Economic Solution of Super Structure for Bridge of 20m Span

International Journal of Emerging Technology and Advanced Engineering

Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 7, July 2015)

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Economic Solution of Super Structure for Bridge of 20m Span Natraj Singh

1, Dr. N.P. Devgan

2, Dr. A. M. Kalra

3

1Dy. Chief Project Manager (IRSE), Dedicated Freight Corridor Corporation of India Ltd., Old Railway Colony, Near Anand

Market, Ambala Cantt.-133001, India 2Senior Structural Consultant, PEC-Centre for Consultancy Engineering, PEC University of Technology, Sector-12,

Chandigarh- 160012, India 3Formerly Prof. in Civil Engineering Department, PEC University of Technology, Sector-12, Chandigarh- 160012, India

Abstract- The present study aims at exploring the

economical solution for superstructure of 20m span bridges

among reinforced concrete T-beam, reinforced concrete I-

beam, prestressed concrete I-beam and steel composite I-

beam. The analysis and design is done under Indian Road

Congress (IRC) loading for selection of most economical

section for all four types of super structures. The effects of the

placement of span are also studied in details for normal

ground condition as well as launching above the Railway line.

In normal ground conditions, reinforced concrete T-beam &

prestressed concrete I-beam are found to be economical.

Whereas in case of above railway line prestressed concrete I-

beam proves to be more economical than other options

considered for the study. When the effect of speed restriction

is also combined with the traffic block cost then the composite

steel girder becomes the most economical option but when the

effect of periodic maintenance is also added, it becomes

costliest option. The effect of sacrificial type of shuttering is

also considered for the cost implication and this is found to be

cheaper in case of bridges over railway lines. The present

paper will facilitate as a hand on tool for selection of

economical superstructure type for 20m span bridges.

Keywords- Prestressed concrete I-beam, railway block cost,

reinforced concrete T-beam, reinforced concrete I- beam,

sacrificial shuttering, steel composite I-beam.

I. INTRODUCTION

The pace of infrastructure development in India has

increased to cope with the requirements of developing

country. The projected gross domestic product (GDP)

growth is likely to remain in double digit in near future.

This increased pace of Infrastructure development has put

lot of thrust on human as well as material resources. In

modern era of growth in Infrastructure field related to road

and rail sector, bridges consume substantial share of

resources and sometimes play a critical role in working out

the economic viability of the project. To meet the growing

demand, infrastructure has to be developed by optimizing

the resources.

Keeping in view the fund constraints faced by

infrastructure organisations, the present study aims to

develop an economic solution for construction of

superstructure for 20m span bridge under Indian Road

Congress (IRC) loading. Four different superstructure

types have been chosen for the economic analysis namely,

reinforced concrete T-beam, reinforced concrete I- beam,

prestressed concrete I-beam and steel composite I-beam.

The design of all the options is based on Indian Road

Congress (IRC) codes. The effects of placement of span in

normal conditions and launching above the railway line

have different cost implications because cost associated

with the Traffic block has a substantial cost share in

launching process. There is another aspect of speed

restriction imposed on the goods and passenger trains

during placement of span, which led to the huge monitory

loss to the Indian railways. Thus an attempt is made in this

study to quantify the cost associated with the traffic block

and the speed restriction. Another important aspect is the

use of sacrificial shuttering in combination with

conventional shuttering and its effects are explored from

the economy point of view.

II. REVIEW OF LITERATURE

Many options are available to the planners with the

advancement in design and construction technology. The

decision of choosing the best option among the available

alternatives is guided by the principal of utilisation of

minimum resources.

The researchers in the past had tried to find economic

solutions for specific conditions. Saxena, et. al.,(2013)

studied and compared the economics of T-beam and box

girder for bridge structure of 25m span. The comparison

shows that the T-beam girder bridge is more economical,

however; for the span length more than 25m the box Girder

is found to be more suitable. Misal et. al., (2014) analyzed

and designed the presstressed box girders and I-section for

span of 16.3m and 31.4m and concluded that; the box

girder is costlier than the I girder, but for the larger spans

this result may not stand true.



