78
X1
Category 1: Buildings
Building geometry and structural system
• Building period: 2012
• Height dimension: 25 m
• Overall length: 40 m
• Overall width: 47 m
Design software
The structural analysis was prepared using a 3D model
with Scia Engineer software.
Excavation
The site is situated within a residential area. The
excavation was designed with steel shoring embedment
due to the bedrock.
Foundations
The foundations combine 900 mm- and 1,200 mm-
diameter bored piles embedded into the bedrock and a
foundation slab 350 mm thick. A “white tank” waterproof
concrete system designed to resist hydro pressure from
ground water is used in the basement.
Load
The design loads conform to EC and National Annex:
Apartments 1.5 kN/m
2
, staircase 3.0 kN/m
2
, commercial
area 2.5 kN/m
2
, parking 2.5 kN/m
2
Structure and design process
Assessing the real behaviour of a load bearing
structure, including its response to variable soil
properties, requires several successive calculations with
different modifications of input data. It is not convenient
to create the structural model in one step including
the different properties of the load bearing structure,
subsoil, materials and methods of founding. However,
such a solution is possible by using the Additional
Module “Soilin” with an analysis of the upper structure
and subsoil.
The basic principle of structural calculation consists
of two steps. The structure is primarily supported
with fixed supports without the influence of geological
conditions. The results of the first step of the structural
analysis were only comprised of the reactions in the
supports. The subsequent step determines the stiffness
of the point supports (piles) for cases of a pre-defined
settlement with the flexible supports. The geological
layers according to the geological survey were assigned
for the shallow support of the base slab. The actual
calculation introduces iteration. Starting iteration
is for the default input parameters C1x, C1y, C1Z,
C2x, C2y. The number of iterations depends on the
compensation contact stress under the base slab for the
specific properties of soil. It usually requires about 10
iterations and several iteration cycles. The results of the
calculation are the internal forces in the base plate that
are needed for the design of the reinforcement and the
distributed reactions to the piles.
Structure
The main bearing structure is contained with reinforced
concrete columns and walls. The class of concrete is
C30/37 XC1. Border walls with a thickness of 200 mm
and elevator walls were designed for the rigidity of the
buildings. The floor slab was designed with a reinforced
concrete slab with a thickness of 280 mm, locally
supported by columns.
A significant interior radial concrete column with
dimensions of 450 mm x 450 mm was designed for the
interior staircase. The storey landing was designed with
a cantilever slab.
Conclusion
Scia Engineer also allowed for the preparation of
several structural alternatives. There were more designs
in the process of the work according to the client’s and
the architect’s demands and Scia Engineer made it
possible to alter the structure very easily.
The real deflections of the structure were measured
on-site, and the results were very near to the calculated
deflections.
Residential Building “Na Santince” - Prague, Czech Republic
Software: Scia Engineer
