Bridge Designs

FUNCTIONS OF THE

ENGINEERING SERVICES

DIVISION

D.K. Rohitha Swarna

Director (Engineering Services),RDA

HISTORICAL DEVELOPMENT

1 Pre British Colonial Period – Prior to 1796

2 British Colonial Period – 1796 to 1948

3 Post Colonial Period 1948 to date

Period Agency primarily responsible for Highway / Bridge

Construction

Other Agencies that were involved in the

Bridge Construction

1796-1815 Quarter master General’s Royal Engineers

1815-1842 Civil Engineer and Surveyor General’s Department sometimes also

referred to as colonial Engineer and land Surveyor’s Department

Royal Engineers. Ceylon pioneer lascars later called the

Military Corps of pioneers

1842-1845 Civil Engineer and Surveyor general’s Department Commissioner of

Roads

Pioneer Corps

1846-1851 Civil engineer’s Department. Commissioner of Road Department Pioneer Corps

1851-1862 Civil engineer and Commissioner of Roads Department Pioneer Corps and Government Factory (from 1858)

1863-1876 Public works Department Pioneer Corps. Government Factory

1877-1938 Public Works Department Government Factory. (Pioneer Corps ceases to exit in

1877)

1938-1968 Public Works Department Formation of a bridges Organization under C.E.

(Bridges) in 1938 . Government Factory

1968-1971 Highways Department C.E. Bridges.

Government Factory.

1971-1978 Territorial Civil Engineering Organization and Highways Department State Development and Construction Corporation

1978-1986 Highways Department Newly formed Bridges Organization under a Deputy

Director Bridges. S.D. & C.C., S.E.C. and some other

private organizations

1986 to date Road Development Authority RC&DC(Presently abolished),Maga Neguma

SD&CC,SEC,CECB and some other private

organizations

BACKGROUND

From the inception of the RDA in 1986, for over a period ofabout 12 years, the Engineering Services Division, has beenresponsible for the overall management of the execution ofspecialized functions namely:

Traffic Engineering and Road Planning Highway Designs Bridge Designs Bridge Inspection & Assessment Land Acquisition and Shifting of Utility Services for

project implementation

For the execution of each of the above specialized functions,there were separate offices consisting of Engineers withsupportive staff for both technical & administrative functionsand each of them was managed by a Deputy Director.

However at present, of the five offices, only the BridgeDesigns office comes under the purview of the Director,Engineering Services.

ADG (C/D)

Director (E/S)

DD (B/D)

SDE SDE SDE SDE

DE

DE

DE

DE

DE

(T)

DE

(T)

DE

(T)

DE

(T)

DE

(T)

DE

(T)

DE

(T)

DE

(T)

DE

(T)

DE

(T)

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(T)

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(T)

DOA

AA

D’mans

(10) Supporting

Staff

ENGINEERING SERVICES DIVISION

Director General

Present Functions of the Division

The Primary Responsibility of the Divisionplan the designing of bridges and the approachroads for bridge improvement and rehabilitationprojects

process the acquisition of land and relocation ofinfrastructure of public services required tofacilitate the implementation

provide advisory and support services to therelevant implementing divisions of RDA inimplementing bridge projects.

Following Routine and Periodic Activities are Involved Preliminary investigations of bridges to

identify the level of rehabilitation. Preparation of preliminary designs and cost

estimates for bridge projects for projectformulation and feasibility analysis andproject appraisals.

Developing optimal basic designs for bridgeprojects and deciding on the designstandards to be adopted in the design.

Finalization of detailed designs, drawings,BOQQ and estimates for bridge projects.

Preparation and finalization of documentsfor land acquisition – acquisition plans,tenement particulars etc.

Diagnosing problems in implementation ofbridge projects and amending designs asrequired to suit the site conditions duringconstruction.

Providing advisory services and guidance inbridge designs to Provincial Directors andChief Engineers.

Providing advisory and support services torelevant Implementing Divisions inimplementation of bridge projects.

Developing and updating of standarddesigns for bridge beams and other bridgecomponents to satisfy requirements ofcurrent standards and code of practiceand finalization of type plans for same.

Implementation of design policy – reviewof design standards and practices andrecommending amendments/changes forupdating them in keeping with recentdevelopments and current trends andtheir adoption.

Preparation of rates for items of worksrelevant for construction of bridges andupdating of the same periodically.

Providing training for RDA Engineers inBridge Designs to enable them to partiallyfulfill the requirements to obtainprofessional qualifications.

Preparation of project proposals for theconsideration of External ResourcesDepartment to seek foreign funds forimplementation

Participation at progress review meetingsand providing advisory and supportservices where required for projectsimplemented by the Project ManagementUnits under foreign funds.

Participation at discussions with ForeignMission /Expatriate Consultants inconnection with bridge rehabilitationprojects to be implemented under foreignfunded programs.

