Guidelines for Survey of Housing and Building Typology in Cyclone Prone Areas for Assessment of Vulnerability of Regions and Post Cyclone Damage Estimation

IS 15499: Scope & Key Specifications Summary

IS 15499 provides guidelines and proformae for assessing building vulnerability and retrofitting needs for cyclone resistance. The scope includes:

• Building Typology & Structural Assessment through detailed proformae.
• Quantitative data collection on dimensions, materials, and structural details.
• Assessment of damage scales and rounding rules as per IS 2:1960.

Key Tables for Data Collection (Sample)

Structural Dimensions & Details to be Recorded

• Overall length, breadth, wall heights, thickness.
• Member sizes (ridge beam, rafters, purlins).
• Foundation depth and type.
• Plinth beam, plaster, door/window frame types.
• Roof details: type, material, eaves projection.
• Connection types and spacing (bolts, nails, straps).

Rounding Rule

• Final test/analysis values rounded as per IS 2:1960.
• Maintain significant digits equal to specified values.

Usage

• Pre-cyclone preparedness and structural weakness identification.
• Post-cyclone damage estimation.
• Input for cost-effective retrofitting design.

flowchart TD
    A[Building Assessment] --> B[Data Collection via Proformae]
    B --> C{Quantitative Data}
    B --> D{Qualitative Data

IS 15499 - Basic Principles for Survey: Key Points

1. Educational Background of Surveyors (Clause 2.4)

• Minimum qualifications recommended:
  • Proforma I: Graduation
  • Proforma IIA: Graduation/Diploma in Civil Engineering
  • Proforma IIB: Diploma in Civil Engineering
  • Proforma IIC: Diploma with 3+ years experience or Degree in Civil Engineering

2. Survey Data Collection (Clause 3.4)

• Two types of questions in proformae:
  • Multiple-choice with coded numeric answers.
  • Quantitative data based on actual site measurements (e.g., member size, spacing).

3. Damage Assessment Scale (Clause 4.6)

• Marginal Damage: >75% columns marginal damage or less, max damage medium.
• Medium Damage: >75% columns medium damage or less, max damage heavy.
• Heavy Damage: >50% columns heavy damage, no failure.
• Failure: >50% columns heavy damage with one or more failed.

4. Proforma I - General Survey Data (Annex A)

• Encodes district, taluk, village, distance from HQ, land use, population, hazard-prone status, shelter availability, communication, warning systems, road types, building typology, and environmental setting.
• Uses coded numeric tables for quick data entry.

Sample Table: Distance from District HQ (km)

Summary Diagram: Survey Process Flow

flowchart TD
    A[Start Survey] --> B[Check Surveyor Qualification]
    B --> C[Fill Proforma I - General Data]
    C --> D[Fill Proforma II - Building Typology]
    D --> E[Damage Assessment Using Clause 4.6]
    E --> F[Compile & Analyze Data]
    F --> G[Submit Report]

This structure ensures systematic, consistent data collection for structural damage and vulnerability assessment following IS 15499 guidelines.

IS 15499: Guidelines for Filling Up the Proformae

Key Points from IS 15499:

• Purpose:
  Identify area preparedness, building typology, structural weaknesses, and damage extent for cyclone resistance and retrofitting.

• Proformae Types & Usage:

  Proforma	Purpose	Mode
  I	Preparedness & accessibility of unit	Each unit
  IIA	Building typology characterization	Stand-alone or with IIB
  IIB	Structural system, member sizes, connections	One per building
  IIC	Post-cyclone damage assessment	Along with IIB

• Filling Instructions (Clause 3.4):

  • Multiple-choice questions: mark the number of choice.
  • Quantitative data: provide actual measurements (e.g., member size, spacing).

Structural Data to be Recorded (Proforma IIB):

• Member dimensions (length, width, thickness)
• Spacing of structural connections
• Type of materials and construction methods
• Structural system classification (e.g., framed, load-bearing)

Damage Scale (Clause 4):

• Use standardized damage scales to quantify damage severity (e.g., minor, moderate, severe).

