Strolling along fuzhou Road, a building made of Victorian style and British neoclassical style is particularly eye-catching, it was built in 1914, it was once the Shanghai Public Concession Ministry and Bureau Building, and then became the new China Shanghai Municipal Government Building, Shanghai's first five-star red flag was raised here, Einstein also spoke here... Today, the municipal cultural relics protection building that witnesses the historical changes of Shencheng for a hundred years has been identified as a demonstration project for urban renewal in Shanghai - a comprehensive renovation project for the protection of 160 neighborhoods in Huangpu District.
The inheritance of history stems from the awe of ingenuity. The general contractor of the construction, Shanghai Construction Engineering Second Construction Group, organized elite soldiers to make the "old municipal government building" shine after a hundred years.
Talking about the bits and pieces in the process of project repair and transformation, project manager Zhou Shan sighed deeply: "The mission of this project is sacred and the responsibility is great. We will always adhere to the craftsman spirit of 'I repair cultural relics on the Bund' and advance the construction in an orderly manner. The construction of the floor will be completed before the Spring Festival in 2022, and the renovation project of Building A (former Ministry of Works and Bureau Building) will be basically completed when the building is completed 100 years ago in 2022, and all will be opened to the public in 2023. We are confident in achieving these engineering nodes! ”
"Opening the Way" for Old Buildings
As a demonstration project of urban renewal in Shanghai and the first start of the "second façade" renovation project of the Bund, the 160 Neighborhood Comprehensive Renovation Project started construction in October 2019 and was built by the Bund Old Building Investment and Development Co., Ltd., a joint venture between Shanghai Real Estate Group's World Expo Land Holding Company and the Bund Investment and Development Group. In order to better revitalize this old municipal government building, the Shanghai Construction Engineering Second Construction Group, the general contractor of the construction, organized elite soldiers, and the 160-neighborhood comprehensive renovation project department was formed by the project teams that participated in the national convention and exhibition center venue function improvement project and the third phase satellite hall project of Pudong International Airport, and Zhou Shan, the "construction hero" of the Shanghai Major Project Meritorious Service Competition, served as the project manager.
In fact, as early as before the start of construction, this group of builders did a lot of preliminary work. Zhou Shan said: "We pay attention to 'pre-service', and before the start of construction, we will map all the buildings in the project area - 'take the pulse', so that we can have a good idea and prepare early." In view of the difficulties in the process of protective comprehensive transformation, the project department has determined various construction plans and processes in advance, such as the "Little Red Building" using a two-time translation scheme, the use of pipe curtain steel pipe jacking technology when the basement is connected to the original Ministry of Works and Bureau building, and the use of paper gluten ash process for gypsum lines in the room.
In the early stage of wreckering, due to the existence of a large number of drilled piles and piles in the original fire station building, affecting the construction of new enclosure structures and engineering piles, and only 8.7 meters away from the subway tunnel, conventional obstacle clearance means have a greater impact on the subway tunnel, the builders and owners, design and professional units continue to optimize the program, using the CD machine to clear the obstacle, adjust the position of the partition wall in the underground continuous wall, and finally greatly reduce the number of engineering piles that need to be cleared, and by optimizing the construction order, reduce the interval time between adjacent engineering piles.
The protective cleaning of a large number of component materials in the old building also makes the builder quite laborious, and some of the damage-susceptible component materials inside the building must not only be dismantled very carefully, but also registered and numbered according to the historical age, material, installation parts, etc., and processed and preserved for subsequent restoration. For example, copper accessories for hardware components such as door and window handles, latches, closet doors and drawer handles should be disassembled, solvent cleaning, and special potion care for bronze utensils before construction. If the copper fittings have damaged parts, they can be repaired; for those that cannot be repaired or missing, please copy them as they are. The atrium area of the old building was originally paved with stone bricks about 1 meter long and 1 meter wide and 5 centimeters thick, with more than 800 pieces. In order to better preserve the historical features, the builders spent a full month carefully digging out the 360 well-preserved stone bricks, cleaning them with special solvents and numbering them for preservation.
I repair artifacts on the Bund
In line with the tenet of "repairing the old as before and recreating the style", the builders hope to find the beautiful past of the century-old building, respect history, and respect history. As Zhou Shan said: "Repair and protection focus on details, and we require every employee in the project department to have the focus and care of 'embroidery'." ”
In the repair of the façade clear water wall and the construction of caulking, the builder has carefully formulated 10 processes such as brick seam cleaning, pan alkali treatment, brick patch repair, bottom seam secondary grout, flat color, water repellent, etc., and the indoor mosaic floor construction includes 13 processes such as grassroots treatment, wet base, pre-row split bullet line, and seam cleaning.