The following obligatory functions are

also involved

Providing counter part services to ForeignMissions, Expatriate Consultants etc. suchas providing data/information, appraising oflocal conditions, reviewing of basic designsand detail engineering work, makingobservations and suggestions.Monitoring, review and acceptance of detailengineering work executed by Consultants forbridge projects.Checking of alternative designs submitted byContractors in the process of executing the bridgeprojects awarded to them to decide onadaptability of same.

oProviding consultancy services in bridgedesigns to outside GovernmentDepartments and Private Agencies.

oExecution of structural assessments ofbridges and providing designs &specifying repairs/strengthening neededfor bridges for transport of abnormallyor extra heavy loads such as ElectricGenerators, Gas Turbines and grantapproval for the movement of those onspecific trailer arrangements.

Bridge Designs Principles

By

D.K. Rohitha SwarnaDirector (Engineering Services)

Road Development Authority

08.12.2011

14

1. Historical Development of Bridges

2. Important Old Bridges in Sri Lanka

3. Investigation of Bridges4. Classification of Bridges5. Various types of Steel Bridges6. Bridge Loadings7. Bridge foundations8. Super Structure – Various deck

types

15

INTRODUCTION TO DESIGN OF BRIDGES

1. Timber Logs2. A rope tied between two supports and a

floor system was suspended3. Masonry Arches – idea obtained from the

naturally formed rock arches or caves 4. Long span arches with cast Iron

The 1st iron bridge in the world was built in England known as “Coalbrookdale” in 1779 over the river “Severn” with a span of 100ft.

5. Wrought Iron bars & cables Girders which can take tensionLater in 1820 the world’s first suspension bridgebuilt with iron bars and cables known as “Menaibridge” with a span of 580ft which consist oftimber decking and this has stood for 115 years.In 1832 1st Wrought iron girder bridge was built.Since the wrought iron was maleable ,ductile andmuch stronger in tension it could be riveted.

16

Historical Development of Bridges

17

6. Open web girders, trusses with the advent of

steel

7. Rfd concrete/Pre-stressed Concrete

First patent for reinforced concrete was published by

England in 1808 and Portland cement concrete was

invented in 1824. The first portland cement concrete bridge

to be built was the “Grand Maitre Aqueduct” across river

Vane in France built in 1874. Fressinet developed

prestressing and the application was adopted in late 1930.

8. Suspension Bridges, Cable Stayed – with the

advent of high strength steel

18

Boat bridge across Kelani Ganga constructed in 1822

Old Victoria Bridge Over Kelani river in 1895 ( Replaced by Sri Lanka- Japan friendship bridge in 1992)

19

20

Old Ulapane Bridge

Old Steel Truss Bridge at Gampola Over Mahaweli River in 1926 (Replaced by 100 m long Post Tension Bridge in 2004)

22

23

Mawanella Brick Arch Bridge constructed in 1832 over Maha oya

71.6 m

Peradeniya Satinwood Bridge constructed in 1833 over Mahaweli River

24

Artistic Impression

25

Present Steel Arch Bridge at Peradeniyaconstructed in 1905 over Mahaweli River

26

68.4m

•Topography•Catchment area•Hydrology•Geo-Technical data•Navigation•Construction Resources•Nearby Bridges•Traffic Data

27

Investigation of Bridges

Structural components of a bridge

28

(i)Super structure

(ii)Sub structure – Abutments, piers, wing walls

(iii)Foundation

Abutment

Pier

Foundation

Super structure

29

Abutment

Pier

Foundation

Super structure

Wing wall

Abutment

Wing wall

Elements of a bridge could be further categorized as follows -

1. Primary elements – structure form, spans, piers

and abutments and their founding requirements and the physical context.

2. Secondary elements – parapets, wing walls,

texture of finish, colour

It is very important to consider what visual impact the finished structure will have on the environment, on the people who use them & those who will be seeing them

30

31

• Type of Material SteelConcrete Timber

• Type of constructionArchSlabBeam & Slab

•Structural BehaviorSimply SupportedContinuousCantilever and Suspension

•Purpose of construction Permanent Bridges

High level Bridge (All weather Bridge)Submersible BridgeTemporary Bridges

PontoonBaileyTimber

Open Web girdersSuspensionCable Stayed

Box Girder Bridges

Design Flood discharge for Bridges

• The determination of the required waterway is the first and mostimportant factor in design of a bridge. Hence the required openinghas to be calculated with a capability of passing the peak floodwithout overtopping the banks or endangering the structure

Contribution factors to the flood flow• Rainfall - intensity

- duration• Terrain Characteristics

- Catchment area, shape, slope ,Nature of soil, Vegetation types

• Stream Characteristics- Slope of the Stream- nature of bed

Since the occurrence of flood depends on combination of above factors its prediction becomes far from exact science.

