This design appraisal report summarizes two structural schemes for the floor plates of Tower 1, a proposed 25-story residential building in Cork, Ireland. Scheme 1 uses a composite steel and concrete construction with deep beams. Scheme 2 uses reinforced concrete flat slabs with shallower construction. Both schemes are found to be viable options, with Scheme 1 offering faster construction but deeper floors, while Scheme 2 has easier services installation but requires propping during construction. Preliminary structural element sizing and calculations in the appendices support the designs' ability to stabilize the tall building against lateral loads.

1. UNIVERSITY OF LIMERICK CONSULTING ENGINEERS
Design Appraisal Report
For Tower 1, Atlantic Quarter development,
Cork city
Conor Meaney
11138874
Team: Conor Meaney, Aseel Alsanea, Kevin Cahir & Danilo Marques
4th
year Civil Engineering
CE4027 Advanced Structures
10/10/14

2. 1.Executive Summary
Contained within this design appraisal report is summary of our design recommendations for Tower
1 on the Atlantic Quarter development in the old docklands area of Cork city, Ireland. Tower 1 is a 25
storey residential apartment building overlooking the River Lee, which at a height of 3.15m a storey,
would make it the tallest building ever constructed in Ireland. This project presented some key
challenges that had to be overcome. The main challenge was providing lateral (horizontal) stability
to a building of such a height, as the higher the building, the lateral stability begins to govern design.
The author believes that the solution presented for this is viable as it follows conventional design for
a building of this height. Presented also in this report are 2 schemes available for a floor-plate design
(the vertical stability element). Once again the author has followed conventional design and
presented two viable solutions with pro’s and con’s for both. Each design solution has preliminary
sizes for each individual structural element presented via preliminary drawings with the appropriate
calculations (to the relevant design standard, Eurocodes) all attached in the appendices.

3. 2.Table of Contents
0. Cover Page – P. 1
1. Executive Summary – P. 2
2. Table of Contents – P. 3
3. Cores and Lateral stability option – P. 4
4. Composite Construction floor plate scheme – P. 4 & 5
5. Reinforced concrete flat slab scheme – P. 5
6. Appendices – P. 6 - onwards
- Calculations
Wind loading
Lateral stability & core sizing
Composite Construction floor plate scheme
Reinforced concrete flat slab scheme
- Drawings
Drawing 1 – Composite Construction floor
plate scheme
Drawing 2 – Reinforced concrete flat slab
scheme

4. 3.Cores and Lateral stability option
The design solution makes use an 8m x 8m reinforced concrete core for its lateral stability. The
particular core size has been designed to resist the horizontal wind loading (forces) which are
expected to be experienced by the building during its design life. The wind loads were calculated
from the relevant design standard (IS EN 1991-1-4:2005). With these wind loads quantified, the
chosen design criteria used to preliminarily size the core was the serviceability limit state of
deflection. As stated earlier, the deflection will be the governing design criteria as the taller a
building gets, the deflection associated with it increases exponentially. The deflection has thus been
limited so as to be within a comfortable tolerance of the human body to resist ‘sway’ or back and
front oscillations. The particular size core is suitable for placing a number of lift shafts (for civilian
and firefighting) and a staircase. A smaller core would be structurally, and thus in the economics of
materials sense, “inefficient” as a much thicker wall would be required (approximately 700mm thick
walls for a 7m by 7m core, then 350mm). An excel sheet for this has been created and can be sent
on request. For the building dimensions of 24m by 24m, this core size also offers the advantage that
no internal columns are required, as would be required for a smaller core as the spans get larger.
Under the proposed 8m sq. grid spaced columns, you avoid the awkward spaces between the core
and columns with a 6m sq. grid. What you essentially have is an open-plan, offering obvious
architectural advantage for apartment layouts. The core has been placed in the centre, but 4 smaller
cores could have equally been placed at the corners (which is valid from a structural point of view)
but from an aesthetics point of view (the river side view of the River Lee), it was decided to allow as
much visual real estate to be accommodated for say by a totally glass-clad façade.
4.Composite Construction Floor plate scheme:
One of the floor plate schemes considered made use of composite construction. This particular
construction involves using structural steel as the beams and columns whilst utilising a reinforced
concrete slab with a steel deck to act as the floor plate. The proprietary system by Tegral known as
‘Compflor’ was examined as a solution for the slab. The scheme offers advantages over the alternate
scheme such as:
- Speed of construction
- Reduced column sizes
- Lighter structure
The particular arrangement (as can be seen in the drawing 1) makes use of a 110mm deep
composite floor deck arrangement (“Compflor 51”), spanning 2.67m onto secondary beams. These
secondary beams (UKB 305x165x54) span 8m to connections in the side of the primary beams (UKB
457x191x106). These primary beams span 8m onto columns (for the ground floor: UKC 305x305x137

5. & 305x305x240). This gives an overall construction depth of 579mm. This construction depth is more
than double that presented in the alternate scheme. This may cause issues with ceiling heights and
headroom. The ability to run services will have to be investigated; options that could be considered
include using cellular beams (beams with holes in them) or running them along the bottom of the
considered primary beam. The design has made so that no propping is required for the beams during
construction which is an obvious advantage from a contractor’s point of view.
5.Reinforced concrete flat slab floor plate
scheme:
The second floor plate scheme considered makes use of reinforced concrete flat slabs spanning onto
reinforced concrete columns. This particular construction involves using concrete as the main
structural component but with steel reinforcing bars required as concrete is a brittle material. This
scheme offers advantages over the alternate scheme such as:
- Reduced construction depth
- Ease of running services along the slab
- Very common construction technique
This arrangement (as can be seen in drawing 2) makes use of a 250mm deep reinforced concrete flat
slab, spanning 8m onto reinforced concrete columns. The columns sized are (on the ground floor)
600mm sq. and (on the twenty second floor) 300mm sq. This thus gives an overall construction
depth of 250mm allowing for more ceiling height or head room. It also has the advantage that
services (e.g. ventilation, cables) can easily be run along it. The size of the ground floor columns are
approximately double that as for the alternate scheme, which will increase the overall weight of the
building. A higher strength concrete is also required (fck = 50MPa) which will have to be strictly
monitored when arriving on-site. There was an issue with what is known as ‘punching shear’ for the
twenty second floor slab under the preliminary sizing, however solutions have been presented
within the calculations attached to this as an appendices. These solutions can be fully designed in a
detailed design stage. As this solution makes use of flat slabs on columns, propping is required for
the formwork and the concrete while it sets, which slows down construction time. As mentioned
above, this technique is very common and thus a large variety of contractors will have experience
with this construction type.

6. 6.Appendices