The
street block is an urban unit which is partly or entirely built-up in a very
diverse way and generates the urban membrane, through its connection with
the systems of road network.
Since the first civilizations, the street block was used to regulate the urban
growth.
In the 2nd century BC, the Greeks dealt "negligently" with the problems
of town planning. The streets which archaeologists could/managed to
identify are traced in an irregular way, except for the Dromos (principal
axis). The Roman insulae were irregular and of modest nature, due to
the little importance of private life, as the major part of the day happened
outside, in the arranged public space (1).In
the 5th century a new political theory is implemented by Hippodamos of Milet.
It recommended a rectangular and uniform grid of street blocks measuring 100
X 175 feet (about 32 X 52 m) (cf. urban road). .
At the same time, the Roman cities take as a starting point the principle of orthogonality: gridiron plan for the division of the pieces of land or the layout of the town plans. They refer to a reticular layout which leads in almost all the cases to a rectangular form, made up on two axes (sometimes only one): the 14 or 15 m wide decumanus and the 7 to 8 m wide cardo, perpendicular to the former. Minor roads parallel to either of the two major axes, and at least 2,5 m wide delimit the square or rectangular insulae every 60 to 70 m (2).
In the 12th and 13th centuries, the period of the Early Middle Ages is marked by a new town planning which is characterized by the creation of bastide towns or new towns. The designer of a bastide town plays with ayrals, small blocks formed by a street grid. "The widest axes are the cart tracks, which continue the roads within the agglomeration. Perpendicular to them, and narrower, are the cross streets which serve the blocks. The jointly owned strip between 2 ayrals is followed by an androne (entry way), which allows each house to look like an independent unit". In Villefranche-de-Rouergue the ayrals measure 4 cannes by 10 (approximately 20 X 50 m) .(3)
In the 17th century, Sebastien Prestre de Vauban, Marshal of France and King's Engineer, is considered by most authors as a theorist of the Renaissance. The town of Neuf Brisach is governed by rules of composition like all of Vauban's towns. It comprises a great central square onto which the principal buildings look, the well proportioned street blocks make the geometry of both the urban fabric and the fortifications balance each other (4)
In the 18th century "Thomas Jefferson, a Founding Father of the United States of America, established a grid following meridians and parallels, to be used for the colonization of the new western territories; each square covers 6 square miles (6 * 256 ha) and can be divided into 2, 4, 8, 16, 32 or 64 smaller parts. Thus was defined the geometrical model on which the urban and rural landscape was to be built" in the United States.(5)
In the 19th century, Cerda carried out the extension plan of Barcelona by introducing for the first time the principle of the diagonal. His plan takes the form of a grid with square 113 m wide small islands, which have a small 20 m long cants at each corner. The street blocks thus configured were octagones of 12 370 m² surface area with gardens at their centre. "Cerda saw in this systematic grid, not a means of facilitating the subdivisions, as it was in the American cities, but the only one able to allow for social equality and optimisation of the relations between two points of the city".(6)
In parallel, the transformation of Paris by Haussmann created a type of city resulting "from the reshaping of the star meshs of the haussmannian networks" .(7) It generally resulted in triangular as well as rectangular street blocks, and their core was occupied by individual or shared courts.
In the
20th century the modern movement made its appearance between the two wars,
expressing a new town planning design which aimed at redefining urban expansion.
In 1905 Tony Garnier arranged a street block by creating open courts while
renouncing the traditional straight building line (8)
Corbusier recommended the abolition of the street block, and the plan for
the town of Saint-Dié is a perfect example of that; made up of eight
buildings on pile, a little similar to that of Marseilles, it represents a
composition which refuses the standards of the traditional city defined by
the block and the street (9)
In 1939 Robert Auzelle envisaged for the Marais district of Paris the curetting
of the courts, the re-establishment of the gardens as well as the opening
of public routes inside the blocks (10)
Today the street block has its own autonomy, it must have a form corresponding
to the geography of the territory and the identity of civilization. In Evry,
taking the English model as a starting point, the developer E. de Penguilly
and his architect D. Montassut propose blocks made of houses with gardens
(11)
As for Christian de Portzamparc, he defends the idea of the open street block
in the layout of ZAC Masséna. Those blocks measure either 90X60 m or
90X30 m and allow for the multiplication of views and the capture of light
(12)
Cf. BUILDING LINE, ANDRONE, AYRAL, BASTIDE TOWN, BLOCK CENTRE, COURT, DIAGONAL, GRID, INSULA, STREET...