GOODING Works | Favorite Fireworks-Renovation and Design Practice of Lianzhu Market

Squeeze out time and go to the market. The fireworks in the world are the most vigorous. You can accumulate a wok of rough cultivation and enjoy a drink forever.

　　

 

Lianzhu Market is located at No. 8, Lianzhu Village Road, Yanziji Street, Qixia District, Nanjing City. It is one of the largest farmers' markets in Yanziji Street. Since its formation in the 8. s and 1990 s, it has been the vegetable basket of "tens of thousands of households" in the surrounding Yanziji street. The dazzling array of fresh vegetables, the rich and diverse service supply, the trust relationship between the neighbors, and 1.1 drops of details are all condensed. All aspects of market life. Visiting Lianzhu market is an interesting experience full of human feelings for Yanziji citizens. These old markets full of details and life flavor carry the memories of many Nanjing people and record the transformation experience of Nanjing city.

　　

 

　　

 

Aerial view of bazaar after transformation

In the early 1990 s, due to the living needs of the surrounding citizens, vendors spontaneously formed Lianzhu bazaars. Limited by the times, there are many main bodies of property rights in the market, most of which do not have real estate certificates, and private construction is serious. After the millennium, due to the rapid development of urban infrastructure construction and the upgrading of municipal facilities, the location of the market was designated as urban green space in the urban master plan and was located in the planned new high-pressure corridor. However, due to objective reasons, the market operation The house was not relocated and constructed. Soon, the 220kV high-voltage electrical tower stood in the southeast corner of the market. With the increase of the residential population in Yanziji community, the illegal construction area of the market is getting larger and larger, and there are more and more merchants and service categories, and business activities are gradually integrated with the electric tower. The buildings of all ages are mixed, the structure is seriously damaged, the basic equipment and facilities of the fire protection system are missing, the basic equipment and facilities such as power supply, water supply and sewage are outdated, the drainage is not smooth, the sewage is overflowing, the sanitary environment is dirty, the business and shopping environment is poor, and the safety hidden danger problem is increasingly prominent. Its transformation and upgrading is imminent.

　　

 

　　

 

　　

 

Internal and external environment of bazaars before transformation

With the continuous improvement of the modernization of Yanziji New City, closely following the pace of urban renewal and comprehensive development, the overall risk elimination transformation of the Lianzhu Market has been put on the government's agenda. In June 2021, the government authorities recovered the market ownership and management rights; in the autumn of the same year, under the leadership of the district government, the District Commerce Bureau, and the Supply and Marketing Cooperative, our Urban Renewal Institute launched a small-scale urban and community space for this project. Renovation research. It is hoped that the acupuncture-style renewal of the bazaar will be used as a starting point to drive the positive outlook of the entire city area from point to point. As the construction of Lianzhu bazaar is mostly a spontaneous act of merchants, only some buildings have obtained construction project planning permits in the early stage, and most of the settled merchants have been serving the public here for decades. Based on the protection of people's livelihood and policy reality, the bazaar construction entities can neither be relocated nor completely demolished and rebuilt. Under this pre-condition, how to solve the hidden dangers in the most efficient way, and make the original merchants move back as soon as possible, resume normal production and life, and ensure the daily needs of tens of thousands of residents in the surrounding area is the most important thing in this transformation. The problem to be solved. The design team of our hospital conducted on-site investigation and multi-party coordination to obtain scattered data on previous renovation and additional construction of the original building. Through reading, research and judgment, and combined with the testing opinions of professional testing institutions, the design team of our hospital conducted a comprehensive technical assessment on the safety of building structure and fire safety. On this basis, after many discussions with the District Bureau of Commerce and the operator, the renovation guidelines of "housing safety standards, complete fire-fighting facilities, overall improvement of the environment, and ensuring that all tenants move back" were formulated.

　　

 

§ Overall renovation of fire safety

The overall length of the bazaar is about 110 meters in the north-south direction and 60 meters in the east-west direction. The east-west side of the original market complex is directly adjacent to the wall of the existing residential area, and the north-south side is adjacent to the urban road. There are two-storey business buildings on the east and west sides of the bazaar, with a single-storey and large-span business area in the middle, three to four-storey business buildings at the south entrance, and two-storey business buildings at the north entrance. The following fire safety problems exist in the original building of the bazaar:(1) disordered fire evacuation system

