for the educational understanding

1. “

2. Challenges Made For Construction
Of Bridge In Hilly Areas”

3. INTRODUCTION
 A bridge is a structure build to span a valley, road, river, body of
water, or any other physical obstacle.
 The first bridges were made by nature itself-as simple as a log fallen
across a stream or stones in the river.
 The first bridges made by humans were probably spans of cut
wooden logs or planks and eventually stones, using a simple support
and cross beam arrangement.
 Hilly region pose unique problem for bridge construction. In restricted
hilly area itself climatic conditions, geological features and
hydrological parameters vary considerably.
 Keeping in view the bridge site and various constraints , type of
bridge and method of construction are to selected carefully for safe,
economical and successful completion of bridge construction.

5. BRIDGE CONSTRUCTION OVERVIEW
 Why the particular site was selected for the bridge.
 Why particular type of bridge is proposed.
 Site data.
 Proposal for preparation drawing.
 Soil strata in the form of bore log.
 Model study detail if already done for scour assessment.
 Salient features of the bridge and quantities of each items involved.
 Upto date approved structural drawings.

6. CHALLENGES IN HILLY AREA
BRIDGES CONSTRUCTION
 Construction of bridge across the gorges;
 Construction of bridge on rivers with boundary beds;
 Construction of bridges in extreme temperature zones;
 Construction of bridges on sharp turn on highways;
 Landslides or debris flow.

7. BRIDGE FOUNDATION AND
SUBSTRUCTURE
 Foundation construction for any large bridge takes time.
 Problems encountered during construction of foundation depend
upon type of foundation, soil strata encountered, equipment/plant
deployed and logistic problems.
 In case of well foundation, the various types of soils are encountered
and it becomes difficult to give any clear time shedule about the
sinking of wells unless the soil details are very clear and the
anticipated profile matched with actual encountered.
 In case of bouldary and clayey soil the rate of sinking shedule is
likely to be slow when compared with the sandy soil.
 Also there may be requirement of pneumatic sinking technique
subsequent to open grabbing due to difficulties in siking of well.

8. SUPER STRUCTURE
For particular site there are numerous structural arrangements
possible.
 Final proposal be made based on the grater examination of site
condition may be technical, aesthetic and construction
methodology.
 Special care need to be taken in case of deep gorge where there
is sizable difference between soffit level and bed level. This may
pose difficulties for staging and shuttering.
 Proposal recommended for site should be well read in advance.
 The quantities of each items involved and execution method are
listed. Basically method statement should be kept ready for
overall execution including job estimate.

9. MANAGEMENT OF CONSTRUCTION
ACTIVITIES
 Management of bridge construction demands that
construction manager to re-orient all the resources in such a
way that the projects are completed without any time/cost
overrun.
 Output of the work depend upon how best the activities are
managed which will vary from site to site based on many
factors.
 Based on the experience, various aspects are identified for
efficient construction management.
 Latest software management tool can be used for this in case
of a major bridge project.

10. PLANT MANAGEMENT
 Requirement of equipment/plant be assessed systematically.
 Time available for work execution ;
 Details of equipment and also minimum requirement as per job
position;
 Rated capacity of equipment /plant;
 Assessed capacity ;
 Scheduled of maintenance
 Inventory of spare parts required;
 Repaired cover to equipment/plant.

11. MATERIAL MANAGEMENT
 Material management is a parallel activity along with start of
the project.
 This cover procurement of camp material, office equipment,
major purchase items, such as aggregates, sand, cement,
steel, structural steel, shuttering consumables, electrical
fittings.
 Forecasting of quantities and cost of various items on monthly
basis must be done at least 3-6 months in advance which
should be regularly reviewed.

12. QUALITY MANAGEMENT
 Quality of work at site is most important activity and manager
should always grapple to improve the same.
 Training to staff should be provided to update the quality
control measure and it should become part of the work
culture.
 At site laboratory be established to check the quality of
concrete.
 Tests are analyzed at site based on the size of job.
 Latest guidelines issued by IRC and MORT&H are followed
for systematic quality assurance.

13. FINANCE MANAGEMENT
 No project and implementation or project and implementation
management can be meaningful without this.
 In case government work the manager should gate his budget
fixed on monthly basis, on the basis of work done, on
minimum to be fed site, on the decision of higher authorities.
 Key measure financial planning lies in taking all above action
and taking suitable measures at appropriate time to ensure
that individual inputs are achieved to the maximum and capital
investment kept at lowest level.

14. SAFETY MANAGEMENT
 Safety of employees at site should be observed very
seriously.
 All the workers are given briefing about the safety
requirements based on the site hazards.
 when the simply supported structure is attempted on deep
gorge, suitable arrangement should be made to avoid any
accident at site during insitu casting of superstructure.
 In case of foundation if the deep excavation is involved, the
quality of surrounded soil be kept in view.
 There are incidents where few workers got buried in deep
excavation due to sudden slide, this should be taken care.

