帷幔之下，钢柱丛林：径山花海帐亭 / 浙农林大园林设计院+东维建筑

编辑：楼樱 | 校对：楼樱 | 2023.07.13 09:44

设计单位 浙江农林大学园林设计院+东维建筑

项目地点 浙江杭州

建成时间 2020年10月

建筑面积 700平方米

返璞归真

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回归自然的建筑

花海帐亭位于杭州余杭径山，距离杭州市区一小时车程，以禅茶和山林闻名。都市的人们来到这里可以暂别喧闹，走进原野山林，深度体验自然、亲子、野餐的乐趣。

The Flower Sea Tent Pavilion is located in Jingshan, which is famous for its tea culture, forests landscape and buddhist mood.

走入山林原野是直面自然，禅茶参悟是直面内心。处在径山这样一个大环境起点处的景观建筑，其设计的出发点正是思考人与自然的原始关系。因此项目初始意向是简单且开放的，这可以追溯到人类最初的本能的建造。那时人类的生存与自然密切相关，出于生存需求而搭建遮蔽物。为了塑造一种原始的空间感，花海帐亭选择悬垂屋面的形式，舒展的骨架和表皮形式自然而然的地产生，正如径山的茶山上随处可见的茶叶遮阳棚这类农业构筑物一般简单而直接。

So, the design started from the thinking of the original relationship between humans and nature, with the initial intention which was simple and open. In order to create a primitive sense, we chose the form of a suspended roof, and the stretching skeleton and skin form naturally emerge, just like the simple tea sunshades that can be seen everywhere on the Tea Mountain in Jingshan.

杭州冬冷夏热，冬夏两季既难于室外游走，花海也无花可赏，因此公园的观赏时段基本是春秋两季。作为花海内主要的停留空间，花海帐亭除了提供简餐、茶饮和咖啡的功能以外，同时也是孩子们植物认知类研学课程的开放课堂。孩子们在开敞的廊屋里聆听讲解、感知周遭环境、记录自然的痕迹。未来随着径山花海的持续开发，这里也将可能成为山野音乐节及啤酒节的场所。

Hangzhou is cold in winter and hot in summer. It is uncomfortable to travel outdoors during that time and there are no flowers in the Flower Sea Park. Therefore, the Tent Pavilion will be used mainly in spring and autumn. By providing simple meals, tea drinks and coffee, Tent Pavilion is also an open-space for children's flower cognition courses.

基于这样的季节气候特征和灵活、综合的使用需求，建筑并没有设置硬性的气候边界，而是做了一个类似“亭”的开放空间，如帐篷或者吊床一样轻轻被撑起、划过花海的地面。考虑到建筑的自然属性和使用安全性，设计没有使用工业化程度较高的膜材料或是地锚拉索。多段开敞的廊区由亲和力强的木材和纤细的钢柱共同构成，材料和形式皆来源于场地诉说出的自然、原始、轻盈的意象。

Based on such seasonal characteristics and flexible usage, the Tent Pavilion does not have a fixed climate boundary, but instead creates an open space, gently propped up like a tent floating on the flower sea land.

花海帐亭整体（材料和形式皆来源于场地诉说出的自然、原始、轻盈的意象） ©东维建筑

空间体验

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场地中心的锚固点

花海帐亭的原场地是园内河流边微微起伏的土地。帐亭以毛石为台基，搭设不同标高的就餐区，延续了场地地形的空间感。考虑到每柱跨间的餐桌数量及活动尺度，整个帐亭以6×6或6×3米的平面模数区分开用餐区和后勤区。加工间和卫生间以不透明的体块居于西侧，东侧由三组条状廊亭就餐区错落分布，向内围合出一片小空间，可以举行仪式或是小型演出，向东、北、南展开视线，朝向不同的景观。

The plan is made up by modulus of 6 × 6m and 6 ×3m, forming activity areas and service areas. Four sets of tents enclosed a central space for ceremonies or small performances.

模块化的设计便于结构单元的控制并简化了屋面的加工，多重悬垂屋面呈现出错落漂浮的状态，给人柔软、被包裹的安全感。嵌入屋面阴角处的柱子没有直接暴露交接节点，而是隐没于悬垂屋面中，创造出屋面无限延绵的空间感。剖面上的轻重倒置使得四周的景观以一种连续的视野被纳入檐下，层层叠叠的屋面无限接近又相互独立。

The modularity method facilitates the design of structural units and simplifies the form of roofs. Layers of roofs exhibit a state of floating. The upper ends of the columns embed in the interior corners of the roof and the junction nodes are hidden from view, creating an infinite sense of space under the roof.

