Highway and Railway Geometric Design PDF

MODULE 4 GEOMETRIC DESIGN FOR HIGHWAYS AND RAILWAYS  Geometric Design of Highways The geometric design of highways involves the physical dimensions and layout of roadways, including alignment, cross-sectional elements, and sight distance, to ensure safety and efficiency.  Geome...

MODULE 4 GEOMETRIC DESIGN FOR HIGHWAYS AND RAILWAYS  Geometric Design of Highways The geometric design of highways involves the physical dimensions and layout of roadways, including alignment, cross-sectional elements, and sight distance, to ensure safety and efficiency.  Geometric Design of Highways The geometric design of highways involves the physical dimensions and layout of roadways, including alignment, cross-sectional elements, and sight distance, to ensure safety and efficiency. Key Elements of Highway Geometric Design 1.Horizontal Alignment ❑ Tangents (Straight Sections): Straight portions of the roadway used to maintain high-speed travel. ❑ Curves: Used to change the direction of the road. Key factors include curve radius, curve length, superelevation (banking), and transition curves. 2. Vertical Alignment ❑Grades (Slopes): The slope of the road, crucial for maintaining vehicle speed, especially on uphill or downhill segments. ❑Vertical Curves: Provide smooth transitions between different grades, enhancing safety and comfort. Crest curves handle upward changes, while sag curves handle downward changes. 3. Cross-Section Elements ❑Lanes: Define the space for vehicle movement, typically 3.0 to 3.6 meters wide. ❑Shoulders: Provide recovery space for vehicles, improve sight distance, and offer space for emergency stops. ❑Medians: Separate opposing traffic flows, enhance safety, and reduce headlight glare. ❑Side Slopes and Drainage Ditches: Ensure proper drainage and prevent water accumulation on the roadway. 4. Intersection and Interchanges ❑At-Grade Intersections: Points where roads cross at the same level; design focuses on traffic control, turning lanes, and visibility. ❑Grade-Separated Interchanges: Structures like overpasses and underpasses used to separate conflicting traffic flows, typically found on freeways. 5. Sight Distance ❑ Stopping Sight Distance (SSD): The distance required for a driver to perceive a hazard and stop the vehicle safely. ❑ Passing Sight Distance (PSD): Required distance for a vehicle to safely overtake another vehicle on a two-lane road. 6. Clear Zones and Roadside Design ❑ Clear Zones: Safe recovery areas free of fixed obstacles. ❑ Roadside Barriers: Protect vehicles from hazardous drop- offs or obstacles. 7. Design Speed ❑ The speed selected as a basis for the geometric features of the road, influencing lane width, curve radii, and sight distances.  Geometric Design of Railways The geometric design of railways focuses on the layout and dimensions of the track, ensuring smooth and safe operations of trains. The design addresses horizontal and vertical alignment, cross-section, and station design.  Key Elements of Railway Geometric Design 1.Horizontal Alignment ❑ Tangents: Straight track segments that allow for maximum train speeds. ❑ Curves: Required to change direction; designed with appropriate radius, transition curves, and cant (superelevation) to manage centrifugal forces. 2. Vertical Alignment ❑ Grades: Longitudinal slopes of the railway track, kept as gentle as possible to minimize traction and braking requirements. ❑ Vertical Curves: Smooth transitions between grades to enhance passenger comfort and maintain train stability. 3. Track Cross-Section ❑ Rails: Steel tracks supported by sleepers, maintaining the gauge. ❑ Ballast: Crushed stone that provides stability, drainage, and load distribution. ❑ Subgrade: The foundational layer beneath the ballast that supports the entire track structure. 4. Stations and Platforms ❑ Station Layout: Designed for efficient passenger movement, train operations, and accessibility. ❑ Sleepers (Ties): Support the rails and maintain their position and gauge. ❑ Platform Design: Includes height, length, and width to ensure safe boarding and alighting from trains. 