Codigo Sismico 2004

SYRIAN SEISMIC CODE 20041:
Two static methods have been issued in Syrian building code 2004 to calculate the lateral seismic forces in the building. The First Static Method: It is the same method in the previous code (1995) with few modifications. It is based on determination of a design base shear force (V), which is then distributed in a specific pattern over the height of the structure forstructure analysis of lateral load resistance. The total design base shear in a given direction (V) is given by:

V = ( ZIKCS
Seismic Zone Factor (Z):

)*W

It is represent the peak ground acceleration in studied site as a percentage of gravity acceleration g (9.81 m/sec2). Z factor for each zone is shown in the table below: Seismic Zone Z factor Importance factor (I): Occupancy Category Allimportant structures which are required for continued operating during earthquakes such as: hospitals, fire and police stations, …..etc. All Structures with occupancy more than 300 persons. All others structures. I value not less than 2 for atomic structures and all hazardous structures. Ductility Factor (K): Building Type or description
All buildings not mentioned in this table Bearing wallsystem Building Frame System or Mixed System according to the following designing case: -Frames can bear 25% of the total lateral loads. -Frames can bear 50% of the total lateral loads. High tanks of water and similar which carried by a group of columns not less than four. Special Building such as: Chimneys, T.V towers …..
1

0 0

1 0.075

2A 0.15

2B 0.20

2C 0.25

3 0.3

I 1.50 1.251.00

K 1.00 1.30

1.00 0.80 2.50 2.00

The original Code is in Arabic and it has been translated to English by Eng. Hussam Eldein Zaineh, National Earthquake Center (NEC).

Dynamic Factor (C): It represents the percentage between equivalent acceleration of the structure to the ground acceleration and it defined from this equation:
C= Where: T: is the fundamental period of the structure(sec) in a given direction, calculated by: 1- approximate determination in case of shear wall system structures: 1
2

10T 3

T(sec) = 0.08 N Where, N is the number of stories. 2- approximate determination in case of frame system structures:

T = 0.1N 3- also, T must be estimated by using this approximate equation:
3

T = γ t .(hn ) Where:

4

hn : building height from the base up tolevel n in meters.

γ t =0.0853 for steel frame.

γ t =0.0731 for RC frame. γ t =0.0488 for other buildings.
Note 1: T is the minimum value from previous three equations. Note 2: C is equal to 0.15 for buildings consist of only one or two stories. Note 3: in other cases C must be less than 0.18. Note 4: in all cases, K.C must be less than 0.38 and more than 0.09.
Soil Coefficient (S):

1-in case of

T ≤ 1: Ts

⎛T T S = 1.0 + − 0.5⎜ ⎜T Ts ⎝ s

⎞ ⎟ ⎟ ⎠

2

2- in case of

T > 1: Ts ⎛T T S = 1.2 + 0.6 − 0.3⎜ ⎜T Ts ⎝ s ⎞ ⎟ ⎟ ⎠
2

Ts: the characteristic site period (sec).
Total weight (W): is equal to all dead loads and 25% of live loads. Lateral Loads distribution:

1-Regular structures or structural frame system: The total lateral force (V) shall be distributed overthe height of the structure in conformance with formulas:

V = Ft + ∑ Fi
i =1

n

Ft: The concentrated force at the top of the structure shall be determined from the

formula:

Ft = 0.07 × T × V
The value of (Ft) need not exceed (0.25 V) and may be considered as zero where T is 0.70 sec or less. T: the fundamental period of the structure (sec) in the considered direction. The remainingportion of the base shear (V- Ft) shall be distributed over the height of the structure According to the following formula:
Fx = (V − Ft ) wx hx

∑w h
i =1

n

i i

Where: wx: the vertical concentrated load at level x which equal to the weight of this level. wi: the portion of (w) located at assigned to level i. hx: height above the base to level x. hi: height above the base to level...