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Employment and Loading of the System Alsipercha System
Report by the Universidad Politécnica de Valencia
(UPV)*
(.../...)
4.- CONCLUSIONS
- This study analyzes the infl uence exerted on the behavior of the
reinforced concrete columns by the use of the Fall Arrest System
developed by ENCOFRADOS J. Alsina, S.A.
(.../...)
The most important conclusions are as follow:
1.- Although the sizes of concrete column sections are usually
selected for shear stress and fl exocompression separately,
this study has considered these jointly, in a similar way to the
analysis of metal structural sections. This makes it easier to
consider the infl uence of the steel tube.
2.- As a result, we estimate that the reduction of section shear
stress resistance caused by the hole in the concrete would
be absorbed assuming, in the fl exocompression calculation,
that the steel of the tube experiences a reduction in elastic
limit which has been taken as 5%, to be on the safe side.
3.- Considering this reduction in the elastic limit of the steel,
the Axis-Moment interaction diagrams for the section were
calculated without modifi cation and including the tube
(for different types of steel and thicknesses of tube).
Accordingly we have determined, for each type of concrete and
steel, the tube thicknesses that cause the interaction diagram
for the modifi ed section to wrap around the original section.
This ensures that there is no loss of resistance for the section for
that thickness of tube.
Report by the Association of Building Consultants
(ACE)*
1. BACKGROUND AND PURPOSE OF THE REPORT
…the checks to assess the structural impact of this system, which is
the subject of this report, will be carried out in accordance with the
following regulations:
- EUROCODE 2: Design of concrete structures. Part 1-1: General rules
and rules for buildings. UNE-EN 1992-1-1:2013
- EUROCODE 3: Design of steel structures. Part 1-1: General rules
and rules for buildings. UNE-EN 1993-1-1:2008
…
5. SUMMARY AND CONCLUSIONS
In the case of a C25/30 concrete column, placing an S-235JR tube
of the dimensions specifi ed in point 2 of this report inside it does not
imply any reduction of its resistant characteristics, as demonstrated in
the previous point.
As a summary, and for different concrete and steel resistances, two tables
(compression and shear) are shown with all possible combinations:
COMPRESSION SHEAR STRESS
Steel Steel
Concrete S235 JR S235 JR S355 JR Concrete S235 JR S235 JR S355 JR
C25/30 1.302 1.524 1.968 C25/30 1.892 2.214 2.858
C30/37 1.085 1.270 1.640 C30/37 1.615 1.890 2.440
C35/45 0.930 1.089 1.405 C35/45 1.411 1.651 2.131
C40/50 0.814 0.953 1.230 C40/50 1.253 1.466 1.893
C45/55 0.724 0.847 1.093 C45/55 1.128 1.320 1.703
C50/60 0.651 0.762 0.984 C50/60 1.025 1.200 1.549
It is observed, for example, that for a steel S-235JR such as that
of the current tube, in concrete with a characteristic strength equal
to or greater than 35 MPa, the safety coeffi cient is lower than the
unit. Therefore, in this case and in all those that appear in red in the
compression table, the incorporated tube as part of the ALSIPERCHA
system supposes a decrease in the resistance capacity of the column.
In these cases, once the formwork has been placed and the system
is no longer used, the hole should be cleaned and then fi lled with a
GROUT mortar of the same resistant characteristics as the concrete
of the column.
We present, for all relevant purposes and based on our fi rm knowledge
and understanding, our opinion which we defer to any other better-
founded opinion, in Girona, on July 11, 2019.
Info
* The original document consists of 8 pages, and is
available to our customers for inspection.
Signed: Pedro A. Calderón García
Dr. Civil Engineering, C. and P.
Head Teacher in Building
and Prefabrication
Signed: Juan Navarro Gregori
Civil Engineering, C. and P.
Assistant Teacher in Concrete
Info
* The original document consists of 17 pages, and is
available to our customers for inspection.
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