15. TYPES OF HILLY AREA BRIDGES
 BEAM BRIDGES
 TRUSS BRIDGE
 CANTILEVER BRIDGE
 ARCH BRIDGE;
 TIDE ARCH BRIDGE;
 SUSPENSION BRIDGE;
 CABLE-STAYED BRIDGE

16. BEAM BRIDGE
 Beam bridges are the simplest structural forms for bridge
spans supported by an abutment or pier at each end.
 No moments are transferred throughout the support, hence
their structural type is known as simply supported.
 The simplest beam bridge could be a stone slab or a wood
plank laid across a stream.
 Bridges design for modes infrastructure will usually be
constructed of steel or reinforced concrete, or a combination
of both.

17. BEAM BRIDGE

18. TRUSS BRIDGE
 A truss bridge is a bridge whose load-bearing superstructure
is composed of a truss , a structure of connected elements
forming triangular units.
 The connected elements may be stressed for tension,
compression or sometimes both in response to dynamic
loads.
 Truss bridges are one of the oldest types of mordern bridges.
 A truss bridge is economical to construct because it uses
some materials efficiently.

19. TRUSS BRIDGE COMPONENTS

20. CANTILEVER BRIDGE
 A cantilever bridge is a bridge built using cantilevers,
structures that project horizontally into space, supported only
one end.
 For small footbridges, the cantilevers may be simple beam;
however, large cantilever bridges designed to handle road or
rail traffic use trusses built for structural steel, or box girders
built from pre-stressed concrete.
 A simple cantilever span is formed by two cantilever arms
extending from opposite sides of an obstacle nto be crossed,
meeting at the centre.

21. Cantilever bridge components

22. HOWRAH BRIDGE

23. ARCH BRIDGE
 An arch bridge is a bridge with abutments at each end shaped
as a curved arch.
 Arch bridges work by transferring the weight of the bridge and
its load partially into a horizontal thrust restrained by the
abutments at either side.
 A long bridge may be made from a series of arches, although
other more economical structures are typically used today.

24. ARCH BRIDGE

25. TIDE ARCH BRIDGE
 A tied-arch bridge is an arch bridge in which the outward-
directed horizontal force of the arch, or top chord, are borne
as tension by the bottom chord, rather than by the ground or
bridge foundations.
 Thrusts downward on such a bridge’s deck are translated, as
tensions, by vertical ties of the deck to the curved top chord ,
tending to flatten it and thereby to push its tips outward into
the abutment, like other arch bridges.
 However, in a tied-arch or bowstring bridge, these
movements are restrained not by the abutments but the
bottom chord, which ties these tips together, taking the thrust
as tension, rather like the string of a bow that is being
flattened. Therefore, the design is often called a bowstring -
arch or bowstring-dirder bridge.

26. TIED ARCH BRIDGES

27. SUSPENSION BRIDGE
 A suspension bridge is a type of bridge in which the deck (the
load-bearing portion) is hung below suspension cables on
vertical suspenders.
 The bridges without vertical suspenders have a long history in
many mountainous part of the world.
 this type of the bridges has cables suspended between
towers, plus vertical suspenders cables that carry the weight
of the deck below, upon which traffic crosses.
 This arrangement allows the deck to be leveled or to arc
upward for additional clearance.

28. SUSPENSION BRIDGE

29. CABLE-STAYED BRIDGE
 A Cable-stayed bridge has one or more towers (or pylons), from
which cables support the bridge decks.
 There are two major classes of Cable-stayed bridges: harp and fan.
 In the harp or a parallel design, the cable are nearly parallel so that
the height of their attachment to the tower is proportional to the
distance from the tower to their mounting on the deck.
 In the fan design, the cables all connect to or pass over the top of the
towers. The fan design is structurally superior with minimum moment
applied to the towers but for practical reasons the modified fan is
preferred as specially where many cables are necessary
 Cable-stayed bridge is optimal for span longer than cantilever
bridges, and shorter than suspension bridges.

30. CABLE-STAYED BRIDGE OVER COOPER RIVER

31. CONCLUSION
 All bridges held generally the same amount of weight. The
arch bridge held a little more than the other bridges. They
were in the1400-1500 gram range. The other bridges were in
the1000-1200 gram range.
 The bridges would not stand up on their own, so a support at
each end had to be constructed, balancing the weights on the
bridges required patience. Clamps were used to hold the
bridges during gluing.
 The bridges supported different amount of weights because
each type has different construction. The arch bridges
supported the most weight because of the great natural
strength of the arch. The pier bridges supported the least
weight because the supporting pier broke during construction.