The Release of Desire: Three Levels of Spatial Expression of Beam in Modern and Contemporary Reinforced Concrete Architecture

Since time immemorial human construction activities cannot avoid spatial concepts of beam structures. Since the nineteenth century the invention of reinforced concrete material is accompanied by advances in structural engineering science, and it is possible to enrich the forms of beam. However, the natural pursuit of pure space concepts under the influence of abstract art, with the discipline gap of structural engineering and architecture, makes structural members to some extent just a tool to serve the realization of abstract space. So the character of the beam in the modern and contemporary context is somehow embarrassing: beneath the floor slab, the beam may become a negative factor in the concept pure space; located above the horizontal line of sight and physical activity of the people, the beam easily becomes a structural member that is ignored by users and even architects; modern building environment relies on mechanical equipment, and the beam often becomes an obstacle in placing pipes. Either the visual existence of beam is canceled, such as Le Corbusier’s DomIno system; or the beam itself is completely ignored without any architectural operation or roughly covered by suspended ceilings together with mechanical pipelines. As a result, the beam lost the possibility of spatial expression in large numbers of modern and contemporary buildings. Abstract: In contemporary context the discipline gap between Structural Engineering and Architecture to some extent leads to the loss of the spatial expression desire of structural members. Two conditions are presented in a large number of common contemporary building projects: Rough lacking the architectural perspective control over the scale and layout of structural members, Absence hiding the beams with decorative elements such as suspended ceiling. Actually, as one of the most important structural members in a building, the beam has great potential for spatial expression. Since the beam plays an increasingly more important role, three progressive levels could be characterized: spatial scenery as the fifth elevation, spatial prop participating in the generation of form, spatial protagonist leading the order of spatial tectonic. According to the above three levels, classification and analysis to several modern and contemporary buildings, especially several reinforced concrete buildings of the 1960s and 1970s, may be helpful in exploring the methodology against these two above trends of contemporary construction Industry.


Introduction
Since time immemorial human construction activities cannot avoid spatial concepts of beam structures. Since the nineteenth century the invention of reinforced concrete material is accompanied by advances in structural engineering science, and it is possible to enrich the forms of beam. However, the natural pursuit of pure space concepts under the influence of abstract art, with the discipline gap of structural engineering and architecture, makes structural members to some extent just a tool to serve the realization of abstract space. So the character of the beam in the modern and contemporary context is somehow embarrassing: beneath the floor slab, the beam may become a negative factor in the concept pure space; located above the horizontal line of sight and physical activity of the people, the beam easily becomes a structural member that is ignored by users and even architects; modern building environment relies on mechanical equipment, and the beam often becomes an obstacle in placing pipes. Either the visual existence of beam is canceled, such as Le Corbusier's Dom-Ino system; or the beam itself is completely ignored without any architectural operation or roughly covered by suspended ceilings together with mechanical pipelines. As a result, the beam lost the possibility of spatial expression in large numbers of modern and contemporary buildings.
Abstract: In contemporary context the discipline gap between Structural Engineering and Architecture to some extent leads to the loss of the spatial expression desire of structural members.
Two conditions are presented in a large number of common contemporary building projects: Rough -lacking the architectural perspective control over the scale and layout of structural members, Absence -hiding the beams with decorative elements such as suspended ceiling. Actually, as one of the most important structural members in a building, the beam has great potential for spatial expression. Since the beam plays an increasingly more important role, three progressive levels could be characterized: spatial scenery -as the fifth elevation, spatial prop -participating in the generation of form, spatial protagonist -leading the order of spatial tectonic. According to the above three levels, classification and analysis to several modern and contemporary buildings, especially several reinforced concrete buildings of the 1960s and 1970s, may be helpful in exploring the methodology against these two above trends of contemporary construction Industry.
Key Words: beam, reinforced concrete, spatial expression, structural member

