Method for repairing and strengthening slanting rafter and purlin joint of ancient building

Abstract

The invention provides a method for repairing and strengthening a slanting rafter and purlin joint of an ancient building. The method comprises a step of replacing a rotten rafter, sawing a head of the rafter into a slope, engraving a hooked convex rafter at an upper rafter head, and engraving a hooked mortise at a lower rafter head, a step of engraving a dovetail mortise in a purlin, making a leading strip whose lower part is inserted into the dovetail mortise, snapping the lower rafter onto the leading strip through a rectangular mortise, cutting round through holes in leading strip verticalsurfaces close to left and right sides of the lower rafter, making two round insertion tenons, and inserting the round insertion tenons into the round holes to clamp the lower rafter, and a step of engraving a rectangular mortise A in the upper rafter, engraving a rectangular mortise B in the lower rafter, making a rectangular insertion tenon whose shape is the same with the combining shapes of the rectangular mortise A and the rectangular mortise B, fixing the upper rafter head and the lower rafter head together through the hooked tenon, and fixing the upper rafter and the lower rafter by inserting the rectangular insertion tenon to complete the repair on the basis of not changing raw materials and construction technology.

Description

technical field [0001] The invention belongs to the protection and repair of the wooden structure layer of the roof of an ancient building, and specifically relates to a method for reinforcing and repairing oblique palm-shaped rafters and purlin nodes of an ancient building. Background technique [0002] The rafters are large wooden components of ancient buildings. They are located between the purlins and the watchboards in the beam frame, and are placed on the upper and lower purlins and girders. They are arranged in a certain order, either at positive or oblique angles. Its section has two kinds of round and square. According to its location, "rafters" have different titles, such as: eaves rafters, brain rafters, flower rack rafters, etc. According to the research, the rafters have been used as early as the era of "wood as a nest", but because the roof was straight at that time, the "rafters" actually played the role of purlins. The dropped roof of the Han Dynasty indicat...

AI Technical Summary

Problems solved by technology

However, this traditional repair method will bring the following disadvantages: First, although this method of fixing with iron nails has strong rigidity in a short period of time, the flexibility and torsion resistance of the joints are insufficient; Subsidence or ground vibration may easily cause the loosening of the connection between the nails and the rafters and purlins, resulting in the failure of the reinforcement effect, thus threatening the safety of the slanted palm rafter head and purlin joints

In addition, iron nails are exposed to the air for a long time, and rust due to oxidation will inevitably lead to weakening of iron nails and reduction of joint stiffness, which will cause the rafter heads to loosen and shift at the joints

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