What are the main aspects of column details of ancient buildings in China?

Generally, five purlins are commonly used in double-slope buildings with a width of about ten feet. From the side of the column frame, from bottom to top, it can be divided into three parts, namely, columns, roof trusses (roof beams and columns), purlins and rafters, which directly support the roof.

(1) pillar

Columns are the main vertical pressure-bearing components in houses, which have several cross-sectional shapes, such as round, square and octagonal, and most of them are round.

As mentioned above, columns are an important factor in determining the scale and scale of single buildings, and different positions have different names. There are four main types of columns: all the columns in the outermost row under the eaves, whether front or back or both sides, are called eaves columns. The columns in the eaves column are all called golden columns except those on the longitudinal center line of the building. On the longitudinal center line of a building, which is close to the roof, but not in the gable, it is called a central column. In the middle of the gable, it reaches the roof, which is called a gable.

(2) Roof truss

In the Qing Dynasty, the official style was mostly vertical roof truss, with no fork and other oblique components, mainly beams, squares and short columns.

(1) Beam-beam is a flexural member, and the weight of tile roof is transferred to vertical column body through purlin. Generally, the beam section is rectangular, but in the south, in order to save materials, a large number of circular sections are used.

The specific name of each beam depends on its position and the number of supporting purlins. For example, as shown in figure 10, the upper beam supports three purlins, which is called a three-frame beam, and the lower beam supports five purlins. In addition, if it is a building with a corridor, there is a short beam between the eaves column and the gold column. In buildings without buckets, the beam head is called the head beam. In a building with a bucket, the beam head is specially made into a more complicated cornice form, like a crown, called a cornice beam. This short beam does not bear load, but only plays the role of hook and contact. When the corridor is deep, melon columns, beams and purlins can be added to the beams. At this time, the lower beam is called two-stage beam and the upper beam is called single-stage beam. Besides the hook and contact, the two-stage beam also has the function of bearing. Trusses and nose ends should be carved at the intersection of beam ends and purlins to prevent purlins or cornices from rolling.

(2) The square-square section is the same as that of the beam, and its main function is to hook the stigma, but sometimes it also bears the weight and becomes a flexural member. As shown in the figure, the one between the stigma of echinochloa is called thorn square, the one between the stigma of Cucurbita melo is called golden square, and the one between the stigma of eaves is called eaves square or forehead square. Even if there is a corridor, there is a square between the eaves and the pillars; In the double-eaved building, there are rafters at the waist of the golden column, and many round holes are dug on the outer skin of the rafters to receive the back end of the rafters under the eaves. In addition, in buildings with a large width and a bucket arch, there are two layers of foreheads, the upper layer is called a large cross-section Fang, and the lower layer is called a small cross-section Fang; Fill in the blanks with thick plates in the middle, called forehead pads; A square is used to support the bucket on a generous top, which is called a square. According to the depth direction, the beam is directly attached to the bottom of the beam, and the beam is connected with the stigma. Large rafters, load-bearing rafters and other components are all rafters with contact and load-bearing functions.

(3) Short columns, etc. -The space between two beams or purlin beams in the roof truss must be filled with short wooden supports. If the height of the support exceeds the width of the wooden body, it is called a melon column, otherwise it is called a melon column. Melon column can be divided into thorn melon column and golden melon column according to different status.

Because the lifting frame is high, the column foot is often supported by the corner back to avoid tilting.

In high-rise buildings, it is placed on the beam, and the lower end does not touch the ground, while the upper end has the same function and position as the eaves column and the gold column.

(3) directly supporting roofing materials

(1) purlin —— Most of the sections are circular and are flexural members. The purlin on the stigma of cornice column is called cornice purlin, and the purlin on ridge melon column is called golden purlin. If it is a roof with more than seven purlins, the number of purlins will increase.

(2) rafts and flying rafters-logs nailed vertically between purlins are called rafters. On the rafters, the diameter is about one third of the latter, and the clear distance of the rafters is arranged according to a diameter. The top row, called the brain rafters, is in contact with the wood that supports the spine. The roll shed type has no spine and no wood to support the spine, and the top is made of curved Luo Guojue. The rafters on each gold purlin are called flower rafters, which are different because of their different status. The rafters in the next step are called eaves rafters, with the inner end placed on the gold purlin and the outer end protruding out of the purlin.

In large buildings, rafters with square cross-section should be nailed to the top of each rafter with circular cross-section to increase the selected depth. The depth of the eaves from the center of the eaves to the outer end of the rafters is generally three-tenths of the height of the eaves column, while the exposed length of the rafters is one-third of the depth of the eaves.

In the Yangtze River valley, the roof is not covered with mud, so it is light in weight. Instead of round rafters, it is made of flat wood, which is only one or two inches thick. Sichuan calls it a rafter.

(3) Other components-nail a board on each purlin to make a row of round holes for the rafters to pass through, which are called rafters. On the roof purlin, there is a wooden block with hexagonal cross section called joist, and a row of round holes are also made on the front-back downward slope to bear the upper end of the brain rafter. At the lower end of the eaves rafters, the rafters are connected with flat wood, which is called a small eaves. Similarly, at the end of the rafter, the rafter is connected with the pentagonal square wood, which is called Dalian eaves. Between the rafters above the eaves, in order to prevent birds from flying, either nailing the whole board is called inner wood, or sealing it with small boards is called door curtain.

The rafters are covered with wooden boards about an inch long, which are called surface boards, and the direction of the boards is perpendicular to the rafters, which is called horizontal surface boards; Or parallel to the rafters, it is called Wang Shunban. There is a narrow wooden board nailed to the eaves of Dalian. The top of the board is the size of a tile, called a tile mouth, which bears dripping water.

(4) About the lifting frame

In the Engineering Practice Example of the Ministry of Industry, Volume 1 1, the calculation of the length of the five-purlin Damushan column is written as follows:

The height of each mountain pillar is determined by the depth, for example, the depth of one foot or two feet is divided into four steps, each slope has two steps, and each step is three feet deep. Step one, add five lifts, with a height of one foot and five inches. The second step, according to the seven lifts, the height is two feet and one inch. Add six inches of leveling water, and make a truss with one third of the purlin diameter, two inches and three points long, and the eaves column is eight feet high and one foot, two feet, four inches and three points long. ……

This record has the following three inspirations for us:

(1) The horizontal distances from eaves to Jinfang and Jinfang to ridges are divided into equal parts according to the depth of front and rear eaves columns, and each part is called one-step frame.

(2) The horizontal distance from the eaves fang to the gold fang is called the eaves step, and the horizontal distance from the gold fang to the ridge fang is called the ridge step.

(3) The vertical distance from the eaves to the golden eaves is obtained by five strokes, that is, three feet by five tenths of the eaves, and the vertical distance is one foot and five inches; Similarly, the vertical distance from the gold cube to the ridge is three feet multiplied by seven-tenths of the ridge step, resulting in a vertical distance of two feet and one inch. To sum up, it can be seen that the lifting frame directly determines the slope of the roof. In the case of five purlins, the depth is small and the highest lift is seven. If it's seven, nine or eleven purlins, the rise and fall will be as high as eight or nine. The lifting method makes the tile slope of the wooden structure building in China a curve rather than a straight line. The curve is steeper up and gentler down, as stated in the examination record.