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1. Haramaya University, Dept. of Civil Eng. Fundamentals of Bridge Design 1 1

2. Haramaya University, Dept. of Civil Eng. Course Outline Course Content 1. Introduction Types of Bridges and their Selection Bridge Loading Superstructure Bearings and Railings Substructures Culverts and Low Level Water Crossings Evaluation &  5% Class Attendance Grading System  10% Quizzes 15% Tests 20% Course Project & Presentation 2 50% Final examination 2

3. Haramaya University, Dept. of Civil Eng. Chapter One: Introduction Definition Comp o nent s o f a bridge Element s of a Bridg e Project Design Objectives Design Philosophy Genera l desig n requirements 3 3

4. Haramaya University, Dept. of Civil Eng. Wha t i s a b ridge ? - Merriam – Webster Dictionary − Bridge = structure carrying a pathway or roadway over a depression or obstacle American association of s tate Highway and T r ansportation Officials (AASHTO) − Bridge= any structure having an opening not less than 6000mm that forms part of a highway or that is located over or under a highway. − Anything smaller is just a culvert 4 Chapter One: Introduction 4

5. Haramaya University, Dept. of Civil Eng. Components of Bridge Superstructure − Any structure above bearing the roadway − Wearing surface Substructure which support − Foundation (pile/spread footing) − Pier (column) − Abutment 5 Chapter One: Introduction 5

6. Haramaya University, Dept. of Civil Eng. Elements of a Bridge Project Design of bridges requires checklist of items to be included in work plan (typical in planning a bridge project) include the followings Feasibility Phase – determines if the bridge is viable or not − Data collection; − Topographical and hydrographical surveys; − Hydrological information; − Geological and geotechnical information; − Site investigation requirements for soil and rock evaluation − Likely budget Assembly of design criteria – focus at establishing design Standards & data collection − Data and properties on the material to be used − foundation considerations; − Loading and design criteria; − Clearance height and width ;criteria for gradients, alignment, etc,; − Hazards such as impact, accident; 6 − Design life and durability considerations. Chapter One: Introduction 6

7. Haramaya University, Dept. of Civil Eng. Elements of a Bridge Project Cont.… − Provision for services (water, sewage, power, electricity, telephone, communications links) Design phase – perform s desig n pe r t h e establishe d d esig n standa r d & data collected − Choice of bridge: − Detailed design of bridge including foundations, substructure and superstructure; − Production of drawings and documentation, − Estimation of cost and program. Construction phase – implementation of the designed works − Contractual matters; − Construction methods; − Budget and financial control; 7 Chapter One: Introduction 7

8. Haramaya University, Dept. of Civil Eng. Elements of a Bridge Project Cont.… − Quality control; − Supervision of construction; Performance phase – operational and maintenances − Obligations of owner; − Management of facility; − Inspection, maintenance and repair; − Rehabilitation a n d r efurbishment r equi r e m e nt s (change o f loading, w idening, change of use and durability aspects); − Decommissioning and demolition 8 Chapter One: Introduction 8

9. Haramaya University, Dept. of Civil Eng. Design Objectives The objectives in a bridge design are: safety , serviceability, economy, constructability and aesthetics Safety - to ensure public safety in the design by ensuring adequate structural safety Serviceability consists of satisfying requirements of deformation , durability, inspect-ability, maintainability and ride-ability Economy - structural types, span lengths and materials should be selected based on cost. The cost of future expenditures during the projected service life of the bridge should also be considered 9 Chapter One: Introduction 9

10. Haramaya University, Dept. of Civil Eng. Design Objectives cont.… Constructability – bridges should be designed in a manner such that fabrication and erection can be performed without undue difficulty or distress and that construction force effects are within tolerable limits Aesthetics – buildings are designed by Architects and bridges are designed by Civil Engineers . Bridges serve for 100yrs or more and therefore should Complement their surroundings Be graceful in form and present an appearance of adequate strength. 10 Chapter One: Introduction 10