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One important study about the life cycle cost is done by

Huang, et. al. for new highway bridge in Taiwan. Three

alternatives, namely the pre-stressed concrete bridge, the

steel bridges with painting, and the steel bridge with

galvanization, are considered for the new bridge and are

evaluated for their life cycle cost. The study reveals that the

life cycle cost of steel bridge is always higher than of Pre-

stressed concrete bridge and pre-stressed concrete bridge

has the lowest life-cycle cost.

The efforts of planners to reach at optimal solutions for

specific bridges are well established. In most of the cases of

cost analysis, generally two options of materials or shapes

are taken and no specific stress on erection/launching

methods is taken into account for comparison. Further in

road over bridges (above railway track), the impact of

traffic block cost on overall construction cost also needs

evaluation. Broadly, so far cost analysis of bridges is

carried with specific location and two variables.

III. DESIGN PHILOSOPHY

The super structure having 21.96m total span and 20.0m

effective span is individually analyzed by the grillage

analysis using main girders along the longitudinal direction

and slabs in the transverse direction.

The system, being a 4 girder system with spacing of

2.65m, is supported with bearings below each girder, is

analyzed separately under dead load of girder. The clear

carriageway is 7.5m and total width of Super structure is

kept 12.0m.The footpath is provided on both sides.

Composite action is considered for the slab load, super

imposed dead load and live loads. Slabs are provided

sloped in the direction of required camber. Girders are

accordingly raised with higher pedestals. Live loads are run

in position concentric to all the 4 girders, and combinations

are worked out based on the minimum distance between the

two lanes.

The depth of deck slab has been kept constant in all the

options. The depth of girders have been chosen on the basis

of guiding formulas and the section properties of all the

four different options have been given in the table I.

TABLE I

SECTIONAL PROPERTIES OF GIRDERS CONSIDERED FOR COMPARISON

No Description

Unit

RCC-

I

Sect.

RCC-

T

beam

PSC-I

Sec.

Steel

Comp.

1 Depth of

deck slab m 0.25 0.25 0.25 0.25

2 Web depth m 1.80 2.25 1.56 1.35

3

Top Flange

width (at

mid span)

m 0.70 0.93 1.00 0.40

4

Web width

(at mid

span)

m 0.35 0.33 0.29 0.012

5 Web width

(at Support) m 0.70 0.63 0.80 0.012

6

Bottom

Flange

width (at

mid span)

m 0.70 0.63 0.80 0.60

7

Area of

section (at

Mid Span)

m2 1.52 1.40 1.40 0.09

8

Area of

section (at

Support)

m2 1.93 1.86 1.94 0.09s

9

Moment of

Inertia (Izz)

at Mid Span

m4 0.69 0.69 0.51 0.02

10

Moment of

Inertia (Izz)

at Support

m4 0.80 0.81 0.62 0.02

For reinforced concrete beams M35 grade of concrete

and for prestressed concrete M40 grade of concrete have

been considered. The grade of reinforcement has been kept

Fe500 for all the options.

After carrying out the analysis, the graphs are drawn for

design shear force and bending moments for various

combination of loads.

The behavior of all four types of beams under live load

for shear force and bending moment is almost similar.



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Fig. 1: Shear force variation along the span of beam under dead load

only

Fig. 2: Shear force variation along the span of beam under super

imposed dead load.

Fig. 3: Shear force variation along the span of beam under live load.

Fig. 4: Bending moment variation along the span of beam under dead

load

Fig. 5: Bending moment variation along the span of beam under super

imposed dead load

Fig. 6: Bending moment variation along the span of beam under live

load



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IV. CONSTRUCTION OF SUPERSTRUCTURE

The planning and coordination between the designer and

site engineers is very important because erection/placing of

span affects the overall cost in significant way. The

erection /placement of span depends upon the ground

conditions, volume of work, repetitive nature of work,

utilization of existing resources etc.

