Week 1 Challenge
INTRODUCTION :-
Here we learn about foundation design,so the example related to bridge foundation. Here we learn about the type of bridge and its component as per IS code and after that application of loading .here we only learn mainly founation loading and design.
AIM :-
Here we find out some requirment as
1.Type of foundation and selection of foundation
2.Sketch of bridge with open foundation with components
PROCEDURE:-
According to IRC-05 (2015),Clause 101.18 , Foundation is the part of A BRIDGE structure, which is in direct contact with and transmitting loads to the founding strata.
According to IS 1904-2021 ,
Foundation are 2 types
1.Shallow foundation(Open foundation) :-
A.Spread or pad foundation
B.Strip foundation
C.Raft foundation
D.Ring and shell foundation
2.Deep foundation:-
A.Pile Foundations
B.Caissons
C.Diaphragm walls
D.Well foundations
Selection of type of foundation :-
For select the type of foundation here we investigate the follow the point which are such as
1.Site investigation :-
2. Depth of foundation
The depth of foundation depends upon the following principal factors:
a) Getting adequate allowable bearing capacity.
b) In the case of clayey soils, penetration below the zone where shrinkage and swelling due to seasonal weather changes, and due to trees and shrubs are likely to cause appreciable movements.
c) In fine sands and silts, penetration below the depth of frost penetration.
d) Maximum depth of scour, wherever relevant, should also be considered and the foundation should be located sufficiently below this depth.
e) Other factors, such as ground movements and heat transmitted from the building to the supporting ground may be important
3.Economical
Now in Second section ,
Here we find out the components of RCC girder Bridge with open foundation .Here an attached copy of Pdf copy for component.
A. Now if our bridge location existing in Seismic zone V then there is some codal provision by IRC -06 wich are such as
Clause -218
GUIDELINES FOR SEISMIC DESIGN OF ROAD BRIDGES
218.1 Applicability
218.1.1 All bridges supported on piers, pier bents and arches, directly or through
bearings, and not exempted below in the category (a) and (b), are to be designed for
horizontal and vertical forces as given in the following clauses.
The following types of bridges need not be checked for seismic effects:
a) Culverts and minor bridges up to 10 m span in all seismic zones
b) Bridges in seismic zones II and III satisfying both limits of total length not
exceeding 60 m and spans not exceeding 15 m
218.1.2 Special investigations should be carried out for the bridges of following
description:
a) Bridges more than 150 m span
b) Bridges with piers taller than 30 m in Zones IV and V
c) Cable supported bridges, such as extradosed, cable stayed and suspension bridges
d) Arch bridges having more than 50 m span
e) Bridges having any of the special seismic resistant features such as seismic isolators, dampers etc.
f) Bridges using innovative structural arrangements and materials.
g) Bridge in near field regions
In all seismic zones, areas covered within 10 km from the known active faults are classified as ‘Near Field Regions’. The information about the active faults should be sought by bridge authorities for projects situated
within 100 km of known epicenters as a part of preliminary investigations at the project preparation stage.For all bridges located within ‘Near Field Regions’, except those exempted
in Clause 218.1.1, special investigations should be carried out.
Notes for special investigations:
1) Special investigations should include aspects such as need for site specific spectra, independency of component motions, spatial variation of excitation, need to include soil-structure interaction, suitable methods of structural analysis in view of geometrical and structural non-linear effects, characteristics and reliability of seismic isolation and other special seismic resistant devices, etc.
2) Site specific spectrum, wherever its need is established in the special investigation, shall be used, subject to the minimum values specified for
relevant seismic zones, given in Fig. 17.
218.1.3 Masonry and plain concrete arch bridges with span more than 10 m shall be
avoided in Zones IV and V and in ‘Near Field Region’.
Load on Open foundation Bridge as per IRC -06
As per IRC-06 Load on bridge
1.Dead load
2.Live load
3.Snow load (If Snow fall area )
4.Seismic load
5.Temperature
6.Earth pressure
7.Impact factor
8.Vechile collosion load
9.Centrifugal force
10.Buoyancy
11.Deformation
12.Wave effect
13.Wind load
In open foundation effect of load on
Free pier :-
If Pier at free bearing location means it will transfer only vertically load to foundation.
Fixed pier :-
If pier react as fixed then it will transfer vertical as well as horizontal load to foundation.
Abutment :-
At Abutment there will both load act vertically as well as horizontally on foundation.