In Zhao County, Hebei Province, there is such a beautiful legend: It is said that Luban set up a bridge on the Weihe River in Zhaozhou overnight, sensationalized the surrounding state of the county, and also attracted Zhang Guolao and Chai Wangye. Zhang Guo was riding the donkey, with the sun and the moon, and Chai Wang pushed the car carrying the "Five-Yue Mountain". Just as soon as he got on the bridge, the bridge was shaken. Luban hurriedly jumped under the bridge and raised his right hand to support the bridge. Because Luban was too strong, his handprint was left under the east arch of the bridge; the bridge also left a hoof print, a lane ditch, a knee print left by Chai Wang when he fell, and Zhang Guo old fight A round pit that was shot on the bridge.

Of course, this is just a mythical story made by people to commemorate the ancient craftsmen and the mysterious coat of Zhaozhou Bridge. In fact, Zhaozhou Bridge was built in the Sui Dynasty, and its real design and construction is not Luban, but Li Chun, a craftsman of the Sui Dynasty. In the early days of the Sui Dynasty, Zhao County, as the main thoroughfare of the north-south traffic, was blocked by the Weihe River outside the city, and the flood season was even more impassable. To this end, Dai Daye decided to build a large stone bridge in the first year to end the long-term traffic inconvenience, and appointed Li Chun to design and build the bridge.

Li Chun led other artisans to conduct a thorough investigation of the Weihe River and the geological conditions on both sides of the river. He chose to build a 1.56-meter-high abutment on the relatively flat sandstone on both sides of the river as the bridge foundation. This is the result of a joint investigation team consisting of four units including the Natural History Group of the Chinese Academy of Sciences in 1979. This result not only shocked the investigation team. In fact, as early as 1933, Mr. Liang Sicheng did not believe this result. He even wrote in the investigation report: "Approximately 70-81 cm under the riverbed at the foot of the voucher was found to be placed under the voucher. The stone wall has five floors and a total height of 1.58 meters. Each floor is slightly out of the upper layer. There is no solid foundation below. It is clearly the diamond wall used for waterproof flow, not the basis of the full load of the bridge. After seeing 30 to 40 cm, the water will be seen, so unless it is excavated on a large scale, it is impossible to reach the position of the large bridge base that we have reasoned to speculate."

But Zhaozhou Bridge was built on such a bridge. The building materials of the bridge body are also the green hard gray sandstone produced by Li Chun on the spot, which is produced in the nearby counties and counties. It is longitudinally laid in the direction of the bridge, and a total of 28 1.03 m thick arch vouchers are built. In order to strengthen the horizontal connection between the arch vouchers, Li Chun designed the arch vouchers according to the method of narrowing the width and the width and slightly “receiving points”, which is to gradually shrink the width from the two ends of the bridge to the top of the bridge, shrinking from the widest 9.6 meters to 9 Meter to strengthen the stability of the bridge.

In addition, in order to increase the horizontal connection of the voucher, Li Chun evenly placed five iron rods on the main vouchers along the width of the bridge, passing through 28 arch vouchers, and the ends of each tie rod were semi-circular heads exposed outside the stone. To hold 28 tickets. The waist stone is also worn between the arches, so that the arches are tightly fitted together, and the arches are mutually dependent, which greatly enhances the stability and reliability of the bridge. These measures have taken the entire bridge into a compact whole, enhancing the stability and reliability of the entire bridge. In order to make the bridge more firm, Li Chun also used arching stones and hookstones to protect the arches outside the bridge.

According to previous experience, long-span bridges generally use semi-circular arches, but their vaults are high, which not only makes pedestrians and bridges inconvenient, but also increases the risk of construction. To this end, Li Chun and the craftsmen creatively adopted the arc arch form, the main span of the main hole is set to 37.02 meters, the arch height is only 7.23 meters, the ratio of arch height to span is about 1:5, thus achieving low The dual purpose of the bridge deck and the large span, but also has the advantages of material saving and convenient construction.

Not only that, Li Chun also made major improvements to the arched shoulders, changing the actual shoulder arch in the previous bridge building to an open shoulder arch, that is, two small arches at each end of the large arch. This large arch and small arched open shoulder arch can not only increase the flood discharge capacity, but also reduce the impact of flood on the bridge. According to calculations, the four small arches increase the water area by about 16%. It also saves a lot of earth and stone materials, reduces the self-weight of the bridge body, thereby reducing the vertical pressure and horizontal thrust of the bridge to the abutment and the bridge foundation, and increasing the stability of the bridge.

The single hole design of Zhaozhou Bridge is also an unprecedented pioneering work in the history of Chinese bridges. In the traditional Chinese construction methods, the longer bridges often use a porous form, so that each hole has a small span and a gentle slope, which is easy to construct. However, there are many piers in the porous bridge, which is not conducive to the navigation of the boat and the flooding. Therefore, when Li Chun designed the bridge, he took the form of a single-hole long span. The river core did not stand the pier, making the stone arch span as much as 37 meters.

This series of designs together constitutes the immortal artistic value of Zhaozhou Bridge. Its ingenious conception and exquisite craftsmanship are not only second to none in China's ancient bridges, but also have leading significance even in the history of world bridges. In the more than 1,400 years since its completion, even after 10 floods, 8 wars and many earthquakes, especially the 7.6 magnitude earthquake occurred in Xingtai on March 8, 1966, Zhaozhou Bridge is only 40 kilometers away from the epicenter. Zhao The state bridge has not been destroyed. "No matter what the internal structure of the bridge, it only shows that it can exist for more than 1400 years," said the famous bridge expert Mao Yisheng. Editor / Zhao Jing