11. Haramaya University, Dept. of Civil Eng. General design requirements (from ERA design manual) Definitions − Free (clear) opening :- face to face distance between vertical components − Total length of bridge :- is the overall distance between the rear wings wall or abutments and should be measured parallel to the alignment of bridge − Effective span :- center to center distance b/n supports − Theoretical span :- center to center distance between bearings 11 Chapter One: Introduction 11

12. Haramaya University, Dept. of Civil Eng. Dimension Footing depth  0.25 m Stem and Head wall/ballast wall of abutment thickness  0.25 m Bearing shelf of abutment or pier  0.40 m Wingwall thickness  0.20 m Pier columns in water, thickness  0.50 m Pier walls thickness  0.30 m Concrete deck depth, excluding any provision for grinding and sacrificial surface  175 mm Concrete deck for pedestrians bridge  150 mm 12 General design requirements cont.… Minimum Dimensions The minimum dimensions listed used in bridge design and construction In designing expansion joints in bridge decks, an additional 20mm space shall be added to the calculated expansion. If the total height of the substructure exceeds 8 m , then 30 mm shall be adde d f o r exceptiona l m ovement s s uc h as s ettlement . 12 Chapter One: Introduction

13. Haramaya University, Dept. of Civil Eng. Application Width (m) Two-lane in “urban” area 10.30 Two-lane in “rural” area 7.30 Single Lane 4.20 Pedestrian Overpass 3.0 13 General design requirements cont.… Width Of Bridge Deck The width is to be measured between the inside of the railings or the curbs. 13 Chapter One: Introduction

14. Haramaya University, Dept. of Civil Eng. Discharge Q (m 3 /s) Vertical clearance (m) - 3.0 0.3 3.0 - 30.0 0.6 30 to 300 0.9 300 1.2 14 General design requirements cont.… Minimum Clearance Above Water, Roads, Railways Etc… − Bridges above water shall normally have a minimum clearance height according to Table unless a refined hydraulic analysis has been made. − Bridge Above roadways clear height of shall normally be 5.1m − Bridges above railways shall have a clearance height of at least 6.1 m − Underpasses for pedestrians and bicycles should not be less than 2.4 m . − For cattle and wildlife underpasses should be designed as the normal 14 height of the actual kind of animal plus 0.5 m. Chapter One: Introduction

15. Haramaya University, Dept. of Civil Eng. General design requirements cont.… Deflection In the a bsence of other c riteria, the f ollowing deflection l imits s hall be considered for concrete , and/or steel construction: − Vehicular load, general ……………………………………Span/500 − Vehicular and/or pedestrian loads………………………....Span/800 − Vehicular load on cantilever arms…………………………Span/300 − Vehicular and/or pedestrian loads on cantilever arms……..Span/400 − Uplift of a free end of the bridge deck ……………………  5 mm. Design Working Life Based on materials − Stone, Steel, Concrete :- 100 years − Timber :- 50 years 15 Chapter One: Introduction 15

16. Haramaya University, Dept. of Civil Eng. Bridge Construction In Ethiopia − On Blue Nile near Alata, Almeida Bridge ( The 1st Bridge ) − During the last 30 years (many bridges were constructed). Slab and T- Girder bridges made using RC , are the most commonly used bridges in Ethiopia . − Most of the bridges so far constructed in the country have now been widened and r e place d becaus e thei r r oadwa y width s we r e t o o r e strictiv e f o r th e s afet y o f accommodating modern traffic 16 Chapter One: Introduction 16

17. Haramaya University, Dept. of Civil Eng. Bridge Construction In Ethiopia cont... 17 Almost 46% of the bridges are found in fair & bad conditions Chapter One: Introduction 17

18. Haramaya University, Dept. of Civil Eng. Bridge Construction In Ethiopia cont... 18 Chapter One: Introduction 18

19. Haramaya University, Dept. of Civil Eng. Bridge Construction In Ethiopia cont... Chapter One: Introduction 19 19

20. Haramaya University, Dept. of Civil Eng. Bridge Construction In Ethiopia cont... 20 Chapter One: Introduction 20

21. Haramaya University, Dept. of Civil Eng. 21 Introduction End of Chapter Many Thanks!! 21

22. Haramaya University, Dept. of Civil Eng. 22 Chapter Two: Types Of Bridges And Their Selection Type s O f Bridges Selectio n o f Bridg e Type Chapter Two: Types Of Bridges And Their Selection 22