The length of the business rooms on the second floor on the east and west sides of the market sales hall is 75 meters and 81 meters respectively. In the northeast corner, there is an outdoor open staircase with a net width of about 1.3 meters that can directly connect to the outside. In other parts, only the indoor open staircase is directly connected to the sales hall. However, the corridors in the building are not interconnected and the staircases cannot be used with each other. The first floor of the market has only two evacuation exits on the north side, both the evacuation width and the evacuation distance did not meet the requirements of the current Code for Fire Protection Design of Buildings GB50016-2014(2018 Edition). (2) Lack of fire-fighting facilities, no fire-fighting water source, no evacuation indication system, no fire alarm system, exposed wires in the market, serious damage, private pulling and disorderly connection are common, electric bicycles are parked at will, there are major fire hazards and self-rescue facilities are scarce. After many rounds of argumentation, the design team of our hospital finally decided to permanently seal up the second-floor business buildings on the east and west sides of the bazaar sales hall and no longer use them. Demolish the north-south entrance building and rebuild the two-storey building to meet the needs of market merchants moving back and operating office. Re-plan the market fire evacuation route to increase the evacuation width and evacuation exit. Plan the centralized parking of electric vehicles as a whole, add fire-fighting facilities such as automatic fire alarm system, indoor and outdoor fire hydrant system, fire extinguisher, automatic sprinkler system and so on in the market, and at the same time, combined with the actual situation on site, add fire-fighting water cannons at the gas building in the central area of the market to enhance fire protection measures. One of the difficulties of this project is to build additional fire water pool and pump house. During the design period, there were many rounds of schemes, such as digging underground and building integrated equipment of above-ground tank pump, etc., which were rejected due to narrow space without construction conditions or high cost and public opinion risk. Finally, combined with comparison, it was decided to set up fire water pool (effective volume 432T) and pump house on the second floor of the newly-built north building to meet the requirements of the fire water.

　　

 

　　

 

Complete fire fighting facilities after renovation

§ Structural safety and risk elimination reinforcement

The Lianzhu Market before the transformation mainly has two structural forms. The outer wall of the market is mainly of frame structure, and the roof over the public stalls in the market center is of large-span light steel structure. The combination of frame structure and light steel structure roof of different heights forms a relatively complex hybrid structure. After the structural identification is carried out according to the relevant provisions GB50292-2015 in the Reliability Identification Standard for Civil Buildings, the structural safety of the internal center of Lianzhu Market is assessed as Dsu level, which seriously affects the overall bearing capacity and is in urgent need of repair and reinforcement. After much thought, the design team decided to partially dismantle and partially reinforce the transformation. The newly-built part adopts the "multi-and high-rise building structural spatial finite element analysis and design software-SATWE" for the overall structural calculation. For the beam and column components of the retained building reinforcement part, the outer section of the steel is enlarged, and the steel plate or carbon fiber is pasted to reinforce and reinforce, and the load-bearing floor slab is enhanced by non-destructive cutting and carbon fiber cladding. The defects such as loose, damaged and serious carbonation of the original structural concrete are repaired. Reinforce and replace the steel structure roof above the original steel structure greenhouse. The reinforcement part adopts the "PKPM-5.2 appraisal reinforcement module" for overall calculation. In order to make the reinforced structure design service life can reach 40 years. The distance between the local reconstruction part and the surrounding current buildings is only 1~3 meters. In the structural foundation design, three types of foundation forms, such as natural foundation raft foundation, under-column strip foundation and independent foundation, are used to solve the structural needs of itself, while avoiding collision with the surrounding existing building foundations, effectively solving the problems of structural settlement caused by the single function of the building and uneven load weight. The combination of the three foundation forms not only ensures the convenience of construction, but also eliminates the potential interference to the adjacent existing buildings.

§ Improvement of indoor and outdoor environment

Due to the long operation time of the market, the lack of property rights, the disorderly construction of illegal buildings, and the lack of maintenance measures in the process of use, the walls, stalls and floors of the whole market are seriously aging or even damaged, resulting in an unsatisfactory shopping environment. After the overall combing of the design team, the landscape reconstruction of the external environment of the building is first carried out: the road space of the site is renovated and combed, and the entrances and exits are opened to make the building rhythm more orderly and open; Secondly, the internal space environment of the building will be renovated: the internal flow lines of the building will be reorganized, the types of public stalls will be planned and managed, and the smart market will be established to enhance the comfort of consumers in shopping. (1) The high-voltage tower is surrounded by illegal buildings built later, and even some buildings are directly built on the basis of the tower, there are many potential safety hazards. As the important and difficult point of this transformation, how to deal with the relationship between the electric tower and the building is the key problem to be considered. Since neither the electric tower nor the market can be relocated or demolished, the district government coordinated major functional departments during the renovation. After several times of communication between various departments and power companies and repeated argumentation by experts, a relatively compromise solution was finally determined: building adjacent to the electric tower, reducing the number of building floors and reducing the building volume during the renovation, opening the distance between the building and the electric tower, and using billboards and bicycle sheds as dividing lines, the traffic line of people will be reorganized to reduce the potential safety hazard between the market and the electric tower.