32

(i) Empirical Method

- Simplest and oldest method and formulae have beenderived based on observed data. Suitable for largercatchment areas.

(ii) Statistical probability Method (Frequency Method)

- Based on the actual observations at the site over a periodof at least 25 to 30 years and applying statistical probabilitydesign flood is arrived fro a desired return period of 50 or100 years

(iii) Rational Method

- More suitable for smaller catchment (25 sq. km). Makeuse of factors covering intensity of rainfall and catchmentcharacteristics.

Two methods are available

(a) Slope – area method

- Get reliable data by enquiring from reliable people for HFL& determine the discharge as for an open channel.

Methods of Determination of Flood Discharge

(b) Unit Hydrograph Method

- More rational & a latest method which needs actual

observations of the discharge at the site for same period and also the rainfall data spread over some years.

34

Scour depth calculationScour is the result of the erosive action of water, excavating and carryingaway material from the bed and banks of stream. Different materials scourat different rates. Loose granular soils are rapidly eroded by flowing water,While cohesive soils are more scour resistant.

Factors affecting scour•Slope and alignment of the natural stream•Bed material of stream and flood plains•Changes or potential changes in the prevailing conditions in the stream orthe catchment, whether man-made or natural.

•Depth, velocity and alignment of flow through the constriction.•Alignment and layout of the bridge and training works.•Accumulation of debris.•Size, shape, orientation and arrangement of piers, footings and piles.•Amount of bed material in transport.

AFFLUX

In order to arrive the design flood discharge, it is recommended to use at least two of the above methods and arrive at a figure which is maximum of the two or 1.5 times the minimum whichever is less.

35

This is another term to be familiar with design of bridges and it can be defined as arise or “heading up” of water level on the upstream side of the bridge. It is causedwhen the effective linear waterway at the obstruction is less than the natural width ofthe stream immediately in the upstream side of the bridge. As such the afflux that canbe produced by piers and projecting abutments has to be calculated in order todetermine the finished road level of the bridge.

The afflux should be kept minimum and limited as far as possible to 150mm in orderto avoid upstream flooding and inundation.

(a) Dead loads(b) Live Loads(c) Braking / Traction(d) Centrifugal Force(e) Skidding force(f) Earth and Surcharge Pressure(g) Floating Debris & Log Impact(h) Wind(i) Temperature(j) Shrinkage & Creep(k) Buoyancy Effect(l) Seismic forces

37

Bridges should be able to resist the effects of the loads & actions as listed below

Bridge Live Loads

To be followed as per BS 5400 part 02 & RDA Bridge Design Manual.

Vehicular – HA & HB

Bridge live loads consists of

Pedestrian

HA Represents normal Traffic and consists of uniformly distributed load and a knife edge load.

Loading is given per notional lane (which is 2.3 – 3.7 m)

W = 151(1/L) 0.475 KN

38Loaded length (m)

Lo

ad

p

er m

o

f la

ne (w

)

30 380

9

30

K.E.L = 120kN Per LanePedestrian Loading = 4 kN/m2

Type HB Loading

HB is an abnormal loading which consists of 4 axles and each axle weighs 25 Tons – 45 Tons

Contact Area:- Wheel load is assumed to be uniformly distributed over a circular contact area to give an effective pressure of 1.1 N/mm2

39

1.0 m

1.0 m

1.0 m

1.8m

6.0 m

1.8m

Direction of Travel

3.5 m wide

40

Classification of Soil

• Cohesive soil → Presence of clay

minerals, eg; clays, plastic silt

• Cohesionless soil → composed of

bulky grains, eg; non-plastic silts and gravel

41

• When the soil is subjected to direct compression, shear stresses develop.

• Shear stresses will develop even in tension, but not relevant since soil fails in tension.

• Failure in soil occurs by relative movement of particles and not by breaking of the particles.

• Shear strength is the principal engineering property which controls the stability of a soil

mass under loads.

42

Shear strength governs following properties.

1. Bearing capacity of soil

2. Stability of slopes

3. Earth pressure against retaining structure

Earth pressure theories

A soil mass is stable when the slope of the surface of the soil mass is flatter than safe slope. Hence in case of places where the space is limited, a retaining structure is required to provide the lateral support to the soil mass.

43

In order to design the retaining structure determination of following are needed.

1. The magnitudedepends on - mode of movement of the wall

- flexibility of the wall- properties of the soil- drainage conditions

2. The line of action of the earth pressure

44

Hence, this is a soil – structure interaction problem & anyhow since it is

Complicated to analyse it is assumed that retaining wall is rigid & soil structure

Interaction is neglected.

Theories adopted -

Coulomb theory (1773)

Rankine theory (1857)

Terzaghi theory (1941) – more improved from

other two with general

conditions, but more complicated

45

Different types of lateral earth pressures

Could be grouped in to 3 depending on the movement of the retaining wall with respect to the soil backfill.