The construction of superstructure involves cast in situ

in case of T-Beam and casting or fabrication of span in

yard and placing it with hydraulic crane in other methods.

Normally in urban areas, the bridges are constructed for

grade separation or for crossing the Railway track. Hence,

following two ground conditions are considered.

A. Normal Ground Condition

In this condition, it is considered that the supporting

ground is having sufficient bearing capacity to support the

launching/erection crane and there is a sufficient space for

stabling the crane for launching without disturbing the local

traffic.

B. Above Railway Track

In this condition, it is considered that the supporting

ground is having sufficient bearing capacity but traffic

block from Railways is required for launching/erection of

super-structure.

Considering above mentioned two ground conditions,

following methods are adopted for erection/placement of

superstructure of 20 M span of bridge.

1. Using Form work (Cast in situ Beams and deck slab)

2. With land based hydraulic cranes (Pre-cast Beams and

Caste-in-situ deck slab)

V. ESTIMATION METHODOLOGY

All the major activities affecting the cost of super-

structure are bifurcated and effects of these activities are

analyzed while calculating the total cost of super-structure.

The activities are bifurcated on the basis of different

Ground Conditions. In this work, two type of shuttering

combinations are considered. In first case the conventional

shuttering is used for casting of girders and deck slab.

This will require placement of shuttering and de-

shuttering for both the girder and deck slab. In other case,

the combination of conventional and sacrificial shuttering

is considered in which conventional shuttering is opted for

the beams and sacrificial shuttering is opted for deck slab.

The sacrificial shuttering is left in place permanently and

will not require temporary support system. This system will

reduce the requirement of speed restriction. The various

steps involved in construction of superstructure common in

both the ground conditions and effects of conventional and

sacrificial shuttering with traffic block and speed restriction

are given in flow chart , i.e., Fig 7.

A. Estimation and Costing details

The estimation of resources and its costing has been

divided into various categories to appreciate effects of each

stage over total costing of super structure.The different

stages involved in estimation for both ground conditions

are shown in the flow chart, i.e., Fig 8.

The various stages of estimation and costing are

discussed below:

B. Attributed to Material Quantities

The quantities of materials have been calculated based

on design parameters. While considering the sacrificial

shuttering, the advantage of substituting the tensile

reinforcement in composite deck slab is not considered.

The quantities of shuttering materials are calculated based

on the two methods. In first method, conventional

shuttering is considered for girders and deck slab and in

second method, conventional shuttering for girders and

sacrificial shuttering for deck slab has been considered.

Among the four options used for comparison, the

superstructure with reinforced cement concrete-T bean is

constructed Caste-in-situ using conventional shuttering

both for girder and deck slab. In all other three options the

pre-caste/pre-fabricated girders are launched with the help

of crane. The casting of girders is done with the

conventional shuttering and the casting of deck slab has

been considered with two options, the first one with

conventional shuttering and second with the sacrificial

shuttering.



117

Fig: 7- Flow Chart for various steps of construction of superstructure.



118

Fig: 8- Flow Chart for Estimation and costing.

TABLE II

QUANTITIES OF MATERIALS REQUIRED FOR VARIOUS TYPE OF SUPER-STRUCTURES OF 20 M SPAN

No

Type of

Superstructur

e

Qty of Material per Span (Including Deck Slab Concrete)