5. Turnouts and Crossings ❑ Crossings (Diamonds): Enable track intersections, allowing two tracks to cross without the need for level separation. 6. Safety and Signaling Systems ❑ Turnouts (Switches): Allow trains to change tracks, critical in junctions and yards. ❑ Geometric design integrates safety features and signaling systems to manage train movements, ensuring smooth and conflict-free operations.  References American Association of State Highway and Transportation Officials (AASHTO), A Policy on Geometric Design of Highways and Streets, 7th Edition, 2018. Highway Capacity Manual (HCM), 6th Edition, 2016. Transportation Research Board, National Academies of Sciences, Engineering, and Medicine. Manual on Uniform Traffic Control Devices (MUTCD), 2009 Edition. Federal Highway Administration (FHWA). AREMA Manual for Railway Engineering, 2021. American Railway Engineering and Maintenance-of-Way Association. Design of Highway and Railway Geometric Elements, Institute of Transportation Engineers (ITE), 2020. O’Flaherty, C. A., Highways: The Location, Design, Construction, and Maintenance of Road Pavements, 2002. Turner, D., and Ellis, M., "Railway Engineering: An Integral Approach", 2017.  Assignment # 2 Expound and discuss the following questions for at least 200 words each. Write your answers using pen (black ink) and paper (short bond paper). 1. What are the challenges in the utilization of highway infrastructures in the Philippines a) by the governing bodies b) passengers or commuters? 2. What are the challenges in the utilization of railroad infrastructures in the Philippines a) by the governing bodies b) passengers or commuters?  FORMAT __________________________________________________________________________ HIGHWAY AND RAILROAD ENGINEERING TCIE 3-3 3-6pm Wed Room: 3105 ASSIGNMENT NO. 2 Dela Cruz, Juan P. Prof: Engr. Crispin S. Lictaoa BSCE 22-1-1234 Date: August 28, 2024 __________________________________________________________________________ 1. Write the question # 1 here. Answers: 2. Write the question # 2 here. Answers:  MODULE 4A HIGHWAY GEOMETRIC DESIGN DESIGN OF HORIZONTAL ALIGNMENT FIELD SURVEY INFORMATION AND INVESTIGATION PRELIMINARY SURVEY FIELD SURVEY INFORMATION AND INVESTIGATION PRELIMINARY SURVEY Objectives of preliminary survey are: To survey the various alternative alignments proposed after the reconnaissance and to collect all the necessary physical information and detail of topography, drainage, and soil. To compare the different proposals in view of the requirements of the good alignment. To estimate quantity of earthwork materials and other construction aspect and to workout the cost of the alternate proposals. FIELD SURVEY INFORMATION AND INVESTIGATION PRELIMINARY SURVEY Methods of preliminary survey are: Conventional approach | survey party carries out surveys using the required field equipment, taking measurement, collecting topographical and other data and carrying out soil survey. Modern rapid approach | by aerial survey taking the required aerial photographs for obtaining the necessary topographic and other maps including details of soil and geology. Finalize the best alignment from all considerations by comparative analysis of alternative routes. FIELD SURVEY INFORMATION AND INVESTIGATION PRELIMINARY SURVEY: HORIZONTAL ALIGNMENT Horizontal alignment involves circular curves, transition curves, and tangents. It aims to ensure safe and uninterrupted travel at a consistent speed for extended road segments. Design considerations include safety, functional classification, desired speed, topography, vertical alignment, construction cost, cultural development, and aesthetics. Properly balancing these factors results in an alignment that is both safe and cost-effective, while also harmonizing with the land's natural contour. A. Circular Curves ❑ Simple Curve – a circular curve is an arc with a single constant radius connecting two tangents. The most common type of curve used in a horizontal alignment. ❑ Compound Curve - composed of two or more adjoining circular arcs of different radii. The centers of the arcs of the compound curves are located on the same side of the alignment. ❑ Broken-Back Curve - the combination of a short length of tangent between two circular curves. ❑ Reverse Curve - consists of two adjoining circular arcs with the arc centers located on opposite sides of the alignment. ❑ Note: Compound and reverse curves are generally used only in specific design situations such as mountainous terrain.  