[摘要] 采用脈動(dòng)法對(duì)兩棟鋼框架結(jié)構(gòu)房屋的動(dòng)力特性進(jìn)行了現(xiàn)場(chǎng)實(shí)測(cè),...（[abstract] the dynamic characteristics of two steel frame structures are measured by pulsating method.）

1、Good is good, but better carries it.精益求精，善益求善。摘要 采用脈動(dòng)法對(duì)兩棟鋼框架結(jié)構(gòu)房屋的動(dòng)力特性進(jìn)行了現(xiàn)場(chǎng)實(shí)測(cè),.（abstract the dynamic characteristics of two steel frame structures are measured by pulsating method.）摘要 采用脈動(dòng)法對(duì)兩棟鋼框架結(jié)構(gòu)房屋的動(dòng)力特性進(jìn)行了現(xiàn)場(chǎng)實(shí)測(cè),摘要 采用脈動(dòng)法對(duì)兩棟鋼框架結(jié)構(gòu)房屋的動(dòng)力特性進(jìn)行了現(xiàn)場(chǎng)實(shí)測(cè),.（abstract the dynamic characteristics of two steel frame

2、structures are measured by pulsating method.）abstract the pulsating method is adopted for the dynamic performance of the steel frame structure house two measured on site, through the comparison of the measured results and finite element calculation results, the research on the floor and filler wall

3、effect on the dynamic characteristics of the pure frame structure steel structure. The test and analysis results show that the vibration type of the pure frame house of multi-layer steel structure is shear type. The damping ratio is between 2% and 5%; The filling wall significantly reduces the self-

4、vibration period of the pure frame of steel structure, so that the measured period is less than the calculation period, and the calculation cycle is reduced when the seismic calculation is calculated. The periodic reduction coefficient is given for reference in engineering design.Keywords: dynamic c

5、haracteristics; The measured; Pulsating method; The periodic reduction factor1 words beforeThe dynamic characteristic of structure refers to the self-vibration period, vibration mode and damping of the structure, which is one of the basic properties of the structure itself, and is the basic paramete

6、r for seismic calculation. In general, the structure of the natural vibration period and vibration mode can be determined by calculation, but as a result of calculated without consideration of the structures such as floor slab and infilled wall of structure stiffness, the influence of the computatio

7、n cycle is often greater than the measurement cycle, aseismic calculation need according to the actual period of the same building to reduction of computation period, otherwise, calculate the smaller earthquakes. In addition, the damping of structure can only be obtained by actual measurement. There

8、fore, field measurement is the basic way to understand structural dynamic characteristics.The construction steel structure in our country is mainly used in the field of industrial buildings, civil construction areas mainly masonry structure and reinforced concrete structure, the two kinds of structu

9、re dynamic characteristics of the measured data is more, the study also more deeply, the code for seismic design of buildings 1 (GB 50011-2001) the relevant provisions of the article 5.2.1 to masonry structure and the "technical specification for concrete structures of tall building" 2 (JG

10、J3-2002) article 3.3.17 cycle reduction factor of reinforced concrete structure regulation, all is the embodiment of the relevant research results.Comparatively speaking, the measured data of the dynamic characteristics of steel structure in our country are relatively few. The literature 3 the measu

11、red dynamic characteristics of jingguang center, Beijing literature 4 the measured the dynamic characteristics of the new otani center in Beijing, the two buildings are steel frame - supported shear wall structure and pure frame structure. Literature 5 and 6 are given respectively in shenzhen diwang

12、 building (steel frame - reinforced concrete core tube structure), the dynamic characteristics of the measured values, the test method is slightly different, but the test results are basically identical. The paper 7 shows the real value of the vibration characteristics of four supertall buildings in

13、 the Shanghai area, two of which are mixed in steel and concrete, and two are reinforced concrete structures. The literature 8 collects the actual measurement and calculation of 37 high-rise steel structures, which is limited to the conditions at that time. Only two buildings are domestic buildings,

