At present, as an important part of urban space, urban large-scale public buildings are not only a breakthrough in form and function, but also a window of the city, showing the context, history, characteristics of the times and future temperament of the city to the world. Its presentation is rich and varied, but its essence lies in respecting the development context of the city, pursuing the openness of public space, striving to achieve the user’s sense of belonging and recognition, thus further stimulating the vitality of the area and even the city.
The design practice of Xixi Green Office Complex tries to explore the significance of the office park to the city. More importantly, in Hangzhou, a new Internet city, a large number of innovative scientific and technological talents are pouring in. Whether this connection between the park and the city can bring new thinking to the innovative office space model in the Internet era is the focus of this exploration.
▼园区鸟瞰，aerial view ©黄金荣
Urban Space and Context Exploring
Xixi Center, located at about 500 meters north of Xixi Wetland. Xixi Wetland integrates urban wetland, agricultural wetland, and cultural wetland. However, along with the urbanization, population boom and ecological damage have adversely impact Xixi. The protection of wetlands promotes the dual benefits of urban economy and culture. However, the protection of wetlands brought by the perfect migration of aborigines seems to be a win-win situation, but it is difficult to reproduce the scenes in which nature and life are intertwined.
▼基地与湿地的关系，relation between site and wetland
The site is close to the wetland landscape and is with excellent natural resources. This region is rapidly developing under the strong promotion from Xihu District Government. Surrounding it, high-end residential areas and financial commerce are densely populated, and many cultural facilities are gradually taking shape. Under the general background of Hangzhou’s multi-center urban planning, it is foreseeable that this region will also become a hustling place.
The project site is in regular shape, facing streets at its four sides. A 60-meter-wide river channel from Xixi crosses the east and west, and an 80-meter-wide planned landscape corridor runs through the north and south until the wetland. As a large-scale park integrating office and business, how to achieve a dynamic urban open space while meeting the reasonable functional needs is the most basic entry point of this design.
▼形态生成分析，analysis of form formation
The business value is reflected through clustered street stores and attractive landmarks. For office, a cohesive and dynamic introverted space is needed. Based on the above understanding of the office complex and the review on the value of spatial functions as well as considering its special cultural and geographical context, we found the possibility of fully integrating the vibrant space and diverse ecology in Xixi Center, shaping an open park, and attracting business. Thus, we extracted the spatial commonality of “peripheral enclosure and internal construction” from traditional wetland city and courtyard organization. Through different internal and external layouts, we created a comfortable office environment and wetland landscape, so as to create a dynamic park environment. Then, with a light and mellow facade design to highlight the beauty of Hangzhou as well as combined with a conventional treatment under unconventional vision, we effectively controlled the cost. At last, we offered polished and lighting atmosphere with detailed design, so as to make this park a focus in this region.
Open Park and Form Control
Focusing on the combination of “landmark” and “openness”, we launched research and exploration on design strategies and compared general layouts of multiple programs. After comparing and optimizing multiple programs, we established following construction strategies: 1. Mass layout follows the principles of different internal and external sides, regular external side and irregular internal side, and penetration by layers; 2. At the four interfaces facing the peripheral urban roads, Chinese traditional courtyard intention should be taken as the blueprint, and in combination with modern and advanced construction techniques, three “large” design methods should be employed to integrate external enclosure mass, i.e., large enclosure, large opening, and large scale. This will not only create an open, grand, and outstanding architectural images at the urban level, but also create a scaled urban public space for urban residents, so as to provide favorable conditions for creating a paradise-like wetland landscape. 3. The internal mass arrangement takes traditional wetland settlement pattern as the blueprint. Three “small” design methods, i.e., small mass, small change, and small cluster should be employed to organize internal settlement. The superior resources of 80-meter landscape belt from south to north and the 60-meter landscape river channel from west to east should be fully integrated. Landscapes penetrate and extend at horizontal direction and roof plantation should be employed to allow the vertical expansion of wetland landscape, making architecture a part of the landscape and finally achieving integration with the landscape.
▼项目采用大围合、大开口、大尺度这三“大”设计手法来对外部围合体量进行整合，large enclosure, large opening, and large scale are employed to integrate the external enclosure mass ©姚力
▼“大开口”设计，large opening design ©黄金荣
On specific form control, the exterior was surrounded by four L-shaped slabs, sides and corners were softened, and opening ratio was coordinated, so as to form a rigid and soft architectural image. The internal small mass architectures took organic combination of single multi-layer retreat platforms and blocks with different height as their basic design method, so as to create an exquisite, peaceful, and delicate architectural temperament. Light gray and elegant white were employed as the main color tone of the architecture, which extended the impression of warm and elegant city. Combined with various facade details designed by architectural energy-saving measures, sense of mass of architectures were hided and the color memory of Jiangnan Water Town was relived.