1.At rest pressure – known as elastic

equilibrium state

2.Active pressure – it is a state of plastic

equilibrium

3.Passive pressure – when the soil tends to

compress horizontally

46

No movement

At rest

pressure

Basement slab

Active

pressure

Movement towards left

Passive

pressure

48

0

Earth pressure

Active

AB

C

At restPassive

Movement

+-No

movement

Movement towards fillMovement away

from fill

Loads on the Abutment- Bearing Pressure is calculated due to the service

loads.

49

Traction / Breaking

P Dead + Live

EARTH PRESURE – ka.r.HPRESSURE DUE TOSURCHARGE – ka. P V

H

HV

M

e

Vehicle Surcharge

Ka = (1-sinΦ) / (1+sinΦ) as per Rankine’s theory

Overall stability against overturning and sliding should be checked at the base

H.F.L.

Bridge Deck

Traction / Braking

Dead + Live

FLOW

Water current + Log Impact

Traction / Braking

Dead + Live

ELEVATION OF THE PIER

PLAN VIEW OF THE PIER

Loads on the Pier

50

Design of Gravity Type Pier

• Loads for Pier Design• Restoring Loads – All Vertical Loads

» Dead Load from the Superstructure

» Dead Load of the Capping Beam

» Dead Load of the Pier

» HA & HB Loads from the Superstructure

» Pedestrian Live Loads

» Superimposed Live Loads

• Restoring Loads – All Vertical Loads» Associated Secondary Live Loads – Tractive Force (80%

of Total Tractive Force)

» Water Current Load

» Load due to Debris

» Load Due to Log Impact

51

Cont.. Gravity Type Pier

• Water Current Load• Max. Pressure

– W = Unit Weight of Water– K = Factor depend on Cut Water

• Maximum Pressure at water surface and zero pressure at the Bed

• Debris Load(Use above eq. with K = 1) • Consider force exerted by a minimum depth of 1.2 m debris

• Log Impact Load• Impact Load

– W = Weight of drifting Item (2T)

52

Cut Water

Loa

d

30°

g

vKWP

2

2

WvP 1.0

Cont.. Gravity Type Pier

• Consider Both the cases High Buoyancy and Low Buoyancy

• Calculate FOS for Stability and Stresses at all critical sections of the pier for all critical Load cases

• Calculations are same done in Abutment Design

53

Different Regions in the Hammerhead Pier

54

VM

Cantilever Region Support Region

Statically IndeterminateStatically Determinate

Design of Wing Walls

Wing wall design is almost same as Abutment

Load for Wing wall DesignRestoring Loads – All Vertical Loads

Dead Loads of the Wing wall

Superimposed Dead Loads

Weight of the Soil Backfill

Surcharge Load

Overturning Loads – All Horizontal Loads

Soil Lateral Pressure

Surcharge Lateral Pressure

55

Types of Bridge Foundation

Mainly two categories are available Shallow foundation

Deep foundation

56

Shallow foundation – Open excavation possible

Design as a direct load bearing structure. Excavation depthwill have practical limitations depending on the type of soiland depth of subsoil water level.

STRUCTURAL DESIGN OF FOUNDATIONS

(A) Allowable bearing Pressure has to be evaluated & settlement can be estimated using soil properties (C ,Φ, values)

(B) In order to do the structural design of the foundation B.M. & S.F. need to be estimated.

Two methods are used;

Rigid Method of Flexible methodAnalysis of Analysis

- Assume the fdn to be rigid - Soil is assumed to be of- Find Soil pressure dis & it infinite no of springs

is a straight line - Elastic const. of spring- Calculate B.M. & S.F. (coeff. Of sub grade rea)- Soil structure interaction is not - Settlement of the soil &

it’s influence - Accounted. Foundation is accounted.

57

Deep foundation – Either pile or well Foundation (caissons)

58

Piles can be either timber, steel or concrete.

Based on construction method piles can be categorized asprecast driven piles and bored piles.

End bearing piles are generally taken up to hard strata such as bed rock.

Friction piles are suitable for cohesive soil not subjected to heavy scour.

Friction cum bearing piles are used in mixed type of soils.

i. Bearing pileii. Friction pileiii. Friction cum bearing pile

Based on how the load is transferred, pilefoundations are divided as;

Well Foundation

59

TYPICAL SECTION OF

WELL FOUNDATION

PIER CAP

PIER

CYLINDER CAPPING BEAM

TOP PLUG

SAND FILL

WELL STEINING

WELL CURB

CUTTING EDGE

BOTTOM PLUG

ROCK

•Available in rectangular or circular sections. Rectangular sections are suitable for shallow depths and circular sections are suitable for larger depths.•Can resist heavy vehicle loads and lateral loads. Only disadvantage is very time consuming process.•Sufficient grip length is required after allowing for scour.

