Challenge 6

Challenge 6

AIM OF ELASTOMERIC BEARING IN BRIDGE

THE PURPOSE OF THE ELASTOMERIC BEARING IS TO SUPPORT A BRIDGE OR OTHER HEAVY STRUCTURE IN A WAY THAT PERMIT THE LOAD TO SHFT SLIGHTLY IN A HORIZONTAL DIRECTION

RELATIVE TO THE GROUND OR FOUNDATION AND REDUCE STRESS INVOLVE.

BANDED ELASTOMERIC BEARING ARE MAINLY USED IN THE STRUCTURE FIELD FOR WHICH THIS PRODUCT HAS MANY ADVANTAGE LONG SERVICE LIFE RELIABLITY MAINTANANCE FREE

LIGHTNESS SMALL OVER DIMENSION AND EASY TO INSTALL.

1. List the requirements for dimensioning of Elastomeric Bearing. Also, mention the notations: “a”, “b”, “ti”, “te”, “n” and “ts”.

LIST OF THE DIMENSIONING OF ELASTOMERIC BEARING-

OVERALL WIDTH OF BEARING IN LONGITUDINAL DIRCTION- a = 420 mm

OVERALL LENGTH OF BEARING IN TRANSVERSE DIRECTION- b= 420mm

THICKNESS OF INDUVIDUAL LAYER OF ELASTOMER- ti = 12 mm

THICKNESS OF TOP/ BOTTOM LAYER OF ELASTOMER- te = 6mm

TOTAL NUMBER OF INTERNAL LAYER - n = 5

THICKNESS OF STEEL LAMINATE - ts = 4mm

TOTAL PLAN AREA A= a*b- A = 176400mm squre

EFFECTIVE PLAN AREA A = (a-U)*b - A = 169320.25 mm squre

2.Design an elastomeric bearing considering following design parameters and design data:

IN QUESTION ASKING DESIGN OF BEARING AND ALSO IN QUESTION GIVEN DESIGN

PARAMETER AND DESIGN DATA.

DESIGN OF BEARING .

A. MEAN PRESSURE - SERVICEABILITY STATE CLAUSE (4.3.3.1)

σm = P/A ≤ 11 mpa = 3.63 mpa

where

P=Pc+Ps

condition verified

B. NO SLIP - SERVICEABILITY STATE (CLAUSE 4.3.3.2)

B.1 σm mini = P mini /A ≥ 2.0mpa = 3.48 mpa

condition verified

B.2 H<f*P

ENTER THE TYPE OF CONTACT OF BEARING FACE WITH THE STRUCTURE M

M FOR METAL FACE

R FOR RUBBER LAYER

f=0.12+0.2/σm

for slow loads

T>GA Uc/(0.12P+0.2P) => T > 24.55 mm

for a rapid loads;

T> GA(Uc+2Us)/(0.12P+0.2A) => T > 25.36mm

condition verified

C. LIMITATION OF DISTORTION- SERVICEABILITY STATE (CLAUSE4.3.3.3)

th/G≤0.7

or T>(Uc+Us)/0.7 => T > 24.08 mm

condition verified