GEOMETRIC DESIGN OF ROADS is the branch of highway engineering concerned with the positioning of the physical elements of the roadway according to standards and constraints. The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage. Geometric design also affects an emerging fifth objective called "livability," which is defined as designing roads to foster broader community goals, including providing access to employment, schools, businesses and residences, accommodate a range of travel modes such as walking, bicycling, transit, and automobiles, and minimizing fuel use, emissions and environmental damage.  GEOMETRIC DESIGN OF ROADS Geometric roadway design can be broken into three main parts: 1. Alignment 2. Profile 3. Cross-section  DESIGN OF HORIZONTAL ALIGMENT Horizontal Curves-provides a transition between two tangent lengths of roadway.  DESIGN OF HORIZONTAL ALIGMENT Types of Curves: 1. Simple Curve 2. Compound Curve 3. Reverse Curve 4. Spiral Curve  Simple Curve ❑ A simple curve is a circular arc, extending from one tangent to the next. ❑ The point where the curve leaves the first tangent is called the "point of curvature" (P.C.) ❑ The point where the curve joins the second tangent is called the "point of tangency" (P.T.). The P.C. and P.T. are often called the tangent points.  Simple Curve ❑ If the tangent be produced, they will meet in a point of intersection called the "vertex". ❑ The distance from the vertex to the P.C. or P.T. is called the "tangent distance". ❑ The distance from the vertex to the curve is called the "external distance" (measured towards the center of curvature). ❑ While the line joining the middle of the curve and the middle of the chord line joining the P.C. and P.T. is called the "middle ordinate". Simple Curve  Sample Problem Simple Curve A simple curve of the proposed extension of Aguinaldo Highway have a direction of tangent AB which is due north and tangent BC bearing N50°E. Point A is at the P.C. whose stationing is 20+130.46. The degree of curve is 4°. 1. Compute the long chord of the curve. 2. Compute the stationing of point D on the curve along a line joining the center of the curve which makes an angle of 54° with the tangent line passing thru the P.C. 3. What is the length of the line from D to the intersection of the tangent AB? Sample Problem Simple Curve  Sample Problem Simple Curve A simple curve have tangents AB and BC intersecting at a common point B. AB has an azimuth of 180° and BC has an azimuth of 230°. The stationing of the point of curvature at A is 10+140.26. If the degree of the curve of the simple curve is 4°: 1. Compute the length of the long chord from A. 2. Compute the tangent distance AB of the curve. 3. Compute the stationing of a point “X” on the curve on which a line passing through the center of the curve makes an angle of 58° with the line AB, intersects the curve at point “X”. Sample Problem Simple Curve  Sample Problem Simple Curve A simple curve connects two tangents AB and BC with bearing N85°30’E and S68°30E’ respectively. If the stationing of the vertex is 4+360.20 and the stationing of PC is 4+288.40. Determine the following: 1. Radius of the curve 2. External Distance 3. Middle Distance 4. Chord Distance 5. Length of the curve  Compound Curves ❑ Compound Curve consists of two or more consecutive simple curves having different radius, but whose centers lie on the same side of the curve, likewise any two consecutive curves must have a common tangent at their meeting point. ❑ When two such curves lie upon opposite sides of the common tangent, the two curves then turns a reversed curve. ❑ In a compound curve, the point of the common tangent where the two curves join is called the point of compound curvature (P.C.C.) Compound Curves  Sample Problem Compound Curve The long chord from the P.C. to the P.T. of a compound curve is 300 meters long and the angles it makes with the longer and shorter tangents are 12° and 15° respectively. If the common tangent is parallel to the long chord: 1. Find the radius of the first curve. 