Manual of Specification and Standards for Expressways

IRC SP 99 — Scope Overview

The Scope of IRC SP 99 covers comprehensive guidelines for highway and expressway projects, including geometric design, structures, tunnels, drainage, traffic devices, and environmental aspects.

Key Specifications & Sections Relevant to Scope:

• Structures (Section 6 & 7):

  • Specify span lengths, special structures (e.g., cable-stayed bridges) [Clause 6.4(iv), 6.4(v)]
  • Tunnel requirements: location, length, lanes [Section 7, 7.1.3]

• Traffic Control & Safety Devices (Section 10):

  • Design report submission with details on type, location, materials, test reports, warranties [Clause 10.12]
  • Overhead sign sizes and locations [Clause 10.2.8]

• Lighting (Section 15):

  • Minimum illumination levels for expressways, toll plazas, lay-byes, interchanges (Table 15.1) [Clause 15.2]

• Project Facilities (Section 13):

  • Locations for service areas, bus stops, border check posts [Clauses 13.1–13.3]

• Environmental & Landscaping (Section 14):

  • Number and locations of trees, landscaping treatment [Clauses 14.3.1, 14.4]

Example: Minimum Illumination Levels (Table 15.1 excerpt)

Typical Deliverables for Scope Compliance

• Design reports with detailed drawings and specifications
• Traffic device proposals with warranties
• Environmental and landscaping plans
• Lighting layout conforming to specified lux levels

flowchart TD
    A[Project Scope] --> B[Geometric Design]
    A --> C[Structures & Tunnels]
    A --> D[Traffic Control Devices]
    A --> E[Lighting & Safety]
    A --> F[Environmental & Landscaping]
    A --> G[Project Facilities]

This structure ensures all aspects from design to environmental considerations are integrated per IRC SP 99.

Key Formulas, Tables & Specifications for Geometric Design (IRC SP 99)

1. Design Objectives (Clause 2.1)

• Ensure safety, mobility, and efficiency.
• Maintain uniform geometric standards throughout.
• Design changes must be gradual to meet driver expectations.
• Address environmental concerns and provide positive driver guidance.

2. Minimum Radii of Horizontal Curves (Clause 2.5)

• Use Desirable Minimum Radius as a standard.
• Absolute Minimum Radius only for constrained sections (per Schedule-B).

3. General Specifications

• Follow liberal geometric standards within Right of Way.
• Maintain uniformity and gradual transitions.
• Consider environmental and safety factors in design.

4. Additional Geometric Parameters (Typical for Expressways)

• Lane width: 3.5 m (minimum)
• Shoulder width: 2.5 m (minimum)
• Superelevation (e): Typically 6-8% based on design speed and curve radius.
• Sight distance: As per design speed for safe stopping.

5. Basic Formula for Minimum Radius of Curve

[ R = \frac{V^2}{127(e + f)} ]

Where:

• (R) = radius of curve (m)
• (V) = design speed (km/h)
• (e) = rate of superelevation (decimal)
• (f) = coefficient of side friction (typically 0.15)

flowchart LR
    A[Design Speed] --> B[Determine Desirable Radius]
    B --> C{Is Right of Way Limited?}
    C -- Yes --> D[Use Absolute Minimum Radius]
    C -- No --> E[Use Desirable Minimum Radius]
    D & E --> F[Apply Superelevation & Friction]

IRC SP 99: Grade Separators and Interchanges - Key Points

1. Types of Intersections (Clause 3.1)

• Grade Separators: Grade-separated intersections without ramps.
• Interchanges: Grade-separated intersections with ramps.

2. Design Basis (Clause 3.1)

• Types and locations follow MORTH Guidelines for Expressways.
• Detailed in Schedule-B of Concession Agreement.

3. Grade Separators (Clause 3.2)

• Location, type, and land requirements depend on traffic and site conditions.
• Length of viaducts and pavement types are specified per design needs.

Clear Zone (Clause 2.3, Fig 2.3)

• Clear zones ensure safety by providing unobstructed roadside space.
• Typical clear zone width ranges from 3.0m to 6.0m, depending on design speed and traffic volume.

