As a treasure of human civilization, ancient buildings have been left behind in the erosion of the long river of history. Every ancient building is an annual ring of time, witnessing the historical process of China over five thousand years, and recording the cultural imprints of each era. The group of ancient buildings is different from ordinary buildings, and the history and significance behind them are significant.

Before determining the reinforcement plan, not only the need for reinforcement must be considered, but also the principle of "repairing the old as the old" must be observed in the restoration of ancient buildings, and the historical value of the cultural relics must not be destroyed. my country's ancient buildings began to evolve from wooden structures to masonry structures after the middle of the Ming Dynasty, and most of the existing ancient buildings are brick-wood mixed structures. Ancient buildings have withstood multiple tests in the long years. Wind and sand erosion, earthquakes and typhoons, and natural aging are the main reasons for the destruction of ancient buildings.

Pillar reinforcement

Resolution of the gap between the wooden pillars

If the gap caused by the lack of water and shrinkage of the wood column is too large, it will harm the load-bearing capacity of the wood and cause the wood's flexural properties to be seriously reduced. If it is not resolved, the gap will expand again, so the wood shrinkage gap needs to be repaired .

For the shrinkage cracks of wooden pillars, when the depth does not exceed 1/3 of the diameter of the pillar (or the cross-sectional dimension in this direction), it can be repaired according to the following embedding methods. When the crack width is not more than 3mm, you can use putty to wipe tightly during the oil decoration or whitening process of the column. When the width of the crack is 3mm～30mm, it can be filled with wooden strips and glued firmly with water-resistant adhesive. When the crack width is greater than 30mm, in addition to using wooden strips to fix it with water-resistant adhesive, two or three iron hoops (or carbon fiber hoops) should be added to the cracked section of the column. If the cracked section of the column is longer, the hoop spacing should not be greater than 0.5m.

Solution of rotten wooden pillars

For the decay of the wooden column in a humid environment, the following methods can be used to repair or strengthen:

When the center of the column is intact, only the surface layer is decayed, and the remaining section can still meet the stress requirements, the decayed part can be removed, and after antiseptic treatment, the dry wood is used to repair it in the original shape and the original size. And use water-resistant adhesive to bond. If it is surrounding trimming, 2 to 3 iron hoops (or carbon fiber hoops) need to be added.

Solution to the destruction of prefabricated components by insects

For prefabricated components destroyed by insects, solutions for insect and corrosion prevention must be developed. Pay special attention to the selection of drugs:

① Use micro-toxic, high-efficiency, anti-corrosion and insect-proof drugs, good durability, and will not cause air pollution;

②After the agent enters the wood, it does not dissolve, evaporate, and does not flow out after encountering water. It can be solved by pressurized immersion, and its anti-corrosion and insect-proof effective period reaches 50 years;

③After the drug is introduced into the wood, the color of the original wood cannot be changed, and the harm to paint and painting is at most mild.

Reinforcement of beams, beams and purlins

Solution to the damaged connection point of column and beam

When the beam is detached due to the rot and crack of the tenon joint, first remove the damaged part and make a mouth at the end of the beam. After the anti-corrosion solution is solved, the newly made mahogany tenon joint is put into the mouth of the mouth. When inlaid, the tenon joint and the original prefabricated component are glued tightly with abrasion-resistant adhesive and fixed with anchor bolts.

For some of the ridge purlins that have tolerated cracks, in order to prevent the gap from developing again, the epoxy resin is filled first, and then the CFRP hoop is set with a width of 5 cm and an interval of 0.5 m, and the wood color paint is painted. In order to prevent the damaged ridge purlin from being damaged by stress during excavation and repair, the cross-sectional damage should be filled with a block and epoxy resin. Subsequently, CFRP hoop armpits with incomplete dimensions along the length and short directions of the prefabricated components were used to bind double layers and painted with wood color paint.

Solutions to other prefabricated components

For the decorative design wood board with large worm holes, pour insect repellent into the worm holes, and after the insect repellent penetrates into the wood, introduce epoxy resin glue to fill the worm holes. Then the surface of the decorative panel is polished and leveled, and painted with wood color paint. For flat roof water seepage areas, it needs to be renovated to prevent moisture.

Carbon fiber reinforcement

Nowadays, more and more ancient buildings and modern antique wood structure buildings have adopted FRP materials in the repair and reinforcement. Common FRP mainly includes aramid fiber AFRP, carbon fiber CFRP, glass fiber GFRP, and basalt fiber BFRP. At present, CFRP is mainly used in the field of reinforcement.

Carbon fiber is a new material with excellent mechanical properties. When used as a reinforcing material, it has the characteristics of high strength and light weight. Its specific gravity is less than 1/4 of steel, but its tensile strength is 7-9 times that of steel. Carbon fiber materials can effectively improve the structural bearing capacity, stiffness and seismic performance of buildings. This is the basis for carbon fiber cloth to be used for ancient building reinforcement.

Carbon fiber reinforcement can better maintain ancient buildings, ensuring that the original historical and cultural information content of the engineering building itself will not be destroyed, and the damage location of the structure must be reinforced and repaired.