2. Find the radius of the 2nd curve. 3. If stationing of P.C. is 10+204.30, find the stationing of P.T. Sample Problem Compound Curve Sample Problem Compound Curve  Reversed Curves ❑ A reversed curve is formed by two circular simple curves having a common tangent but lies on opposite sides. ❑ The method of laying out a reversed curve is just the same as the deflection angle method of laying out simple curves. ❑ At the point where the curve reversed in its direction is called the Point of Reversed Curvature. ❑ After this point has been laid out from the P.C., the instrument is then transferred to this point (P.R.C.). With the transit at P.R.C. and a reading equal to the. total deflection angle from the P.C. to the PRC., the P.C. is backsighted. ❑ If the line of sight is rotated about the vertical axis until horizontal circle reading becomes zero, this line of sight falls on the common tangent. The next simple curve could be laid out on the opposite side of this tangent by deflection angle method. Reversed Curves Reversed Curves Reversed Curves Sample Problem No. 1 Reversed Curve Sample Problem Reversed Curve  Sample Problem No. 2 (Reversed Curve) Two converging tangents have azimuth of 300° and 90° respectively, while that of the common tangent is 320°. The distance from the point intersection of the tangents of PI of the second curve is 100m while the station of PI of the first curve is 10+432.24. If the radius of the first curve is 285.40m, determine the following: a. Radius of the second curve b. Stationing of PRC c. Stationing of PT  Midterm Seatwork No. 1 (30 points) Given the perpendicular distance between two parallel tangents equal to 6m, the central angle being equal to 7° and the radius of the curvature of the first curve equal to 163.8 meters. Find the radius of the second curve of the reversed curve. Illustrate the R.C.  MODULE 5 STRUCTURAL DESIGN OF RAILWAYS AND PAVEMENTS The structural design of railways and pavements involves ensuring these systems can withstand loads and environmental factors while providing safety and durability. Railway Structural Design 1.Track Structure: ❑ Rails: Typically made of steel, rails must be designed to handle the dynamic loads from trains. They are laid on sleepers or ties. ❑ Sleepers/Ties: Wooden, concrete, or steel beams that support and maintain the gauge of the rails. ❑ Ballast: Crushed stone or gravel placed under and around the sleepers to support the load and facilitate drainage. ❑ Subgrade: The prepared ground or foundation that the track structure rests upon. It must be stable and capable of supporting the railway loads. 2. Track Geometry: ❑ Horizontal Alignment: Curves need to be designed to accommodate the centrifugal forces and ensure safe train operation. ❑ Vertical Alignment: Includes gradients and transitions that must be managed to prevent excessive wear and ensure safe acceleration and braking. 3. Load Considerations: ❑ Dynamic Loads: Trains exert dynamic loads that vary with speed, load, and track conditions. This needs to be accounted for in design. ❑ Static Loads: The static load from the weight of the rail and sleepers also needs to be supported by the subgrade. 4. Maintenance: ❑ Regular maintenance is crucial to address issues such as track deformation, ballast degradation, and rail wear. 5. Drainage: ❑ Proper drainage systems must be incorporated to prevent water accumulation, which can weaken the track structure and cause damage.  