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Thursday, August 13, 2009

Classification of piles




Piles is classified in to the following with respect to material;
  1. Timber
  2. Concrete
  3. Steel
  4. Composite piles
Timber piles
  • Timber pile is most suitable for long cohesion piling and piling beneath embankments.
  • Keeping the timber below the ground water level will protect the timber against decay and putrefaction.
  • Pressure creosoting is the usual method of protecting timber piles.




Concrete pile
  • Pre cast concrete Piles or Pre fabricated concrete piles : Usually of square, triangle, circle or octagonal section, they are produced in short length in one meter intervals between 3 and 13 meters.
  • They are pre-caste so that they can be easily connected together in order to reach to the required length.
  • Pre stressed concrete piles are also used and are becoming more popular than the ordinary pre cast as less reinforcement is required .


Steel piles
  • Steel piles are suitable for handling and driving in long lengths.
  • Their relatively small cross-sectional area combined with their high strength makes penetration easier in firm soil




Composite piles
  • Combination of different materials in the same of pile.
  • One main advantage of the composite concrete pile is that the longer-slender-lower-upper pile is much cheaper per unit length than the shorter-wider-upper pile.

High-strength concrete


High-performance concrete (HPC) is a term used to describe concrete with special properties not attributed to normal concrete. HPC was first known to be concrete with high strengths for structural purposes. However, advances in concrete technology have generated a new definition for HPC. High-performance means that the concrete has one or more of the following properties: low shrinkage, low permeability, a high modulus of elasticity, or high strength. As a consequence HPC is referred as concrete with better durability or higher strength compared to normal and moderate strength concrete.

High-strength concrete has a compressive strength generally greater than 6,000 pounds/square inch (40 MPa). High-strength concrete is made by lowering the water-cement (w/c) ratio to 0.35 or lower. Often silica fume is added to prevent the formation of free calcium hydroxide crystals in the cement matrix, which might reduce the strength at the cement-aggregate bond.
High-strength concrete is typically recognized as concrete with a 28-day compressive strength greater than 6000 psi (42 Mpa). More generally, concrete with a uniaxial compressive strength and flexural strength greater than that of moderate strength concrete. Strengths of up to 20,000 psi (140 Mpa) have been used in different site applications; for instance, Seattle's 58-story Two Union Square Building was called to have concrete with a compressive strength of 14,000 psi (96.5 Mpa), although testing revealed it to be near19,000 psi (131 Mpa). The most recognizable building with high strength concrete is the Twins Petronas Towers Kuala Lumpur, Malaysia; which has concrete with strengths around 20,000 psi (138 Mpa).

Low w/c ratios and the use of silica fume make concrete mixes significantly less workable, which is particularly likely to be a problem in high-strength concrete applications where dense rebar cages are likely to be used. To compensate for the reduced workability, superplasticizers are commonly added to high-strength mixtures. Aggregate must be selected carefully for high-strength mixes, as weaker aggregates may not be strong enough to resist the loads imposed on the concrete and cause failure to start in the aggregate rather than in the matrix or at a void, as normally occurs in regular concrete.
In some applications of high-strength concrete the design criterion is the elastic modulus rather than the ultimate compressive strength.
Laboratories have produced strengths approaching 60,000 psi (800 Mpa). High strength concrete can resist loads that normal-strength concrete cannot. Several distinct advantages and disadvantages can be analyzed. It is important to consider all peripheral results of selecting high strength concrete since special considerations must be addressed beyond strength properties.

High early strength concrete can also be produced as a high quality product. Early age properties in concrete might be very important for construction loads, speed of construction, and they can significantly affect long term performance. Early age strength concrete can be obtained using different approaches, and the desired strength can be reached within hours or days. This type of concrete may be useful in a variety of situations; for instance, bridge decks or overlay replacements can be performed without affecting the normal traffic flow of a bridge if construction work is done at night. The concrete deck could reach its design strength and the bridge could be open to traffic in a matter of hours. Another application occurs during construction of high rise buildings; time of construction is an important driven factor for contractors and owners alike, therefore during high rise building construction the early strength concrete provides quick floor to floor construction.

