Scaffold Engineering Lecture 1 A .


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Bridge Engineering Lecture 1 A. Planning of Bridges Dr. Shahzad Rahman. Bridge Planning. Traffic Studies Hydrotechnical Studies Geotechnical Studies Environmental Considerations Alternatives for Bridge Type Economic Feasibility Bridge Selection and Detailed Design. Traffic Studies.
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Connect Engineering Lecture 1 A Planning of Bridges Dr. Shahzad Rahman

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Bridge Planning Traffic Studies Hydrotechnical Studies Geotechnical Studies Environmental Considerations Alternatives for Bridge Type Economic Feasibility Bridge Selection and Detailed Design

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Traffic Studies River New Road Link Existing Network New Bridge City Center

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Traffic Studies Traffic contemplates should be done to find out the measure of activity that will use the New or Widened Bridge This is expected to decide Economic Feasibility of the Bridge For this Services of a Transportation Planner as well as Traffic Engineer are Required Such Studies are finished with help of Traffic Software, for example, TransCAD, EMME2 and so on

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Traffic Studies Traffic Studies ought to give taking after data Traffic on Bridge quickly in the wake of opening Amount of movement at different circumstances amid life of the Bridge Traffic Mix i.e. number of motorcars, transports, overwhelming trucks and different vehicles Effect of the new connection on existing street organize Predominant Origin and Destination of movement that will utilize the Bridge Strategic significance of the new/enhanced Bridge

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Hydrotechnical Studies A careful comprehension of the waterway and waterway administration is critical to arranging of Bridge over a waterway Hydrotechnical Studies ought to include: Topographic Survey 2km upstream and 2km downstream for little streams including Longitudinal segment and X-segments For huge streams 5kms U/S and 2kms D/S ought to be reviewed Navigational Requirements

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Hydrotechnical Studies Scale of the topographic guide 1:2000 for little waterways 1:5000 for huge waterways The High Flood Levels and the Observed Flood Level ought to be shown outline Number of x-segments ought to be taken and HFL and OFL set apart on them River Bed studying would require soundings

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Hydrotechnical Studies Catchment Area Map Scale suggested 1:50,000 or 1:25,000 Map can be made utilizing GT Sheets accessible from Survey of Pakistan All Reservoirs, Rain Gages Stns., River Gage Stns., ought to be set apart on guide Catchment of River Indus

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Hydrotechnical Studies River Catchment Area

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Hydrotechnical Studies River Catchment Boundaries with Tributaries

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Hydrotechnical Studies River Catchment Boundaries with Sub-Basin Boundaries

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Hydrological Data Following Hydrological Data ought to be gathered: Rainfall Data from Rain Gage Stations in the Catchment Area Isohyetal Map of the Catchment Area indicating shapes of Annual Rainfall Hydrographs of Floods at River Gage Stations Flow Velocities Sediment Load in River Flow amid surges

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Hydrologic Data Example of an ISOHYETAL MAP

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Hydrologic Data Example of River Hydrograph

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Hydrologic Data Example of a River Hydrograph

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Design Flood Levels AASHTO Gives Following Guidelines for Estimating Design Flood Levels

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Design Flood Levels AASHTO Gives Following Guidelines for Estimating Design Flood Levels

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Design Flood Levels CANADIAN MINISTRY OF TRANSPORTATION Gives Following Guidelines for Estimating Design Flood Levels

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Design Flood Levels CANADIAN MINISTRY OF TRANSPORTATION Gives Following Guidelines for Estimating Design Flood Levels

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Design Flood Levels FREEBOARD REQUIREMENTS CANADIAN MINISTRY OF TRANSPORTATION Gives Following Guidelines for Estimating Freeboard Requirements

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Estimating Design Flood Peak Discharge at Stream or River Location Depends upon: Catchment Area Characteristics Size and state of catchment range Nature of catchment soil and vegetation Elevation contrasts in catchment and amongst catchment and extension site area Rainfall Climatic Characteristics Rainfall power term and its spatial appropriation Stream/River Characteristics Slope of the waterway Baseline stream in the stream River Regulation Facilities/Dams, Barrages on the stream

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Methods of Estimating Design Flood Empirical Methods Flood Frequency Analysis Rational Method

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Empirical Methods of Peak Flood Estimation Empirical Formulae have been resolved that relate Catchment Area and other climate or stream parameters to Peak Flood Discharge Popular Formulae for Indo-Pak are: Dickens Formula Q = Discharge in Cusecs A = Catchment Area in Sq. Miles Inglis Formula Ryve\'s Formula C = 450 for zones inside 15 miles off drift 560 between 15 – 100 miles off drift

