influences that might be exposed to.


3 must not exceed the stresses in the section of the stake from tapping or load operating voltage limit for the type of wood used in accordance with the following schedule taking into account the effect of buckling property, if any.


The type of wood used Kkhazouk

Operating voltage allowed by the pressure in the direction of fiber
Mijanewton / m 2

(Kg / cm 2)
Azizi (pitch pine) or Maimathlh
Oak (oak) or Maimathlh

4
5.4

(40)
(54)










4 sets of the site piles with lengths in excess of the estimated lengths in the light of borings and piles Althrbh including at least 500 mm, after which accuracy remains excessive lengths or may be affected by the percussion.


Table (1 2) the impact of property on the buckling Buckling load limit for a working piles as columns
Ratio less than half the effective diameter of the movement AltduyemihEffective length
Radius of gyration (r)

Reduction factor of pregnancy allowed * as a result of the piles that are buckling as columns
Wood

Reinforced Concrete

Steel 37

Steel 52
Zero
10
20
30
40
50
60
70
80
90
100
110
120
130

1.00
0.98
0.95
0.93
0.89
0.82
0.72
0.61
0.50
0.41
0.34
0.28
0.24
0.21

-
-
-
-
-
1.00
0.88
0.76
0.67
0.59
0.52
-
-
-

1.00
0.95
0.89
0.84
0.78
0.73
0.68
0.62
0.57
0.51
0.46
0.41
0.36
0.32

1.000
0.940
0.875
0.815
0.750
0.685
0.625
0.565
0.500
0.435
0.375
0.325
0.280
0.245


* Pregnancy allowable buckling coefficient = voltage × negligently allowed buckling × sectional area for sensation.


5 You must provide the tapered bottom of the pile butt of iron or steel, and placed a cordon of steel around the Cape to maintain the stake during the ticking.
6 can increase the length of pile lengths other wooden plug of the same section that the link works from the sectors of metal, wood or sizes suitable to withstand the stresses experienced by safely.










1/3/3/1/2 Steel Piles
Include piles of which the sector transferee loads of iron, for example, only sector (H) sector round (pipe open or blocked from the lower end) bars private box or rectangle .. Etc.. They also include piles Leptospira For these piles strength structural high and can be welded before or during implementation and access Botoalha to large values, but its flaws are subject to rust and then corrosion particularly the part of the stake, which are important direct when the soil is loose incoherent or in part of the soil near the limit separation between water and air.

 
A rolled steel piles
Are sectors of the Piles The withdrawn or vehicle and manufactured specifically for use Kjuazik carrier (Box Culverts) is often the sector used in the form of (H), where the length and thickness of each of the lip "flange" and nerve "web" identical and care must be taken while moving the piles and storage, especially in Piles long with a small-scale sector as well as knocking the pile during the same sector (H) can bend and take different paths to the theoretical course and so it is prudent to strengthen the lower end of the stake to prevent breaking or changing its course during the tapping in the ground very hard.


With piles of round sector (pipe)
This type of sector round piles and piles with diameters of these manufactures and Tkhanat multiple and can be up in the pipe diameter piles with a sector open to 3 meters and a wall thickness to 75 mm when used in water installations.

 
C Piles Leptospira
Piling is a sector with a round provider of spiral welded steel plate on the bottom of the pipe and soil types used in the weak and the purpose of the helix is ​​to increase the loading area, increasing the loading capacity for sensation

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