Typical Design Considerations (from MORTH & IRC)

graph TD
    A[Intersection] --> B[Grade Separator (No Ramps)]
    A --> C[Interchange (With Ramps)]
    B --> D[Viaduct Length]
    B --> E[Pavement Type]
    C --> F[Ramp Design]
    C --> G[Land Requirement]

Summary: Design grade separators and interchanges per MORTH guidelines, ensuring adequate clear zones, vertical/horizontal clearances, and appropriate viaduct length and pavement types. Refer to Schedule-B for project-specific details.

Embankment and Cut Sections (IRC SP 99 - Section 4)

Key Specifications:

• Slopes for Cut Sections (Table 4.1):

• Design & Construction:
  • Follow Section 300 of MORTH Specifications for embankment and cutting.
  • Includes subgrade and earthen shoulder standards.

Notes:

• Rock slopes vary widely based on rock quality; steeper slopes (e.g., 1/8:1) for sound rock.
• Ordinary soil slopes are gentler for stability (2:1 to 3:1).

Typical Ramp Cross-Section (Clause 3.3, Fig 3.3):

• Refer to IRC SP 99 Fig 3.3 for ramp geometry.
• Ensure proper drainage and stability in embankment/cut design.

graph TD;
    A[Embankment] --> B[Subgrade]
    B --> C[Shoulder]
    A --> D[Cut Section]
    D --> B
    B --> E[Drainage]

Summary: Use soil-specific slopes (Table 4.1), adhere to MORTH Section 300, and ensure proper subgrade and shoulder design for safe embankment and cutting.

Pavement Design & Maintenance (IRC SP 99 Key Points):

1. Design Criteria (Clause 5.1.1)

• Follow criteria, standards, and specifications in the Manual.
• For innovations, refer to Para 1.10 provisions.

2. Material Testing (Clause 13.3)

• Use test values of aggregates as per IRC:SP:19 Tables 13.3 & 13.4.
• Tests must comply with MORTH Specifications.
• Report traffic growth, axle load, Vehicle Damage Factor (VDF), and traffic projections.

3. Flexible Pavement Design (Clause 5.3.1)

• Design based on traffic, climate, and soil.
• Use IRC:37 guidelines or internationally accepted methods.
• Ensure cost-effective, durable pavement meeting performance needs.

Key Design Formula (Flexible Pavement)

Structural Number (SN) Calculation (from IRC:37):

[ SN = a_1 D_1 + a_2 D_2 m_2 + a_3 D_3 m_3 ]

• (a_i) = layer coefficient
• (D_i) = thickness of layer (cm)
• (m_i) = drainage coefficient

Typical Layer Coefficients (IRC:37)

Traffic Projection & VDF

• Estimate Equivalent Standard Axle Loads (ESAL)
• Apply Vehicle Damage Factor (VDF) to account for heavy vehicles.

flowchart TD
    A[Pavement Design Inputs] --> B[Traffic Data & Projections]
    A --> C[Soil & Climate Data]
    A --> D[Material Properties (IRC:SP:19)]
    B --> E[Calculate ESAL & VDF]
    D --> F[Select Layer Materials & Thickness]
    C --> F
    E --> G[Structural Number Calculation]
    F --> G
    G --> H[Design Pavement Structure]

Summary: Use IRC:37 or equivalent for flexible pavement design,

IRC SP 99 - Retaining Structures and Earthworks

Key Specifications from Clause 6.9 (Reinforced Earth Retaining Structures)

• Design & construction must follow Section 3100 of MORTH Specifications.
• Avoid reinforced earth structures near water bodies.
• Ensure local and global stability.
• Pay special attention to design, construction, ground improvement, maintenance, and system selection.

Important Tables & Guidelines

Table 4.1: Slopes for Roadway in Cutting (Clause 4.1)

Typical Design Checks for Reinforced Earth Retaining Walls

• Stability against sliding:

[ F_s = \frac{(c \times L + W \times \tan \phi)}{H} \geq 1.5 ]

• Bearing capacity:

[ q_{allow} \geq \frac{W}{B} ]

• Reinforcement length: Usually 0.7 to 1 times the wall height.

