According to experts in the industry, the regulations clearly define the objectives of urban seismic planning should be achieved, as well as the content of the model should be included. At present, China's engineering seismic defense of the overall level has improved greatly, the new project has established a "small earthquake is not bad, the earthquake can be repaired, the earthquake does not fall" defense ideas. China's current use of structural columns, ring beam constraints on the masonry structure, the level of defense has reached an advanced level in the world.
Question 2: seismic measures Seismic structural measures What are the non-structural components, such as daughter walls, enclosure walls, canopies, facades, sealing walls, etc., attention should be paid to its reliable connection and anchorage with the main structure to avoid collapse and injury in the event of an earthquake. For the connection of enclosure walls and partition walls with the main structure, their unreasonable setting should be avoided to cause damage to the main structure. The ceiling should be avoided from collapsing and injuring people during earthquakes. It should avoid affixing or hanging heavy decorations, or take reliable protective measures.
Question 3: What measures have been taken in China to prevent earthquakes? China's ancestors used to get a lot of first-hand experience in earthquake-proofing their houses. Taiwan is China's most frequent earthquake province, the ancient Taiwanese Chinese ancestors in Taiwan, when building cities, that is, already noticed that 'Taiwan (Taiwan region) rare all year round without earthquake' this characteristic, and take certain anti-seismic measures. For example, in Tamsui, some of the city walls were built with bamboo and wood. The use of bamboo and wood to build a city is not only locally sourced, economical and convenient, but more importantly, bamboo and wood are flexible, lightweight, and have high seismic performance, making them good earthquake-resistant building materials. Other earthquake areas of the Chinese ancestors also have this experience, for example, Yunnan, where earthquakes often occur, often using wattle, wood sinew grass and other materials to weave the wall, is also based on this reasoning to choose.
China's ancestors in the earth, construction, building houses, bridges, towers, temples, in order to be durable and safe and reliable, generally pay close attention to solid foundations, strong buildings, good integrity. Especially in earthquake-prone areas, they are more aware of the threat of earthquakes, careful consideration of these issues. From the examination of ancient Chinese buildings, we can see the outstanding wisdom of the Chinese ancestors in this regard, they have a very rich knowledge of earthquake-resistant design and construction. For example, the Guanyin Pavilion of the Dule Temple in Jixian County, Tianjin, built in the Song Dynasty, the wooden pagoda in Yingxian County, Shanxi, which reaches a height of more than 60 meters, and the Zhaozhou Bridge, which was built in Zhao County, Hebei Province, in the Sui Dynasty and spans across the Ordnance Survey, are about 1,000 years old today. They are located in the more seismic North China earthquake zone, after a number of different degrees of earthquake shock, to the present still standing, not only can prove that China's forefathers in the construction technology on the outstanding achievements, but also for today's study of the seismic performance of the building for the use of.
Question 4: What are the anti-seismic measures for masonry structure design The most important anti-seismic measures for masonry structure are structural columns and ring beams, structural columns and ring beams to form a frame as a whole, so as to improve the structural integrity and reduce the uneven settlement of the foundation, the chicken ring beams as far as possible in the same level, and the structural columns should be as far as possible up and down through.
Question 5: when to use seismic measures when to use seismic structural measures Seismic measures include seismic calculations of the internal force adjustment measures and a variety of seismic structural measures. Reinforced concrete houses should be based on the seismic intensity of the region and the building seismic category (A, B, C, D) to take appropriate seismic measures to determine its seismic effect.
In some cases, the seismic grade of seismic-resistant construction measures may be different from the seismic grade of seismic-resistant measures, which may be raised or lowered. Detailed reference to the "high-rise building coagulation field structure technical regulations", "building seismic design code" in the specific provisions.
Question 6: What are the seismic structural measures? Seismic measures include internal force adjustment measures and various seismic structural measures in seismic calculations. Reinforced concrete houses should be based on the regional seismic intensity and building seismic category (Class A, Class B, Class C, Class D) to take appropriate seismic measures to determine its seismic effect.