　　

 

Before the renovation, the electric tower was mixed with the building.

(2) The current situation of the overall renovation and upgrading of the roof The market roof is old, and the three different roofs have been damaged to varying degrees. Garbage and equipment are mixed, and even weeds grow in local areas, which increases the safety hazards of the building. The overall transformation of the building roof is imminent, so that it is full of new vitality and new life. Technical measures for overall renovation and upgrading of all roofs in the design: 1. For steel structure sloping roofs, choose to use the original roof slope, remove all steel structure purlins and replace them with C250 * 75*20*2.5 C- shaped steel purlins, remove all steel structure roofs and replace them with double-layer profiled metal plate composite insulation roofs; 2. For reinforced concrete flat roofs, the roof surface layer is seriously damaged, the slope of the building shall be found again after all surface layers are removed to the base of the structure. And the use of super weather-resistant high elastic acrylic waterproof coating, with good fracture extension and tensile strength bubble water does not bubble, bond does not fall off, long life in the sun, low temperature does not crack and so on.

　　

 

Roof before renovation

　　

 

Roof after renovation

(3) Keep the new status quo of the building as a whole. The outer wall surface layer falls off, the wall surface cracks, and the perception is poor. During the design, the hollowed and cracked parts of the original external wall shall be removed → cleaned → repaired and leveled with WPM20 wet cement mortar → brushed with one layer of interface agent → paved with a layer of 5-thick polymer anti-crack mortar alkali-resistant glass fiber grid cloth → brushed with two layers of waterproof putty for the external wall and then made a new surface layer. The surface layer is planned to adopt waterproof and decorative integrated coating, which has the advantages of more stain-resistant, super weather-resistant, true waterproof and true environmental protection than traditional exterior wall coatings. In addition, local exterior walls are upgraded and transformed by Etenet board to enhance the appearance of the building facade. The external shop signs will be incorporated into the overall style design system of the bazaar building, and the door head, facade, lighting and shop sign fonts will be designed and managed in a unified way, so as to establish the connection between the external shop and the indoor activities of the market and increase the attractiveness of the market to the residents in the surrounding communities.

　　

 

Front facade

　　

 

After the renovation, the facade (4) before the indoor renovation and upgrading, the overall wall surface in the market was seriously damaged, the indoor drainage, ventilation and power supply were disorderly, the stalls in the market were not arranged according to the enclosed layout, and the internal storage space of the operators was exposed, which affected the cleanliness and beauty of the market environment. There is no obvious uniform material, category, raw and cooked, color distinction, imperfect software and hardware, resulting in the market "dirty" dirty. In the process of upgrading and renovation, the design team took the direct line of movement and clear line of sight as the design principle to reorganize the internal activity flow line of the market and reduce beating around the bush. Inside the transformed bazaar, the first thing that comes into view is the neatly arranged vegetable island, with neat and uniform stalls and clear functional divisions, with a dazzling array of colorful vegetables on display, while the east and west sides are full of white walls and black tiles. the smell of Qinhuai misty rain with hooked eaves. The transformation of drainage ditches and sewers in ground water production areas has made the ground no longer accumulate water and the market no longer has peculiar smell, which greatly improves the comfort of consumers in the shopping process.

　　

 

Inside the market before transformation

　　

 

Inside the market after transformation

(5) In addition to upgrading the decoration environment and saying goodbye to "dirty, messy and poor", the intelligent market transformation also uses digital and intelligent means to upgrade the market management mode, helping the operation to achieve efficiency improvement, cost reduction, customer experience optimization, and helping the bazaar to complete the intelligent transformation and upgrading. Market transaction data, passenger flow, number of stalls, number of merchants, testing data, guiding vegetable prices, merchant category sales crown, market plan and other data are clearly displayed on the smart big screen, so that managers can accurately and comprehensively grasp market information, supervise and standardize the business behavior of merchants, improve business enthusiasm, and provide consumers with a more assured market shopping atmosphere.