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Flood Frequency Analysis Method Usable at gaged locales where stream release information is accessible for adequate time in past Following Methods are ordinarily utilized Normal Distribution Method Log-Normal Distribution Log-Plot Graphical Method

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Flood Frequency Analysis Method Normal Distribution Method Based on Assumption that occasions take after the state of Standard Normal Distribution Curve

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Normal Distribution Method likelihood Q P = Discharge Associated with Probability of Occurrence P QM = Mean Discharge over the information set σ Q = Standard Deviation of the Discharge information set KTr = Frequency figure relating to Probability of Occurrence P

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Example of Peak Flood Estimation Flood

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Example of Peak Flood Estimation Flood

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Example of Peak Flood Estimation Flood

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Log-Normal Distribution Method Yields better Results Compared to Normal Distribution Method likelihood Log Q or Ln Q lnQ P = Log of Discharge Associated with Probability of Occurrence P lnQ M = Mean of Log Discharge over the information set σ lnQ = Standard Deviation of the Log of Discharge information set K Tr = Frequency calculate relating to Probability of Occurrence P Q P = Antilog (ln Q P ) = Discharge Associated with Probability of Occurrence P

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Example of Peak Flood Estimation Flood Log-Plot Method

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Rational Method of Peak Flood Estimation Attempts to give gauge of Design Discharge considering: The Catchment Characteristics Rainfall Intensity Discharge Characteristics of the Catchment Q = Design Discharge I T = Average precipitation force (in/hr) for some repeat interim, T amid that timeframe equivalent to Tc. Tc = Time of Concentration A = Area of the catchment in Sq. miles C = Runoff coefficient; division of overflow, communicated as a dimensionless decimal part, that shows up as surface spillover from the contributing seepage territory.

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Rational Method of Peak Flood Estimation Time of Concentration can be evaluated utilizing Barnsby Williams Formula which is broadly utilized by US Highway Engineers L = Length of Stream in Miles A = Area of the catchment in Sq. miles S = Average level from source to site in percent

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Rational Formula – Runoff Coefficient

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Geotechnical Studies Geotechnical Studies ought to give the accompanying Information: The sorts of Rocks, Dips, Faults and Fissures Subsoil Ground Water Level, Quality, Artesian Conditions if any Location and degree of delicate layers Identification of hard bearing strata Physical properties of soil layers

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Geotechnical Studies Example Geological Profile: Cross segment of the dirt on the course of the Paris The outline above demonstrates the traverse the Seine by means of the Bir Hakeim connect and the limestone quarries under Trocadéro

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Geotechnical Studies Example: Cross segment of the Kansas River, west of Silver Lake, Kansas Typical Borehole

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Seismic Considerations Source: Building Code of Pakistan

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Tectonic Setting of the Bridge Site Source: Geological Survey of Pakistan

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Environmental Considerations Impact on Following Features of Environment need to considered: River Ecology which incorporates: Marine Life Wildlife along waterway banks Riverbed Flora and fauna along waterway banks Impact upon abodes along the stream if any Impact upon urban environment if the extension in a urban zone Possible effect upon archeological destinations in region

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Bridge Economic Feasibility Economic Analysis is Required at Feasibility Stage to legitimize consumption of open or private supports A Bridge is the most costly part of a street transportation organize Types of Economic Analyses Cost Benefit Ratio Analysis Internal Rate of Return (IRR) Analysis

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Bridge Economic Analysis/Life Cycle Cost Analysis (LCCA) Costs Stream Benefits Stream Time Construction Stage Project Start Date Project Life End Date Salvage Value Project Life

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Project Cost Benefit Analysis The target of LCCA is to Estimate the expenses connected with the Project amid Construction an its administration life. These incorporate routine support costs + Major Rehab Costs Estimate the Benefits that will collect from the Project including time reserve funds to street clients, advantages to business exercises and so forth. Cut down the expenses and advantages to a typical reference pt. in time i.e. only preceding begin of venture (basic leadership time) Facilitate basic leadership about monetary possibility by computing quantifiable measuring sticks, for example, Benefit to Cost Ratio (BCR) and Internal Rate of Return (IRR) Note: Salvage Value might be taken as a Benefit This incorporates cost of the Right-of-Way and substructure

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What is Life Cycle Cost? A financial examination system that utilizations building inputs Compares contending choices considering every single critical cost Expresses brings about equal dollars (display worth)

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Time Period of Analysis Normally level with for all options Should incorporate no less than one noteworthy restoration Needed to catch the genuine monetary advantage of every option Bridge configuration today depends on a probabilistic model of 100 years

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Bridge Economic Analysis/Life Cycle Cost Analysis (LCCA) Costs Stream Time Benef

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