Summary

• Follow MORTH Section 3100 for detailed design.
• Use slopes per soil type (Table 4.1).
• Check global stability and avoid water proximity.
• Reinforcement design must ensure adequate length and strength.

flowchart TD
    A[Soil Type] --> B{Slope (H:V)}
    B -->|Ordinary Soil| C[3:1 to 2:1]
    B -->|Rock| D[1/2:1 to 1/8:1]
    E[Reinforced Earth Wall] --> F[Design per MORTH 3100]
    F --> G[Check Stability]
    F --> H[Check Reinforcement Length]
    F --> I[Ground Improvement if Needed]

IRC SP 99: Tunnel Design and Furnishing - Key Points

1. Tunnel Classification (Clause 7.5, Fig. 7.5)

• Tunnels classified by function, size, and construction type (e.g., mining type).
• Important for selecting design parameters and furnishing.

2. Typical Tunnel Cross-Section (Clause 7.2, Fig. 7.2)

• Example: Three-lane mining type tunnel
• Dimensions in meters
• Includes carriageway width, footpaths, ventilation ducts, and clearances.

3. Tunnel Furnishing (Clause 7.9)

• Provision for:
  • Sign boards (directional, safety)
  • Fire fighting arrangements (hydrants, extinguishers)
  • Cable trays for telephone and power lines
• Coordination with local authorities mandatory.

4. Crash Barriers (Clause 6.6, Fig. 6.6)

• Details from IRC:5 for safety barriers inside tunnels.
• Dimensions in millimeters for precise installation.

Summary Table: Tunnel Furnishing Components

flowchart LR
    A[Tunnel Design] --> B[Classification (Fig.7.5)]
    B --> C[Cross-section (Fig.7.2)]
    C --> D[Tunnel Furnishing (Clause 7.9)]
    D --> E[Sign Boards]
    D --> F[Fire Fighting]
    D --> G[Cable Trays]
    D --> H[Crash Barriers (IRC:5)]

Note: Always refer to IRC SP 99 and IRC:5 for detailed dimensioning and local authority consultation for furnishing specifics.

Drainage System Key Points from IRC SP 99

• Clause 9.8: Drainage design for structures must ensure no water accumulation affecting structural stability.
• Clause 9.1.2: Follow Clause 309 of MORTH Specifications, IRC:SP:42, IRC:SP:50, and IRC:SP:90 for overall expressway drainage including structures.
• Clause 9.2: Surface drainage should efficiently remove runoff, avoiding ponding on pavement or near structures.
• Clause 9.6.13: Subsurface drainage design must be rational, referencing IRC:SP:42 for guidelines.

Key Formulas & Specifications

1. Surface Runoff (Rational Method)
   [ Q = CiA ]

   • (Q) = peak runoff (m³/s)
   • (C) = runoff coefficient (dimensionless)
   • (i) = rainfall intensity (mm/hr)
   • (A) = catchment area (ha)

2. Drainage Pipe Sizing (from IRC:SP:42)

   • Use Manning’s equation for flow capacity:
     [ Q = \frac{1}{n} A R^{2/3} S^{1/2} ] where:
     • (n) = Manning’s roughness coefficient
     • (A) = cross-sectional flow area (m²)
     • (R) = hydraulic radius (m)
     • (S) = slope of the energy grade line

3. Subsurface Drainage

   • Provide filter materials (sand/gravel) to prevent soil clogging.
   • Ensure proper gradient for gravity flow.
   • Use perforated pipes or drains as per IRC:SP:42.

Summary Table: Drainage Design References

IRC SP 99 - Drainage and Water Management Key Points

1. Surface Drainage (Clause 9.2)

• Ensure efficient removal of rainwater from pavement and shoulders.
• Provide adequate cross slopes (typically 2-3%) for runoff.
• Use side drains, shoulders, and longitudinal drains as per terrain.

2. Drainage for Structures (Clause 9.8)

• Design drainage to prevent water accumulation near foundations.
• Provide weeping holes, filter materials, and subsoil drains to avoid hydrostatic pressure.

3. Subsurface Drainage (Clause 9.6.13)

• Design based on rational hydraulic principles.
• Use perforated pipes, gravel filters, and drainage blankets.
• Refer IRC:SP:42 for detailed design methods.

4. General Guidelines (Clause 9.1.2)

• Follow Clause 309 of MORTH Specifications and IRC SPs 42, 50, 90.
• Ensure integrated drainage system covering surface and subsurface water.

