Renovation of Nanjing Daily Plot in Xi Nan Li / AZL Architects

Renovation of Nanjing Daily Plot in Xi Nan Li / AZL Architects

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The Context. Originally built during the Jiaqing period of the Qing Dynasty, Ganxi Mansion, commonly known as “Ninety-nine Rooms and A Half”, is the largest and most completed old house compound existing in large Chinese cities. Usually, Xi Nan Li district refers to an area to the south side of Ganxi Mansion, which is a representative area of Nanjing Old City South, with the boundaries of Zhongshan Road on the east, Dingxin Road on the west, Shengzhou Road on the south, and Nima Lane on the north. During the Ming dynasty, this district might be one of the most prosperous areas in China. Starting from the archway of “South Street”, continuing to the shops on “North Street”, it was filled up with crowds and offering vast arrays of goods. However, from the end of the Qing Dynasty to the Republic of China, wars caused the gradual decline of these blocks, and instead of business, the function began to change into residential. Since 1949, the Xi Nan Li area still runs as a residential area. With the continuous improvement of Nanjing’s urban development and city functions, overall urban renewal work starts. While carrying Ganxi Mansion, Pingshi Street, Daban Lane, and Rongzhuang Street’s historic and cultural resources, and relying on the south market culture of the old city of Nanjing, Xi Nan Li district gradually develops into a very representative historical and cultural leisure district, including opera performance, intangible cultural heritage display, time-honored brands, master studios, and other formats, reproducing the scene of Southern Capital’s commercial prosperity, illustrated by Ming Dynasty artist Qiu Ying.

Nanjing Daily Plot sits in the core of Xi Nan Li District, facing Rongzhuang Street on its East and Qianzhang Lane on its North, with the national historic site Ganxi Mansion located on its southeast corner. Nanjing Daily Plot covers a total area of 1764 sqm2. The Master Studio renovated this time occupies the north part of the plot, and originally it was the factory of Nanjing and was renovated into a dormitory in the 1980s. With a five-floor height, the building covers 3515 sqm2 in total floor area. The Master Studio is enclosed by the south, north, and west sides. A courtyard with outdoor red steps in the middle while facing Rongzhuang Street functions as a vibrant living room in this block. A design gallery is subtly arranged underneath those red steps and opens to the public with a design exhibition “Learning From Nanjing” from every Tuesday to Sunday, enriching the culture and design aesthetics in this neighborhood. Throughout hundreds of years, within the urban development context, the change of venue in Nanjing Old City South has always appeared in an appropriate way.

Structure Reinforcement. Before this renovation, the dormitory of Nanjing Daily Post was a five-story building with brick – a concrete structure. Masonry members and concrete beams in some specific places are the main load-bearing components. Obviously, the 3.3-meter wide room and load-bearing partition walls cannot meet the special requirements for a new open office. The renovation replanned the building column grid, keeping the core of the original brick column or at the corner of a brick wall, tiring steel bars around, and pouring concrete to form frame columns. Concrete beams are added to both sides of some load-bearing brick walls to form double-sandwiched beams. In this way, the frame columns and the double-sandwiched beams work together to support the floors and partition walls, and the overall brick-concrete structure has been nicely transformed into a concrete frame structure.

In addition, where the bearing capacity of the original concrete beams is insufficient, CFRP has been pasted on the bottom and sides of the beams for strength, and steel beams are also added to bear the load under the partially new partition walls. Once the overall frame was done, the original load-bearing partition walls were removed, and the loose bricks in the middle of the double-sandwiched beams were reinforced and repaired by sticking CFRP. Previously, a whole raft plate was laid under the brick walls of the dormitory. With the structure transformation, the bearing capacity of the independent column foundation is insufficient, thus the renovation plan sets up double sandwiched beams between independent columns, forming a beam-slab-raft foundation to meet the requirements of the bearing capacity of the ground and the baseplate. In addition, driven cast-in-place piles are used to strengthen the column footing in some parts which have additional walls.

The part with red concrete steps is a newly built shear wall structure, and the root piles with the diameter of 300mm have been used to reinforce the soil layer to form the composite foundation. Along the concrete walls, strip foundations are laid there and deformation joints are set between the new addition of red steps and the current structure to avoid any possible settlements.

The original floors and roofs use 120mm thick precast hollow slabs. After retaining the hollow floor slabs and removing the surface layer, a surface layer of 50mm thick fine aggregate concrete was poured on, equipped with φ6@150 two-way steel meshes. After cleaning the surface layer, there are inconsistencies in elevation and plate thickness at some positions. The renovation plan removes the hollow slabs at those parts with large elevation differences and pours some concrete slabs to keep the floor elevation consistent. The design retains most of the hollow floors, so it was difficult to bury the support derricks when the equipment pipelines were installed. Through the way of adding channel steels between the structural beam spans, the plan solved the problems of setting up fire protection, water supply, and drainage pipe networks and hanging strong & weak electricity bridges and HVAC equipment. The living function of the former dormitory now is changed into a large open office space, and the working load has been increased. The renovation plan meets the requirements of bearing capacity by bonding fiber composite material at the bottom of the prefabricated hollow slabs. The old brick and concrete structure of the dormitory building, with elaborate design and reinforcement, is subtly transformed into a frame structure that meets the structural load and usage needs of a large and open space design studio. Now the whole building takes on a fresh new look, from its internal space to its external image.

