Project 1

1) Mention the need for a metro rail in a developing economy.

• 'Metro Rail' is a commuter-friendly transport providing the traveling public with a fast, safer, reliable, comfortable, pollution-free, affordable, convenient, and eco-friendly service. The high-capacity Metro Rail System would reduce the ever-increasing traffic congestion on the city roads.
• The most efficient transportation system is space occupancy, energy consumption, and numbers transported.
• They are very high-capacity carriers, transporting many people during peak hours.
• Unlike buses and other modes of public transportation, metro rails are eco-friendly, cause much less sound pollution, and have no air pollution.
• They possess greater traffic capacity. It carries as much traffic as seven lanes of bus traffic and 24 lanes of car traffic.
• It reduces the journey time from 50% to 75%.
• The usage of metros should be promoted more and more as it helps in reducing the levels of greenhouse gases.
• The number of road accidents has also gone down drastically as people have chosen the Metro. Speeding usually happens when people are late for their work.
• Metro provides air-conditioned traveling with the best comfort at relatively cheap rates

2) Perform longitudinal analysis of 3 x 25m prestressed I-girder for metro viaduct in STAAD by creating the nodes, beams, and supports being assigned to those nodes for a slab and girder that has been presented in the videos.

Step (1) - Creating Grid Modeling in STAAD.Pro

Creating node (0,0,0) > Selecting Node using node cursor > Copy it in X direction using Translation repeat option 

Connect both the node > Geometry > Add beam 

• According to the suitable size create a Girl model

Step (2):- Assigning Support 

Specification > Support > Create > Fix but > Release ( MX, MY, MZ ) > Add > Select support 2 > Select node > Assign to selected nodes > Assign 

Specification > Support > Create > Fix but > Release ( FX, MX, MY, MZ ) > Add > Select support 3 > Select node > Assign to selected nodes > Assign 

Specification > Support > Create > Fix but > Release ( FZ, MX, MY, MZ ) > Add > Select support 4 > Select node > Assign to selected nodes > Assign 

Specification > Support > Create > Fix but > Release ( FX, FZ, MX, MY, MZ ) > Add > Select support 5 > Select node > Assign to selected nodes > Assign 

• Select a node according to suitable support and assign to it

Step (3):- Assign Property to Model

Specification > Property > Define > General > Insert the value Cross-section dimension of beam > Add > Select the property > Select the beam > Assign to selected beam > Assign 

• Repeat the same step according to the suitable dimension of different types of beam

Step (4):- Applying Loading on Model

I. Vehicle Definition

Loading > Load & Definition > Definitions > Vehicle Definition > Add 

II. Dead Load.

Loading > Load & Defination > Load Case Detail > Total ( Dead Load ) > Add > Select Dead Load > Add > Self Weight Factor -1 > Add > Select Selfweight - 1 > Assign to view > Assign.

III. SIDL

Loading > Load & Definition > Load Case Detail > Title ( SIDL ) > Add > Select SIDL > Add > Member Load > Uniform Force >  W1 -8.34 Direction GY > Add > Select Load > Select Suitable beam  Beam > Assign to selected beam > Assign

• Repeat the same procedure for different beams according to suitable force.

IV. Load Generation

Loading > Load & Definition > Load Case Detail > Add > Load Genaration > No of load to be generated > Add > Generted Load > Position of coordinate > Add

Step (5):- Analysis And Result

Analysis And Design > Analysis Commands > Run Analysis > Go to post prossing mode > Done 

(3) Prepare a transverse STAAD model of a U-girder with the following specifications:

Given Data:- 

• Finite element model of U-girder with a span length of 30m.
• Having supports at 0.7m from both ends.
• Having the following geometrical properties:
  • Thickness of bottom slab – 300mm
  • Thickness of top web (both sides) – 240mm
  • Thickness of slant web - varying from 300mm to 240mm
  • Concrete grade M55.
  • Reference inputs can be taken from the relevant video sessions if needed.