Concrete

Reinforcement

Conventiona

l Shuttering

Combination of Shuttering Pre-

Stressing

Cable

Structural

Steel Conventional for

girders

Sacrificial for deck

slab

Unit Cum MT Sqm Sqm Sqm Kg. MT

1 RCC T-beam 159.0 29.0 680.0 680.0 0.0 0.0 0.0

2 RCC I-beam 173.0 38.0 644.0 427.0 217.0 0.0 0.0

3 PSC I-Section 162.0 19.5 563.0 373.0 190.0 3420.0 0.0

4 Composite

Steel girder and

RCC deck slab

62.0 9.5 243.0 0.00 243.0 0.00 35.0



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The rates adopted for the estimation of cost are based on

the Bridge works executed by Indian Railways in Northern

Part of India. The old tender rates are updated based on

WPI index. For the sacrificial shuttering rates are taken

from market. The cost estimation for casting/ fabrication of

girders including deck slab considering conventional

shuttering only and combination of conventional and

sacrificial shuttering has been calculated by multiplying the

quantities (given in Table-II) with Cost and this cost is

considered same for both the cases, i.e., in normal ground

condition as well as above railway track.

C. Composite cost for Normal Ground Condition

To arrive at total cost, the estimation of machinery and

other resources required for launching of beams is

calculated for the normal ground condition.

It is considered that two cranes will work simultaneously

from both ends.

There is no constraint on working hours of crane and

sufficient space is available for working of cranes. The

crane capacity for reinforced concrete I- beam and

prestressed concrete I- beam is kept 75 MT which is more

than double the load to be carried. The rates for hiring of

cranes are taken from the market.

The Composite Steel girder having weight 8 MT is the

lightest among all the four options and launching cost of

Rs. 80,000.0 for composite steel girder is least among all

the categories considered. The launching cost of Rs.

3,00,000.0 for pre-stressed concrete beams having weight

65MT and reinforced concrete beams having weight 75

MT is same and is approximately 3.75 times the launching

cost of steel beams.

The total cost of superstructure in case of normal ground

conditions is calculated by adding the cost attributed to

material quantities, launching resources and other allied

activities.

TABLE III

COMPOSITE COST STATEMENT CONSISTING OF CONSTRUCTION/FABRICATION COST (MATERIAL COST )AND PLACEMENT COST IN CASE OF NORMAL

GROUND CONDITIONS (IN INDIAN RUPEES)

N

o

Type of

Superstructu

re

Construction/ Fabrication Cost

(material cost)

Launching

Cost by

Crane(placeme

nt cost)

Total Cost

Conventional

Shuttering

Combinati

on of

Shuttering

With Conventional

Shuttering

With Sacrificial

Shuttering

1 RCC T-beam 3341800 3341800 NA 3341800 3341800

2 RCC- I-beam 4041500 4160850 300000 4341500 4460850

3 PSC I-Section 3253000 3357500 300000 3553000 3657500

4

Composite

Steel and

RCC Girder

3797200 3857950 80000 3877200 3937950

D. Composite cost above Railway Track

To arrive at total cost in this case, the cost of railway

traffic block and cost associated with speed restrictions and

launching is considered. The Railway traffic block due to

detention of moving trains plays significant role in the total

cost of super structure. Presently, there are no clear

guidelines to charge the cost effect of speed restriction in

addition to the traffic block cost.

The railway traffic block cost depends upon no of trains

plying in the section. This cost of block per hour has been

calculated for trains varying from 20 to 80 running on

section per 24 hours. The cost associated with speed

restriction of 20 Kmph in a stretch of 100 meters has also

been calculated.

The work of placement of spans above railway track will

be carried out during the traffic block. There is provision of

extra crane to meet out any failure during the block period.

The capacity of extra crane is kept the same to utilize in

case of defect in the regular working crane. Two Crane will

work simultaneously from both ends and third crane will be

kept as stand by. It is assumed that work of placement of

girders in the traffic block will be completed in two days.

The cost of hiring of cranes is taken for complete job per

span, which is Rs. 6, 00,000.0 for reinforced & prestressed

beams and Rs. 1, 60,000.0 for steel composite beams.

The cost of placement of super-structure includes cost of

launching and block cost. Here cost of speed restriction is

not included.



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The cost of placement for all the four options of super-

structure is calculated by adding the cost of launching and

cost of traffic block for various frequencies of running of

trains in a section.