In some cases, the seismic grade of seismic-resistant construction measures may be different from the seismic grade of seismic-resistant measures, which may be raised or lowered. Detailed reference to the "high-rise building concrete structure technical regulations", "building seismic design code" in the specific provisions.
Question 7: What are the seismic measures for brick masonry structures, say more than three How to enhance the seismic capacity of masonry houses?
First, the corner of the external wall and the junction of the internal and external walls and large holes on both sides of the building (electrical) staircase between the addition of earthquake-resistant structural columns. The distance between the columns in the wall should not be greater than the height of the floor and should not be greater than 4.2 meters.
Structural columns can improve the ultimate deformation capacity of the masonry wall, enhance the integrity of the internal and external wall joints, so that the masonry wall in the strong seismic effects of the masonry collapse constraints on the collapse of the masonry to prevent the sudden collapse of the masonry, the stiffness degradation of slow. Structural column is not to increase the shear bearing capacity of the wall, mainly play a role in restraining the wall, so its cross-section is generally the same as the wall thickness, generally 240L × 240L, 4B12 reinforcement, 7 degrees over six, 8 degrees over five and 9 degrees, the longitudinal reinforcement of structural columns 4B14, hoop [email protected] / 200, corner columns, side columns and stairwells structural columns should be appropriate to increase the reinforcement. Increase the reinforcement. From the Wenchuan earthquake collapsed school building, the steel reinforcement is thin and lack of hoop, is one of the main reasons for its collapse. Structural columns and walls at the connection of the wall masonry hewing, first masonry wall after pouring concrete structural columns, along the height of the wall at intervals of 500L set 2A6 tie bars. The longitudinal tendons of the structural column should pass through the ring beam to ensure its up and down continuity.
The use of concrete small hollow blocks should be set up reinforced concrete core column, core column cross-section should not be less than 120L × 120L, concrete strength grade should not be less than C20. core column in the wall body uniform arrangement, the net distance between the electric should not be greater than 2 m.
Secondly, the core column should be set up at intervals of 500 L, to ensure the continuity of the top and bottom.
Secondly, the ring beam. The role of the ring beam is to hoop the floor, through the wall, increase the integrity of the building, play the brick wall in the plane of the shear bearing capacity, improve the horizontal stiffness of the building cover, to limit the development and extension of the wall diagonal cracks, to improve the vertical stiffness of the house, to prevent the building from settling unevenly, to resist earthquakes and other vibrations on the building's adverse effects.
The lateral force-resisting system with reinforced concrete borders composed of ductile members such as ring beams and structural columns forms a division and encirclement of the masonry structure, and although the bearing capacity of the whole masonry is not much higher, the integrity of the masonry structure can be strengthened, and its deformation capacity, energy-consuming capacity, and collapse prevention capacity are greatly improved.
It is appropriate to set ring beams at each level, and the cross-section and reinforcement of ring beams at the foundation, outer wall and roof should be increased, and the ring beams should be pulled through.
If the 60L high reinforced concrete belt is added in the middle of the wall, the area surrounded by structural columns, ring beams and reinforced concrete belt is smaller, which can significantly improve its seismic performance.
Third, the use of reinforced masonry. Horizontal reinforced masonry wall bearing capacity increases with the increase in the rate of reinforcement, and its deformation capacity is also proportionally increased, more than double the deformation capacity than unreinforced masonry wall. But this is obviously to increase the cost and cost.
The four flat and elevation arrangement rules, so that the force of each part is uniform, reducing the weak links. Due to the randomness and complexity of the seismic effect, from the previous earthquake damage analysis, the body shape of the irregular structure earthquake damage is heavier. If it is impossible to change the layout of the building, then the complex building can be divided into regular units through the installation of seismic joints to reduce the earthquake damage. Stairwells should not be set at the end and corner of the house, because the corners of the outer walls at the two ends of the house are easy to be damaged, and the staircase at the end of the house is not conducive to the evacuation of people. The horizontal wall of the stairwell is more seriously damaged than other horizontal walls due to the horizontal seismic action induced by the diagonal bracing of the stair treads. Stairwell wall should be through the full width of the house.
