This document compares alternative construction methods for underground car parks. It examines the cut and cover method and room and pillar method, providing case studies and cost analyses for each. The cut and cover method involves excavating and then covering the excavated area, while the room and pillar method uses natural rock pillars for support. The analyses found that the room and pillar method has much lower costs per square meter due to revenues from raw materials and not requiring extensive support systems. It was concluded that the room and pillar method offers the most economically feasible solution for underground parking construction.

1. COMPARATIVE EVALUATION OF ALTERNATIVE METHODS
FOR THE CONSTRUCTION OF UNDERGROUND CAR PARKS
M.C. PAPPA
Civil Engineer, Msc, Greece
A.G. Benardos
Phd, Lab. of Mining & Environmental
Technology-NTUA, Greece

2. Importance of parking spaces – Underground car parks
The problem.
Lack of parking spaces in the large urban
centers.
The consequences.
Traffic jams and long delays.
Environmental pollution.
The solution. Underground parking areas.

3. Advantages
Preservation of valuable surface space.
High availability.
Environmental protection.
High construction
and service cost.
Importance of parking spaces – Underground car parks
Disadvantages

4. Motives for the construction of underground parking stations
Subsidy 4.108 € / per parking place
Conditions
Creation of at least 40 parking places stations of public use.
 Demonstration of the necessity of the underground parking construction.

5. Alternative Methods for the Construction of Underground Car Parks
Cut and Cover Room and Pillar

6. Cut and Cover Method
 Field of Application .
Loose soil of top layers.
Hard soil (in exceptional cases).
General outline
 Support of the cutting perimetric walls.
Steel strands.
Reinforced concrete.
Tensile anchors.

7. Cases examined
Parking Station Surface (m2) Volume (m3) Floors
Capacity
(cars)
Paidon Hospital Square 17.433 54.764 5 576
Rizari Street 18.997 56.339 4 664
Kaniggos Square 15.401 49.283 4 491
Cut and Cover Method

8. Cut and Cover Method
Kaniggos Square

9. Cost Analysis – Key issues
0
5
10
15
20
25
30
35
40
Design
Studies
Support
Excavation
Concrete
W
aterproofing
Pavements
Coatings
Landscaping/decoration
Electrical&
Mechanical
ParallelworksGeneralexpences
As-buildCost(%)
Paidon Square station
Rizari street station
Cut and Cover Method

10. Parking Station Total Cost (x103 € )
Cost/parking
place (€ )
Cost/m2 (€ )
Paidon Hospital Square 5.283 9.170 303
Rizari Street 4.830 7.275 254
Kaniggos Square 9.856 20.075 640
Cut and Cover Method
Cost Analysis – Key issues

11. Cut and Cover Method
Cost Analysis – Key issues
 Factors examined:
Local conditions in the
construction area.
Geological background.
Excavation depth.
Parallel works (Rerouting of
the traffic, pedestrian passages,
rearrangement of utility
networks).
Support.
Renovation and landscaping.
Support.
Excavation.
Support.
Excavation.

12. Room and Pillar Method
General outline
 Support.
Natural support.
The pillars of the rock
support the overburden.
 Field of Application .
Horizontal or slightly inclined formations , located in low to
medium depth and characterised of high to medium strengh.

13. Parking Station Surface (m2) Volume (m3) Floors
Capacity
(cars)
Agia Paraskevi 13.248 66.240 1 360
Tourkovounia 11.319 45.276 1 346
Katehaki Bus depot 59.917 479.336 1
284
(buses)
Room and Pillar Method
Cases examined

14. Entrance –
Exit of
Pedestrians
Entrance – Exit of
Vehicles
Agia Paraskevi
Parking Station
Room and Pillar Method
Cases examined

15. Cost Analysis – Key issues
 Major cost components
Excavation cost.
Development cost.
Income gained from
the sale of the raw
materials.
Parking Station Total Cost (x103 € )
Cost/parking
place (€ )
Cost/m2 (€ )
Agia Paraskevi 1.353 3.760 102
Tourkovounia 3.067 8.865 297
Katehaki Bus depot 3.667 12.910 61
 Factors examined:
Location.
Volume.
Excavation
method.
Room and Pillar Method
Creation of
an economy
of scale.

16. Comparative evaluation
 Much lower cost/m2 in the room and pillar cases than of
the cut and cover ones due to:
Revenues from the raw materials sales.
Natural support  absence of major support systems and
concrete works.
The room and pillar method constitutes a radical solution
which is able to offer the optimal financial results.
Agia Paraskevi
102
Τourkovounia
297
Paidon Hospital
Square
303 Rizari Street
254
Kaniggos Square
640
Katehaki
Bus Depot
61
0
150
300
450
600
750
Totalcost(€/m2)
Hospital Paidon Square
Rizari Street
Kaniggos Square
Agia Paraskevi
Thermal Bus Company
Τourkovounia

17. Conclusions
The development of underground car parks is essential for modern
cities as it provides an efficient way to facilitate the parking needs.
A further research should be realized in order to construct
underground parking stations using methods which combine
feasibility with greatest economy.

18. End of Presentation
Thank you very much!