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Monday, January 30, 2017

EXTRADOSED PC BRIDGES





An extradosed prestressing concept, is a new type of structural system in which the tendons are installed outside and above the main girder and deviated by short towers located at supports. 

Extradosed PC bridges have several positive characteristics. The girder height may be lower than that of ordinary girder bridges, thus reducing self-weight of structures. The ratio of the girder height to the span length (H/L) in extradosed bridges ranges between 1/15 and 1/35, while it is approximately 1/15~1/17 for box-girder bridges. Comparing to cable-stayed bridges, the height of the main tower in extradosed bridges is lower; hence, a reduction in labor costs of construction can be achieved.

Sunday, January 29, 2017

JOINT COORDINATE COMMAND SPECIFICATION IN STAADPRO

Example 1
JOINT COORDINATES
1 10.5 2.0 8.5
2 0.0 0.0 0.0
3 5.25 0.0 8.5 6 50.25 0.0 8.5
In this example, X Y Z coordinates of joints 1 to 6 are provided. Note that the joints between 3 & 6 will be generated with joints equally spaced from 3 to 6. Hence, joint 4 will have coordinates of 20.25 0.0 8.5 and joint 5 will have coordinates of 35.25 0.0 8.5.


These commands allow the user to specify and generate the coordinates of the joints of the structure. The JOINT COORDINATES command initiates the specification of the coordinates. The REPEAT and REPEAT ALL commands allow easy generation of coordinates using repetitive patterns.




General Format
JOINT COORDINATES (CYLINDRICAL (REVERSE)) (NOCHECK)
band-spec
i1, x1, y1, z1, ( i2, x2, y2, z2, i3 )

REPEAT n, xi1, yi1, zi1, (xi2, yi2, zi2,..., xin, yin, zin)
REPEAT ALL n, xi1, yi1, zi1, (xi2, yi2, zi2,..., xin, yin,
zin)
n is limited to 150

JTORIG xOrigin yOrigin zOrigin
band-spec = (NOREDUCE BAND)
Where:

NOCHECK = Do not perform check for multiple structures or orphan
joints.

Description
The command JOINT COORDINATES specifies a Cartesian Coordinate System. Joints are defined using the global X, Y and Z coordinates. The command JOINT COORDINATES CYLINDRICAL specifies a Cylindrical Coordinate System. Joints are defined using the r, q and z coordinates. JOINT COORDINATES CYLINDRICAL REVERSE specifies a Reverse Cylindrical Coordinate system. Joints are defined using the r, y and q coordinates.
JTORIG causes the program to use a different origin than (0, 0, 0) for all of the joints entered with this JOINT COORDINATES command. It is useful in instances such as when the center of cylinder is not at (0, 0, 0) but at a different point in space. The JTORIG command should be entered on a separate command line.
Basically after the joint coordinates are entered or generated, then the xOrigin, yOrigin, and zOrigin values are added to the coordinates. For example a cylinder could be generated about the Y axis then moved by this command to its proper place. To create multiple offset structural parts, enter additional JOINT COORDINATES commands, each one followed by its JTORIG command. 


PYLON





SHAPE OF CONCRETE PYLON ON BALUARTE BRIDGE IN MEXICO RESEMBLE INVERTED Y.
SHAPE OF CONCRETE PYLON ON BALUARTE BRIDGE IN MEXICO RESEMBLE INVERTED Y.



Friday, January 27, 2017

LAUNCHING OF SEGMENT





SIDE SHUTTERING OF SEGMENT



SEGMENT



STAAD USES TWO TYPES OF COORDINATE SYSTEMS

STAAD uses two types of coordinate systems to define the structure geometry and loading patterns. 

  1. Global coordinate system
  2. Local coordinate system




Global coordinate system

The Global coordinate system is an arbitrary coordinate system in space which is utilized to specify the overall geometry & loading pattern of the structure. 

Tuesday, January 24, 2017

Sunday, January 22, 2017

Example of Joint Coordinates command in StaadPro

Example of Joint Coordinate command in editor is represented by


JOINT COORDINATES
1 0 0 0; 2 6.5 0 0; 3 0 5.4 0; 4 6.5 5.4 0

Here 1 represent joint number, and 0 represent x, y, z coordinate of joint separated by single space.

Similarly 2 is joint number, 
               6.5 is x coordinate , 
              0 is y coordinate and 
              0 is z coordinate.

Friday, January 20, 2017

What does input width command means in Staadpro?

If you open your Staad file editor, you will find fifth line having following information:

INPUT WIDTH 79

it shows allowable width of code line in the editor.

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