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Inventory Collection
For Hazus analysis following inventories of a study area need to be collected.
1. General Building Stock
2. Essential Facilities
3. Transportation Systems
4. Utility Systems
Most crucial part of inventory collection is collecting the data for general building stock. Because other inventories like essential facilities , transportation systems, utility systems can be collected from different government officials or from the google maps or purchased maps. For the GBS (General Building Stock) data we need to conduct survey in our study region.
We need to collect some information of each building in our study region like:
Basic information:
- Structural Type
- Occupancy Class
Vulnerability factors:
- Soft Storey
- Heavy Overhang
- Pounding Possibility
- Short Column
Demographic information:
- No. of Occupants (day & night)
- No. of Storey & Apartment etc.
All information can be collected by field survey. In our region we prepared a questioner like bellow.
Structural Type:
As in a study area there are thousands of buildings, for the convenience of the analysis we need to categorize all the buildings in certain groups.
In Hazus there are 36 types of structure.
Damage is predicted based on
building structural type.
1-2 wooden building, 3-15 steel building, 16-28 concrete building, 29-35 masonry building and 36 Mobile building.
L= Low Rise (1 to 3 stories)
M=Mid Rise (4 to 7 stories)
H=High Rise (8 or above 8 stories)
Some common types of structures seen in Bangladesh are
C3L = beam , column (frame) with brick wall low rise
1 storied building (C3L)
3 storied building (C3L)
C3M = beam , column (frame) with brick wall mid rise
6 storied building (C3M)
C3H = beam , column (frame) with brick wall high rise
8 storied building (C3H)
URML = unreinforced masonry building low rise
2 storied building (URML)
URMM = unreinforced masonry building mid rise
4 storied building (URMM)
MH = mobile homes
Tin shed building (MH)
Bamboo building (MH)
For more detail please see the Hazus manual.
Occupancy Class:
Occupancy class of a building indicates the purpose of usage of that building like that building is residential or commercial or religious or mixed etc. Hazus categorize the occupancy class like
Occupancy class is important in
determining economic loss, since
building value is primarily a function of building use.
Vulnerability Factors:
Soft Storey: Soft storey is the larger open space in the ground floor usually used for car parking. For earthquake soft storey is considered as a vulnerability factor as partition wall can resist lateral force in a certain extent.
Heavy Overhang: It is considered as a vulnerable factor because of its geometric shape. Bellow picture can best illustrate the heavy overhang terminology.
Pounding Possibility: Every building has its own natural frequency. When an earthquake strike , every building tends to vibrate. It requires some free space surrounding it so that it can vibrate without collision with other buildings. If two adjacent buildings of different height do not have sufficient space to freely vibrate, it is said that there exists pounding possibility between these buildings.
Short Column: The columns are made more vulnerable to damage when their spans are shortened by the balcony parapets or other masonry infills.. This is knows as the 'short column' effect. When columns are shortened, the effect is to make them less ductile.
For better understanding of short column effect you can follow this link