In the design, Three aspects to cover•Depth of well•Size(diameter) of the well•Thickness of the well steining

Depth of well is governed by

- Depth of scour- There should be adequate grip length (to

resist horizontal forces)

Size of the well is mainly governed by theallowable bearing pressure of the soil.

Size of the steining depends on (i) Adequate working space (Minm 1.8 m is

preferred)(ii) Steining will get subject to various stresses

during sinking.(iii) Thickness of well steining should be such

that it should be able to overcome the skin friction during sinking.

60

TYPICAL AVERAGE BEARING CAPACITIES OF VARIOUS SOIL TYPES

SOIL TYPE BEARING CAPACITY (KN/M2)

SILT (Sandy/elayer) 50Clay (Soft) 150Clay (Stiff) 200Sand (Compact Coarse) 400

(loose gravel)Gravel – Sand mixture 800 Saft Rock 1000(Broken bedrock)Sedimentary Rock 2500(Sandstone, limestone Siltstone)Medium hard rock 4000Hard Rock 8000(Dolomite, gneiss, granite)

61

Superstructure -Design Aspects

62

•The structure of the bridge which directly takes the loadand transmits to the abutments and piers throughbearings

•The superstructure design depend on the different typesof bridges that is based on type of construction, floorarrangement (in case of steel bridges) and structuralbehavior

•The design of a superstructure of a bridge is similar to thatof any structure except that a bridge has to carry a movingload in combination with other loads like wind,temperature, seismic, longitudinal and lateral forces

(a) DECK TRUSS

(b) PONY TRUSS

(c) THROUGH TRUSS

Types of Steel Trusses Based on Travel Surface Configuration

63

65

100 m long Langer Truss (Modified Warren Truss) at Muwagama over Kalu Ganga

7400 Carriage way.

CROSS SECTION OF DECK.

9800 Overall width

1200 Foot walk.

110mm dia. PVC pipe rain-

water outlets at 2300 crs.

75

10mm Fall

Rain water catch pit. - Refer detail.

15 nos. 7010 mm.

(23'-0") long PSC beams

Drg: No: T / B / 030.

Slope 1 in 60

1 : 30.

15 R 20 . 1 . 460. Tie bars.

Wearing surface not shown for clarity.c

32 R 6 . 2 . 300.

L

24 T 10 . 3 . 300.

22

DETAILS REPEATS ABOUT CENTRE LINE.

24T10.4.300.

1200 Foot walk.

3 T10.6.200.

To be filled with

cement mortar

after fixing bolts.

T10 Shear

connectors at 600 crs.

2 4

6

50 Thick wearing surface.

Minimum 50 mm.

Type pre cast uprights and hand rails as per Drg:No:T/B/102 A&B.

Pre cast kerb. Drg:No:T/B/106 -Rev. 1.

150x50 insitu lower kerb. Conc:Grade 20(14).

57

0

10

0

Service

duct

50 mm dia. PVC drain pipe at 2300 crs.

GENERAL DETAILS R. C. DETAILS

610

50

610

110

610 610

24 T 10 . 5 . 300.

500x450x75 thick R.C.cover slabs with R/F T10 @ 100 crs. both ways.

Grade : 40 (20)

Infiller concrete in Lower kerb. Concrete:

Grade 20(14)

Grade : 25 (20)

Foot walk in

Minimum 110

20 dia. stainless steel dowels at fixed ends only.

6 mm. dia. wire links to be provided to tie rods

and top reinforcement along the groove.

450 350 400

110

6841

50

50mm

Chamfer

100

Drip

6 6

5

5

100

66

7 m long PSC Beam Deck

22 R 20 .1. 450. Tie bars.

7170

7400 Carriageway.

9800 Overall width.

110 dia. PVC. pipe rain water outlets at 3250 crs..

50 dia. PVC. drain pipes at 3250 crs..



500x450x100 thick pre cast R.C. slabs.

Minimum 75 mm.


Rain water catch pit. -Refer detail.


425

1075 10

425 350

500

1200 Foot walk.

Pockets for

fixing uprights.

100

205 500500

110

GENERAL DETAILS.

340

745

300

5mm.fall.

50

Service

duct.

230

Wearing surface not

shown for clarity.

64 T10 . 3 . 150.

Minimum 135mm

screed concrete

1 : 30.

CROSS SECTION OF 9 500 LONG DECK

Slope 1:60.

20 dia. stainless steel

dowels at fixed ends only.

Infiller concrete in

Grade : 40 (20)

32 T10 . 2

18 Nos.9 500 mm long

(finished length) PSC. beams

as per Drg:No: T/B/507


cL

33 T10 . 6 . 300. 33 T10 . 5 .300.

1200 Foot walk.

R.C. Ties at foot walk

-Refer detail.