23. Haramaya University, Dept. of Civil Eng. Types of Bridges Bridges can be classified on the basis of the following characteristics Functionality as Road bridge , Railway bridge , Pedestrian bridge & Other types (pipelines, utilities, airport structure) Construction material as Steel , Concrete , Timber or combination Span length as short , medium or large . Structural forms as Slab , T-Girder , Box Girder , Arch , Cable stayed , Suspension Span type as single or multi-span . Movements as movable or fixed Bridges Arrangement as curved , skewed , Inclined , straight , .. Life span as Temporary , Permanent 23 Chapter Two: Types Of Bridges And Their Selection 23

24. Haramaya University, Dept. of Civil Eng. Type Based on Functionality Type: Pedestrian bridge 24 Chapter Two: Types Of Bridges And Their Selection 24

25. Haramaya University, Dept. of Civil Eng. Type Based on Functionality Cont.… Type: Road bridge Type: Railway bridge 25 Chapter Two: Types Of Bridges And Their Selection 25

26. Haramaya University, Dept. of Civil Eng. Type Based on Functionality Cont.… Type: Others bridge Type: Others bridge 26 Chapter Two: Types Of Bridges And Their Selection 26

27. Haramaya University, Dept. of Civil Eng. Type Based on Construction material Type: Timber Bridge Type: Steel Bridge 27 Chapter Two: Types Of Bridges And Their Selection 27

28. Haramaya University, Dept. of Civil Eng. T yp e Base d o n Const r uctio n materia l Cont.… C:\Users\user\Desktop\pretentioning.PNG Type: Concrete Bridge Type: Concrete Bridge C:\Users\user\Desktop\posttentioning.PNG 28 Chapter Two: Types Of Bridges And Their Selection 28

29. Haramaya University, Dept. of Civil Eng. Type Based on Span length Culverts (up to 6m) Small Span Bridges (up to 15m) Medium Span Bridges (up to 50m) Large Span Bridges (up to 150m) Extra Large ( Long ) Span Bridges (over 150m) 29 Chapter Two: Types Of Bridges And Their Selection 29

30. Haramaya University, Dept. of Civil Eng. Type Based on Structural forms Type: Slab bridge Type: Girder Bridges 30 Chapter Two: Types Of Bridges And Their Selection 30

31. Haramaya University, Dept. of Civil Eng. Type Based on Structural forms Cont.… Type: Box Girder Type: Arch Bridges 31 Chapter Two: Types Of Bridges And Their Selection 31

32. Haramaya University, Dept. of Civil Eng. Type Based on Structural forms Cont.… Type: Truss Bridge Type: Cable Stayed Bridge 32 Chapter Two: Types Of Bridges And Their Selection 32

33. Haramaya University, Dept. of Civil Eng. Type Based on Structural forms Cont.… Type: Suspension Bridges No suspension bridge is found in Ethiopia 33 Chapter Two: Types Of Bridges And Their Selection 33

34. Haramaya University, Dept. of Civil Eng. Type Based on Movements Type: Movable Bridge 34 Chapter Two: Types Of Bridges And Their Selection 34

35. Haramaya University, Dept. of Civil Eng. Type Based on Span type 35 Chapter Two: Types Of Bridges And Their Selection 35

36. Haramaya University, Dept. of Civil Eng. Unique Bridges Around the World Cont.… Pedestrian Bridge, Texas This beautiful arched bridge in Lake Austin was a private build by Miro Rivera Architects and is used to connect the client's main house to the smaller guest house on the other side of the water. The idea was to make the bridge seem as natural as possible within its surroundings and to do this they made the decking and reed-like hand rails as imperfect as possible. The result is a bridge that looks extremely fragile but definitely worth the risk. 36 Chapter Two: Types Of Bridges And Their Selection 36