From the table IV, it is clear that cost of placement is

less in case of RCC T Beam and steel composite girders.

The cost of placement of RCC I Beam and PSC I Section is

same but is higher than the other two options. As the

frequency of trains increases in a section, the difference in

cost in the placement of girders for options 1 & 4 and 2 & 3

increases sharply.

The total cost of Super-Structure above Railway Track is

calculated by adding the construction/fabrication cost of

girders, launching cost of girders, Cast-In-Situ cost (T

Beam), and Railway Traffic Block cost. This total cost of

Super-Structure has been calculated for both combinations

of shuttering and various frequencies of trains in a section.

This cost comparison does not include the cost of speed

restriction and the affect of sacrificial shuttering is not

appreciable in the table VA & VB.

TABLE IV

COST STATEMENT CONSISTING OF PLACEMENT OF SPAN INCLUDING LAUNCHING COST AND BLOCK COST ABOVE RAILWAY TRACK (IN INDIAN RUPEES)

S

N

o

Type of

Superstructur

e

Block

Duratio

n (in

hours)

Total Cost for Placement of Span

20 Trains per

day

35 Trains per

day

50 Trains per

day

65 Trains per

day

80 Trains per

day

1 RCC T-beam 2 4137036 7009383 9881731 12754078 15626426

2 RCC- I-beam 3 6805553 7609383 15422596 19731118 24039639

3 PSC I-Section 3 6805553 7609383 15422596 19731118 24039639

4

Composite

Steel and RCC

Girder

2 4297036 7169383 10041731 12914078 15786426

TABLE VA .

COMPOSITE COST STATEMENT CONSISTING OF CONSTRUCTION/FABRICATION COST (MATERIAL COST) AND PLACEMENT COST ABOVE RAILWAY TRACK

(IN INDIAN RUPEES)

No

Type of Super-

Structure

20 Trains per day 35 Trains per day 50 Trains per day

with

Conventional

Shuttering

with

Sacrificial

Shuttering

with

Conventional

Shuttering

with

Sacrificial

Shuttering

with

Conventional

Shuttering

with

Sacrificial

Shuttering

1 RCC T-beam 7478836 7478836 10351183 10351183 13223531 13223531

2 RCC- I-beam 10847053 10966403 11650883 11770233 19464096 19583446

3 PSC I-Section 10058553 10163053 10862383 10966883 18675596 18780096

4

Composite

Steel and RCC

Girder

8094236 8154986 10966583 11027333 13838931 13899681



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TABLE VB

COMPOSITE COST STATEMENT CONSISTING OF CONSTRUCTION/FABRICATION COST (MATERIAL COST) AND PLACEMENT COST ABOVE RAILWAY

TRACK (IN INDIAN RUPEES)

No Type of Superstructure

65 Trains per day 80 Trains per day

with Conventional

Shuttering

with Sacrificial

Shuttering

with Conventional

Shuttering

with Sacrificial

Shuttering

1 RCC T-beam 16095878 16095878 18968226 18968226

2 RCC- I-beam 23772618 23891968 28081139 28200489

3 PSC I-Section 22984118 23088618 27292639 27397139

4 Composite Steel and RCC

Girder 16711278 16772028 19583626 19644376

To understand the benefits of sacrificial shuttering, the

affect of cost of speed restriction imposed during the

construction of Super-Structure is added in the already

calculated total cost vide table VA-VB . It is assumed that

speed restriction of 20 KMPH for conventional shuttering

of deck slab will be imposed for 45 days for reinforced

concrete T-beam and 21 days for other three types of

superstructure.

This time period will remain same for reinforced

concrete T- beam and will be reduced to 07 days for

sacrificial shuttering of deck slab for other three types. In

Table No. VI the cost has been calculated for conventional

shuttering only.