205

64 T 10 . 4 .150.15 T12 . 7

500 500

110

REINFORCEMENT DETAILS.

64 T 10 . 8 . 150

Lower kerb. Concrete:

Grade 20(14)

Service

duct.

25500

CAST LENGTH = 9.42m.

FINISHED LENGTH = 9.5m.

Drg: No: T/B/507.

200

50

50

100

80

380

100

75

9.5m. long.

Foot walk in

Grade : 25 (20)

67

9.5 m long PSC Beam Deck

26 R 20 .1. 450. Tie bars.

9800 Overall width.

7400 Carriageway.

7170


50 dia. PVC. drain pipes at 3250 crs..







Minimum 75 mm.

Pockets for

fixing uprights.

500 500205110

GENERAL DETAILS.

10

425

10

75

425

500

350

10 mm. fall

100

5mm.fall.

340

815

300

50

Service

duct.

230

1200 Foot walk.



1 : 30.

CROSS SECTION OF 11 500 LONG DECK

Minimum 135mm

screed concrete

Slope 1:60.

Wearing surface not

shown for clarity.

32 T10 . 2Infiller concrete in

Grade : 40 (20)


Lc

77 T10 . 3 . 150.

705

15 T12 . 7

500

110

77 T 10 . 4 .150.

77 T 10 . 8 . 150


Drg: No: T/B/506.

CAST LENGTH = 11.42m..


450


Grade 20(14)

38 T10 . 6 . 300. 38 T10 . 5 .300.

R.C. Ties at footwalk-Refer detail.

1200 Foot walk.

Service

duct.

Grade : 25 (20)

Foot walk in

120

25

100

50

500

80

100

75

11.5m. long.

200

68



Grade 20(14)

30 R 20 .1. 450. Tie bars.

9800 Overall width.

7400 Carriageway.

7170

50 dia. PVC. drain

pipes at 3250 crs..110 dia. PVC. pipe rain water outlets at 3250 crs..

Pockets for

fixing uprights.



Displacers to be curtailed

at 300 either side of pipe




Minimum 75 mm.

32

5

89

0

GENERAL DETAILS.

500110

205 500

100

10500

425

75

50

45

0

Service

duct.

23

0

5 mm. fall.

425

10

10 mm. fall

350

1200 Foot walk.

500x450x100 thick

pre cast R.C. slabs.

18 Nos.13500 mm long

(finished length) PSC. beams

as per Drg:No: T/B/505Wearing surface not

shown for clarity.

Minimum 135mm

screed concrete

CROSS SECTION OF 13500 LONG DECK

150 dia. displacers of polythene

-tubes filled with light materials

such as saw dust paddy husk etc.

27

5

Slope !:60.



1:30.

Grade : 40 (19)

Infiller concrete in 32 T10 . 2

90 T10 . 3 . 150.

DETAILS REPEATS ABOUT CENTRE LINE.Lc

52

5

1200 Foot walk.

80

100

25

75

FINISHED LENGTH=13.5m.

CAST LENGTH=13.42m.

90 T 10 . 8 . 150

15 T12 . 7

90 T 10 . 4 .150.

500


205110

500

Service

duct.

46 T10 . 5 .300.46 T10 . 6 . 300.

R.C. Ties at footwalk

500

Drg: No: T/B/505.

13.5m. long.

50

195Grade : 25 (19)

Foot walk in

100

200

69


STAGE- 3: SEVEN DAYS AFTER STAGE TWO: BALANCE-

(FOOT WALK) TO BE DONE WITH GRADE 25 (20) CONCRETE.


Grade 20(14)

R.C. Ties at footwalk

49 T 10 . 6 . 300.

32 R 20 . 1 . 450.

7 400 Carriage way.

6680

9 800 Overall width.

Type pre cast uprights and hand rails as per Drg:No:T/B/102 A&B. c

1 200 Foot walk.




50 dia. PVC. drain

pipes at 4000 crs..

Pockets for

fixing uprights.

STAGE -1: AFTER LAUNCHING THE BEAM IN POSITION:

GRADE 40 (20) CONCRETE UP TO THE BOTTOM OFSERVICE DUCT.

Minimum 75 mm.






NOTES: CONCRETING

SEQUENCE OF EDGE BEAM.

GENERAL DETAILS.

535

service

Duct.

965

500

100

160500400

325

5mm. fall.

10

450

75

300450

10600

10010mm. fall.

STAGE -2: SEVEN DAYS AFTER STAGE ONE : 500mm THICK

GRADE 40 (20) CONCRETE UP TO TOP OF SCREED LEVEL.

CROSS SECTION OF 14500 LONG DECK. 1:30.




Minimum 135mm

screed concrete

300

Slope 1 : 60.