▼柔化的边角带来刚柔并济的建筑形象，the exterior, with sides and corners softened, forms a rigid and soft architectural image ©姚力
▼淡灰与雅白的主色调延续温润雅致的城市印象，light gray and elegant white were employed as the main color tone of the architecture, which extended the impression of warm and elegant city ©姚力
Office layout with large space was employed as the form for internal space. The slab-type architecture was provided with office atrium which was located at the middle of core tube and with height of 35 meters. The office atrium can effectively bring sunlight into lower floors. Four sets of elevators arranged in the atrium, exposed running track, and structural column created a sense of technology and future. The passenger elevator had a load capacity of 1.6 tons, a speed of 1.5m/s, and net height of lift car of 3.2m.
▼内部共享空间，Internal Shared Space ©黄金荣
Commercial stores were arranged at bottom floor of exterior slab-type architecture. The needs of equipment and commercial image were taken into account when designing the store units. The division of store facade corresponded to a 9-meter column grid modulus, which was divided into four equal sections with width of 2250 for each section. Each standard commercial unit consists of a concave commercial entrance door bucket and three sections of French large-face glasses. The size of single display window was of 2,250*3,000, which can guarantee excellent commercial display effect. A full-length metal grille was placed on the upper part of glass window to meet the needs of equipment exhaust and store ventilation. In addition, on the ground floor, we set up metal canopies that continuously overhang by 2.1m to provide shelter for people and to enhance overall sense of shape of the building.
▼玻璃橱窗上部设置通长的金属格栅，满足设备排烟以及商铺通风的需求，a full-length metal grille was placed on the upper part of glass window to meet the needs of equipment exhaust and store ventilation ©黄金荣
In the design of small mass architectures which were spot distributed at inside, the atrium and traffic space were combined to complete effective transition from dynamic to static zones. The traffic space was connected to the auxiliary function. The separation of auxiliary space from used space increased the universality and flexibility of the space.
▼内部独栋办公，internal stand-alone office ©黄金荣
▼独栋办公平面，stand-alone office plan
▼小独栋剖面，stand-alone office section
On the landscape design, we took Xixi waterscape as the theme, and on the basis of original river channel, we reshaped the impression of Xixi Wetland as “one stream with light mist”. By creating a multi-water environment such as rivers, streams, ponds, lakes, swamps, pools, etc., so as to bring back the base with original ecological wetland landscape. The roof of interior single-family office architecture was soil covered with average thickness of 0.9m and the thickest of 1.5m. Large broad-leaved trees were planted, and grasses were planted on the architecture roof. By this way, green coverage of the park extended from the plane dimension to stereoscopic dimension, which was conducive to form a sound park climate, reduce energy consumption for air conditioning, and increase comfort level of the top floor. Two arched steel structural bridges were designed across the river channel for the north and south blocks, under which, ships can pass through. While connecting the north and south blocks, the arched bridges’ shape echoed the wetland landscape and restored the image of wetland.
▼内部景观重塑西溪“一曲溪流一曲烟”的烟水西溪湿地意象，the design of landscape reshaped the impression of Xixi Wetland as “one stream with light mist” ©黄金荣
▼园区内部绿化能够降低空调能耗，提高建筑顶层的舒适度，green coverage of the park extended from the plane dimension to stereoscopic dimension to reduce energy consumption for air conditioning and increase comfort level of the top floor ©黄金荣
▼跨河道处设计拱状钢结构连桥，下可通船，arched steel structural bridges were designed across the river channel, under which, ships can pass through ©黄金荣
Curtain Wall and Material Construction
The softened corners, large-span hollowed corners, and the treatment of retreat platform solved the oppressing sensation caused by large mass, but, meanwhile, technical problems such as on large scale cantilever, curved curtain wall, etc. occurred. For cost consideration, we decided to use conventional construction strategy to achieve unconventional visual impression.
▼大跨度开口化解了大体量的压迫感，the large-span opening solved the oppressing sensation caused by large mass ©姚力
▼大跨度开口细部，detailed view of the large opening ©姚力
In general, the cost of curtain wall for large curved architectures is usually much higher than that of ordinary architectures. For economic reasons, we decided to simplify the complicated curved form and use conventional construction strategies to achieve unconventional vision impressions.
The double curved surface was not employed as the curved glass of curtain wall; single curved glass was employed at special-shaped corner and upturned place; and other parts were orthogonally processed. At the corner end and the hole, we had limited radius and horizontal position of each piece of glass, so as to combine single glass unit and create effect of double curved surface, which not only guaranteed unconventional gentle curve that we pursued, but also can effectively reduce cost and construction difficulty.