Table No. VII shows total cost for placement of super-

structure including the cost of speed restriction imposed for

combination of conventional shuttering for girder &

sacrificial shuttering for deck slab.

TABLE VI

COMPOSITE COST STATEMENT CONSISTING OF CONSTRUCTION/FABRICATION COST (MATERIAL COST), PLACEMENT COST AND SPEED RESTRICTION

COST ABOVE RAILWAY TRACK (CONVENTIONAL SHUTTERING) IN INDIAN RUPEES

No Type of Superstructure 20 Trains per

day

35 Trains per

day

50 Trains per

day

65 Trains per

day

80 Trains per day

1 RCC T-beam 14485354 21128511 27771674 34414831 41057995

2 RCC- I-beam 14116762 16680303 26253230 32321462 38389698

3 PSC I-Section 13328262 15891803 25464730 31532962 37601198


Girder 11363944 15996003 20628064 25260123 29892185



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TABLE VII

COMPOSITE COST STATEMENT CONSISTING OF CONSTRUCTION/FABRICATION COST (MATERIAL COST), PLACEMENT COST AND SPEED RESTRICTION

COST ABOVE RAILWAY TRACK (COMBINATION OF SACRIFICIAL SHUTTERING) IN INDIAN RUPEES

No Type of Superstructure 20 Trains per

day

35 Trains per

day

50 Trains per

day

65 Trains per

day

80 Trains per day

1 RCC T-beam 14485354 21128511 27771674 34414831 41057995

2 RCC- I-beam 12056306 13446706 21846491 26741583 31636675

3 PSC I-Section 11252956 12643356 21043141 25938233 30833325


Girder 9244888 12703806 16162725 19621643 23080562

The total cost for the reinforced concrete T- beam

remains same in table VI & VII, because caste-in-situ

construction of reinforced concrete T- beam considered

with conventional shuttering only. There will be no

advantage of using sacrificial shuttering in this case,

because speed restriction will remain in place due to the

erection of staging along the track for support of cast-in-

situ beam.

E. Maintenance Cost

Among the four options used for comparison, only

composite steel beam will require periodic painting and

maintenance. All other three options are being constructed

with cement concrete and will not require any periodic

maintenance as concrete structures are considered free from

maintenance. The normal frequency for painting of steel

structure of the bridge is as taken as 6 years.

The total area of the steel composite girders for complete

super structure is calculated as 437.0Sqm, and the cost per

unit area of painting has been arrived at Rs. 115.0 per sqm

as per the current prevailing rates. It is assumed that the

bridge will be painted 16 times in its life span of 100 years.

By considering 5% yearly inflation in the rates, the total

cost of all the 16 cycles of paintings comes out to Rs.

14273117.

F. Effect of web-depth of girder on bridge approaches

It is clear from the table I, that the web-depth varies

considerably in all four superstructure types. The maximum

web depth is of reinforced concrete T-beam among all the

four options. The extra cost required for more height of

approaches due to increase in web depth in case of T-beam

in comparison with all other three options is tabulated in

table VIII.

TABLE VIII

EXTRA COST OF MATERIAL CONSUMED IN APPROACHES BY THE REINFORCED CONCRETE T-BEAM IN COMPARISON WITH OTHER OPTIONS DUE TO

DIFFERENCE IN WEB-DEPTH.

No Cost details Reinforced cement I-

beam

Prestressed I-

beam

Steel composite I-beam

1 Cost of Retaining wall

a. with Reinforced Earth wall 94500 144900 189000

b. with Reinforced Concrete wall 216000 331200 432000

2 Cost of Filling material 48600 74520 97200

3 Total cost with RE wall 143100 219420 286200

4 Total Cost with RC wall 264600 405720 529200



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VI. CONCLUSIONS

The conclusions are drawn for different ground

conditions, different shuttering types, different shapes and

their effects on approaches. The lifecycle cost of

superstructure considering the initial capital cost and

periodic maintenance cost is considered for evaluating

various options.