17 nos. 14 500 long PSC.

beams Drg:No: T/B/503/A.


dowels at fixed end only.

Wearing surface not shown.


Grade : 40 (19)

L

97 T 10 . 3 . 150.

44 T 10 . 2.

55 55

450 120

600

300 450

1200


EDGE BEAM INFILLER

CONCRETING HAS TO

BE DONE IN THREE

STAGES.

REFER NOTES.

100

225

80

50



STAGE: 2.

20 T12 . 8.

500

49 T 10 . 4 . 300.

500160

400

Service

Duct.

STAGE: 1.

49 T 10 . 7 . 300.

49 T 10 . 5 . 300.

Foot walk in concrete

Grade: 25 (20)

25500

STAGE: 3.

Drg: No: T/B/503/A.

100

14.5m long.

200

70


7 400 Carriage way.

CROSS SECTION OF 15500 LONG DECK.

6680






50 dia. PVC. drain

pipes at 4000 crs.

Pockets for

fixing uprights.






1 200 Foot walk.


10

325

585

600

400 500

GENERAL DETAILS.

300450

10

15

500

5mm. fall.

75

450

50

10

service

Duct.

10mm. fall.

160

100

Minimum 75 mm.

cL




Minimum 135mm

screed concrete

300

Slope 1 : 60.


Grade : 40 (19)

53 T10 . 7 .300.

Foot walk in

Grade : 25 (19)

1200

400

20 T12 . 8.

500


53 T 10 . 4 . 300.

450300


Grade 20(14)



104 T 10 . 3 . 150.

55 55

44 T 10 . 2.

500

34 R 20 . 1 . 450.

160

53 T 10 . 6 . 300.

53 T 10 . 5 . 300.

Service

Duct.

100

50

225

650

450

EDGE BEAM INFILLER

CONCRETING HAS TO

BE DONE IN THREE

STAGES.

REFER NOTES.

80

100


STAGE: 2.

STAGE: 3.

STAGE: 1.

CAST LENGTH = 15.42m..

Drg: No: T/B/502/A.

500 25

170

15.5m. long.

200

71


STAGE -2: SEVEN DAYS AFTER STAGE ONE : 500mm THICK

GRADE 40 (20) CONCRETE UP TO TOP OF SCREED LEVEL.


Grade : 40 (19)





CROSS SECTION OF 16500 LONG DECK.

6680

7 400 Carriage way.


Pockets for

fixing uprights. 50 dia. PVC. drain

pipes at 4000 crs..




1 200 Foot walk.

STAGE -1: AFTER LAUNCHING THE BEAM IN POSITION:

GRADE 40 (20) CONCRETE UP TO THE BOTTOM OFSERVICE DUCT.






GENERAL DETAILS.

NOTES: CONCRETING

SEQUENCE OF EDGE BEAM.


10

300450

600

500400

635

service

Duct.

10

65

500

325

5mm. fall.

75

450

50

10

10mm. fall.

Minimum 75 mm.

100

160

Minimum 135mm

screed concrete



300

Slope 1 : 60.

cL

220

700

200

1200

STAGE- 3: SEVEN DAYS AFTER STAGE TWO: BALANCE-

(FOOT WALK) TO BE DONE WITH GRADE 25 (20) CONCRETE.

Foot walk in

Grade : 25 (19)

56 T 10 . 7 . 300.

450

56 T 10 . 4 . 300.

500400

20 T12 . 8.

REINFORCEMENT DETAILS.1 : 30.


Grade 20(14)



5555

111 T 10 . 3 . 150.

44 T 10 . 2.

500

36 R 20 . 1 . 450.

160

Service

Duct.

56 T 10 . 6 . 300.

56 T 10 . 5 . 300.

300

100


STAGE: 2.

EDGE BEAM INFILLER

CONCRETING HAS TO

BE DONE IN THREE

STAGES.

REFER NOTES.

STAGE: 1.

100

STAGE: 3.

500


Drg: No: T/B/501/A.

450

25

50

225

80

1 : 30.

16.5m. long.

72


R.C. Ties at footwalkRefer detail.

Type pre cast uprights

and hand rails as per

Drg:No:T/B/102 A&B.

500x450x100 thick

pre cast R.C. slabs.

200

10050

34

5

80

25

25

100

SCALE:-1:5

25 500

SECTION OF BEAM

22

582

5

56 T 10 . 7 . 300.

Service

Duct.

56 T 10 . 5 . 300.

Foot walk

in concrete

Grade: 25 (19)

1200

400500160

20 T12 . 8.

500

56 T 10 . 4 . 300.

44 T 10 . 2.


Grade: 40 (20)

55

111 T 10 . 3 . 150.

1 :30.



Lc

50 mm thick wearing surface.

Minimum 135 mm screed concrete.


beams Drg:No: T/B/508.

30

0





55

CROSS SECTION OF 19 000 LONG DECK.