37. Haramaya University, Dept. of Civil Eng. Unique Bridges Around the World Cont.… Octavio Frias d e Oliveira Bridge , Sao Paulo, Brazil The Octavio Frias de Oliveira Bridge is a stunning x-shaped cable-stayed bridge that crosses the Pinheiros River in Sao Paulo. It's design is unique in that the 2 curved decks of the bridge cross each other through its x-shaped supporting tower, an illuminated structure that stands 450ft tall and has attached to it 144 steel cables. 37 Chapter Two: Types Of Bridges And Their Selection 37

38. Haramaya University, Dept. of Civil Eng. Unique Bridges Around the World Cont.… Kintaikyo, Iwakuni, Japan The original Kintai Bridge was built in 1673 and didn't stand very long until it was damaged due to flooding. It was then rebuilt and survived for more than 200 years until a typhoon battered it to death in 1950. The bridge that stands now over the Nishiki Riveris the 3rd build and looks magnificent, it's 5 wooden arches displaying an incredible amount of detail and craftmanship. Interesting fact: no nails or 38 bolts have been used to build the arches, only clamps and wires . Chapter Two: Types Of Bridges And Their Selection 38

39. Haramaya University, Dept. of Civil Eng. Unique Bridges Around the World Cont.… 39 Juscelino Kubitschek Bridge, Brasilia, Brazil The JK Bridge in Brasilia is a lesson in elegant bridge design. The 3 huge arches diagonally hopping over the deck of the bridge give the structure an amazing visual fluidity and make the whole 1.2km bridge look effortlessly cool. Since being built the bridge has won awards for its design but is still massively underappreciated on a wider scale. Chapter Two: Types Of Bridges And Their Selection 39

40. Haramaya University, Dept. of Civil Eng. Unique Bridges Around the World Cont.… Beipanjian g River Railroad Bridge, Guizhou, China 40 Chapter Two: Types Of Bridges And Their Selection 40

41. Haramaya University, Dept. of Civil Eng. Selection of Bridge Type Criteria to select bridge include: Geometric Condition of the Site: depend on − The horizontal and vertical alignment of the highway route and − The clearances above and below the road way. If the alignment is on a curve, box and slab type bridges are best options Subsurface Conditions of the Site: The foundation soils at a site will determine whether abutments and piers can be founded on spread footings, driven piles & etc. Functional Requirements − The bridge must also function to carry present and future traffic volumes. Decisions must be made on the number of lanes of traffic, inclusion of sidewalks and/or bike paths, whether width of the bridge deck should include medians, drainage of the surface waters, snow removal, and future wearing surface. 41 Chapter Two: Types Of Bridges And Their Selection 41

42. Haramaya University, Dept. of Civil Eng. Selection of Bridge Type If future widening or replacement of bridge decks is a concern girder type bridge is best option Aesthetics − It should be the goal of every bridge designer to obtain a positive aesthetic response to the bridge type selected. Economics And Ease Of Maintenance − It is difficult to separate first cost and maintenance cost over the life of the bridge when comparing the economics of different bridge types. A general rule is that the bridge with the minimum number of spans, fewest deck joints, and widest spacing of girders, will be the most economical. Generally, concrete structures require less maintenance than steel structures 42 Chapter Two: Types Of Bridges And Their Selection 42

43. Haramaya University, Dept. of Civil Eng. Selection of Bridge Type Cont.… Construction and erection considerations: − In general, the larger the prefabricated or precast member, the shorter the construction time. However, the larger the members, the more difficult they are to transport and lift into place. − The availability of skilled labour and specified materials will also influence the choice of a particular bridge type. Legal Considerations: − Applicable laws like environmental laws also govern the type of bridge. 43 Chapter Two: Types Of Bridges And Their Selection 43

44. Haramaya University, Dept. of Civil Eng. 44 Types Of Bridges And Their Selection End of Chapter Many Thanks!! 44