Procedure:- 

Step (1) - Creating Grid Modeling in STAAD.Pro

• Arranging the node in the shape of U Grider

• Connecting node by using add beam option

• Copy the node in X direction using the translation repeat option and assign the plate using add plate option

• Making Full U Girder model using translation repeat option.

Step (2):- Assigning Support 

Specification > Pinned suport > Add > select support 2 then select node > Assign

Step (3):- Assign Property to Model

For Plate

Specification > Property > Thickness > (Insert Plate thickness size) >  Add > Select Plate > assign

• Repeat the same procedure for different plates & also assess thickness in variable conditions. 

For Beam 

Specification > Property > Define > Rectangular > Size 0.01 x 0.01 material as DUMMY > Select beam > Assign to selected beam > Assign

Step (4):- Applying Loading on Model

I. Dead Load.

Loading > Load & Defination > Load Case Detail > Tital ( Dead Load ) > Add > Select Dead Load > Add > Self Weight Factor -1 > Add > Select Selfweight - 1 > Assign to view > Assign.

II. SIDL

Loading > Load & Definition > Load Case Detail > Title ( SIDL ) > Add > Select SIDL > Add > Plate Load > Partial Plate Pressure >  W1=-10 , X1= -0.8 , X2=0.8 , Y1=-0.5 , Y2=0.5 , Direction GY > Add > Select Load > Select all bottom plate > Assign to selected plate > Assign

III. Live Load

Loading > Load & Definition > Load Case Detail > Title ( Live Load ) > Add > Select Live > Add > Plate Load > Concentrated Load >  W1=-78 , X= 0.2 , Y=0.245 , Direction GY > Add > Select Load > Select Suitable plate > Assign to selected plate > Assign

• For Other Plate repeat the same procedure and change the value of X, Y

IV. Combination Of SLS & ULS

Loading > Load & Definition > Load Case Detail > Add > Define Combination > Select load and insert the factor according to given in IRS CBC > Add > Close

Step (5):- Analysis And Result

Analysis And Design > Analysis Commands > Run Analysis > Go to post prossing mode > Done 

• Maximum MY in SLS combination

Plate no 197 has a maximum bending moment

• Maximum MY in ULS combination

(4) For a prestressed U girder, calculate the following with the given data

Given Data:- 

• Area = 2.1735m2
• I = 0.74035m4
  • Calculate Prestressing force considering 76.5% jacking stress with 72 no. of strands.
  • Calculate the Section Modulus of U-girder considering y_bot = 0.594m
  • Calculate eccentricity of Prestress tendons from CG of section considering y_bot = 0.594m and cg of PT cables = 0.140m from soffit level.
  • Calculate Stress at bottom of U-girder considering M=10628.58kN-m and details mentioned previously.

Assumption data of characteristics of prestressing steel:- 

• Nominal area of strand: As = 140 mm2.
• Nominal ultimate stress : fpu = 1860 Mpa
• Maximum jacking stress : 0.765 fpu = 1422.9 Mpa
• Modulus of elasticity: Ep = 195000 Mpa.

Question (1). Calculate Prestressing force 

• No of Strand used (n) = 72
• Prestressing force applied (P)

             = (0.765 fpu X As X n X (1- Loss)) / 1000 kN

             = (1422.9 X 140 X 72 X 76.5 ) / 1000 kN

             = 10972.2 kN

(2). Calculating section Modulus ( Z ) = I/Y

• For Checking stress st bottom, y_bot = 0.594m

         Z  = 0.740350.594>0.74035/0.594

             = 1.2464 m3

(3). Calculate eccentricity of Prestress tendons from CG of section

• CG of the section to Cg of tendons (e)

            = 0.594 - 0.140 M

            = 0.454 M

 (4) Calculate Stress at bottom of the U-girder

• Stress @ Bottom

           = PA+P×eZ-MZ">P/A+(P×e)/Z−M/Z

           = 10972.22.1735+10972.2×0.4541.2464-10628.581.2464>10972.2/2.1735+(10972.2×0.454)/1.2464−10628.58/1.2464

           =  0.517 N/mm2