Multi-storey car parks for public use

Since the beginning of the 900th century, with the widespread use of automobiles, the need to solve the problem of parking vehicles has been felt. To this end, design saw the emergence of a new branch, specialized in providing concrete answers to this difficulty. The actual introduction of the category corresponds to the beginning of the XNUMXth century, when France distinguished itself for the construction of the first multi-storey car park for public use above ground. In close relation to American garages, the Perret Brothers designed a multi-storey car park in Paris, contained within an urban building in Art Nouveau style. This re-functionalisation opened a large series of examples that affected the years preceding the Second World War, a period in which motorisation was still limited and for this reason structures specifically designed for parking cars were not conceived. The solution of using a part of the existing buildings that lend themselves to this purpose for this function is still widespread today, specifically within urban contexts, in areas of historical character, where the available space is limited and the retrofitting of existing buildings prevails over new construction.

In contrast to historic centers and small urban centers, within large cities, in the more peripheral areas, there are structures specifically designed to accommodate parked cars. These are buildings developed on multiple floors that sometimes stand out in the urban landscape for their particular aesthetic features, sometimes they are camouflaged through the use of neutralizing solutions. The latter can be represented by vegetation or decorative elements that hide the underlying structure, which is very modern and has an impact from an aesthetic point of view. Over the course of history, however, these features have been highlighted in American cities, where the architectural culture of verticality and the use of glass and metal have opened the way to multi-storey car parks developed in height. These are structures that are necessary from a functional point of view, inserted in a reality in which the car is considered indispensable for the daily life of the citizen.
This is how the parking structure becomes an integral part of the urban landscape. The typical vertical development of multi-storey systems involves the overlapping of horizontal and inclined surfaces, suitable for hosting vehicles. Each floor is connected by special ramps that are distinguished by distribution and direction of travel.
In conclusion, it is important to keep in mind that each structure is designed to meet the needs of a well-defined user base, but it is essential to always take into account the characteristics of the context in which it is located.

Guidelines for correct design

In order to ensure the success of the multi-storey car park design, it is necessary to observe some principles. The first consists in identifying the surface accesses for vehicles and how they can be reached taking into account the expected car traffic flows. Furthermore, it is a good idea to indicate at the entrance to each car park the characteristics that cars must have in order to enter (max. height, weight), so as to avoid accidents when cars with different characteristics pass by.
The second element that is of great importance is represented by the connecting ramps between the various floors. These components can have a rectilinear or curvilinear trend, depending on the physical and structural conformation of the spaces used for parking. The third analysis concerns the safety and accessibility that must be ensured for users, through the inclusion of sized stairwells, visible emergency exits and efficient fire-fighting systems. All these components are considered individually and designed appropriately and in accordance with current legislation, in order to guarantee a complete and safe whole.

To be considered functional, a multi-storey car park must ensure:

• space maximization
• compositional and overall rationality
• quality of parking spaces
• functionality and visibility of driveway accesses
• safety of pedestrian paths within the parking area

The design of such parking areas must be conducted in order to make conscious choices that optimize their functionality. In fact, several studies have shown that cars remain in a stalled position for most of the day and consequently the spaces used to accommodate them must be considered an integral part of urban mobility.

Types of multi-storey car parks

The multi-storey structures designed to accommodate stalled cars vary according to specific needs, in terms of number of spaces, dimensions to be respected and constraints related to the area of ​​interest.
The first distinction that can be made for this type of parking concerns its development: on the surface or below the walking surface.

MULTI-STOREY ABOVE GROUND PARKING

It represents the typology with the greatest impact on the urban context in which it is located and for this reason the design process must pay particular attention to its correct insertion. Starting from the characteristics of the place, it is necessary to consider the road morphology and the needs of the area in terms of the number of parking spaces dependent on the possible presence of attraction poles and interchange places with the subway, buses or trains. The new structure must respect the distances of relevance with respect to existing artifacts, without compromising the consistency of natural elements and assets to be preserved. Precisely for this purpose, the Italian and European scenario prefers artifacts that are mitigated through the insertion of green elements such as hedges and climbing plants or decorative panels, provided that there are no aesthetic constraints and the budget allows it.