Pavement Structural Design 1. Pavement Layers: ❑ Surface Course: This is the top layer and must provide a smooth, skid- resistant surface. Materials include asphalt or concrete. The design involves selecting the appropriate mix and thickness to handle traffic loads and environmental conditions. ❑ Base Course: This layer distributes the loads from the surface course to the subbase. It typically consists of crushed stone or gravel. The design focuses on achieving the required strength and stability. ❑ Subbase: The subbase improves load distribution and provides additional support. It is often composed of granular materials that facilitate drainage. ❑ Subgrade: The natural soil or rock layer underneath the pavement. It must be adequately prepared and stabilized to support the pavement structure. Geotechnical analysis is used to assess the suitability of the subgrade. 2. Load Distribution: ❑ Traffic Loads: Pavements must be designed to support various vehicle loads, including heavy trucks and cars. Design methods like those outlined in the AASHTO (American Association of State Highway and Transportation Officials) guide are used to determine the required pavement thickness and materials. ❑ Environmental Loads: Pavements must withstand environmental conditions such as temperature variations, precipitation, and freeze-thaw cycles. The design includes provisions for thermal expansion and contraction. 3. Design Considerations: ❑ Structural Capacity: The pavement must be designed to distribute loads to the underlying layers without causing excessive deformation. Structural capacity is determined based on expected traffic loads and material properties. ❑ Durability: The materials used must be durable enough to resist wear from traffic and environmental conditions. This includes selecting appropriate mixes and construction techniques. 4. Drainage: ❑ Pavement Drainage: Effective drainage systems are crucial to prevent water infiltration that can weaken the pavement. This includes designing appropriate cross-slopes and drainage channels. 5. Maintenance: ❑ Pavement Maintenance: Regular maintenance activities include crack sealing, pothole repair, and resurfacing to address wear and extend the pavement's lifespan.  References “Introduction to Railway Engineering” by Joseph A. Dyer. This book provides foundational knowledge on railway track design and maintenance. AREMA Manual for Railway Engineering: A comprehensive guide that covers various aspects of railway engineering, including track structure and geometry. “The Track and Track Work” by the International Union of Railways (UIC). This document offers detailed information on track design and construction standards. “Principles of Pavement Design” by E. J. Yoder and M. W. Witczak. This book covers the fundamental principles of pavement design and analysis. AASHTO Guide for Design of Pavement Structures: Provides guidelines for the design of pavement structures, including material selection and layer thicknesses. “Asphalt Pavements: A Practical Guide to Design, Production, and Maintenance” by Bob M. Green and R. L. Parsons. This guide offers practical insights into the design and maintenance of asphalt pavements.  MODULE 6 Failures, Maintenance and Rehabilitation of Transportation Structure “Transportation infrastructure, including railways and pavements, is subject to various types of failures over time. Understanding these failures, and implementing appropriate maintenance and rehabilitation strategies, is crucial for ensuring safety, reliability, and longevity.”  Railway Infrastructure Failures: ❑ Track Failures: These can include rail defects (e.g., cracks or breaks), misalignment, and excessive wear. Track failures can be caused by dynamic loads, poor maintenance, or material fatigue. ❑ Sleeper/Tie Failures: Wooden sleepers may decay, while concrete or steel sleepers can suffer from cracking or corrosion. Poor drainage or overloading can exacerbate these issues. ❑ Ballast Failures: Ballast can become degraded over time due to traffic loads, weather conditions, and poor drainage. This leads to track instability and misalignment. ❑ Subgrade Failures: Weak or unstable subgrade can lead to track settlement and deformation. This can be due to inadequate compaction, water infiltration, or soil erosion.  