Discussion on the development of masonry structure design method in China

1956 approved the popularization and application of the design standard of masonry structure in the former Soviet Union in China. From the end of 1960s to 1980s, a large-scale experimental research and investigation on masonry structures were carried out nationwide, and a set of advanced masonry structure theories, calculation methods and experiences in line with the reality in China were summarized. For example, the national standard "Code for Design of Masonry Structures" GBJ 3-73 promulgated by 1973 is the first code for design of masonry structures in China. GBJ 3-88 issued by 1988 makes the design theory and method of masonry structure in China tend to be perfect. The latest Code for Design of Masonry Structures (GB50003-200 1) issued by 65438+ 10 in June 2002 further improved the theoretical and practical basis of masonry structure design. The latest Code for Design of Masonry Structures (GB50003-20 1 1) has been implemented since August 12. Masonry buildings are made of bricks and stones. For example, pyramids built with huge processed stones have been preserved until modern times. Among them, the three great pyramids (2723-2563 BC) built in Giza, the Nile Delta, are exact square pyramids. The largest pyramid of khufu, with a tower height146.6m and a base length of 230.60m, is made of about 2.3 million stones and weighs 2.5t.. Another example is the Colossim Colosseum, which was built in 70 ~ 82 AD. Its plane is oval, its major axis 189 m, its minor axis 156.4 m and its height is 48.5 m. It is divided into four floors and can accommodate 50,000 to 80,000 spectators. It is also made of stone. In the Middle Ages, arches, coupons, domes and domes made of processed natural stones and bricks developed greatly in Europe. For example, the church of Hagia Sophia, built in Constantinople in 532-537, is 77 meters long from east to west and 7 1.7 meters long from north to south, with a dome with a diameter of 32.6 meters in the middle and a height of 15 meters. The walls and domes are made of bricks. From 12 to 15 century, Gothic architecture centered on France in western Europe concentrated on cross arches, skeleton coupons, double-heart pointed arches and pointed coupons. The temples, temples, palaces and pagodas built with brick and wood structures in feudal China reflect the achievements of ancient masonry structures in China. Among them, the brick tower is a high-rise building, such as the Song Yue Temple Tower in Dengfeng, Henan Province (see color map) is a brick single-tube structure; The Big Wild Goose Pagoda in Xi 'an (Figure 1) is also a brick single-tube structure, with a height of more than 60 meters, 1200 years. After several earthquakes, it still stands tall. The material enemy tower in Dingxian County, Hebei Province is about 84 meters high and has a brick double-tube structure. The famous Great Wall, part of which is made of sintered bricks. In terms of bridge construction, the Zhao Zhouqiao built by Li Chun in the Sui Dynasty in China is the oldest single-hole hollow stone arch bridge in China and the longest span at that time (see color map). Another example is the Hudu Bridge in Zhangzhou, Fujian, which was built in the Northern Song Dynasty. Liang Shi has a maximum span of 23 meters, Liang Kuan 1.9 meters, a thickness of about 1.7 meters and a weight of 200 tons. Three Liang Shi Bridges, as bridge decks, are the heaviest simply supported Liang Shi Bridge in ancient China. 1949 After the founding of People's Republic of China (PRC), masonry structures have been greatly developed and widely used, and brick walls are widely used in residential buildings and multi-storey civil buildings (Figure 2). Small and medium-sized single-storey industrial buildings and multi-storey light industrial buildings also often use brick walls for load bearing. After improvement, the traditional hollow brick wall in China has been used as the load-bearing wall of 2 ~ 4-story buildings. Since the late 1950s, a five-story residential building has been built with vibrating brick walls, and the thickness of the load-bearing wall is only 12cm. In the earthquake area, measures such as setting reinforced concrete seismic columns at the corner of load-bearing brick walls and the junction of internal and external vertical and horizontal walls, setting longitudinal reinforcement in hollow bricks or hollow block holes and pouring concrete are taken to improve the seismic performance of masonry structures (see wallboard structure). The span of traditional stone arch bridge is greatly increased and its thickness is relatively reduced. The span of hollow stone arch bridge with variable cross-section for highway has exceeded 100 meter. In addition, stone arch dams and aqueducts are also used. For example, Chendai Aqueduct, a large-scale water diversion project across Xiao Yun and Dongshan counties, built in Fujian, has a total length of more than 4,400 meters and a height of 20 meters. In the aspect of new structure, various types of thin brick shells have been studied and built. In terms of new materials, the sintered brick of fly ash and coal gangue, steamed fly ash brick, cinder brick and lime-sand brick have been developed. Adopt and improve silicate blocks and various load-bearing and non-load-bearing hollow bricks. In terms of new technology, various reinforced masonry structures are adopted, including prestressed hollow brick floor. Special brick structures such as chimneys are also widely used. Since 1970s, on the basis of experimental research, the design method of masonry structure has been improved. For example, according to the spatial stiffness of the building, the static calculation of the masonry structure building is carried out according to three schemes (rigid, rigid and elastic), which makes the internal force calculation of the wall under the combined action of vertical and horizontal loads closer to the actual situation. The strength calculation of compression members of unreinforced masonry changes the calculation method of dividing members into large eccentric compression and small eccentric compression (see brick walls and brick columns), which makes the calculation more convenient. Using high-strength masonry and mortar to build high-rise buildings with thin load-bearing walls is the main feature of modern masonry structures. For example, in Switzerland, an apartment building with a floor of 16 is supported by a brick wall with a thickness of 15 cm; 18-story apartment, built with special BS brick with compressive strength of 40 MPa. 19-story and 24-story tower residential buildings were built with porous bricks with compressive strength of 60 MPa and porosity of 28%. Brick walls are only 38 centimeters thick. In Britain, 1 1 ~ 19-storey apartments are built with Calculon porous bricks with compressive strengths of 35 MPa, 49 MPa and 70 MPa. A 2 1 floor apartment was built in the United States, with two 9 cm thick single brick walls with a 7 cm thick reinforced grouting layer between them. A 18-story hotel adopts grouted reinforced concrete block wall. Precast brick wall slab improves the degree of construction mechanization, with fast construction speed and easy quality assurance. The form of precast masonry walls varies with the climate, geographical conditions and architectural traditions of different countries. Most of them use sandwich structure, and a few use hollow bricks. Some are reinforced with perforated bricks and grouted in the holes; Some use lightweight concrete as heat insulation material inside. The size of the wallboard is the same as that of the room wall. Precast brick walls are mostly used in low-rise houses and high-rise apartments as load-bearing walls or non-load-bearing walls. The main trend of masonry structure development is to require that brick and block materials have light weight and high strength, and mortar has high strength, especially high bond strength, especially when high-strength hollow brick or hollow block masonry is used. Reasonable arrangement of longitudinal reinforcement in the wall is of great significance to overcome the shortcomings of masonry structure, reduce the cross-sectional size of members, reduce their own weight and speed up construction. It is also an important subject to study the design theory, improve the calculation method of component strength and improve the degree of construction mechanization.