MULTI-STOREY UNDERGROUND PARKING

For the design of the underground multi-storey car park, the aesthetic conditions change, as in this case, the impact that the structure will have on the built environment will be reduced to a minimum. However, although the surface appearance is not to be considered primary, since only the accesses will be present at street level, at the end of the work it will be necessary to restore the initial state of the context or even better redevelop it. In most cases, in fact, recreational areas are created in which the street furniture and vegetation contribute to increasing the psycho-physical well-being of the citizen. Along the external perimeter of the area used for parking, it will be necessary to provide for the insertion of special natural ventilation systems, in order to ensure the healthiness of the environments and safety. In fact, in the event of fires spreading, the flames and smoke produced would prove lethal if they were not immediately countered.

By inserting ventilation devices, it will be possible to reduce heat, facilitate the release of toxic air and increase visibility to reach escape routes. In addition, it is good to ensure the right measures against possible explosions caused by flammable substances generated by cars.
The second classification of the multi-storey car park concerns the type of vehicle movement which can be manual or automatic. In the first case, if the car needs to be moved or picked up, the staff of the facility will take care of it, in the second case instead, such movements are carried out by mechanized systems.
Parking lots with these characteristics are classified as:

GARAGES
Of varying dimensions, they house multiple vehicles, the management of which is the responsibility of the facility's employees. Sometimes, this category also includes smaller systems for private or semi-private use: supervised parking lots belonging to residences, hotel and gym parking areas.

SILOS CAR PARK
Complex and large structures where many cars are stored, managed by automatic systems capable of responding to various needs. In fact, following storage by the owner, the car will be moved and safely stored, through special computerized systems that will also take care of preparing the vehicle for collection at the end of the service. Multi-storey car parks are very advantageous within complex urban contexts, since they guarantee the maximization of the limited usable space by offering many parking spaces. These structures protect vehicles from vandalism and harmful maneuvers (since there is no possibility of accessing the parking lot except for storing and collecting the car) and reduce the production of smog thanks to management with the engine off. The spaces involved in this type of parking can be of the blocked or interchangeable type. In the first case, the cars are moved through a motorized roller that can work horizontally or vertically and once positioned they are no longer moved until the moment of collection. Mobile parking spaces, on the other hand, involve the vehicle being moved to "make room" for the next one, until all the spaces are filled.

Finally, a further distinction can be made depending on the type of vehicle that the multi-storey car park will accommodate:

MULTI-STOREY PARKING FOR HEAVY VEHICLES

Intended for all those categories of vehicles having dimensional and weight characteristics greater than
to normal cars. These include buses, lorries, trucks, car transporters, vans, articulated buses and vehicles intended for the transport of goods. One of the most important aspects for this type of vehicle is security: the entire area must be under video surveillance and inaccessible except by personnel in charge and the owners of the vehicles. From a dimensional point of view, the structure must be designed for very different needs compared to those intended for cars.
First of all, the height of the inter-floor, designed to ensure the transit and parking of larger vehicles. Furthermore, in the entrance areas to the parking lot, the presence of suspended oscillating panels is required, which provide an indication of the maximum height that vehicles must have in order to access the structure.

MULTI-STOREY PARKING FOR VEHICLES IN DEPOSIT

These structures are intended for the storage of cars and heavy vehicles for variable and even prolonged periods of time. In these parking lots, safety and reliability in the custody of the vehicles are guaranteed, thanks to the presence of video surveillance systems active 24 hours a day.

Minimum dimensions and aspects to observe

As with the construction of any other type of building, the design process for multi-storey car parks must take into account some fundamental aspects to obtain a satisfactory result, first and foremost from a functional point of view. It must be considered that any typological choice is strictly bound to the building regulations and the legislation in force in the territory in which the intervention is located. The value of the average surface area intended for a single car park varies depending on the functional area in which it is located and on average corresponds to approximately 10-12 mXNUMX. As regards multi-storey car parks, as the term indicates, they are made up of several floors that must have aminimum height equal to 2.4 m and higher, depending on the characteristics of the vehicles they are designed to accommodate. In the case of multi-storey car parks, the height can drop to 1.8 m.

The height of the floors is increased at the exit points of the cars, at the end of the connecting ramps, since the lifting causes an inclination of the vehicle that could sometimes lead to direct contact between the roof of the vehicle and the parking roof slab. The structure can be composed of a single level or multiple staggered or oblique levels, connected to each other by floors with a dual function of ramp and lane. The ramps can have a straight or curved path, can provide for one or two-way traffic and can be located outside or inside the parking area.