Pavement Failures: ❑ Cracking: Common types include transverse, longitudinal, and alligator cracks. Cracking can result from thermal stress, load-induced stress, or poor construction practices. ❑ Potholes: These are depressions or holes that form due to the combined effects of traffic loads and moisture infiltration. Freeze-thaw cycles often exacerbate pothole formation. ❑ Rutting: Permanent deformations in the wheel paths caused by the accumulation of plastic deformations in the asphalt layer. Rutting can be caused by heavy traffic loads and high temperatures. ❑ Settlement: Uneven settling or subsidence can occur due to inadequate compaction of the subgrade, changes in moisture content, or soil erosion.  MAINTENANCE 1. Railway Maintenance: ❑ Track Inspection and Repair: Regular inspections are conducted to identify defects in rails, sleepers, and track alignment. Maintenance tasks include rail grinding, replacing defective components, and adjusting track alignment. ❑ Ballast Maintenance: Periodic renewal of ballast is necessary to maintain track stability. This includes reballasting, tamping to restore proper track geometry, and ensuring effective drainage. ❑ Subgrade Stabilization: Techniques such as soil stabilization, drainage improvement, and reinforcing with geotextiles are used to address subgrade issues and prevent further settlement. 2. Pavement Maintenance: ❑ Crack Sealing: Applying sealant to cracks helps prevent water infiltration and further damage. This is a common preventive maintenance measure. ❑ Pothole Repair: Potholes are typically repaired using cold mix or hot mix asphalt. Proper preparation and compaction are essential to ensure durability. ❑ Surface Sealing: Applying a surface sealant or overlay can extend the life of the pavement by providing a new wearing surface and protecting against moisture and UV damage. ❑ Rejuvenation: For asphalt pavements, rejuvenating agents can be applied to restore the flexibility and reduce the effects of aging.  REHABILITATION 1. Railway Rehabilitation: ❑ Track Renewal: Involves replacing old rails and sleepers, and sometimes the ballast. This is often necessary when the track has reached the end of its service life. ❑ Subgrade Reconstruction: If the subgrade has deteriorated significantly, it may need to be reconstructed or reinforced to restore its load-bearing capacity. ❑ Upgrading Track Structure: This may include improving track geometry, adding additional support structures, or modernizing signaling and control systems. 2. Pavement Rehabilitation: ❑ Overlay: Adding a new layer of asphalt or concrete over the existing pavement can address surface distresses and improve the structural capacity. This is known as a surface or structural overlay. ❑ Full-Depth Reclamation (FDR): This involves milling the entire pavement layer, mixing it with stabilizing agents, and then re-laying it. FDR is used when the existing pavement is severely damaged. ❑ Pavement Reconstruction: This is a more extensive process that involves completely removing and rebuilding the pavement structure, including the base and subbase layers. ❑ Milling and Resurfacing: Milling involves removing the top layer of the pavement to a specified depth and then resurfacing it with new material. This method is often used to correct surface distresses and improve ride quality.  References “Introduction to Railway Engineering” by Joseph A. Dyer. This book provides an overview of railway track design, maintenance, and rehabilitation. AREMA Manual for Railway Engineering: This comprehensive guide covers track structure, maintenance practices, and rehabilitation techniques. “The Track and Track Work” by the International Union of Railways (UIC). Detailed information on track maintenance and failure management. “Principles of Pavement Design” by E. J. Yoder and M. W. Witczak. This book covers the design, failure mechanisms, and rehabilitation strategies for pavements. AASHTO Guide for Design of Pavement Structures: Offers guidelines on the design, maintenance, and rehabilitation of pavement structures. “Asphalt Pavements: A Practical Guide to Design, Production, and Maintenance” by Bob M. Green and R. L. Parsons. This guide includes practical insights on pavement maintenance and rehabilitation techniques.  