„SAMB” - Computer system of static analysis

of shear wall structures in tall buildings

In Pozna University of Technology a computer system of static

analysis of shear wall structures in tall buildings has been elaborated.

Using the system it is possible to carry out the analysis of stresses as well

as displacements of wide class of shear wall structures in multistorey

buildings subjected to complex loads.

Methods of analysis of shear wall structures in tall buildings, currently used in designing

practice, are characterised by introduction of considerable simplifications with reference to the

structure model and loads description as well as the method of solving the problem. Therefore,

the obtained values of displacements and stresses in the structure elements are considerably

approximate.

At the Institute of Structure Engineering of Pozna University of Technology in the team

supervised by prof. Kazimierz Wrze niowski there has been elaborated a computer system for the

strength analysis of shear wall structures in tall buildings in order to make a more precise analysis

of the complex structures possible. Originally, the system was used on ICL 1900 and Odra 1300

computers. Now it is possible to take advantage of the system making use of computers

compatible with IBM PC with medium size operating memory and DOS standard operating

system as well as Windows 3.1, Windows 95 and Windows NT environments.

Making use of the system it is possible to analyse structures the plan of which includes

walls and connecting beams arbitrarily located in the plan (Fig.1). The structures under

consideration can be exposed to horizontal loads (distributed arbitrarily along the building height

or applied on its top), vertical loads (arbitrarily located in the plan and arbitrarily changeable along

the height) and non-uniform settlement of foundations. The analysed structure , after its

description using a three-dimensional continuous model, is analysed without introducing

additional simplyfying assumptions. Input data of the SAMB (Static Analysis of Multistorey

Buildings) system include the information about arrangement of walls and connecting beams,

geometry and strength features which can be read from drawings of the building as well as data

describing loads. On the basis of the data determined in this way the system generates systems of

differential equations describing behaviour of the structure. Due to the consistent separation of

these systems it is possible to analyse the structure using a small operating memory field. Owing

to replacement of numerical integration by the integration according to formulas introduced

analytically and the best use of memory on magnetic discs, short computation times have been

obtained.

The results of the system constitute shearing forces and bending moments in connecting

beams, displacements of selected points of the building and values of normal, shear and principal

stresses at characteristic points of the structure. Internal forces in shear walls can be printed

optionally. All these groups of results are calculated for each load scheme and for described set

of extremes. The results are printed for arbitrary structure ordinates determined in the data. The

elaboration of the macro-command of operating system, the data number being its only

parameter, makes use of the system really simple. Using the system allows for the extensive

analysis of the structure in a short period of time. The above-described version of the SAMB

system, has been elaborated in the eighties, partly within the grant No 05.12 coordinated by the

Institute of Fundamental Technological Research of the Polish Academy of Sciences in Warsaw.

Since then many calculations concerning buildings being designed and erected or the existing ones

being modernised, have been made in Wielkopolska, l sk and Zielona Góra.

The system is being improved and developed continuously. In the past few years it has

been completed by new graphic pre- and postprocessors and a new subsystem of data

transmission to speed up computations.

The research has been focused currently on the development of the analysis taking into

account a non-linear model of the structure material.

Fig.1 Three-dimensional shear wall structure in tall building:

1 - 3-D shear wall, 2 - band of connecting beams, 3 - trace of floor slabs