▼转角幕墙，corner curtain wall
▼板楼出挑处剖面，section at the overhang of slab floor
The horizontal sunshade louver was an important element of this project design. In order to achieve a smooth, exquisite, and light design effect, we considered multiple programs on materials and shapes of the louver. While considering details of louver end, effect of seam, bending process, and other factors, we finally selected the design with main body of composite aluminum plate and end of aluminum alloy profile. Meanwhile, we make strict requirements on color uniformity of the profile and aluminum plate, perfect fitting of the bending precision, width of seam gap, etc. to ensure the best effect. In addition, we thoroughly considered and designed horizontal keel at inside of the louver, so as to ensure the uniformity of internal and external forms, minimize the visual psychological impact of cross section of horizontal frame, and increase the viewing surface.
▼层层出挑的百叶，louver overhung by layer ©姚力
▼百叶节点及遮阳分析，analysis of louver sunshade
The floor height was set to be 4 meters and the sunshade louvers were horizontally divided with interval of 1 meter, which made indoor vision unobstructed while blocked external line of sight. Since the summer sunshine in Hangzhou was relatively strong, the light-colored louvers that were horizontally overhung allowed sunlight to enter room through reflection, which can effectively play the role of shading and energy saving. The three-dimensional irregular plastic body was realized through dividing the body block by using two-dimensional horizontal line texture of horizontal louver. We also thoroughly considered elevations and positions of four sections of louvers for standard floor. We guaranteed the optimal line of sight. Also, we generally considered design requirements such as on height of fence, setting of opening fan, reasonable height link of structural beam, etc.
▼百叶夜景效果，nightscape effect of the louver
In order to ensure the effect of facade, we used mechanical exhaust system. For the opening fan that meets usual ventilation requirements, we arranged it at the bottom side of curtain wall, by which way, outer frame of the opening fan cannot be saw at indoor within normal range of visibility, and purity of sight line was secured. Meanwhile, the opening fan that was arranged at bottom side of curtain wall can be easily opened, which can save cost of window regulator. We arranged fixed glass at outside of bottom opening fan, so as to ensure safety while taking into account the integrity of the facade. We carefully scrutinized opening size and fixing method of outer glass, so as to ensure uniformity and rational use of the facade.
▼标准单元剖面，Section of Standard Unit
For lighting glasses, we compared multiple programs and made the optimum choice under the premise that the thermal performance was satisfied. We finally chose ordinary white Low-E glass. Also, gray translucent membrane with reflectance of 16% was selected to make the architectural curtain wall will not be too cold and create an intimate architectural atmosphere together with rounded horizontal louvers.
▼白色Low-E玻璃与圆润的横向百叶共同营造出亲切的建筑氛围，white Low-E glass creates an intimate architectural atmosphere together with rounded horizontal louvers ©姚力
In the design of interior single-family office curtain wall, the principle of typology was used to summarize facade texture with different transparency indicators. Then, according to advantages and disadvantages of external resources, for example, landscape orientation, the facade of each interface was arranged. In the direction of south and west, electric sunshade louver was arranged, by which way, the maximum sunshade effect can be secured in summer without affecting natural day-lighting in the room, while the sunlight will not be blocked in winter.
▼小独栋办公外立面，stand-alone office facade ©姚力
▼立面结构分析，structural detail ©黄金荣(右)
▼独栋办公室外花园，outdoor garden of the stand-alone office ©黄金荣
Modularization and Structural Design
The most economical 9-meter column grid module was employed for office of slab-type architecture and basement, on the upper part of which, 2250 basic office units can be formed. The column grid modulus of single-family office was of 12 meters to avoid the basement lifting column. The outer slab-type architecture was provided with circular chamfer modulus with radius of 3 meters and the interior single-family architecture was provided with circular chamfer modulus with radius of 1 meter. Core tube of slab-type architecture had two layouts, namely, mid-island and one-sided layout, providing a more flexible and economic transportation structure. The single-family office was with height of 4.2 meters and was horizontally divided with a modulus of 1.4 meters. The curtain wall was lowered by 350mm in total and located at the place of 1,050mm to replace railing, so as to make the shape be more pure.
Considering different forms of architectural parts, mixed structural design was employed. At the entrance of urban interface, large-span open-air steel truss system was used for the overhead section with large span. Reinforced concrete frame-shear wall structure was employed by the slab-type architecture. Steel-reinforced concrete column was employed by partial column. Reinforced concrete composite floor was employed by partial floor.