The difference between one-way and two-way ramps consists in the distinction between the ascent and descent of vehicles or in the coexistence of the two directions in a single lane. This last choice presupposes the advantage of maximizing space (two functions in a single space) but entails the need to provide a larger area of ​​the entry and exit zones, in order to avoid traffic jams and dangerous collisions between vehicles in circulation.
As regards the minimum width that a ramp must have to be functional, the Ministerial Decree of February 1986 establishes the values ​​of 3 m when it is one-way and 4.5 m when it is two-way. The slope of all types of ramps must not exceed 20°.
The lanes, on the other hand, must be at least 5,5 m wide to ensure the free movement of vehicles and facilitate the entry and exit of cars from the parking space. This last element, of fundamental importance, must be sized on the characteristics of a "typical" car, taken as a reference. By calculating the average length and width of a vehicle, increased by a margin of variability depending on the type of vehicle, the law establishes the standard measurements of a parking space equal to 2.5x5 m. However, in the case of public multi-storey car parks, accessible to customers, it is mandatory to include a parking space for disabled people, every 50 standard spaces. This parking space will be wider and will be flanked by two lateral spaces suitable for accommodating a wheelchair.
From the point of view of the efficiency of individual parking spaces, the 90° arrangement with respect to the lanes is optimal, to the detriment of the 45° arrangement. Taking these aspects into consideration, the load-bearing structure of the multi-storey car park must necessarily allow for manoeuvring and ensure minimum distances between lanes and parking spaces, in order to guarantee practical use in the complete absence of obstacles.

Even the spaces used for passage or waiting must be designed to ensure free use and total accessibility: this is the case of pedestrian paths and stairwells and elevators. The former must guarantee adequate safety in terms of size and materials used on the surface, as well as the total absence of architectural barriers. The study of stairwells must take into account the optimal measurements of risers, treads and landings, and provide parapets, handrails and signs for the visually impaired. The spaces in front of the elevator must be free of obstacles and well lit, while the cabin must also allow use by disabled people who move around in wheelchairs. The button panels and signs must provide translation into Braille to allow their correct use also by the disabled.

Lighting and safety

A very important aspect to ensure the free and safe use of a multi-storey car park is the lighting of the spaces that compose it. According to the regulations, the value must not be less than 20 lux, just like in passage areas such as stairwells, lanes and pedestrian paths. As regards the work and control areas, occupied by the staff of the facility, they must enjoy a greater light intensity, in order to guarantee the free performance of work activities. Furthermore, lighting has an indispensable function in terms of safety, with emergency devices able to ensure the presence of light in entry and exit areas even in the event of a malfunction of the main lighting system. Finally, the multi-storey car park is equipped with practical information displays, equipped with LED lights that facilitate the correct use of the parking and maneuvering spaces.

Information and control systems

With regard to safety and usability for the user, multi-storey car parks can be equipped with specific systems aimed at increasing their functionality and success.

WARNING DEVICES
In order to inform the user coming from outside about the occupancy status of the parking spaces distributed on the various floors, it is optimal to insert information displays at the entrance to the multi-storey car park. These are illuminated systems (green light - red light) that are very frequently found in structures used for public parking, in correspondence with city attraction centres such as shopping centres, multiplexes, sports areas. The devices include an addressing system to the floors and to the free space. In this way, unnecessary queues are avoided and the use of the structure is facilitated by the user who already knows the direction to follow.

MANAGEMENT SYSTEMS
This category includes all those systems that transmit useful data to the warning devices. These are sensors that provide information on the parking situation of the cars, communicating to the general control system how many spaces are free and how many are occupied in a specific area of ​​the multi-storey car park. The management systems of these structures are essential for the correct functioning of the warning devices, inserted with the aim of improving the customer experience by reducing the time spent searching for a parking space and indicating the route to follow to reach the free space.

CONTROL SYSTEMS
As for individual parking spaces, sometimes, in the case of multi-storey structures that provide for the service of prolonged and supervised custody, there may be solutions for controlling the stall. If reserved areas are provided, they will be equipped with fixed or mobile deterrents that guarantee their reservation and inaccessibility to other cars entering.

