Seismic Vulnerability Assessment in the Built-Up Environment of Rispana River Catchment, Dehradun, Indian Himalayas

Abstract

Seismic assessment of built-up environment deals with the level of earthquake exposure of the region and building vulnerability. It defines seismic risk for the physical consequences as well as the potential aspect in the occurrence of a seismic event. The present study was carried to assess the seismic vulnerability of the built-up environment of Rispana river of Dehradun, Uttarakhand, Indian Himalayas. Vulnerability was assessed by the detailed investigation and corrective measures rapid visual screening method. This methodology requires identification of primary structural lateral load resisting system of the building and attribute of the building which modify seismic recital. The spatial and non-spatial information have been collected by field survey and analysed under remote sensing and GIS environment. Multi-temporal satellite imageries of Cartosat-1 with spatial resolution of 2.5 m were used to assess the data. The study revealed the poor quality of construction and lack of maintenance of buildings in the Rispana catchment. Non-engineered construction appears one of the main causes of poor quality of the buildings. As per damageability, class grade 1 and grade 2 indicate no and slight damage together with slight and moderate non-structural damage. The highest 47% of buildings falling under grade 4 predicated heavy structural damage and collapse of buildings structures during the seismic events. Retrofitting and reconstruction of grade 5, grade 4 and grade 3 buildings are therefore recommended in the Rispana catchment.

Appendix

1. Background of the Respondent

1.1	Name of the Respondent
1.2	Sex	Male				Female
1.3	Age
1.4	Marital Status	Single		Married		Widowed
1.5	Head of the Family	Male				Female
1.6	Family members	1–3		2–4		2–5	3–6	3–7
1.7	Educational Qualification of the Head of the family	10 – 12th		Graduation		Masters	Others
1.8	Occupation
1.9	Number of children under 10 years in your household	1		2		3	4	5

2. Does your family live in a disaster prone area?

3. Hazard Assessment

3.1 What are the main hazards that have affected your community during the last five years?

Flash flood
Earthquake
Landslide
Drought
Forest Fire

4. Vulnerability Assessment

4.1. Building assessment:

Building type	Storage	Shop	Residential	School	Office
Floor material	Cement	Tile	Wood
Wall material	Ply wood	Wood	RCC	Cement	Mix	Concrete
No of floor	1	2	3	4	5
Roof type	Clay	Tin	Cement	Roof shape
Plan of Building		Symmetric				Asymmetric

4.2. Construction age of building:

4.3. Building condition and maintenance:

4.4. Building site located at:

4.5. Soil type:

4.6. Shape of building:

4.7. Foundation:

5. Buildings Assessment

5.1. Through stone:

5.2. Earthquake resistance features provided in the building:

5.3. Thickness of exterior wall: ___________mm.

5.4. Designed by:

5.5. Road faced width:

5.6. Use condition:

5.7. Building state:

5.8. Height of the building:

Low
<20 (1flr)
>20 < 50 (2–3flr)
>50 < 100 (4–8flr)
>100 < (9–12flr)

5.9. Window support type:

Punched
Glass & Metal framing
Ribbon
Point supported

5.10. Type and organization of the resisting system:

R.C. wall	1	Tie-beam/ties at all level	1
Solid infill + frame	2	Good interlocking of walls	2
Weak infill + rigid frame	3	No tie-beams, bad interlocking	3
Frame without infill	4

5.11. Quality of Resisting System:

5.12. Floor systems:

Staggered floor
Well conn
Badly conn

5.13. Elevation shape:

Porch/open gallery area
Soft story, ground level

5.14. Roof System: Tie-beam at roof level.

Steel tie at roof level
Roof perimeter