MODULE 6A THEORIES AND PROCEDURES ON VISUAL ROAD CONDITION (ROCOND) ASSESSMENT Road Condition (RoCond) Survey Objectives: Record, describe and measure the condition of the road at the time of rating Provide a sequence of recorded condition that can be analyzed to indicate performance trends Provide condition data for analysis in the Pavement Management System (PMS), Routine Maintenance Management System (RMMS), and eventually for budgeting in the Multi-Year Programming System (MYPS).  Procedures in RoCond Assessment I. Survey Preparation Survey schedule and form a survey team. Survey instruments, survey forms, service vehicle, etc. Prepare survey gadgets, food and water. Survey Equipment: Measuring tools and Safety gears Service Vehicle Measuring Wheel/Measuring Crack Width Scale Tape Straight Edge, 1.2m long & Spray Paint (or other appropriate road Measuring Wedge Field Worksheets/pen or marking materials, e.g. Chalk, Charcoal) pencil Jackets/Long Sleeves Shirt Hats/Caps Rubber Shoes Safety devices for Traffic guide: Safety Vests Traffic Guidance Cones Appropriate Advance Warning Signs (Flags, Tarpaulin, etc…) Straight Edge and Measuring Wedge  Procedures in RoCond Assessment II. RoCond Survey Activities a) Ensure the observance of proper road safety precaution, before and during the survey.  Procedures in RoCond Assessment II. RoCond Survey Activities b) Establish RATING SEGMENTS along the entire road sections. c) Establish the GAUGING LENGTH for every rating segment created and mark every 100m distance thereafter within the segment. d) Mark the measured distances with paint along the edge of the pavement or other adjacent permanent references in increasing direction. These markings will be the basis of the conduct of surveys for the succeeding years to avoid re-measurement of distances and shorten the duration of survey. e) Start assessing, measuring and recording the distresses found along each segment in accordance with RoCond Procedures and Guidelines. Road Condition Survey Lane Designation: GENERAL RULE: Negative Direction Asphalt Surface Positive Direction If there are road Negative Direction widening in both outer lane. The designation of Positive Direction Lane number will change.  Elements of RoCond Assessment ✓ RATING SEGMENT ✓ GAUGING LENGTH ✓ ROAD DISTRESSES/DEFECTS I. RATING SEGMENTS Segmenting Procedure RATING GENERAL RULE: SEGMENT Assessment of segments designated as between consecutive kilometer posts of homogenous surface types but should not exceed 1300-meters. Segment 1 Concrete Surface L ≤ 1300m  Segmenting Procedure: RATING SEGMENT a.) If the distance between two (2) consecutive kilometer posts exceeds 1300m of homogenous surface type, adopt the 1000 meter rating segment and the remaining length should be considered as another segment.  Segmenting Procedure: RATING SEGMENT b.) Change in Surface Type  Segmenting Procedure: c.) Change in No. of Lanes  Segmenting Procedure: d.) Distinct change in the condition of pavement  Segmenting Procedure: e.) Segments of asphalt and concrete with length less than 50m are considered not assessable except for gravel/earth which are assessed (regardless of length). Segment 1 Segment 2 Segment 3 Segment 4 (not assessable) (assessable) Asphalt Concrete Earth Concrete Surface Surface Surface Surface L1 L2 200mm Width = 220mm Length = 13m Width = 210mm Length = 1m  EDGE BREAK Edge Break: 75 < 200mm Width = 150mm Length = 1m FLEXIBLE PAVEMENT (ASPHALT) EDGE BREAK FLEXIBLE PAVEMENT DES FORM: (ASPHALT) 15 L  FLEXIBLE PAVEMENT PATCHES (ASPHALT) Defined as a successfully executed permanent repair with a surface condition similar to the surrounding pavement Assessed over the total area of segment Defective patches are not rated as patches but the defects within the patch are rated under the applicable defects (ex. Cracks, potholes/base failure) The length of patches is recorded per width category PATCHES FLEXIBLE PAVEMENT (ASPHALT) PATCHES FLEXIBLE PAVEMENT DES FORM: (ASPHALT) 10  FLEXIBLE PAVEMENT POTHOLES/BASE FAILURE (ASPHALT) ❑ Defined as the holes of various shapes and sizes in the pavement surface reaching the base coarse/unbound layer. ❑ For rating purposes, severe cracking with base failure/settlement/ depression shall also be considered as potholes. Potholes/Base failures are recorded as the number of potholes equivalent to 0.25 m2 per pothole. The total area of potholes for the first 100m multiply by 4 to get the no. of potholes. Assessed over the total area of segment.  