14、 namely Beijing Beijing center and the center of the fufu palace.At present, with the development of our country civil steel structure building, in addition to the high-level and super-tall building, steel structure in multistoried building more and more, this to study the dynamic performance of the

15、 steel structure building provides objective conditions; At present, on the other hand, the steel structure housing cycle reduction factor, in the "technical specification for steel structure of tall buildings" 9 (JGJ 99-98) the provisions of article 4.3.6 is general, not to distinguish th

16、e structure form and the filler wall type, shall be 0.9. In actual engineering, the filling wall type is many, and the contribution of structural rigidity is different, and the rationality of this rule needs further examination.In this paper, by using two method of pulse characteristics of pure fram

17、e steel structure house has carried on the field measurement, and through the field measurement results are compared and finite element calculation results, the floor and filling wall effect on dynamic characteristics of the steel frame structure, and the cycle time reduction factor of pure steel st

18、ructure framework are discussed in this paper.The actual measurement and calculation of the dynamic characteristics of the pure frame house of steel structureAnalytical method2.1 measurement of dynamic characteristics(1) test basis: construction earthquake resistance test method (jgj101-96);(2) test

19、 instruments and equipment: 941B sensor, 941 amplifier and ws-usb data collection analyzer;(3) test principle: the building of each measuring point measured by the speed of response, displacement response by integral transform from the schedule, then through Fourier transform to get Fourier displace

20、ment spectrum, then determine the structure of the former several order natural frequency and vibration mode, damping ratio of the structure of half power method is used to get.2.2 finite element analysis model of dynamic characteristicsIn order to study the influence of floor slab and filler wall o

21、n structural dynamic characteristics, the self-vibration period and mode of the structure are calculated using the space structure analysis and calculation software ETABS8.4.5. Three calculation models are considered in the calculation:Model 1: when modeling, only the stiffness of the main structure

22、 consisting of the frame beam and the frame column is considered, i.e. only the frame beam and the frame column are input, and the beam column is calculated using the space beam unit.Model 2: not only consider the stiffness of the main structure of the frame and frame column, but also the stiffness

23、of the floor. This model not only input beam column, but also input floor board. The beams are simulated with the space beam element and the floor is simulated by shell element.Model 3: when modeling, not only the stiffness of the frame and frame columns, but also the stiffness of the floor and the

24、wall. When modelling, not only input beam column, floor, but input fill wall. The beams are simulated with the space beam element, the floor slab and the filling wall. In order to compare with the measured value, the floor living load is not considered, and the permanent load on the floor only consi

25、ders the structure of the floor.The results of field measurement and finite element calculation3.1 measurement and calculation of the 3rd floor of panzhihua village3.1.1 engineering introductionThe building area is about 5000m2, with a building area of about 5000m2, the six layers and the seventh fl

26、oor. The building plane size is 58.100 m x 14.350 m, the floor height is 2.800 m, and the total height is 20.500 m. Seismic fortification intensity of 7 degrees, design basic earthquake acceleration value of 0.10 g, the second group, class field, the basic wind pressure 0.3 kN/m2.The upper structure

27、 of the residential building adopts the steel frame structure system, the column net is 4.5 m by 3m, 4.4.5 m x 4.5 m, and the steel beam with 250mm x 160mm welding rectangular steel tube and 250mm x 150mm welder, Q345B steel. In order not to expose the beam, the steel column moves along the wall. Th

28、e floor slab is made of 120mm thick C30 reinforced concrete cast-in-place floor and connected with steel girder. The enclosure structure is filled with hollow brick block, and the outer wall and the partition wall are 200mm thick.The interior partition walls are 100mm thick. The standard layer layou

29、t is shown in figure 1.INCLUDEPICTURE " * MERGEFORMATINETThe interior layer of the court was made from top to bottom, which was filled with soil, silt and silt clay, and gravel and sandy soil, and mixed rocks, and the interior of the site was buried deep 9.00 15.40 m, which is a kind of porous