The old building plaster line has a unique style, not only rich in ornamentation, but also paper ribs and gray plaster lines. Paper gluten ash process is a kind of material made of straw or fiber material mixed with lime and sand, with the development of construction technology, this traditional process gradually faded out of people's vision. The builders once again picked up the traditional craftsmanship, bringing the plaster lines back to their original appearance.
Many of the components and materials of the old building are different from those used now. For example, the atrium area is laid with irregular stone bricks, the hidden works are made of twisted rebar, and the tracks used for old elevators are made of wood... "Many materials are now difficult to find, they have actually become cultural relics... Invisible materials in concealed projects should also be protected and archived. For example, the rebar used in the old building is very special, and the texture of the rebar we commonly use now is completely different, it is twisted. We take out the different materials in these hidden projects for archival protection as a witness to history and use them for future display. Zhou Shan said.
In the comprehensive transformation project of 160 neighborhoods, one wall and one corner, one door and one window, one stone and one brick are all infiltrated with the painstaking efforts of Erjian people. "The repair and protection of old buildings cannot be sloppy, and for us two builders, we must come up with a meticulous and careful attitude of repairing cultural relics and making works of art, and do our best to continue the cultural context and reproduce the style of historical old buildings, which is our mission." Zhou Shan said.
Fulfill the dream of "encirclement" for a hundred years
On the original design drawings, the old city hall building is a boxy enclosed building with no gaps, which is not the same as the actual appearance of the current building. According to reports, due to the settlement of the foundation and some historical reasons, the building was not successfully built, which is always a big regret.
In order to realize the dream of "encirclement" for a hundred years, in this comprehensive transformation, the builders will build a new 3-storey basement and 2 underground passages between the old ministry and bureau in the atrium area on the basis of the repair and reinforcement protection of the old ministry and bureau building, and then build two new prefabricated steel structure buildingS building C, so that the existing L-shaped gap of the building will be enclosed, so that its appearance is consistent with the design drawings when it was originally built. "New and old buildings must not only achieve internal structural connectivity, but also achieve aesthetic harmony in external buildings. What we have to do is to use innovative technology, innovative technology, innovative solutions to transform. Zhou Shan said.
The in-situ protective repair of the "Little Red Chamber" after the two translations is undoubtedly the highlight of the comprehensive transformation, but also the difficulty. According to the renovation plan, it is necessary to build a new basement in the plot, in order to take into account the overall construction of the underground space of the project and the repair and protection of the "Little Red Chamber" in the courtyard, the project team finally decided to implement the "Little Red Chamber" two-time translation plan after several rounds of demonstration according to the analysis of the site construction conditions: first demolish the fire station and other sporadic buildings in the plot, give priority to the construction of the pile foundation and ground wall in the temporary placement area of the "Little Red Chamber" on the east side, and move the "Little Red Chamber" to the east to the temporary placement area. After the basement earthwork in other areas of the block was excavated and built back to the basement roof, the "Little Red Chamber" was moved to the permanent position of the basement roof, and finally the basement earthwork excavation at the temporary site and subsequent structural construction were carried out. The first translation was carried out in December 2020, and the project team, after precise measurement and calculation, installed pulleys at the bottom of the "Little Red House", using PLC hydraulic synchronous control system for jacking, and the sliding device used off-site prefabricated steel cylinder concrete sliders. The entire translation process lasted more than ten days, and the largest and heaviest masonry structure project in Shanghai, the "Little Red Chamber" weighing 3800 tons, was successfully relocated to the designated position, with a total displacement of 32.33 meters, writing a strong stroke in the history of Shanghai's urban renewal.
Another highlight of the project, the pipe curtain steel pipe jacking technology, also embodies the wisdom and painstaking efforts of the second construction person. "When we implemented the construction of connecting the basement with the original Ministry and Bureau Building, in view of the actual situation of narrow construction space, in order to reduce the impact on the surrounding area, we adopted advanced pipe curtain steel pipe jacking technology." Zhou Shan revealed. The project department adopts 3 sets of φ800 mm special high-precision slurry water balance steel pipe curtain TBM, in view of the high-precision direction control requirements of the pipe curtain jacking, Erjian has made a lot of improvements in the pipe jacking machine equipment and the head attitude display system, and installed the inclinometer sensor, laser guidance, laser reflection device, pipe jacking machine laser correction system, cutterhead current alarm device and other devices. "A total of 70 steel pipes need to be pushed into the steel pipe curtain of this project, of which 36 are each 9 meters long and 34 are each 10 meters long, for a total of 664 meters. The technology is rarely used in the field of construction and is a bold innovation. Zhou Shan said.
Author: Shi Bozhen