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Architects: Chen Donghua Architects
- Area: 9600 m²
- Year: 2024
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Photographs:Siming Wu
The gap of time and space
This is a renovation project that uses the time gap of summer vacation to fill in the space gap around the campus. It requires the whole process to be extremely fast, flexible, effective while all things come to be highly reasonable and operational.
The orthogonal spatial structure inside the Nanhai Primary School collides with the polygonal street interface outside, which produces many "remaining spaces". Based on this spatial structure, we introduce the entrance corridor, parking shed, folding courtyard & pavilion, fence renovation, etc. to reconnect and activate those "remaining spaces". This renovation not only meets the functional requirements, but also enriches the original spatial structure. In addition, due to the school's urgent need for usable area, we added different sheds and mezzanine spaces at different levels, including rooftop multi-functional shed, roof gardens, reading sheds, etc., to further expand the possibility of space in the vertical direction. These new sheds on the ground or on the roof are semi-outdoor structures that adapt with the subtropical climate and the daily use, and thus create the shadow that accommodate the everyday life without air-conditioner. At the same time, this type of structure also reduces the approval process for formal construction applications. Other renovations include corridors, toilets, facade renovations, etc. We hope to carry out an integrated renovation for Nanhai Primary School at all scales and levels.
Different But Similar "Shed Species"
We learn from the everyday sheds in the Pearl River Delta. They present an alternative folk wisdom of "going with the flow" in terms of climatic conditions, space planning, material selection, lightweight structures, cost management, etc. In the Shenzhen Nanhai Primary School renovation project, we also introduce such a relaxed, daily attitude and method, and released the spatial effects of various sheds in the marginal sites of different forms, sizes, elevations, etc.
In addition, during the short design and construction period, these various scaffolds need to contain similar relationships to achieve the derivative effect of drawing inferences. These internal similarities include space, structure, materials, usage, etc. For example, in the horizontal, vertical and diagonal dimensions of the plan, we weave diverse and similar spatial layouts by re-inventing the orthogonal grid of the original internal building and the oblique angles of external urban interface; while in the horizontal, vertical, and diagonal dimension of the section, we form an intrinsically related skeleton series relatively corresponding spans/beams, heights/supports, slope finding/drainage/structural constraints, etc.
We regard these shed as a series of "species". The internally similar skeleton relationships derive different incarnation and performances in different environments, which are different but similar.
Rooftop Multi-functional Shed
The renovation of the rooftop multifunctional shed complies with the column-span of the original structure at the bottom, which is mostly 6 meters and ends at 8 meters. Therefore, the structural form of the shed has also changed at the position of the 8-meter column span. For example, while maintaining the same slope of the facade diagonal columns, the truss at the 8-meter column span have been made into a reverse beam form. When viewed from an indoor angle, the bottom beam disappeared and was replaced by a skylight. In this way, the structural form not only follows the columns and spans of the original structure, but also breaks the original order, causing a natural dislocation and creating another form and space. This mutation is accidental, dominant but also natural, relaxed.
The structural system of the multifunctional shed is a three-dimensional steel frame system. The column is a three-dimensional diagonal brace in form of an inverted triangular pyramid, and the beam is a truss form. Therefore, the force on the structural member is mainly axial force, and the slenderness ratio can be made relatively large. The thickest diameter is the 108mm diameter of the diagonal-brace column. The diameter of other members ranges from 50mm to 80mm. Therefore, under the limited reinforcement conditions of the original building and limited budget, this shed needs to be made very light, as if it is floating on the treetops.
Those 108mm diameter of diagonal-brace column are of the same diameter as the drainage pipes. These two kinds of white and equal-diameter pipe are basically integrated into one, and hardly distinguished from each other. Therefore, the low-cost treatment for rainwater pipes here is "camouflage" rather than "wrapping".
The roof of the corridor on the east side of the multi-functional shed is also newly added, and a series of door frames are connected in series to create a sense of depth in the corridor. At the same time, it also echoes the direction and module of the multi-functional shed.
Triangular Parking Shed (No. 1)
These are the remaining two "triangular" parking lots intertwined with the original orthogonal relationship between the main building and the site boundary. However, the original parking shed has been damaged, and the dense pillars and roof leakage problems inside it greatly hinder parking. In addition, since the main entrance of the school is sometimes used for the vehicles, the angle between the road and the opening of the parking lot also makes exiting or reversing a car a big problem.
Therefore, the new parking shed, as if parasitic on the original main building, conforms to its orthogonal grid, while its opening boundaries are parallel to the road, maximizing the use of space. We have eliminated columns at the 22-meter-wide opening interface that faces the road, as well as at the internal parking area; the only columns are located on the inner L-shaped boundary, and the roof therefore adopts a cantilevered structure with a strong floating feel with the cantilever spans range from 5.6 meters to 11 meters. When the column-free space is released, teachers can park "as they please". The bottom-up density and even disorder are the daily conditions of this parking shed.
However, it is not easy to build a long-span semi-outdoor roof on the southern coast. Because we need to simultaneously resist gravity loads, resist uplift from typhoons, and prevent different loads under extreme natural conditions. Therefore, the stress conditions of this roof can be roughly divided into three types: when the main load is gravity, the roof is supported by front upturned truss and rear columns as the rear cables can play a role reducing the load as well as dimensions of the front truss; when extreme situations occur (such as typhoons blowing down or trees falling down), the cables can give full play to their high load-bearing performance and improve the ultimate load-bearing capacity of the structure; when the main load is from the upturned wind force, the roof is supported by the upturned trusses and pulled by the columns, while the rear cables are ineffective.
So, for this "indeterminate" parking shed, do we want the upturned truss to be light or heavy?