Typical Drainage Design Parameters

flowchart LR
    Rainwater --> Pavement_Surface
    Pavement_Surface --> Side_Drains
    Side_Drains --> Longitudinal_Drains
    Pavement_Surface --> Subsurface_Drainage
    Subsurface_Drainage --> Foundation_Protection
    Foundation_Protection --> Safe_Discharge

Summary: Follow IRC SP 99 clauses with references to IRC SP 42 and MORTH specs for a comprehensive drainage system ensuring surface runoff and subsurface water are efficiently managed to protect pavement and structures.

IRC SP 99 - Traffic Control Devices & Safety Features Summary

Key Components (Clause 10.1)

• Road signs, markings, object & hazard markers
• Studs, delineators, attenuators
• Safety barriers, boundary fences, stones
• Follow MORTH Guidelines for Expressways & Section 800 MORTH Specs

Design Report (Clause 10.12)

• Submit proposals with:
  • Type, location, material specs
  • Test reports & installation details
  • Warranties for field performance
• Review by Independent Engineer mandatory

Typical Structures (Figures 10.1A & 10.1B)

• Overhead mounted sign structures (dimensions/site-specific)
• Exit gore signs (typical layout)
• Optional solar lighting integration

Important Notes

• All dimensions in mm
• Design to suit site conditions
• Refer to Section 10 of IRC SP 99 and MORTH Section 800 for detailed specs & tables

Example: Road Sign Dimensions (Indicative)

flowchart LR
  A[Traffic Control Devices] --> B[Road Signs]
  A --> C[Road Markings]
  A --> D[Safety Barriers]
  A --> E[Roadside Furniture]
  B --> F[Overhead Signs]
  B --> G[Exit Gore Signs]
  D --> H[Attenuators]
  D --> I[Delineators]

For detailed tables and specifications, consult MORTH Section 800 and IRC SP 99 Section 10.

IRC SP 99: Lighting & Electrical Installations Key Points

1. Minimum Illumination Levels (Table 15.1) for Expressways

• UO = Minimum illuminance / Average illuminance
• U1 = Minimum illuminance along road axis / Maximum illuminance
• T1 = Threshold increment (glare control)

2. Lighting System Design

• Layout & luminaire types must ensure minimum illumination (Clause 15.2).
• Overhead power/telecom lines must maintain safe clearances per IRC:32.
• Fixtures, cables, lamps must meet relevant BIS specifications.
• Independent Engineer reviews the lighting design for compliance.

3. Lighting Quality Components (Clause 15.3)

• Average luminance: Key for safety and power consumption.
• Uniformity: Both across (UO) and along (U1) the road.
• Glare control: Keep T1 low to reduce driver discomfort.
• Guidance lighting: Small direct light to indicate road layout.

4. Toll Plaza Lighting (Clause 12.4.17)

IRC SP 99 - Toll Plazas: Key Formulas, Tables, and Specifications

1. Layout & Design (Clause 12.4)

• Toll plazas should ensure smooth traffic flow with adequate lane width (3.5 m min) and lane spacing (3.0 m).
• Design includes toll lanes, service lanes, and pedestrian paths.
• Toll islands (Clause 12.4.5) must be designed for safety and operational efficiency, typically 1.2 m wide and length as per booth size.

2. Typical Layouts (Clause 12.3, Figs. 12.3 & 12.4)

• Layouts show arrangements of toll booths, toll islands, and approach/departure lanes.
• Include service facilities (Clause 12.2, Fig. 12.2) such as:
  • Administrative block
  • Control center
  • Maintenance base camp
  • Underpass for service vehicles

3. Pavement & Barrier Specifications

• Concrete pavement thickness: minimum 250 mm for toll plaza area.
• Transition zones must be designed for smooth vehicle movement.
• Removable barriers used for lane control and emergency access.

Summary Table: Toll Plaza Key Dimensions

flowchart LR
    A[Approach Lanes] --> B[Toll Plaza]
    B --> C{Toll Booths}
    B --> D[Toll Islands]
    B --> E[Service Facilities]
    E --> F[Administrative Block]
    E --> G[Control Centre]
    E --> H[Maintenance Base]
    B --> I[Underpass for Service Vehicles]

Note: Refer to IRC SP 99 Clause 12 for detailed drawings and exact dimensional requirements.