§ Thinking

As a first-line urban renewal design practitioner, through participating in the whole process of the reconstruction project of Lianzhu bazaar, he has a deeper understanding and thinking about the complexity and diversity of urban renewal projects. The renovation of existing buildings inevitably belongs to the category of sociology. Compared with the relatively simplified social relations of new buildings, there are intertwined social contradictions in old buildings. Space is the place carrier of these contradictions, and space reorganization is the means to solve these contradictions. The transformation of existing buildings is a circular process of space production, and produces new social relations in the city. Improper space production will not only not solve social problems, but will also bring more and bigger problems. The transformation of existing buildings faces several difficulties. First of all, the data are incomplete: due to the long time and tracing back to the source, all the data related to the project cannot be found, and the lack of data will hinder the progress of building renovation. The second is the integration of new and old buildings after renovation: the renovation of existing public buildings is divided into three categories, the first category belongs to the renovation of the external facade only; The second category belongs to the external facade and internal functions need to be renovated, it is difficult to integrate with the surrounding buildings and meet the requirements of facade transformation. The third category belongs to the transformation of internal functions only under the condition of ensuring the unchanged facade. After the transformation, the integration of new and old buildings will cause difficulties in the transformation of existing public buildings. How to connect the new functions with the old functions and how to form a whole with the old buildings requires designers to consider well at the beginning of the transformation to meet the integration of new and old buildings and create a good practical design work. Finally, because the building has been built for a long time, the old and new technical standards have changed: how to use the existing technology combined with the use of functions to carry out technical transformation of the existing public buildings built for a long time, so that it can meet the requirements of the new specification has become one of the difficulties to be discussed.

Evaluation and Analysis of Foundation Condition of Original Building
Professional	Sub-item	Main evaluation contents
Planning Professional	Related to the nature of land	The current planning land use situation, the existing property rights situation, whether there are functional transformation restrictions.
	Planning related	Relevant contents of project original planning approval, latest policy follow-up and adjustable degree analysis.
architectural specialty	Perimeter Assessment	Large block planning function analysis, building surrounding environment assessment. Contains possible future risk items, cell environment, including shared entrances and exits, etc.
	Basic data	Whether the project drawings and related approval contents are complete, and whether it is necessary to start drawing surveying and mapping related work before design.
	construction age	According to the analysis of the construction age, the project transformation may encounter related risks, including planning declaration risks, fire chart review declaration risks, etc.
	building foundation analysis	Evaluate the possibility and intensity of functional transformation according to the current pattern (layout, floor height, etc.).
Structure specialty	Whether structure inspection is required	According to the comprehensive assessment of the building age, the integrity of the existing drawings and data, and the suggestions on the strength of the building renovation, the assessment requires structural inspection.
	Structure form	Analysis of the form of building structure, whether there is a serious problem of non-conformity with the current norms.
	add possibility analysis	Whether it has the possibility of large-scale adjustment of mezzanine, opening and spatial pattern.
HVAC specialty	Normative assessment	Analysis of the degree of conformity and the degree of use of the relevant contents of the fire control and smoke extraction system with the latest specifications.
	Status quo assessment	The status of the original heating and air conditioning system, and the division of the interface with large properties (small municipalities) and the cold and heat sources. Analyze the proportion of 1I available or the reason why replacement is necessary.
Water supply and drainage specialty	Normative assessment	The conformity of the main system with the existing specifications and whether the equipment must be updated.
	Status quo assessment	Does the total amount of water supply and drainage in and out of households meet the requirements of function adjustment?
Electrical specialty	Normative assessment	Fire compliance assessment and the impact of modifications required.
	Status quo assessment	The study of the total electricity consumption of the current situation of the project may support the function analysis of the transformation and the function that must be increased.

In addition to the early stage of the design should be many times to survey the site, master the complete project information, in the design process should consider many constraints, the difficulties into favorable conditions, technical transformation, to achieve the transformation of the new function and the old foundation, to achieve the transition of the old and new functions. To do a good job in the renovation of an existing building is a very cumbersome process, which requires more patience and care than new projects. As a designer, you should sort out the relevant data in the early stage of the project, read carefully to deepen your impression, and then go to the site for many times to see if each area can match the original drawings and whether it is consistent with the data, and mark different positions to find relevant data to deeply analyze the problems that may be brought about in the transformation process.

 

§ Conclusion

Under the leadership of Qixia District Government, District Commerce Bureau and supply and marketing cooperatives, in the construction unit, agent construction unit, design unit and construction unit. With the joint efforts of the supervision unit, the Lianzhu Market started research and design from September 2021 until the construction started in September 2022. During the construction process, the interference factors such as tight construction period and epidemic impact were overcome. The market transformation project was completed on schedule and successfully opened on New Year's Day 2023. The clean and tidy internal and external environment, uniform booth layout and brand-new shopping experience have been well received by tenants and surrounding residents. The joint efforts of many participating units have enabled the residents of Yanziji New City to carry a more civilized and hygienic "vegetable basket". With the experience and lessons accumulated in this renovation, we will continue to explore and improve in the future urban renewal work.