Rectangular Parking Shed (No. 2)
The original parking shed on the site was blown down by a typhoon in the summer of 2023, so we need to build a new one. The new parking shed basically follows the original plan, but is different in term of structure and materials. The floor plan of the structure presents a C shape. It locates no columns in the front facade or inside space, similar to the triangular parking shed. The roof beams are suspended by upturned trusses and tensile rods, while naturally-hanging waterproof fabric under the roof forms a continuous translucent top surface. Sunlight and tree shadows intertwine on the fabric, forming another shadow silhouette; at the same time, fallen leaves can accumulate on the soft roof, and cleaners only need to gently poke or blow, and the leaves can slide off.
Bicycle Shed
Taking advantage of the pillars of the fence itself and the height difference between inside campus and outside street, we built a one-way cantilevered bicycle shed based on a part of the fence, with diagonal tensile rods tied to the outside of the fence. The plan is staggered along the linear fence according to the location of the original trees, and the roof is covered with a single layer of lightweight corrugated aluminum panels. The original thin wall interface is extended here as the thickness of the use space.
Playground Shading Shed
The playground shading shed is similar with the bicycle shed as the thin wall interface also expands the depth of the usage space and is staggered with the original border trees to provide a shaded resting place for the playground. At the same time, like the soft fabric roof of the rectangular parking shed, the roof forms a continuous shading surface underneath, carrying the dynamic tree shadows above. Similarly, fallen leaves can be slid down with simple handling by workers. The whirling light-and-shadow and the loose curved surface seem to be aesthetic problem, but in fact they are also pragmatic ones.
Since the wall of the shed faces an external park, the fence presents physical permeability and transparency. In order to prevent footballs from flying out, the fence needs to be high, so its column slenderness ratio and structural form are different from other fence parts.
Entrance Wind-and-rain Corridor
The wind-and-rain corridor reconnects the teaching building and the entrance. The columns of the corridor adopt a diagonally offset plan layout, forming a natural combination with the folded roof and "truss" beams, which also hints at the multi-directional turns of the corridor. The "truss" here is not the most structurally-efficient form. The angle of the oblique bar is parallel to the roof panel and does not reach a more inclined angle. In addition, the elimination of corner column in the corridor creates certain cantilever, which also helps reduce the bending moment in the middle span. The roof adopts a double-layer aluminum plate method, in which the top surface is a waterproof functional layer, while the suspended ceiling is a non-waterproof densely assembled aluminum veneer, emphasizing the abstract triangular folded surface, which is similar with the double-layer roof structure of a triangular parking shed.
Single-Column Pavilion and Folding-Corridor Courtyard
The place is a group of pavilion-corridor-courtyard spaces between the main building and the outside flower pond. Therefore, the folding corridor is in an orthogonal zigzag shape here, which complies with the relationship between the internal orthogonal grid and the external road, and thus creating several remaining triangular flower ponds on the outside. This lingering folding corridor and folding wall also form a kind of game maze for primary school students. In addition, the campus-culture exhibition area is the main demand of the school here, so we made the wall into multi-section folded surfaces to create sufficient length and area of the exhibition wall. Therefore, the operation of "folding" is both spatial and practical.
In the structural section, the single-column pavilion similarly responds to the horizontal, vertical, and diagonal spatial relationships through "central support, four-way cantilevers, and sloping roof." In term of tectonic, it is also similar to other double-layer aluminum plate roofs by separating upper-level waterproof functional requirements from lower-level geometric requirements.
Rooftop Wind-and-rain Corridor
The corridor directly connects the roofs of the two teaching buildings in a straight line. The structure of the single door frame is similar with but different from the corridor of the multi-functional shed: the beams here have become upper and lower chords.
Double-layer Insulated Roof Shed
The newly added roof of the double-layered roof has three layers of aluminum veneers: the top layer is a waterproof triangularly-folded surface, and the bottom cavity is used for natural ventilation to reduce heat; the middle layer is a flat and sloped waterproof layer; and the bottom layer is a non-waterproof suspended ceiling.
Roof Retractable Shed
A flexible site and its the corresponding roof is a diagonal retractable shed that can provide both shade and waterproofing. The retractable shed uses the beams of the original main building and the newly added frame on the roof, and can be easily installed.
Stair Canopy
We renovated two staircases and their canopies. The intersection points between the canopy and the original stair shear wall need to be as few as possible to reduce the impact on the original structure.
Library Renovation
We also completed an overall renovation of the original library and recording-classroom (which is flexible as a reading area), and added a mezzanine to the library collection.
In the vertical direction, since the original structure only has a net height of 3.8 meters, the new mezzanine structure needs to be as thin as possible. We take advantage of the library's load-bearing advantage on the ground floor and therefore convert the fixed bookcases under the mezzanine into steel plate-lattice columns. Therefore, our mezzanine beam and floor can be integrated into a lattice plate with a thickness of only 50mm.
In the horizontal direction, we rotate floor of the mezzanine by 45 degrees, so that only one touching corner point of the mezzanine connects with the original column near the window, in order to reduce the blocking of natural lighting on the west side by the mezzanine, while the columns and bookcases under the mezzanine remain orthogonal to the original building. We actively created four corner full-height spaces, correspondingly arranged with two staircases, a rest space, a corner for connecting library and recording-classroom. The actively generated corner space inside the window and the passive remaining triangular parking lot outside the window, coincidently form a pair of spatial inversions of "negative and positive".
As for the side columns and corner columns that are welded by two I-beams, each column eliminates its own corners to form eight sides with alternating void and solid sides, and obtains two directions of orthogonal and oblique directions at the same time.