柱子以看似随机的形态错落分布于木制“帷幔”之下，穿行其间恰似漫步于林中。台基边茂盛的苇草攀附到石基上，逐渐将钢柱形成的“丛林”包裹，呈现出郊野的趣味。当晨间微暮时，承托屋面的细柱自上而下地逐渐消隐，原生于自然的形式为游者静静擎起一片天地。

The pillars are distributed randomly under the wooden "curtains", making people passing through them as if strolling through the forest. The thin pillars supporting the roof gradually disappear from the roof to the ground, and the natural form lifts up a quietly space for visitors.

大地之上

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力与形的结合

对于“刚性悬垂屋面”的实现，方案阶段的结构概念是从悬垂的角度出发，使用类似吊桥的做法，即以钢索穿过木方条后悬垂于两端的门式钢架之上，通过后张拉的方法使屋面固定。

For the implementation of "rigid suspended roof", the initial idea was similar to a suspension bridge, that is to use steel cables to pass through wooden bars and make the roof rigid through post tensioning.

但项目深化中面临诸多问题，如：方木条本身的自重过大、木材抗压能力较弱、连续曲面的高空后张拉难以操作、门式钢架抗弯强度提高后导致结构构件过粗等等不良因素。因此初步设计中决定以竖向结构构件（承重及抗侧力）在满足设计使用工况的前提下采用极小高细比的圆钢柱，屋面结构系统采用柔性钢木组合形式——木材预制筒壳单元放置于悬链钢板带之上——组成曲面结构顶棚。

However, there are many problems such as weak compressive strength of wood and difficulty in operating high-altitude post tensioning of continuous curved roofs.

悬垂曲线、屋脊梁与柱

进入设计深化阶段，我们与结构师进行了反复的推敲，将结构的力学体系、秩序乃至比例和细部构成等数理性问题逐步纳入设计范畴，初步决定采用在基本的屋面单元内（6×6米或6×3米），木材预制的筒壳单元放置于每两榀门式钢架之间悬挂的4~6条悬链钢带之上的结构建造方式。曲面筒壳在体系中可忽略其面外刚度仅考虑其面内刚度，作为弹性膜传递屋面载荷；所有顶棚系统的自重及外力（风、雪）荷载藉由木板壳（面）施加于钢板带（线），并传递至屋脊处的横梁。顶棚的悬链弧线形态根本上是由其自身而定义（而非通过建筑方案上的主观定义）——其承担的重量、支点跨距、弧线的刚度这三者决定了其弯曲度。

Therefore, a flexible steel wood combination form was adopted in the deepening design phase. Wooden prefabricated shell units are placed on top of 4-6 hanging steel strips suspended between each two portal steel frames. Curved cylindrical shells ignore their out-plane stiffness and only consider their in-plane stiffness as elastic membranes to transmit roof loads. The self-weight and external forces (wind, snow) are applied to the steel strip from the wooden shell and transmitted to the crossbeam on the top of portal steel frames.

结构部分：最不利积雪荷载况下的跨中最大竖向挠度值约11毫米，相对6米跨度比约为1：545 ©张冲冲

通常结构梁作为单一具体的截面形式（矩形、箱形、工字形等）应对其跨距，但对于本案而言，屋脊横梁6米的跨度，梁势必比曲面板凸出，从而影响屋面顶棚下部的观感。屋脊梁主要承受屋盖悬链的斜向坡面拉力（也可分解为水平拉力和竖向剪力），从工程需要出发，结合屋脊的尖顶形态，结构决定屋脊的两侧设置随坡面的桁架，其坡面的夹角也使该组桁架形成具有抗弯剪刚度的折面刚架。

The form of the crossbeam follows the shape of the roof ridge. The angle between the roof slopes also makes the trusses as folded rigid trusses with bending resistance and shear stiffness.

花海帐亭为开敞式的单层弱屋盖系统，单一的细钢柱为类悬臂的柔性杆，通常难以承担较大的压力和侧向力，而单跨的结构也缺少冗余度而具有天然的安全隐患。因此我们将关键部位的柱子根数加密，邻近的3~4根细柱顶部通过顶部的立体钢架组成强抗侧单元，形成具有制衡顶棚荷载能力的门架系统，同时也与建筑空间追求的看似随机分布的钢柱形成的“丛林感”相契合。

The Tent Pavilion is an open single story weak roof system, with steel columns act as flexible cantilever rod. It is difficult to bear significant pressure and lateral forces for single columns and the single span structure also lacks redundancy. Therefore, we increased the number of columns in key areas and combine them through a three-dimensional steel frame at the ridge, forming a strong lateral unit with the ability to balance the load of the ceiling. At the same time, these seemingly randomly distributed steel columns also fit with the "jungle-like space" pursued by the architectural concept.