Summary Table for Proformae Filling:

flowchart TD
    A[Start Survey] --> B{Select Proforma}
    B -->|Preparedness| C[Proforma I]
    B -->|Building Typology| D[Proforma IIA]
    B -->|Structural Details| E[Proforma IIB]
    B -->|Damage Assessment| F[Proforma IIC]
    E --> F
    D --> E

IS 15499: Damage Scales Key Points

1. Damage Scale Definitions (Clause 4)

• Marginal Damage: Minor issues like few loosened connections, partial cladding blown off (<50%), tilted posts.
• Medium Damage: Larger damage such as some sheets blown off (<25%), bent truss elements, noticeable sagging.
• Heavy Damage: Extensive damage including total roof/wall failure, multiple truss failures, large cladding loss.

2. Overall Assessment of Column Damage (Clause 4.6)

3. Proformae Quantitative Data (Annex A)

• Use coded tables for parameters like distance, area, land use, population, cyclone/flood prone status.
• Quantitative inputs include member sizes, spacing, wind speed, damage percentage.

Summary Table: Damage to Columns (Clause 4.6)

Practical Use:

• Surveyors record damage using proformae with multiple-choice and quantitative inputs.
• Damage scales guide post-cyclone structural assessment and repair prioritization.

flowchart TD
    A[Start: Survey Columns] --> B{Damage Level?}
    B -->|Marginal| C[Mark as Marginal]
    B -->|Medium| D[Mark as Medium]
    B -->|Heavy| E[Mark as Heavy]
    C --> F{% Columns Marginal?}
    D --> F
    E --> F
    F -->|>75% Marginal & max medium| G[Overall Marginal]
    F -->|>75% Medium & max heavy| H[Overall Medium]
    F -->|>50% Heavy no failure| I[Overall Heavy (No failure)]
    F -->|>50%

IS 15499 — Proformae for Survey: Key Specifications

Educational Background of Surveyors (Clause 2.4)

• Proforma I: Graduation.
• Proforma IIA: Graduation or Civil Engineering Diploma.
• Proforma IIB: Civil Engineering Diploma.
• Proforma IIC: Civil Engineering Diploma + 3 years experience or Civil Engineering Degree.

Proformae Types & Usage (Clause 2.2, 3.3)

Filling Guidelines (Clause 3.4)

• Multiple-choice questions: Mark option number.
• Quantitative data: Provide actual measurements (member size, spacing, etc.).

Summary Diagram

graph TD
  A[Surveyor Qualification] -->|Assign| B(Proforma I)
  A -->|Assign| C(Proforma IIA)
  A -->|Assign| D(Proforma IIB)
  A -->|Assign| E(Proforma IIC)
  B --> F[Preparedness Survey]
  C --> G[Building Typology]
  D --> H[Structural Assessment]
  E --> I[Damage Survey]
  G & H --> J[Retrofit Design]
  H & I --> K[Post-Disaster Analysis]

Use these proformae systematically for cyclone vulnerability and damage assessment surveys as per IS 15499.

IS 15499 - Composition of the Committee

• The detailed composition of the Committee responsible for formulating IS 15499 is provided in Annex B of the standard.
• The Committee is the Cyclone Resistant Structures Sectional Committee, CED 57.
• Members typically include experts from:
  • Structural engineering
  • Cyclone-resistant construction
  • Building typology studies
  • Government agencies and research institutions

Key Specifications Related to Committee Work (From IS 15499)

• Sample Size for Building Typology Survey (Clause 2.3):

• Reference for Construction Types:
  IS 15498:2004 for definitions of non-engineered, semi-engineered, and engineered buildings.

Summary Diagram of Committee Composition & Scope

graph LR
A[IS 15499 Committee] --> B[Cyclone Resistant Structures Sectional Committee, CED 57]
B --> C[Structural Engineers]
B --> D[Cyclone Experts]
B --> E[Building Typology Specialists]
B --> F[Government & Research Bodies]

For detailed member names and affiliations, refer to Annex B of IS 15499.