POTHOLES/BASE FAILURE FLEXIBLE PAVEMENT No. of Potholes = (ASPHALT) Area*4 Width 1.0m  POTHOLES/BASE FAILURE No. of Potholes = FLEXIBLE PAVEMENT Area*4 (ASPHALT) Width 1.5m  POTHOLES/BASE FAILURE Split or Cut the rating segment to separate the portion with base failure (at least 50m length) FLEXIBLE PAVEMENT (ASPHALT)  POTHOLES/BASE FAILURE FLEXIBLE PAVEMENT DES FORM: (ASPHALT) SURFACE FAILURE Defined as loss of the wearing course layer. These failures can be caused by surface delamination or mechanical damage. Assessed over the total area of segment Surface Failures are recorded as the number of surface failures equivalent to 0.25 m2 per surface failures. The total area of surface failures multiply by 4 to get the no. of surface failures. FLEXIBLE PAVEMENT (ASPHALT)  FLEXIBLE PAVEMENT SURFACE FAILURE (ASPHALT) No. of Surface Failure = Area*4 Width Width 1m 0.5m Length 1m SURFACE FAILURE DES FORM: FLEXIBLE PAVEMENT (ASPHALT)  WEARING SURFACE This rating includes both Raveling and Bleeding Raveling is the loss or disintegration of stones, typically occurring in the wheel path Bleeding/Flushing is the occurrence of excessive bitumen on the surface of the pavement Assessed over the total area of segment FLEXIBLE PAVEMENT (ASPHALT)  FLEXIBLE PAVEMENT WEARING SURFACE (ASPHALT) Raveling Bleeding/Flushing Minor Wearing  FLEXIBLE PAVEMENT WEARING SURFACE (ASPHALT) SEVERITY: Minor 'M' = Surface still relatively smooth with only some loss of fine aggregate or in the case of bleeding there are some signs of excess binder. Severe 'S' = Surface rough or pitted with both fine and coarse aggregate lost or in the case of bleeding the surface is covered with excess binder with skid resistance poor. WEARING SURFACE FLEXIBLE PAVEMENT DES FORM: (ASPHALT)  PAVEMENT CRACKING Assessed over the total area of segment Rated according to the type of cracking, i.e. Longitudinal, Crocodile, or Transverse Crackings Severity: Wide Cracks (>3mm) Narrow Cracks (3mm) or Narrow Cracks (99mm 2 - Depth of gravel 50mm - 99mm 3 - Depth of gravel 25mm - 49mm 4 - Depth of gravel 0mm - 24mm  UNPAVED ROAD B. Material Quality ⮚ The Material Quality of the imported material or exposed sub-grade is rated for Gravel roads. ⮚ The in-situ Material Quality is rated for Earth Roads. ⮚ Local knowledge of the roads must be used, if the surveyors know the road is problematic after rains, then this must be considered when rating the condition. CONDITION SCORE: 1 – GOOD MATERIAL QUALITY 2 – FAIR MATERIAL QUALITY 3 – POOR MATERIAL QUALITY 4 – BAD MATERIAL QUALITY  UNPAVED ROAD B. Material Quality Even size distribution with sufficient plasticity to bind the material – no significant oversize material (not bigger than 2 inches in diameter). Material Quality - Good (1)  UNPAVED ROAD B. Material Quality Material Quality - Fair (2) Loose material or stones clearly visible  UNPAVED ROAD B. Material Quality Poor particle size distribution Material Quality - Poor (3) with excessive oversize material. Plasticity is high enough to cause slipperiness or low enough to cause excessive loose material resulting in loss of traction  UNPAVED ROAD B. Material Quality Poorly distributed range of particle sizes, zero or excessive plasticity, excessive oversize material Material Quality - Bad (4)  UNPAVED ROAD C. Crown Shape ⮚ Crown Shape is determined to be the height of the center of the road above the edge of the road ⮚ This determines the ability of the road to shed water from it surface CONDITION SCORE: 1 – GOOD MATERIAL QUALITY 2 – FAIR MATERIAL QUALITY 3 – POOR MATERIAL QUALITY 4 – BAD MATERIAL QUALITY  UNPAVED ROAD C. Crown Shape Crown Shape - Good (1) >2% crossfall – no significant ponding  UNPAVED ROAD C. Crown Shape Crown Shape - Fair (2) Crossfall mostly