IRC SP 99 - Service Areas and Facilities Key Points

1. Service Area Size & Facilities (Clause 13.1, 13.1.3)

• Minimum service area size: 5 hectares, manageable up to 15 hectares for landscaping & future expansion.
• Facilities include:
  • Vehicle: Separate parking (cars, buses, trucks), fuel stations, garages.
  • Passengers/Drivers: Walkways, toilets (men, women, physically challenged), kiosks, restaurants, rest cubicles, business lounges, first aid, waste bins.
  • Operations: Water tanks, electricity, incinerator, service roads, sewage disposal, staff rooms.

2. Parking Space Calculation (Clause 13.1 & Annex 13.1)

[ N = ADT \times UR \times DHF \times L ]

Where:

• (N) = Number of parking spaces
• (ADT) = Average Daily Traffic (one direction)
• (UR) = Usage Ratio
• (DHF) = Design Hour Factor
• (L) = Stay in hours

3. Usage Factors & Parking Spaces per 1000 Vehicles

Summary Diagram of Service Area Facilities:

graph TD
  A[Service Area] --> B[Vehicle Facilities]
  A --> C[Passenger/Driver Facilities]
  A --> D[Operation & Maintenance]

  B --> B1[Parking Lots (Cars, Buses, Trucks)]
  B --> B2[Fuel Station]
  B --> B3[Garage]

  C --> C1[Walkways & Access Roads]
  C --> C2[Toilets]
  C --> C3[Kiosks & Restaurants]
  C -->

Key Specifications and Guidelines for Plantation and Landscaping (IRC SP 99):

1. Shrubs in Medians (Clause 1.5)

• Median width > 3 m: Plant shrubs/flowering plants to block headlight glare.
• Height of shrubs: Maintain at 1.5 m.
• Planting pattern: Continuous rows or baffles.
• Shape control: Prevent vertical/horizontal overgrowth beyond paved median edge.

2. Avenue Trees Spacing (Clause 14.3)

• Spacing: 10 to 15 m depending on species and growth.
• Tree selection criteria:
  • Suitability to soil, rainfall, temperature, water level.
  • Avoid very wide trees to prevent traffic interference.

3. Set-back Distance from Roadway (Clause 14.3.2a)

• Minimum 14 m from centerline of left paved shoulder to tree base.
• Especially critical near curves, medians, ramps, cut slopes for vehicle recovery.

4. Plantation in Medians (Clause 14.3.2b)

• Trees and shrubs planted at median edges.
• Maintain visibility and safety.

Summary Table: Plantation Parameters

flowchart LR
    A[Median width > 3m] --> B[Plant shrubs/flowering plants]
    B --> C[Height = 1.5 m]
    A --> D[Shape control to avoid overgrowth]
    E[Avenue Trees] --> F[Spacing 10-15 m]
    F --> G[Select species based on soil, climate, growth]
    H[Roadside Trees] --> I[Set-back ≥ 14 m from left shoulder centerline]
    I --> J[Safety & visibility maintained]

Note: Maintenance of plants and trees as per schedule is mandatory throughout the

IRC SP 99: Operation & Maintenance (O&M) Key Points

1. Operation & Maintenance Plan (Clause 13.1.7)

• Develop a comprehensive O&M plan covering:
  • Equipment details (types, models, locations)
  • Wiring diagrams
  • Water & sewer lines
  • Pumps, septic tanks, water coolers
  • Lighting fixtures
• Document all details in an O&M Manual for the expressway service area.

2. Emergency Contacts (Clause 13.1.7 ii)

• Maintain and display a list of emergency contacts with phone numbers and addresses at service areas.

3. Pavement Strength Monitoring (Clause 5.6 v)

• Periodically evaluate pavement strength via deflection measurements.
• Identify and repair stretches with structural deficiencies.

4. Illumination Specifications (Clause 15.2 i)

• Maintain minimum illumination levels as per Table 15.1 (expressway stretches, toll plazas, lay-byes, interchanges).

Typical Minimum Illumination Levels (Example from IRC standards)

Summary Diagram: O&M Plan Components

graph TD
  A[Operation & Maintenance Plan] --> B[Equipment Documentation]
  A --> C[Wiring & Utilities]
  A --> D[Pavement Strength Monitoring]
  A --> E[Lighting & Illumination]
  A --> F[Emergency Contacts]

Ensure regular updates of the O&M manual and periodic inspections to maintain expressway safety and functionality.