Environmental mitigation solutions

As previously mentioned, the growing need for parking spaces, caused by the habits of citizens increasingly tied to vehicular travel, is the primary cause of the increase in demand for structures intended for this use. Furthermore, the search for a free space where to leave the car would cause 30% of traffic congestion and a consequent significant increase in smog. Within this scenario, designers have begun to think of solutions that could integrate parking structures into the urban context. A concrete example of this is the ecological interpretation of multi-storey underground car parks, equipped with roofs used for the insertion of common green areas.

This is an increasingly widespread trend that has the dual purpose of redeveloping the area of ​​interest and providing citizens with recreational spaces that act as true lungs of the urban fabric. At the heart of this modus operandi is the principle of sustainability interpreted 360°, from an ecological, economic and social point of view. In fact, multi-storey structures guarantee the maximization of space, providing a high number of parking spaces for cars with the same volume, an optimization of management costs and a greater functional quality. In the case of mechanized silos for example, the use of automated systems for managing cars significantly reduces the smog produced by vehicles that in this case are moved with the engine off. It is therefore up to the designer to use the best choices, in order to optimize costs and promote energy savings in all structures used for multi-storey parking.

Realized examples

From the beginning, the design of multi-storey car parks has neglected the aesthetic aspect, in favour of a purely functional exasperation. This is a serious mistake, especially in the case of above-ground structures, since these systems represent real building typologies that fit into the urban fabric. However, in recent decades there have been several examples built, worthy of note in terms of construction quality and aesthetic value. Sometimes these structures are considered real works of contemporary architecture.

Al Jahra Court Automatic Parking System – Kuwait – 2016

It has been defined as the largest automated parking lot and with over 2000 parking spaces, it holds the world record of its kind. The maximization of space and the very rapid times of management and recovery of vehicles, make it an exemplary creation. Located in the area adjacent to the judicial complex of Al Jahra in Kuwait, the structure is characterized by its high capacity, tripled compared to other types with the same volume. The parking lot uses automation systems capable of managing vehicles during the entire reception, parking and exit time.

Cliniques Universitaires Saint Luc, Brussels Belgium – 2016 (hospital visitor park)

The primary objective of this parking project was to provide a structure that combines aesthetics and functionality for visitors to the adjacent hospital. Built using extensive natural materials, the multi-storey car park guarantees a high level of natural lighting and ventilation. Its generous dimensions are designed to accommodate over 900 spaces for future users' vehicles. The structure, inaugurated in October 2011, integrates harmoniously with the context and is spread over two levels above ground and three underground. The roof has been transformed into a green garden that connects to the nearby residences. The facades, made of rigid wooden panels, contrast with the archetypes of the pre-existing structure but blend well with the surrounding hilly landscape. The sinuous lines of the car park, which has been compared to a canyon due to the voids created to facilitate the passage of light and air, fit perfectly into the lot. The result is a multi-storey car park that is far from the concept of an unsightly structure with an impact on the environment in which it is located.

Quick Morelli Parking, Naples – 2011 (historical fabric parking)

This is a very ambitious project that aimed to combine the historical value of a pre-existing asset and the innovative value of the new structure intended for parking. Located in the heart of Naples, in the Chiaia district, full of shops and services, the cave has always been a historical symbol of the city. The need for parking spaces in this district was particularly felt and for this reason the new structure was designed to offer 2000 spaces on a rotation basis between garages and car parking spaces.
Thanks to the generous heights of the cave (in some areas it reaches 40 meters), the project included the insertion of a structure that develops on seven floors, four of which are above ground and three underground.

The various levels are connected to each other by driveway ramps and elevators enclosed in glass casings, thanks to which it is possible to enjoy the scenic view of the cave. The extensive video surveillance system guarantees the safety of cars 24 hours a day and the rotation function allows the use of the parking lot by a large user base. In addition to this use, the Quick Morelli parking lot offers many other services to citizens and tourists: car wash, bike rental, electric car charging, ATM. Furthermore, in a central position there is a large area used as multifunctional spaces for private parties, exhibitions and conferences. This example of perfect functional cohesion between ancient and modern has earned the title of "most beautiful parking in the world".

Sinking Ship, Seattle – 1965