When we are discussing the definition of “structure”, the term varies within different disciplines. In the context of the built environment, "structure" refers to anything that is constructed or built from different interrelated parts with a fixed location on the ground.
Nevertheless, if we are examining structural design from a sensual perspective, and looking at structures in our buildings as to how they respond to people's everyday living requirements, the realm of structural design can be divided into several levels.
The most basic level starts at the technical buildability: first, we need to check if a building can be constructed under the existing technical capabilities. Next, we need to ensure that the internal structural engineering is reliable and meets current safety requirements and building codes.
Types of Structure
Structure is a very general concept. It can be roughly divided into several categories: one is the structure controlled by natural principles. For example, the mathematical structure produced in calculation, and the turbulent structure produced in fluid.
The second type which is the structure born out of subjectivity, such as the composition in paintings, the melody in music, and the skeletons in sculpture, is the opposite. These structures follow rules created by people's subjective consciousness, woven into structures to express people’s internal emotions or abstract concepts.
The third type of structure is relatively closer to the structural design we usually deal with in architecture. Such structures often experience evolutionary processes as well as a series of design-derived form generations. Between structure and architecture, interesting ideas often emerge during the process of evolution.
Structure Redistributes Circulation
Pingshan Pedestrian Bridge is located at the gate of Pingshan High school in Shenzhen. With the close collaboration of NODE Architecture & Urbanism and AND office, the 70-meter-span bridge for pedestrians and bicycles is built across the Pingshan River and opposite the Zhenhuan Road.
In order to disperse the flow of people after school, the bridge is planned in a “Y” shape, so that the congestion of the intersection can be avoided. Additionally, the covered bridge can be used to adapt to the high temperature and rainy climate in this region.
After in-depth communication, the architect and structural designers reached a mutual agreement that contains: a “Y” shape plan; a lightweight bridge roof; open sight on both sides of the mid-span part. Instead of using the traditional truss structure, and three-pronged string structure, the architect and structural designer explored the possibility of a unified arrangement for the bridge deck and roof.
As a result, the final plan appears complex and variable. The facade looks like a dissimilated truss.
The simple support allows the roof girder on the top of the bridge to slide along the bridge at the bifurcation point. The three-pronged girder for the bridge deck is hanged in the cable section, cantilevering part of the long-span side.
The cable part is deliberately used for plate appearance in order to achieve balance with the dense column frame of the bifurcation section, emphasizing the relationship between void and solid.
Structure Reintegrates the Old and the New
Shanghai Modern Art Museum located along the Huangpu River, is an example of the transformation and reuse of industrial buildings.
Combining the idea of "bamboo hat", the structural system design is as follows: all expansions are made of steel structure; the roof steel trusses are raised on all sides; the lower floors are hung under the cantilever trusses through vertical steel tie rods in turn.
This system avoids the newly added foundation; at the same time, the expansion part of each floor can be hinged and connected with the original structure, avoiding the rigid connection structure; and the cross-sectional size of the steel tie rod is less than 50mm, and it is only located on the external facade, and can be combined with the curtain wall column.
The new structure "wears" the old structure, making more effective use of the older part, and at the same time, it has the posture of separating the old from the new.
The lead architectural consultant, Atelier Deshaus, believes that, compared to the main part of the art gallery, the structural actions of the corridor transformation are more clearly readable on the surface of the building. The original ruin-like structure has lost its function and meaning as a building. It seems to have been “dead”. The new structure serves as a clear system that clamps the old concrete pillars and supports the upper structure.
The structural consultant AND Office decided to place the string beam on the old concrete frame beam and suspend the new structure downward. The old structure cannot support all the new structures, but since it still carries most of the weight, it becomes an indispensable part. The new vitality reappears, and the old ruins come back to life. Structure turns out to become something that can bring life and emotion.
Structure Reinterprets Construction Technology
"Red Pavilion" is the main reception pavilion in the digital pavilions group of the World Internet Conference in Wuzhen. Architects have chosen large-span space brick arches as the basic structural system to achieve architectural requirements while trying to challenge the span and parametric construction technology with extremely thin thickness.
The building covers an area of 273 square meters, its main body is located within a circular base with a diameter of 30 meters, and the main body is raised up by 5 supports, forming a self-supporting compression shell.
The building features a shell that has a surface area of 625 square meters, with an entrance opened to visitors from the top. The maximum span is 40.5 meters with a thickness of 150mm, spatially overlapping the shell shape.
Through utilizing different relaxation coefficients for different areas of the shell, the final balance shape corresponding to the design factors such as clear height and edge warpage, which can be easily achieved according to the specific requirements of architectural design.
The masonry materials of the shell are made of terracotta bricks and polymer mortar. The masonry structure is made of three bricks with two mortar layers. The arch support is partially equipped with concrete cores to increase the thickness to 450~750mm. The finished reinforced masonry has characteristics similar to the concrete structure but has a different mechanical property in directions.
The Future of Structural Design
Yimin Guo, the Associate Professor from School of Architecture in Southeast University, stated that:
“The structure is like a human body. If a person has a good figure and muscles, he will be able to show them off. Decorating a house is like putting clothes on a person. Although the body can be beautified by clothes, you can easily find a body’s shortcomings if the original structure of the body is not well designed."
From the perspective of structural engineers, the value of the structure is no longer just to ensure safety and control budget. In the future, we should explore more fusions between structures and architecture. By doing so, materials, structures, buildings, bodies, and places can be all connected together. Therefore, a building will truly belong to its location.
This article is part of the ArchDaily Topic: Collective Design. Every month we explore a topic in-depth through articles, interviews, news, and projects. Learn more about our monthly topics. As always, at ArchDaily we welcome the contributions of our readers; if you want to submit an article or project, contact us.