30、diving. Basis using strip foundation under column, for the first (1) layer of filled soil, filled soil layer thickness is 11.60 21.10 m, through the study of the dynamic compaction of foundation soil reinforcement, field dynamic compaction standard value of subgrade bearing capacity is 180 kPa, dyna

31、mic compaction effective influence depth is 6.5 m.3.1.2 test results(1) location: in the middle unit of the building, a measuring point is arranged on each floor. The first floor of the observation point is: 1, 3, 4, 5, 6 and 7; The 2nd floor of the measuring point is: 2, 3, 4, 5, 6 and 7.(2) test w

32、hen the structure of the state: the measured in April 2003, when the experiment building is the main structure completed, exterior and interior wall has been laying completed, is in the stage of decoration and equipment installation.(3) the measured results: after the analysis of experimental data,

33、the transverse and longitudinal self-vibration period and damping of the structure are shown in table 1, and the modes are shown in FIG. 2. Based on the measured model, the vibration curve of no.3 is convex and has the characteristics of shear deformation, and the structure is mainly shear deformati

34、on.INCLUDEPICTURE " * MERGEFORMATINETINCLUDEPICTURE " * MERGEFORMATINET3.1.3 finite element analysis resultsThe results of self-vibration period and mode of vibration are shown in table 2 and figure 3. As can be seen from table 2, the calculation results of model 3 are relatively close to

35、the measured self-oscillation period. The mode of model 1 and model 2 are basically consistent, and model 3 is close to the actual vibration mode.INCLUDEPICTURE " * MERGEFORMATINET3.2 the measurement and analysis of the no.b2 building of "xin lai Eiffel garden"3.2.1 engineering profil

36、eShandong jinan "letter lai? Eiffel garden" B2, multi-storey steel structure residential building area of 5828 m2, underground, five plus step 6 layers on the ground, the height of 2.8 m, cornice height of 15.000 m, building plane size 73.550 m * 11.750 m. Seismic fortification intensity o

37、f 6 degrees, design basic earthquake acceleration of 0.05 g, design earthquake are grouped into the second group, site soil class. Basic wind pressure 0.45kn/m2, basic snow pressure 0.30kn/m2.The upper structure of the residential building adopts the steel frame structure system, and the frame colum

38、n adopts the outsour-type rigid socket. The steel adopts Q345B, the basic external wall and roof concrete are C30, the floor C25, the steel bar is HPB235, HRB335. The column section is H shaped steel HM294 x 200 x 8 x 12, beam is H shaped steel HN346 x 174 * 6 x 9, HN300 x 150 x 6.5 x 9, the beam co

39、lumn connection adopts rigid node. The floor board adopts 100mm thick concrete of concrete,The roof is made of light steel roof. The external wall adopts 130mm thick composite light insulation wall board, and the inner partition adopts 75mm thick composite light insulation wall. Two 200mm thick cera

40、mic concrete hollow blocks are used for partition walls and staircases and basement partitions. The standard layer structure layout is shown in figure 5.INCLUDEPICTURE " * MERGEFORMATINETGround layer from top to bottom on the mainland, respectively (1) 0.5 3.5 m thickness of filled soil, (2) th

41、e thickness of 4.5 7.6 m silty clay clay, (4), (3) 0.3 3.2 m thickness 1.5 5.7 m thickness silty clay, (5) 9.10 15.50 m thickness silty clay, 6 0.7 3.6 m thick weathered gabbro, 7) 0.8 5.5 m thickness strong weathering gabbro, end of medium weathering gabbro, embedded depth of groundwater is 1.90 2.