▼大跨度开口架空部位采用大跨空腹钢桁架体系，large-span open-air steel truss system was used for the overhead section with large span ©黄金荣
▼大跨悬挑结构施工现场，construction site of long-span cantilever structure
▼小独栋结构分析，structural analysis of stand-alone office
The single-family office that was dot distributed at interior side was independently opened. In order to realize office layout with large space and plane mode of free flowing, the structure of flat beam and thick plate were adopted. The column grid was of 12 meters with four sides overhanging by 3 meters respectively. This structure was light and the indoor space was spacious and bright. The architectural structure was separated from the architectural surface and the core tube was placed at one side, providing more possibilities for a free and economical plane. We optimized the design of internal pipelines for single-family office. Also, we concentrated all pipelines that affect height of the floor in the central area to reduce occupation of these pipelines. Further, we ensured that the height of cantilever space around the outer side was maximized, so as to obtain the optimum viewing. Through teasing of pipeline arrangement, consistency on design target for space, structure, and equipment was maintained. Then, whether the ceiling will be made or not in later interior decoration, a sound space effect will be secured.
▼小独栋办公外观，appearance of stand-alone office ©黄金荣
At the architecture’s special shaped corner, under the premise of ensuring reasonable support, components were simplified and processed, so as to make inside and outside of the architecture be coordinated and unified. For standard parts, the glass is directly fixed to the vertical keel supporting the curtain wall system. The vertical keel supporting curtain wall system is not vertical up and down at the special-shaped corner. If the same glass fixing method is used, a lot of vertical members will be added. In order to ensure the purity of the interior space, we consider strengthening the transverse keel at the corner, fixing the glass directly between the transverse keels, and providing the most spacious and transparent interior space.
▼转角处结构分析，structure detail of the special shaped corner
The under-hanging curtain wall and canopy support system at the entrance of office were independent with the structural column, ensuring continuous pass-through of architecture’s curtain wall. The bottom plate of revolving door was lowered to place electromechanical equipment, so as to realize a frameless design.
▼悬挑雨棚，the under-hanging curtain wall and canopy ©姚力
For the floodlight design of facade of the architecture, after three rounds of site adjustment on design program, the linear dynamic LED was finally selected. Together with specifically designed lamp head node and light barrier, the light can show a sound state in terms of concealment and continuity.
▼LED灯光节点，LED light node
▼夜景，night view ©姚力
Compared with small-scaled projects that emphasize sensory experience and creativity, design methods for large mass projects such as Xixi Center require more prudent design strategy. Under a deep understanding of requests from the owner, an intermediate state was sought to find the creative space and breakthrough. Mature, reliable, and thorough consideration was required for function, space, and material. Under the background of commercialization and urbanization, the visual style should be market-oriented. Rather than taking personal preference as the start point, the design shall conform to the principle of integrating into urban background. For detail processing, precise and professional control was required to ensure the quality after completion. Also, continuous design work after construction drawing shall not be ignored.
▼绿意盎然的园区，a campus with luxuriantly green ©黄金荣
A north-south urban public green axis and an east-west River divide the project site into four parts. Now, in retrospect, the restriction that once troubled us just made us realize the real garden office. Five years ago, the question of whether the wetland wilderness landscape and the high-end business atmosphere of the office park can live in harmony is no longer the question. Nowadays, the green park cannot tell whether it is the landscape in the building or the architecture in the landscape.
▼真正的花园式办公，an authentic garden office ©黄金荣
When the project is completed, what gives us the most sense of achievement is not to create a strong visual image of the building, but to persuade the owners of the park to adopt open management after the construction is put into use. The realization of publicity has brought vitality and vitality to the park. The quiet integration of the life scenes of walking dogs and children blurs the boundary between work and life. As an architect, it is gratifying to see such scenes. This is also a practical exploration and attempt of the future office park mode. The process is arduous and there are many regrets. We look forward to new breakthroughs in the future.
▼园区整体外观，overview of the campus ©姚力
2018 意大利A’ Design Award Platinum 白金奖
2018 英国Blueprint Awards Shortlists 入围奖
Client: China Energy Conservation and Environmental Protection Group
Location: Intersection of Wenyi Road and Chongren Road, Hangzhou, China
Design date: 2012.9
Completion date: 2018.6
Area: 148156㎡(above ground) , 100000㎡(underground)
Project director: Zhang Wei
Design leader: Meng Fanhao
Design team: Xie Lei, Zhu Mingsong, Zhumin, Sun Tao, Miao Chunle, Tang Yan, Zhao Liang
Structural design: Hu Damin, Zhang Zhiyu, Li Xiaoling, Liu Bin, Qian Luxi, Peng Zhi, Guo Jun, Wang Xin, Lu Zhegang
Equipment design: Wu Wenjian, Qi Yi, Lu Baiqing, Zhang Bin, Sun Bo, Hu Ting, Chen Feiyan, Tang Yonghui, Shan Jinlong, Shen Fengqiang, Li Jinniu, Liu Chuanpu, Yang Hongfeng
Photographer: Yao Li, Huang Jinrong