Brick curtain walls. The protection planning zone of Xi Nan Li Historic District includes historic buildings such as Ganxi Mansion, as well as some courtyards which have already been reconstructed according to the shape and structure of traditional residences. The overall color of the district is brick grey, tile green, wall white, and wood component maroon. After the renovation, the facades of the Master Studio are composed of bare concrete columns and walls, and light gray brick curtain walls. The size of each brick is 240*120*60mm, and the tension between bricks is regulated by two 12mm-diameter steel bars, which are vertically tied to the steel plate keels above and below, with two ends tensioned with nuts to achieve pre-tensioning effects. The gaps between the steel bars and the bricks have been filled with epoxy glue to form an integral brick curtain wall system. The bare concrete and light gray brick curtain walls give an impression of lowkey and simple, blending well into the context of the Xi Nan Li district in a harmonious but different way. The brick facades take inspiration from movable-type printing, hoping to unlock the cultural code as the building’s early days functioning as the daily post plot. With the catalyst for the interactions between the inside and the outside in the building renovation strategy, the brick curtain walls play a similar role to the ornamental windows on the walls of Ganxi Mansion. Through the gaps in the brick walls, we can experience the historical texture of this historic block, and the poetic superposition of traditional texture and contemporary space. The brick curtain walls enrich the spatial permeability and sense of hierarchy of the historic district. Indoor and outdoor scenes appear and disappear with the movement of the sight and the change of view angles. While viewed closely, the walls become the “view”, and while viewed from a distance, they become the “landscape”.

Calcined clay limestone cement. Facing Rongzhuang Street, in the courtyard on the east side of the building, there locates the azLa Gallery is the public space in this block, which is built with red LC3 cement. The big red steps correspond well to the color of wooden elements in this grey-ish environment, becoming an active element to stimulate the vitality of the place. By adding limestone and calcined clay to the original Portland cement, which replaces about 20% of conventional Portland cement clinker, the production of LC3 reduces carbon dioxide emissions by 40% and energy consumption by 15-20% compared to conventional cement production. At the same time, calcined clay and limestone can significantly optimize the pore structure and reduce the porosity of concrete materials, and its mechanical properties and impermeability are still better than ordinary Portland cement, while its chloride diffusion coefficient is reduced by 80%.  LC3 cement reduces the energy consumption and carbon emissions of the cement industry without affecting the mechanics and durability of concrete, which demonstrates a sustainable significance.

A composited space. Xi Nan Li Historical and Culture Leisure District is an urban renewal project which is elaborately organized by Nanjing Tourism Group Xi Nan Li Company. The renovation of the previous Nanjing Daily Post Plot into the Master Studio, fully reflects that this district’s transformation breaks the boundaries between the industry, culture, and lifestyle, uses design to leverage economic productivity, and inspires creativity from historical cultural resources value. Through the guidance of design aesthetics, good renovation projects link visitors to the place experience, create new aesthetic throbs and ignite new engines for continuous explosions of local aesthetic productivity. The Master Studio, as a composited space integrating cultural creativities and aesthetic experiences of new life, greatly enriches the business types and spatial levels in the Xi Nan Li district.

On the occasion of completing the Studio, the azLa Gallery located underneath the big red steps opened at the same time as the design exhibition “Learning from Nanjing”. With the theme of “Basic Architecture”, the exhibition showcases 40 representative Nanjing projects of AZL Architects (azL) designed from 2001 to 2021. And under the theme of “Cultural Codes”, the new creative ideas and design work of azLa studio (azLa) since 2021 are displayed. In addition to architectural works, the “free mortise” series of furniture and accessories, which are jointly exhibited and sold during this exhibition, create the oriental connotation through “interlocking joints, stableness, and openness, free links”, strengthening asymmetric details, and presenting the free and lively cubism aesthetic. In the overall simple geometric relationships, the “Little Bear Shadow” series of lamps and lanterns flexibly use the beauty of the structure, material changes, and color contrast, showing the unique design aesthetics of azLa studio and research of lifestyle aesthetics brand LAVA Lab. Design into a whole — Construct the overall design aesthetics from the public space to the architectural space and then to the living space. With very limited building space, the renovation of Nanjing Daily Post Plot includes different functions as a whole, with the upper floors for the Master Design Studio sharing communication space, and a Design Gallery and a dining space on the first floor, which eliminates the boundaries of the building, effectively promotes the building the public cultural space to link the inside and outside, provide a catalyst for public communication between visitors and surrounding residents. Now the Master Studio has become the most daily and aesthetically vibrant public cultural place in Xi Nan Li District.