Spatial Concept of Beam Structure in Ancient Construction
Humans have had the concept of beam structures from ancient times. The Stonehenge in the Neolithic Age might be seen as one of the earliest beam structures built by mankind. A 7-ton stone strip was attached to two columns to form a simply supported beam and then arranged to a concentric circle. Goemetric meanings remains a mystery, the simple form and arrangement of the beams show a strong geometric composition and a desire to resist the gravity. In the book Aesthetics and Technology in Building Pier Luigi Nervi once questioned the meaning that the span of the beams at the two ends equal to the middle beams in the pediments of the Greek temples 1 (fig. 1). If the usual understanding of letting the corner columns adduct and enhance its feeling of stable is not the constructor's starting point, then the consistency of beams span and the difference of columns distance may stem from the pursuit of space under such a technical constraint: let each stone beam reach the maximum span under uniform cross-section conditions. After all, the material properties are such that the horizontal span is especially valuable when the stone is utilized as a horizontal loadbearing member. The spanning capability of these stone beams determines the adducting of two corner columns and then involves the monolith of the whole temple. In the East there are also a few allusions to the relationship between the beam and the space. In Chinese "the reverberation around the beams, incessant more than three days" is used to describe the endless aftertaste of a music. 2 Why is the reverberation around the beams rather than the columns or other elements? Physically, the stacked structure of the beams beneath the roof provides space for multiple reflections of sound waves. Although the surrounding music is invisible, by imagination, the picture is vividly presented in our minds. Besides, another Chinese allusion literally translated "Gentleman on the Beam" is used to refer to the thief. 3 In the East Asian wooden houses, the beams are usually above people's sight of daily living, which can

Spatial Scenery -As the Fifth Elevation
Cubic volume is a kind of space operation prototype that modern architects are obsessed with. As a linear element in a building volume, besides the load-bearing function, the beams that under the control of structural logic and geometric order always has a great impact on the visual effect of the top surface, and become a representative fifth facade of a building.
(a) Point: Size and Shape.
A point in the geometric sense has specific location but not size, its existence is just for defining spatial coordinates. A point in the   The trace of a line movement forms a plane. The geometrical plane has area but not depth degree, and its existence is just for measuring the extending area. In terms of structural and architectural form, the most typical surface-shaped member is the slab, which can be distinguish by deep or shallow, heavy or light. In a building the contradiction between the strength and the weight of the slab makes the beams act as a protagonist of horizontal load-bearing and spatial expression. When the parallel ribs of a rib-beam slab and the crossing beams of a waffle slab intense to a certain extent, several lines weave a plane, and several ribs approach a slab. Compared with the smooth surface of thick reinforced concrete slab, the plane formed by rib beams and the waffle beams has much greater potential of spatial expression: the height and density of beams are  Acting as "trampoline lines," 9 these two primary beams stretched the concrete slabs up to 650mm in the mid-air, and completed the spatial expression of "light like a bird."

Spatial Prop -Participating in the Generation of Form
In the context of Japanese architectural design, the term structure encompasses the meaning of framework + place. The structure is not only a technical concept, but also a place with spatial concept.
When the beam exists as a framework + place, its way of intervening in space will let it be a kind of prop of spatial expression.

Conclusions
Since beams are playing an increasingly more important role in architecture, three progressive levels of modern and contemporary architecture practices could be characterized: spatial scenery -as the fifth elevation, spatial prop -participating in the generation of form, spatial protagonist -leading the order of spatial tectonic.
Confined to the length of the thesis, a large number of those cases that have been classified could not be mentioned. This classification is based on two main lines: one is the typology classification based    we ask what a beam want to be, the beam might respond to the desire to be the space itself.
Notes 1 "The pediments of the Greek temples are the clearest example of the building limitations imposed by marble. The space between columns is determined by the spanning capability of the monolithic architraves. One might well ask oneself if the lesser span between the end columns, which adds so much to the aesthetic expression of the colonnade, was not the result of the constructional expediency of leaving the length of the end architraves equal to the others instead of increasing them by half a column with." Pier Luigi Nervi, Aesthetics and Technology in Building, trans. Robert Einaudi (Cambridge: Harvard University Press, 1965), 11.