Structural and Analysis of Double Storey Structure using SAP2000

This article discusses the structural analysis of a double storey structure using SAP2000 software. It covers the calculation of live loads, dead loads, load combinations, and wind loads. The article also recommends checking for inadequate support mechanism, internal mechanisms, zero and negative stiffness properties, and extremely large stiffness properties.

Structural and Analysis
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Introduction
The structure which is drawn using the SAP2000 is a double storey structure with 14
structures. In the structure, the live loads, the dead loads , the combination of the loads and the
total of the live an the dead loads in the whole structure can be calculated. The structure drawn
is a block structure with measurements of the floors which are equal to each other.
Computer and the structures
This is a structural software for the earthquake engineering which was then founded in
1957 based on the Walnut. The SAP2000 is a good example of the computer and structures
software which is used for the purpose of the structural analysis and designs.
Structure Analysis
From the analysis of the structure using the SAP2000, the structure is found to be unstable or
it is ill conditioned, for that reason it is recommended that the following be checked in the
structure;
i. The inadequate support mechanism
ii. One or more tan one internal mechanisms
iii. The zero and the negative stiffness properties
iv. The stiffness properties which are extremely large
The roof of the structure is not provided therefore the live and dead loads of the roof will be
exempted in the calculations below.
The dead loads pf the first storey can therefore be calculated as follows;
The Dead load
With the assumption that the slab of the first storey is not suspended;
Then the floor finishes is assumed to be 0.75 kPa * ( ( 5.6 / 2) + ( 4.4 / 2 ) ) * ( (6 / 2)
+ ( 4 / 2 ) ) = 18.75 kN
The Column = 0.45 * 0.4 * 4.75 * 21 = 17.955 kN

The wall of the brick = 20 * 0.175 * 4.75* ( ( 6 / 2) + ( 4 / 2) ) = 83.13 kN
The Total live load is therefore calculated at 113.85 kN
The above dead load is for the first storey for the first column of the storey only. In
order to calculate the dead load of the 14 storeys, then the total load of the whole
structure column will be 113.85 * 21 storeys =2390.85 Kn
Therefore the total dead load of the whole structure is 2390.85 kN
The live load
With the assumption of the 4kN
The live load is therefore = 4 kN / m2 * ( 5.6 / 2 + 4.4 / 2 ) * ( 6/2 + 4/2) = 100 Kn
The live load is for the first storey only, for the 14 storeys available, then the live load
will be 100Kn*21= 2100Kn
Therefore the total live load is 2100 kN
Load combination:
The combination of the load in accordance to Eurocode can be considered as the summation of the
products of the load effects which is in correspondence to the normal primary value of the load or load
factor as below
Yp∗Sp+∑
k
❑
( Yk ) +¿ Sk ¿
Where Sp and Sk are the load effects and Yp and Yk are the Basic loads
From our values, Yp =2100Kn and Yk =2390.85Kn Sp =2100/2390.85Kn and
Sk =2390.85/2100Kn
The Load combination is therefore calculated as 2100*0.8793 + (2390.85+1.1385)
1846.53+2391.9885Kn =4238.5185Kn
The wind load
The wind load =P*A*Cd

Where p=pressure of the wind
A= the area of the building
Cd= drag coefficient
A = base area= 4.4*5.6=24.64
P= pressure= 0.00256v2 according to engineering code
Cd for long building is 2.0
The wind load therefore = 24.64* 0.00256v2* 2
But V2=70 hence p=0.00256*70= 12.5psf
Wind load therefore = 24.64* 12.5 * 2 =616lbs
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