花海帐亭高台（端部及中间关键部分的钢柱加密，形成看似随机分布的“柱丛林感”） ©东维建筑

对于中间跨，跨间钢板带的拉力基本可实现自平衡，但对于边跨，末端的斜向檐始终承受着不平衡的单边拉力，且不具备中间跨屋脊的双坡条件，无法形成檐口处横梁的折面刚度，对于角柱亦是如此。针对边跨端部的不平衡力，结构通过在边跨跨中增加钢柱，并统一对边跨的柱子设置一定的反向朝外倾角，使得屋面斜拉力更多地转化为微斜柱的轴向力。当屋面安装完毕，边柱将会被拉直至竖直位置。类似于古建筑常见的外圈柱子柱脚向外的“侧脚”，花海屋面边跨柱子的顶部外倾同样是对于结构力学的转译和应对，视觉上比铅垂的边柱给人以更好的力学直觉。

For the middle span, the tension of the steel strip can basically achieve self-balancing. But for the side span, the eaves at the end always bear unbalanced unilateral tension. They do not have the double slope ridges which exist in the middle span so can’t form the bending stiffness. For corner columns the situation is the same. To deal with the unbalanced force, we add steel columns in the middle of the side span, and all set a certain reverse camber angle for the columns of the side span so that the inclined tension of the roof is more transformed into the axial force of the micro inclined column.

结构部分：最终结构模型——边跨预变形（对边跨的柱子设置一定的反向朝外倾角，使得屋面斜拉力更多的转化为微斜柱的轴向力，当屋面安装完毕，边柱将会被拉直至竖直位置） ©张冲冲

结构部分：端跨预倾斜可在长期荷载下抵消[准永久组合下水平变形抵消预倾斜，约1-100H] ©张冲冲

意外的反复

因造价限制，之前预想的胶合木材质只能替换为常规的柳桉木。虽然木制屋面的原设计构造厚度达到100毫米，但屋面6米×6米的全木制筒壳尺度仍然会导致其难以在吊装过程中承担自重和保持稳定的形态，当将板片固定在木龙骨上时，在重力及风力的作用下也很容易发生挤压和断裂。而如果要坚持保留木板的整体性，设计只有继续加厚板材——随即导致两个问题：造价的上涨和屋面的厚重感增大。

Due to cost constraints, the previously envisagedized glued wood of the shell can only be replaced with the conventional eucalyptus wood. Although the original design thickness of the wooden shell panel reached 100mm, the shell size of 6m ×6m will still make it difficult to bear its own weight during the lifting process.

因此，最后的项目深化阶段我们决定采用定制曲面格栅轻钢龙骨代替木龙骨，这一改变遂即将悬链曲面的柔性钢板带+木制筒壳体系变更为具有一定刚性的曲面钢格栅，钢格栅和直纹方向铺设的通长木板形成稳定的面内结构，壳面的面内外刚度均得到提高，有利于屋面的弧度、厚度控制在较为的理想范围内。此时顶棚弧线的弯曲度仍以其自重和弧面刚度来完成定义。

Therefore, it was decided to adopt customized curved grid light steel keel instead of wooden keel in the construction phase. This modification changed the flexible steel belt + wooden cylinder shell system to curved steel grid with certain rigidity + wooden panel skin. The steel grid and the wood panel laid in the straight direction form a stable in-plane structure and the rigidity of the shell is improved both inside and outside of the surface.

自重之外的附加的荷载（包括风力、堆雪荷载等）除了传递为钢格栅的轴向力也部分内化为钢管内的弯矩。对边跨而言，不平衡的拉力也因此进一步得到缓解，有利于控制边跨柱的外倾抵抗角。额外的，原木筒壳下部的钢板带也得以因钢格栅龙骨的替代而被取消，没有了板带的遮挡，木制悬幕的内表面空间的呈现也变得更为纯粹。

In addition, the original steel strips at the bottom of wooden shell have been removed due to the application of the steel grid keel. Without the shielding of the steel strips, the presentation of the internal surface of the wooden suspension shell has become mush pure.