Challenge

Challenge 9

KKumar Souryaman6 Aug 2022

DESIGN

CHALLENGES- 9

Explain in detail the steps involved in calculation of the loads considered in piers.

AIM:

Here i am going to explain about the steps involved in the calculation of the loads considered in the piers.

Dead load of structure

Dead load of U- girder Dead load of pier cap

Density of concrete - 2.50 t/m³ volume of pier cap- 31.00

Cross-sectional area of U- girder - 2.173m² Dead load of pier cap- 31*2.5= 77.50 Ton

Dead load of 27m U-girder - 2.173*2.5*27= 146.7 ton

Dead load of pier

Area of pier ( circular pier diameter =1.7m)-2.27

Dead load of pier/m = 2.27*2.5=5.67 Ton

superimposed dead load

Load due to SIDL - 2.20 Ton/m/track

SIDL of 27 m U- girder- 2.2*27= 59.40 Ton

LIVE LOAD

one track one side loaded (longitudinal direction)
one track both side loaded (longitudinal direction)
both track one side loaded (longitudinal direction)

4.both track both side loaded(longitudinal direction)

AXLE LOAD

The load of a vehicle applied through the wheels at both ends of an axle and equaling twice the wheel load.c

We calculate the axle loads

All axle loads = 16.0 Ton

Maximum number of successive cars : 6

configuration:

a = 2.2 m

b= 2.3 m

c= 12.4 m

( 2a+2b+c)= 21.4 m

Braking load:

It is taken as 18 percent of the unfactored vertical loads.

Traction load:

It is taken as 20 percent of the unfactored vertical loads

since each track is supported by a single U - girder tractive force of one track and braking force of another track will be taken in athe same direction to produce the worst condition of loading

CENTIRIFUGAL FORCE :

Centrifugal force is a force which arises due to the inertia of the moving body and is directed outwards from the axis of rotation of the body. Centrifugal force is characterized by an acceleration pushing the body outwards. Examples of centrifugal force: A vehicle driving around a curve on the road.

Speed of train v = 90 km/h

radius of curvature R = 100000m

CF = WV²/127 R

CENTRIFUGAL LOAD FACTOR ac = 0.001

CENTRIFUGAL FORCE( W×ac) = w×0.001t

ACTING ABOVE RAIL LEVEL = 1.83m

WIND LOAD

calculation of wind load is based on IS - 875(PART3) - 1987.

The design wind at height z is considered as fallow .

Vz= Vb.K1.K2.K3

Vb(m/s) Reginal basic wind speed taken 47 m/s for varanshi

GENERAL PARAMETERS Vb

total structure Height above ground H = 13.6m

Regional basic wind speed Vb = 47m/s

probability factor = 1.07

Terrain Height and structure size factor K2 = 0.856 ASSUMING CATEGORY 3 TERRAIN

TOPOGRAPHY FACTOR K3= 1.0 class c structure

design wind speed at height z, Vz

Vz= Vb. K1. K2.K3= 43.1m/s

wind pressure = 1112.41 N/m²

Pz= 0.6×Vz²= 0.113 t/m²

LOAD FROM SUPERSTRUCTURE

Over width of both U- girder combined b = 10.15m

contributing length of superstructure l= 27.00m

Total Depth of superstructure d = 1.87m

Height of live load above U- girder h= 3.232m

Transverse wind load without live load = 50.49m

Project area of structure A1 = l×d = 5.73m

PD= Pz×At = 15.62m

Acting @above pier bottom

Transverse wind load with live load

Project area of structure A1= l×d+h = 137.75m

PD= PZ×At = 15.62m

Acting @above pier bottom = 14.80m

Vertical wind load Pv =

Plan Area of superstructure Av= b×l = 274.05m²

Pv= Pz×Av = 31.08t

LOAD ON SUBSTRUCTURE

PIER CAP

Width of pier cap ( conservation)b = 3.10m

length of pier cap d = 9.60m

height of pier cap h = 2.00m

height of pier cap above ground h = 11.55m

wind in longitudinal direction

Ratio a/b=d/b = 0.32

force coefficient Cf = 1.22

projected area of structure At= h×d= 19.20m³

wind force F= Cf×Pz×At= 2.65t

Acting @above pier bottom = 11.05m

wind in transverse direction

Ratio a/b =b/d = 3.10

force coefficient Cf = 1.04

Projected Area structure A1 =h×b = 6.20m³

wind force F = 0.73t

Acting@above pier bottom = 11.05m

PIER

Diametre of pier , b= 1.70m

Height of pier above Ground h = 9.55m

wind in longitudinal /transverse direction

Ratio height /Breadth = h/b = 5.62

force cofficient Cf = 0.80

projected area of structure A1 = h×b = 16.24m²

wind force F = 1.47t

Acting@above pier bottom = 5.28m

SEISMIC ACCELERATION : Ah= (z/2)*(l/R)*(sa/g) where:

Ah= horizontal seismic coefficent to be considered in design

Z= zone factor = 0.16( for varanasi region)

I= importance factor= 1.50

R= response Reduction factor

=4 for pier

sa/g being computed as per irc 6:2017 for medium soil sites

mathematics expressions are:

sa/g=1+15T for 0.0< T <0.10

sa/g=2.5 for 0.10<T<0.55

sa/g = 1.36/T for 0.55<T<4.00

2.Elaborate the design codal provisions for piers of metro viaducts.

AIM

HERE I AM GOING TO ELABORATE THE DESIGN CODAL PROVISION FOR PIER OF METRO VIADUCTS

THIS CODAL PROVISION FOR R.C.C PIER AND PRESTRESS CONCRETE PIER CAP IN THIS WE FIND OUT HOW MANY CONCRETE REINFORCEMENT AND PRE STRESSING TENDON NEEDED WE CALCULATE

ACCORDING TO CODAL PROVISION FCK THAT MEANS COMPRESSIVE STRENGTH OF STRUCTURE .

* TABLE 11 CLAUSE 10.2.2 OF IRS CBC STRESS LIMITATIONS FOR THE SERVICELIBLITY LIMIT STATE.

MATERIAL TYPE OF STRESS UNDER DESIGN LOADING TYPE OF CONSTRUCTION

R.C.C PSC

CONCRETE TRIANGULAR OR MEAR TRIANGULAR COMPRESSIVE STRESS 0.50FCK 0.40FCK

UNIFORM OR NEAR UNIFORM COMPRESSIVE STRESS (E.G Y

DUE TO AXIAL LOADING 0.38FCK 0.30FCK

REINFORCEMENT COMPRESSION TENSION 0.75FY NA

PRE-STRESSING TENDONS TENSION NA DEEMED TO SATISFIED BY

16.8.1

TABLE 10 ( CLAUSE 10.2.1) OF IRS CBC DESIGN CRACK WIDTH THE VARIOUS EXPOSURE CONDITIONS

EXPOSURE CONDITION DESIGN CRACK WIDTH IN MM

MODERATE _ 0.20
SERVERE _ 0.10
EXTREME _ 0.10

Challenge 9

Ship work like this
in your own course.

Talk to a career counsellor

Ship work like thisin your own course.

Talk to a career counsellor

Ship work like this
in your own course.