42、70 m, buried shallow, pore type of diving. Based on the foundation of the beam rafting board, the strength layer is the first layer powder clay, the bearing capacity of the foundation is 100 kPa, and the base is laid with 300 thick layers of sand and stone bedding.3.2.2 test measurement(1) location:

43、 in the middle unit of the building, a measuring point is arranged on each floor. The floors of the measuring points are 1, 3, 4, 5, 6 and 6.(2) test when the structure of the state: the measured in December 2003, when the experiment building is the main structure completed, exterior and interior wa

44、ll has been laying completed, is in the decoration and equipment installation phase;(3) the results of the measured results: after the analysis of the experimental data, the horizontal and vertical self-oscillation period and the damping of the structure are shown in table 3, and the vibration patte

45、rn is shown in figure 4. From the measured model, the vibration curve of the B2 residential building is convex and has the characteristics of shear deformation, and the structure is mainly shear deformation.INCLUDEPICTURE " * MERGEFORMATINETINCLUDEPICTURE " * MERGEFORMATINET3.2.3 finite el

46、ement analysis resultsThe results of self-vibration period and mode of vibration are shown in table 4 and fig.5. As you can see from table 4, the result of model 3 is closer to the measured self-oscillation period. From the mode of vibration mode, the mode of model 1 and model 2 is basically consist

47、ent with the vibration mode of model 3.INCLUDEPICTURE " * MERGEFORMATINETThe periodic reduction factor of the pure frame of steel structureBased on the dynamic characteristics of the two steel structure, the results can be obtained:The ratio of calculation cycle and measured period of the third

48、 building of panzhihua residential area is:Horizontal: 1.7163/0.366 = 4.69Vertical: 1.7499/0.427 = 4.10The ratio of the calculation period and the measured period of the no.b2 building in jinan "xin lai Eiffel garden" in jinan is:Horizontal: 1.0565/0.281 = 3.76Vertical: 1.6926/0.315 = 5.37

49、The ratio of the calculation period of two houses to the measured period is 4.48.However, according to the statistical analysis of 8,The ratio of the calculation period of the high-rise steel structure to the measured period is 1.24, and the ratio of the calculation period and the measured period of

50、 the two houses in this paper is quite different. Investigate its reason, on the one hand is due to the large high-rise steel structure, width and depth, interior wall and most of the use of lightweight partition number less, exterior wall with curtain wall, filling wall has little effect on stiffne

51、ss of the structure. Panzhihua welcome garden district no. 3 floor and jinan "letter lai? Eiffel garden" B2 building residential building, partition wall is more, studio, the depth is relatively small, and adopted its own large stiffness of masonry structures and precast aerated concrete w

52、all panel structure, have a great effect on stiffness of the structure, calculation and analysis also shows that this; On the other hand, there may be more statistics in 8, but only two of them are domestic buildings, and the building partition system does not adequately reflect China's national

53、 conditions. Literature 4, for example, the Beijing new otani center (steel frame) of experimental analysis shows that although the two directions of computing cycles are basically the same, but in horizontal and vertical calculation cycle and the ratio of the measured period was 1.04 and 1.04, resp

54、ectively, the differences.Due to the measurement cycle reflects the structure under slight vibration cycle, deformation of the structure under the effect of more severe earthquake far more, filler wall unstructured component may have slight damage, such as stiffness is reduced, cycle will be extende

55、d. Some studies have shown that 11 13, the self-vibration period of the building under earthquake is generally 1.10 2.0 times of the measured period before the earthquake, and some even reach four times. The ratio of the period of steel structure earthquake to the measured period is larger than that

56、 of masonry structure and reinforced concrete structure. If the period of the earthquake is considered to be twice as long, the periodic reduction coefficient is 2 x 1/4.48 = 0.45. Of course, due to the lack of measured data, the periodic reduction coefficient given here is for reference only.5 conc

57、lusion(1) the measured vibration mode of the pure frame structure of multi-layer steel structure is the shear type, and the structure is mainly shear deformation.(2) the damping ratio of the house is between 2% and 5%;(3) the filler wall stiffness big, quantity of multi-layer steel framework structure building measured natural vibration period is shorter, is far less than the pure frame structure to calculate the cycle, the cycle time reduction factor should not be greater than 0.5, otherwise to c