Due to the unpredictability of earthquakes, it is difficult to accurately predict the seismic characteristics and basic parameters of high-rise building structures in the design process, and it is difficult to make high-rise building structures have good seismic performance only through calculation, which requires every structural engineer to pay attention to the seismic conceptual design of building structures. Therefore, in the seismic design of high-rise buildings, we should pay attention to the following points:
1) floor plan of building structure. The plane layout of the building structure is an important factor that affects the earthquake resistance of the structure, and the reasonable plane layout of the building is very important for the design of the building structure. A large number of earthquake damages show that building structures with simple plane layout, regular symmetry, uniform distribution of mass and stiffness and clear transmission path are not easy to be damaged during earthquakes. Regular structure can accurately predict the action effect and response of the structure during earthquake, and it is easier to take effective seismic measures and corresponding structural measures to strengthen its seismic performance. On the contrary, it is difficult to estimate the seismic effect of structures with complex, asymmetric and irregular plane layout. Therefore, the Code for Structure of High-rise Buildings stipulates that regular structure should be adopted, rather than seriously irregular structure.
2) System selection of building structure. In the structural design of high-rise buildings, the structural system with multiple lines of defense is given priority. Such as frame-shear wall structure, shear wall structure and tube structure. These three structures can be used as the first choice system for high-rise buildings in earthquake areas. When the building height is not high and the number of floors is small, the frame structure can be used. However, when the building is located in the earthquake area and the height is high, the frame structure and slab-column shear wall structure should be avoided. Because earthquakes are destructive, lasting for a long time and reciprocating many times, they will cause cumulative damage to buildings. When a single structural system is damaged in an earthquake, it is easy to cause houses to collapse and endanger people's lives and property. When the structural system has multiple lines of defense, when the first line of defense is destroyed in the earthquake, the subsequent lines of defense can still resist the impact of the earthquake, which can prevent the collapse of buildings to the maximum extent, give people enough time to escape and ensure people's life safety. Therefore, multiple lines of defense in seismic design of high-rise buildings are necessary for seismic design.
3) structural weak layer. When the lateral stiffness distribution of the building structure is uneven, the vertical lateral resistance members are discontinuous, and the bearing capacity of the floor suddenly changes, it is easy to produce weak layers. The weak layer is the first part to be destroyed in the earthquake. Therefore, for structures with obvious weak layers, corresponding seismic structural measures should be taken to improve their seismic capacity. The actual bearing capacity of structural members is the basis for judging the position of weak layers. It is an important means to improve the seismic performance of the structure by consciously and purposefully controlling the position of the weak layer to make it have enough deformation ability and not transferring the weak layer.
2 common problems in seismic design of high-rise buildings
1) Foundation problems of high-rise buildings. In the structural design stage of high-rise buildings, there should be a perfect geotechnical investigation report to provide basic design basis for structural engineering. The location of the building structure should be selected in a favorable area with relatively stable bedrock, open and flat, hard or dense soil layer, and should not be built in an unfavorable area prone to landslide, collapse, collapse and debris flow, or in an earthquake-resistant dangerous area. The construction of favorable areas is very beneficial to the earthquake resistance of buildings. Sometimes, due to the construction period requirements of the construction unit, after the scheme is determined, the designers directly enter the construction drawing design stage, thus ignoring the selection of geotechnical investigation materials and sites, which brings unnecessary trouble to the follow-up work.
2) Plane layout of high-rise building structure. In order to pursue the beautiful facade effect, high-rise buildings are designed as irregular and asymmetrical structures with large cavities or holes, which is very unfavorable for earthquake resistance. Therefore, before the architectural scheme is formally determined, structural engineers should put forward their own opinions on architectural layout, modeling and other contents, communicate with architects in time, and try to choose a plane layout with plane symmetry, vertical rules, unified quality, stiffness and bearing capacity, which is very beneficial to earthquake resistance.
3) The height of high-rise building structure. Nowadays, the height of high-rise buildings is getting higher and higher, and even many super-high-rise buildings have appeared, which puts forward higher requirements for the professional knowledge of structural engineers. Different heights correspond to different structural systems, which are clearly stipulated in the specification. Once the structure exceeds the limit height specified in the code, it should be more strictly calculated, analyzed and studied through special inspection and demonstration.
4) Selection of seismic fortification level of high-rise buildings. Seismic grade is an important basis for seismic design of structures. Improper selection of seismic grade will bring many hidden dangers to the safety of buildings and unnecessary waste to the project cost. The seismic grade is comprehensively evaluated according to the site category, seismic fortification intensity, building height, structure type and other factors of the house. Every structural engineer should be familiar with the knowledge of structural seismic conceptual design and specification. If the seismic grade is improved, it will be improved, and if it is reduced, it will be appropriately reduced.
5) Reasonable application of computing software. In the seismic design of high-rise buildings, formal structural design software should be used, and all parameters in the software can correctly reflect the characteristics of the building. Structural engineers can correctly analyze the results of structural software calculation and make correct judgments. But sometimes computer design will bring an illusion to structural engineers, and some structural engineers often rely too much on the calculation results, thus reducing the conceptual learning of structures. Once the wrong calculation parameters are selected, it will lead to problems in structural design and affect the safety and economy of the structure. Therefore, structural engineers should strengthen their business study and understanding of seismic conceptual design, master relevant structural conceptual design skillfully, and choose the best structural design scheme according to their professional knowledge and calculation results.
Today, with the rapid development of modernization, the development of high-rise buildings has also advanced by leaps and bounds. The scale and height of buildings with unique and novel architectural shapes are getting bigger and bigger. With the further development of the construction industry, the materials, forms and overall mechanical models that meet the needs of high-rise buildings will tend to be complex and diversified, which requires every structural engineer to have excellent professional knowledge, clear conceptual analysis and the ability to handle problems, and continue to explore and study, so as to contribute to the development of China's construction industry.
The above papers on seismic design and high-rise buildings were collected by Zhong Da Consulting Company.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd