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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)
DE
(T)
DE
(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
21
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.
36
(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
64
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..
50 Thick wearing surface.
Type pre cast uprights and hand rails as per Drg:No:T/B/102 A&B.
500x450x100 thick pre cast R.C. slabs.
Minimum 75 mm.
Pre cast kerb. Drg:No:T/B/106 -Rev. 1.
Rain water catch pit. -Refer detail.
150x50 insitu lower kerb. Conc:Grade 20(14).
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
DETAILS REPEATS ABOUT CENTRE LINE.
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
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.
Type pre cast uprights and hand rails as per Drg:No:T/B/102 A&B.
50 Thick wearing surface.
150x50 insitu lower kerb. Conc:Grade 20(14).
Rain water catch pit. -Refer detail.
Pre cast kerb. Drg:No:T/B/106 -Rev. 1.
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.
20 dia. stainless steel
dowels at fixed ends only.
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)
DETAILS REPEATS ABOUT CENTRE LINE.
Lc
77 T10 . 3 . 150.
705
15 T12 . 7
500
110
77 T 10 . 4 .150.
77 T 10 . 8 . 150
REINFORCEMENT DETAILS.
Drg: No: T/B/506.
CAST LENGTH = 11.42m..
FINISHED LENGTH = 11.5m.
450
Lower kerb. Concrete:
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
11.5 m long PSC Beam Deck
Lower kerb. Concrete:
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.
Type pre cast uprights and hand rails as per Drg:No:T/B/102 A&B.
50 Thick wearing surface.
Displacers to be curtailed
at 300 either side of pipe
150x50 insitu lower kerb. Conc:Grade 20(14).
Rain water catch pit. -Refer detail.
Pre cast kerb. Drg:No:T/B/106 -Rev. 1.
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.
20 dia. stainless steel
dowels at fixed ends only.
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
REINFORCEMENT DETAILS.
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
13.5 m long PSC Beam Deck
STAGE- 3: SEVEN DAYS AFTER STAGE TWO: BALANCE-
(FOOT WALK) TO BE DONE WITH GRADE 25 (20) CONCRETE.
Lower kerb. 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.
110 dia. PVC. pipe rain water outlets at 4000 crs..
Displacers to be curtailed
at 300 either side of pipe
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.
Pre cast kerb. Drg:No:T/B/106 -Rev. 1.
Rain water catch pit. -Refer detail.
500x450x100 thick pre cast R.C. slabs.
50 Thick wearing surface.
150x50 insitu lower kerb. Conc:Grade 20(14).
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.
225 dia. displacers of polythene
-tubes filled with light materials
such as saw dust paddy husk etc.
Minimum 135mm
screed concrete
300
Slope 1 : 60.
17 nos. 14 500 long PSC.
beams Drg:No: T/B/503/A.
20 dia. stainless steel
dowels at fixed end only.
Wearing surface not shown.
Infiller concrete in
Grade : 40 (19)
L
97 T 10 . 3 . 150.
44 T 10 . 2.
55 55
450 120
600
300 450
1200
REINFORCEMENT DETAILS.
EDGE BEAM INFILLER
CONCRETING HAS TO
BE DONE IN THREE
STAGES.
REFER NOTES.
100
225
80
50
CAST LENGTH = 14.42m.
FINISHED LENGTH = 14.5m.
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
14.5 m long PSC Beam Deck
7 400 Carriage way.
CROSS SECTION OF 15500 LONG DECK.
6680
Wearing surface not shown.
9 800 Overall width.
Displacers to be curtailed
at 300 either side of pipe
110 dia. PVC. pipe rain water outlets at 4000 crs..
50 dia. PVC. drain
pipes at 4000 crs.
Pockets for
fixing uprights.
150x50 insitu lower kerb. Conc:Grade 20(14).
Type pre cast uprights and hand rails as per Drg:No:T/B/102 A&B.
50 Thick wearing surface.
Rain water catch pit. -Refer detail.
Pre cast kerb. Drg:No:T/B/106 -Rev. 1.
1 200 Foot walk.
500x450x100 thick pre cast R.C. slabs.
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
225 dia. displacers of polythene
-tubes filled with light materials
such as saw dust paddy husk etc.
Minimum 135mm
screed concrete
300
Slope 1 : 60.
Infiller concrete in
Grade : 40 (19)
53 T10 . 7 .300.
Foot walk in
Grade : 25 (19)
1200
400
20 T12 . 8.
500
REINFORCEMENT DETAILS.
53 T 10 . 4 . 300.
450300
Lower kerb. Concrete:
Grade 20(14)
17 nos. 15 500 long PSC.
beams Drg:No: T/B/502/A.
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
FINISHED LENGTH = 15.5m.
STAGE: 2.
STAGE: 3.
STAGE: 1.
CAST LENGTH = 15.42m..
Drg: No: T/B/502/A.
500 25
170
15.5m. long.
200
71
15.5 m long PSC Beam Deck
STAGE -2: SEVEN DAYS AFTER STAGE ONE : 500mm THICK
GRADE 40 (20) CONCRETE UP TO TOP OF SCREED LEVEL.
Infiller concrete in
Grade : 40 (19)
Wearing surface not shown.
225 dia. displacers of polythene
-tubes filled with light materials
such as saw dust paddy husk etc.
CROSS SECTION OF 16500 LONG DECK.
6680
7 400 Carriage way.
9 800 Overall width.
Pockets for
fixing uprights. 50 dia. PVC. drain
pipes at 4000 crs..
Displacers to be curtailed
at 300 either side of pipe
110 dia. PVC. pipe rain water outlets 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.
150x50 insitu lower kerb. Conc:Grade 20(14).
Type pre cast uprights and hand rails as per Drg:No:T/B/102 A&B.
50 Thick wearing surface.
Rain water catch pit. -Refer detail.
Pre cast kerb. Drg:No:T/B/106 -Rev. 1.
GENERAL DETAILS.
NOTES: CONCRETING
SEQUENCE OF EDGE BEAM.
500x450x100 thick pre cast R.C. slabs.
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
17 nos. 14 500 long PSC.
beams Drg:No: T/B/503/A.
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.
Lower kerb. Concrete:
Grade 20(14)
20 dia. stainless steel
dowels at fixed end only.
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
FINISHED LENGTH = 16.5m.
STAGE: 2.
EDGE BEAM INFILLER
CONCRETING HAS TO
BE DONE IN THREE
STAGES.
REFER NOTES.
STAGE: 1.
100
STAGE: 3.
500
CAST LENGTH = 16.42m.
Drg: No: T/B/501/A.
450
25
50
225
80
1 : 30.
16.5m. long.
72
16.5 m long PSC Beam Deck
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.
Infiller concrete in
Grade: 40 (20)
55
111 T 10 . 3 . 150.
1 :30.
20 dia. stainless steel
dowels at fixed end only.
Lc
50 mm thick wearing surface.
Minimum 135 mm screed concrete.
17 nos. 19 000 long PSC.
beams Drg:No: T/B/508.
30
0
225 dia. displacers of polythene
-tubes filled with light materials
such as saw dust paddy husk etc.
Wearing surface not shown.
55
CROSS SECTION OF 19 000 LONG DECK.
Rain water catch pit. - Refer detail.
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
9 800 Overall width.
56 T 10 . 6 . 300.
36 R 20 . 1 . 450.
REINFORCEMENT DETAILS.
73
19 m long PSC Beam Deck
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)
Rain water catch pit. - Refer detail.
1200 Foot walk.
50 Thick wearing surface.
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
25 m long PSC Beam Deck
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
79
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