Fifth, control the height of the house, the number of floors, floor height and aspect ratio, for hospitals, teaching buildings and other open buildings, the total height, the total number of floors should be reduced, the floor height should not exceed 3.6 meters.
Six structural system to be reasonable, should give priority to the use of vertical and horizontal walls *** with the load-bearing structural system. The Wenchuan earthquake collapsed the majority of the school building group is hollow prefabricated panel floor cover system, prefabricated hollow plate has a major defect is to make the brick wall unidirectional force, that is, the longitudinal wall load-bearing wall, horizontal wall for non-load-bearing wall, shear load bearing capacity is reduced. Longitudinal wall due to the plate and the wall is not a reliable connection and the collapse of pieces, floor falling. Longitudinal and transverse walls *** with the load-bearing houses can both relatively direct transmission of lateral seismic effects, but also directly or through the connection of longitudinal and transverse walls to transmit seismic forces. Longitudinal and transverse wall arrangement should be uniform and symmetrical, uniform width. In-plane alignment through, up and down continuous, reduce the brick walls, floor slabs and other force components of the intermediate transmission links, so that the transmission path is simple, clear and reasonable, without interruption. Floor should have a greater horizontal stiffness, try to use cast-in-place reinforced concrete floor, should not use prefabricated floor.
Question 8: What is the difference between seismic measures and seismic construction measures? Code of internal force adjustment includes what 1, "seismic measures" and "seismic structural measures" are both related and different concepts. "Seismic measures" in the definition of "including seismic structural measures", on the surface seems to be directly understood as they should correspond to the same seismic intensity requirements, but the actual situation is not so. The intensity of defense corresponding to "seismic structural measures" in "seismic measures" and the intensity of defense corresponding to other parts of "seismic measures" can be different.
The specific differences between seismic-resistant measures and seismic-resistant structural measures are as follows:
1.1 Seismic-resistant measures (specification 2.1.9): In addition to the calculation of seismic effects and the calculation of resistance, the seismic-resistant design content, including seismic-resistant structural measures.
1.2 Seismic structural measures (specification 2.1.10): according to the seismic conceptual design principles, generally do not need to calculate the structural and non-structural parts of the structure must be taken in a variety of detail requirements.
2, the specification of the internal force adjustment include:
2.1, high-rise building structure under the action of the load, after the structural analysis and calculation, the standard value of the internal force of each component, and then a variety of corrections and adjustments to get the design value.
2.2, internal corrections and adjustments are generally divided into two categories. The first category belongs to the structural adjustment of the overall internal force, mainly including: the minimum floor seismic force limit control, weak layer seismic shear amplification, frame shear structure in the frame part of the total seismic shear adjustment and frame support conversion layer in the frame strut seismic shear adjustment, etc.
2.2, internal force correction and adjustment is generally divided into two categories.
2.3, this type of adjustment is characterized by some provisions of the code is not satisfied before the adjustment, and the adjustment of the part and the size of the adjustment factor generally need to be determined after the calculation. The second category is the adjustment of internal force or combination of internal force of members of beams and columns. This type of adjustment is clear, the size of the adjustment factor can be determined according to the seismic grade.
Question 9: What is the difference between seismic measures and seismic construction measures? What are the internal force adjustments included in the code? In the "building seismic design code" (GB 50011-2001) in the "earthquake measures" and "seismic construction measures" have different definitions. Seismic measures (Article 2.1.9 of the specification): Seismic design contents other than calculation of seismic effects and resistance calculation, including seismic structural measures. Seismic structural measures (specification 2.1.10): according to the seismic conceptual design principles, generally do not need to calculate the structural and non-structural parts of the structure must take a variety of detailing requirements.