A. Normal ground conditions

1. Considering total capital cost

From Table III, it is clear that the total cost of

superstructure consisting of fabrication/casting cost

(Material Cost ) and placement cost in normal ground

conditions using conventional shuttering is minimum for

reinforced cement concrete-T beam and the total cost using

combination of conventional and sacrificial shuttering is

also minimum for reinforced cement concrete-T beam

among the four options used for comparison.

In normal ground conditions, the total superstructure

cost with sacrificial shuttering is higher than the total cost

with conventional shuttering. However, the difference in

both the cases is small, but where the time is essence for

early completion of the project; the sacrificial shuttering

may proves to be better choice.

2. Considering maintenance cost(Life Cycle Cost)

Considering the periodic maintenance requirement, the

composite steel I-beam becomes the costliest option and

reinforced concrete T beam is again the most economical

option among all the four superstructure types.

3. Considering the effects on approaches

After adding the additional cost of approaches due to

increase in the height of superstructure, the cost of

superstructure with reinforced concrete T-beam and

prestressed concrete I-beam is almost same subject to the

condition that, approaches are built with reinforced earth

walls. If the approaches are built with reinforced concrete

retaining wall then prestressed concrete I-beam is the most

economical option.

B. Above railway track

1. Considering total capital cost

From Table V-A & V-B, it is clear that the total cost of


(Material Cost) and placement cost (launching cost

including railway block Cost), using conventional

shuttering as well as combination of conventional and

sacrificial shuttering; is minimum for reinforced concrete-

T beam among the four options used for comparison.

It is important to mention that the cost is considerably

less in case of reinforced concreteT- beam being case-in-

situ.

From table V-A & V-B, it is clear that among the

options of pre-casted/pre-fabricated, the cost of Composite

steel girder is lowest in both the cases, i.e. with

conventional and with sacrificial shuttering. With increase

in number of trains per day in the section the cost

implication is increased considerably, but the Composite

steel girder remains the cheapest. The reinforced concrete-

I beam and pre-stressed concrete-I girders are costliest with

little cost difference between them.

From table VI, it is clear that the total cost of


(Material Cost), placement cost (launching cost,railway

block Cost and speed restriction cost), using conventional

shuttering; the cost of Composite steel girder is lowest.

With increase in no of trains per day in the section the cost

implication is increased considerably, but the Composite

steel girder remains the cheapest. The reinforced concrete-

T beam is the costliest due to imposition of longer duration

of speed restriction for casting of deck slab.

From table VII, it is clear that the total cost of


(Material Cost), placement cost( launching cost, railway

block Cost and speed restriction cost), using combination

of conventional and sacrificial shuttering; the cost of

Composite steel girder is lowest. With increase in no of

trains per day in the section the cost implication is

increased considerably, but the Composite steel girder

remains the cheapest. The reinforced concrete T- beam is

the costliest due to imposition of longer duration of speed

restriction for casting of deck slab.

2. Considering maintenance cost (life cycle cost)

Considering the periodic maintenance requirement, the

composite steel I-beam becomes the costliest option and

prestressed concrete I-beam comes out most economical

option among all the four superstructure types.

3. Considering the effects on approaches

After adding the additional cost of approaches due to

increase in the height of superstructure, the cost of

superstructure with prestressed concrete I-beam is most

economical with any type of retaining wall in approaches.

From the overall study it is concluded that, in all the four

options used for study; total cost for placement of spans is

higher with sacrificial shuttering than conventional

shuttering for normal ground conditions as well as over

railway track without considering the speed restriction cost.



124

The advantage of sacrificial shuttering comes into

picture when the cost implication of the speed restriction is

also combined with the traffic block cost.

The effect of sacrificial shuttering is more pronounced

when the numbers of trains in a section are high. The

difference in cost for conventional and combination of

sacrificial shuttering for prestressed I-beam is Rs. 2075300

with 20 trains in a section and this difference increases to

Rs. 6767873 with 80 trains in a section.