Tuesday, August 11, 2009

264 AutoCAD shortcut keys


264 AutoCAD shortcuts
to increase the speed of your work, try these shortcuts.

key
Command

key
Command
3A 3DARRAY
TLT LDRTXTT
3F 3DFACE
LD LEADR
3DO 3DORBIT
LDA LEADRA
3P 3DPOLY
LDB LEADRB
AT ACTILE
LDD LEADRD
AL ALIGN
LDS LEADRS
AP APPLOAD
LDT LEADRT
APS APS-CONFIG
L LINE
KLH APS-CONFIG
LT LINETYPE
DO APS-DONUT
LI LIST
O APS-OFFSET
LS LIST
A ARC
LTS LTSCALE
AA AREA
LW LWEIGHT
AR ARRAY
MA MATCHPROP
AC ATTCOUNT
ME MEASURE
ATT ATTDEF
MI MIRROR
BL BBLLDR
ML MLINE
BH BHATCH
M MOVE
H BHATCH
MS MSPACE
BM BLIPM
MT MTEXT
B20 BLK20
T MTEXT
B2B BLK20BB
MV MVIEW
B2L BLK20BL
NL NEWLINE
B BLOCK
NS NEWSCHEME
BO BOUNDARY
N NOTES
BR BREAK
NC NOTESC
BI BRKINT
CW O-CWIND
BF C-BIFOLD
OC O-CWIND
BP C-BIPASS
DD O-DDOOR
CCW C-CWIND
ODD O-DDOOR
CDD C-DDOOR
O2 OF2LAYR
DDC C-DDOOR
OH O-OHEAD
CHA CHAMFER
OPD O-PATDOOR
CL CHLAYR
PDO O-PATDOOR
C CIRCLE
OP OPTIONS
BBL CLOUD
PR OPTIONS
OHC C-OHEAD
OR O-RWIND
COL COLOR
RW O-RWIND
CO COPY
OD O-SDOOR
CP COPY
SD O-SDOOR
PDC C-PATDOOR
OSL O-SLIDER
C2F CPY2FLR
OS OSNAP
C2 CPY2LAYR
P PAN
CB CPYBLK
PA PASTESPEC
CC CPYCONT
PE PEDIT
CM CPYMULT
PJ PJOIN
CT CPYTXT
PD PKDTCH
CLA CRVL
PB PLANBLKS
CLAA CRVLA
PH PLANHATCH
CLB CRVLB
PL PLINE
CLD CRVLD
PP PLOTPREP
CLS CRVLS
PLY PLYWD
CLT CRVLT
PO POINT
CR C-RWIND
POL POLYGON
RWC C-RWIND
CH PROPERTIEs
CD C-SDOOR
MO PROPERTIES
DRC C-SDOOR
PS PSPACE
CS C-SLIDER
PU PURGE
SDC C-SLIDER
PAL PURGEALL
DAL DALIGN
PW PWID
DAN DANGULAR
Q QDIMENSION
DCO DCON
LE QLEADER
ED DDEDIT
SA QSAVE
GR DDGRIPS
QT QTXT
DDI DDIAM
REC RECTANGLE
UC DDUCS
RS RECTSLD
VP DDVPOINT
R REDRAW
DTL DETAILER
RA REDRAWALL
DH DETLHATCH
RE REGEN
DBA DIMBASELINE
REA REGENALL
DCE DIMCENTER
REG REGION
D DIMSTYLE
REN RENAME
DST DIMSTYLE
RD RESTOREDIM
DI DIST
REV REVOLVE
DB DIVBLK
RL RGNLAYR
DIV DIVIDE
RO ROTATE
DLI DLINEAR
SC SCALE
DRA DRADIUS
SCR SCRIPT
DR DRAWORDER
SEC SECTION
DRO DROTATED
SET SETVAR
DS DSETTINGS
SHA SHADE
SE DSETTINGS
SB SHDWBOX
DT DTEXT
LL SLEADR
DV DVIEW
LLA SLEADRA
DW DWELEV
LLB SLEADRB
EB ELEVBLKS
LLD SLEADRD
EH ELEVHATCH
LLS SLEADRS
EL ELLIPSE
LLT SLEADRT
EM EMODE
SL SLICE
E ERASE
SN SNAP
X2 EXP2LAYR
SO SOLID
X EXPLODE
SP SPELL
EX EXTEND
SPL SPLINE
F FILLET0
S STRETCHC
FR FILLRAD
STC STRETCHCP
FI FILTER
ST STYLE
FL FZLYR
SU SUBTRACT
GL GLULAM
SR SURNOT
G GROUP
TAL TALIGN
GB GYPBD
TC TCLEAN
HE HATCHEDIT
TH THICKNESS
HR HATCHREL
TI TILEMODE
HI HIDE
TO TOOLBAR
HL HILITE
TR TRIM
IAT IMAGEATTACH
T2M TXT2MTXT
IMP IMPORT
AE TXTEDT
I INSERT
TE TXTEDT
IO INSERTOBJ
TT TXTRIM
JD JDOOR
UI UCSI
JH JHANG
UL UNDERLINE
JW JWIND
UNI UNION
KN KEYNOT
UN UNITS
KNA KEYNOTA
UP UPCASE
KNB KEYNOTB
V VIEW
KND KEYNOTD
WF WALLFILL
KNS KEYNOTS
W WBLOCK
KNT KEYNOTT
WE WEDGE
LA LAYER
WG WGRID
LO LAYOUT
XA XATTACH
IS LAYRISO
XB XBIND
LLK LAYRLOCK
XCL XCLEAN
LF LAYROFF
XC XCLIP
LON LAYRON
XL XLINE
LST LAYRSET
XR XREF
LU LAYRUNLOCK
Z ZOOM
LC LCLEAN
ZA ZOOM ALL
TL LDRTXT
ZD ZOOM DYNAMIC
TLA LDRTXTA
ZE ZOOM EXTENTS
TLB LDRTXTB
ZP ZOOM PREVIOUS
TLD LDRTXTD
ZV ZOOM VMAX
TLS LDRTXTS
ZW ZOOM WINDOW



How to print to scale??

go to layout> right click> modfy> change scale to mm and 1:1 than press OK
now u see its very small, now delete this outlines, now that everything is gone, type "MV" and press space button twice.
now u see all the drawing, type "z" press enter, now type ur scale for example 1:100 than type "1/100xp" press enter.

now u can print to scale.
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