Minimum 75 mm.

1 200 Foot walk.

10

75

10 600

100

450 450 300

Displacers to be

curtailed at 300

either side of pipe.

160

45

0

GENERAL DETAILS.

500 400 500

100

63

5

50mm Chamfer.

Pockets

for fixing uprights.

10

65

75

50 dia. P.V.C. drain pipes at 4000 crs.

110 dia. PVC. pipe rain water outlets at 4000 crs.

150x50 Insitu lower kerb.

Conc.Grade: 20(14)

Pre cast kerb. Drg:No: T/B/106-Rev. 1.

7 400 Carriage way.

6680


56 T 10 . 6 . 300.

36 R 20 . 1 . 450.


73


50300

cL

28

0

50

50

400

160

3013

0

50

30

10

80

315

80

CROSS SECTION OF BEAM.

30910

970

44

0

60

120 120

11

20

4 T 12 . 4

Foot walk in

Conc:Grade 40(20)

85T10.5.300.

505 T 16 . 1 . 100.

(252 bottom, 253 top.)

Concrete: Grade 40(20)

Wearing surface not shown for clarity.

DETAILS REPEATS ABOUT CENTRE LINE.Lower kerb in.

Conc. Grade: 20(14)

R C. DETAILS.

160 970

1 : 30

30

970

30

970

30

970

1200 Foot walk.

Clear cover 35 mm.

Clear cover 50 mm

81 T 12 . 2 . 250.

40 bottom, 41 top.)

Type pre cast uprights

& hand-rails.

Drg: No: T/B/102 A&B.

7530mm Chamfer.

500x450x75 thick

pre cast RC. cover slab.

Pre cast kerb. Drg:No: T/B/106-Rev. 1.

20 thick

permanent

form work.

30

970

30

970

30

50 dia. P.V.C. drain

pipes at 3500 crs.

9 nos. 25000 long

PSC.beams Drg:No:

110 dia. PVC. pipe rain-

water outlets at 3500 crs.

570

GENERAL DETAILS.

970 160

Top of Capping beam.

Bearing plinth & pad to detail.

970

150x50 Insitu lower kerb. Conc. Grade: 20(14)


1200 Foot walk.


170 20

0

RC. deck-

slab.

51

0

500

350 350

7400 Carriage way

CROSS SECTION OF 25000 LONG DECK

9800 Overall width of Deck.

970

9230

21

0

85 T 10 . 3 . 300.

74


75

550550

CROSS SECTION OF DECK SHOWING GENERAL DETAILS.

16940

10401040 550

250

550 1040550 1040 10401040 5501040 550

100

550 1040550 1040 10401040 550

250

30 m Box Beam Deck

76

8T12-10

2000

8T12-11

T12-5

2000 1390

INTERMEDIATE BEAMEND BEAM

CARRIAGEWAY

CROSS SECTION THROUGH DECK

50 MM THICK

WEARING SURFACE

50 x 150 LOWER

KERB CONCRETE

GRADE 20 (14)

65

725

45

5

22

5

55

95R12-1-30095R6-2-300

190R6-12-300 (T & B)

78T12-13-150

13 13

95R10-14-300

150

520

620

SCALE 1 : 20

77

450

UP STREAM

290460

CROSS SECTION OF DECK - GENERAL DETAILS

50 Thick wearing surface

cL

DOWN STREAM

575

280

50

230

290 460 450

30

200

250025002500

1200 8000 1200

10400

R. C. DETAILS OF DECK

Lc

155

230

230

155

505

5030

210

78

UP STREAM

CROSS SECTION OF DECK

Lc

DOWN STREAM

UP STREAM

CROSS SECTION OF DECK

Lc

DOWN STREAM

FAILURE OF

PARAGASTHOTA

STEEL BRIDGE

BACKGROUND

• Initial Construction: Has been carried out in 1965-1966 by PWD, using removed timber deck (Brotherhood truss) from Kalaoya Bridge Site at Anuradhapura – Padeniya rd.(A028)

• Type : Simply Supported at one end and roller supported at the other end.

• Length : 164 ft. , Width : 18 ft. Height : 10 ft. 8 in.

• Timber decked, old steel truss (Brotherhood truss)• Supported on Abutment • Founded on Bored piles

• Max. allowable load : 10 Ton Single load at the middle at a time

Bridge deck was repaired and opened back to the public in year1990

THE INCIDENT :1999 – 10th July afternoon

• Bridge was Collapsed

• This was revealed by the experimental result been observed for the member no. 17 at the mid of the span

Construction of a new bridge of 3 spans, simply supported P S C Beam deck

Length of a Span: 16.5 m

Overall width :7.3m

Foundation :Pile Foundation

Present Condition

Present Condition

Thank You

Bridge Designs

Documents

Transcript of Bridge Designs