Fig:9- variation in cost of superstructure with Conventional and

Combination of sacrificial shuttering due to increase in frequency of

trains in section.

Overall the prestressed concrete I-beam proves to be

most economical in all the conditions studied for arriving at

best solution for the selection of superstructure for 20m

span.

REFERENCES

[1] Alimchandani C.R., Kumar Vijay, Kanitkar V.K., and Shukla U. J., Ganga Bridge at Bhagalpur, Indian Road Congress Journal, 2005,

Paper No 492.

[2] Fowler John R., and Stofko Bob, Precast options for bridge superstructure design, Economical and Social Linkages Session,

2007 Annual Conference of the Transportation Association of Canada, Saskatoon, Saskatchewan.

[3] Heggade V.N., Mehta R.K., and Prakash R., Design and

Construction of Pre-Tensioned Sutlej Bridge in Punjab, Indian Road Congress Journal, 2006, Paper No 524.

[4] Huang Rong-yau, and Chen Ping Fu, Life Cycle Cost Analysis of

Steel and Pre-stressed Concrete Bridges-A case study of a New

Highway Bridge in Taiwan, Doctoral Thesis.

[5] Khatri Vikash, Singh P.K., and Maiti P. R., Comparative Study of

Economical Design Aspect of Steel-Concrete Composite Bridge with MS, HPS, and Hybrid Steel, International Journal of

Engineering Research and Development, 2012, Volume 4(6).

[6] Khatri Vikash, Singh P.K. and Maiti P. R., Comparative Study of Prestressed steel-concrete composite bridge of different span length

and girder spacing, International Journal of Modern Engineering

Research,2012, Volume 2(5), pp 3917-3922.

[7] Khatri Vikash, Singh P.K.and Maiti P.R., Comparative Study for

Different Girder Spacing of Short Span Steel-Concrete Composite bridges with MS and HPS, International Journal of Emerging

Technology and Advanced Engineering, 2012, Volume 2(9).

[8] M. Kishore Kumar and Rao Ch. Hanumantha, Economics of Alternative Structural Schemes of Prestressed Concrete Bridge: Few

Case Studies, International Journal of Civil and Structural

Engineering,2010, Volume 1(3).

[9] Misal Vishal U, Gore N. G. and Salunke P. J., Analysis and design

of Prestressed Concrete Girder, International Journal of Incentive Engineering and sciences, 2014, Volume 2(2).

[10] Pawar A.R. and Pataskar S.V, Life cycle Cost Analysis of bridge

Superstructure, International Journal of Emerging Technology and Advanced Engineering, Volume 2(9).

[11] Vasani P.C. and Mehta Bhoomika P, Different types of Bridges and Its Suitability, Structural Engineering Forum of India.

[12] Saxena Amit and Maru Dr. Savitri, Comparative Study of the Analysis and Design of T-Beam Girder and Box Girder

Supersructure, International Journal of Research in Engineering &

Advanced Technology, April-May 2013, Vol-I, Issue 2.

[13] Design criteria for Pre-stressed concrete road bridges (Post-

tensioned Concrete), IRC: 18-2000, The Indian Road Congress.

[14] Standard Specifications and code of practice for road bridges, IRC:

6-2000, The Indian Road Congress.

[15] Code of practice for Pre-stressed concrete, IS: 1343-1980, Bureau of Indian Standards.

[16] Standard Specifications and code of practice for road bridges, section III-cement concrete (plain & reinforced), IRC: 21-2000, The

Indian Road Congress.

[17] Standard Specifications and code of practice for road bridges, section IV- composite construction (first revision), IRC: 22-1986,

The Indian Road Congress.

[18] Raju N. Krishna, Design of Bridges, Oxford & IBH Publishing Co.

Pvt. Ltd., Fourth Edition 2009.

Documents

Economic Solution of Super Structure for Bridge of 20m Span