For long-span structures, such as long bridges and underground pipelines, the loss of correlation of ground movements during an earthquake should be taken into account for seismic analyses. In this paper, longitudinal seismic responses of underground pipelines, which are modeled as distributed mass pipelines with fixed-fixed ends, are derived with a pseudo-excitation method. The seismic excitation is considered a random process and partially correlated. The root mean square (RMS) axial stresses and displacements are compared between pipelines with fixed-fixed and free-free ends. The effects of slenderness ratio and pipe thickness on the seismic responses are also investigated. The results show that the seismic response of fixed-ends and free-ends pipelines matches well when the slenderness ratio is large enough. On the contrary, the boundary conditions should be taken into account for short pipes or pipes with a large external radius. The RMS axial stresses at the midpoint of the pipes decrease with the increase of pipe thickness, and no significant difference is found between fixed-ends and free-ends pipes.

To investigate the dynamic characteristics of the horizontally encrypted column network spring vibration isolated turbine-generator foundation, according to similarity theory, a 10:1 scale model of the horizontally encrypted column network spring vibration isolated turbine-generator foundation, including two condensers, was tested on site, and the dynamic characteristics of the model are analyzed by excitation method, and the natural frequencies, mode shapes and damping ratio of the integral structure are acquired. This study shows that the first two mode shapes of the turbine-generator foundation are translation and torsion, the high mode shape is accompanied by column-end swing and local distortion; the condenser is more stable in the integral structure; the natural frequency of this foundation is higher than the dual-row column spring vibration isolated turbine-generator foundation, and it is significantly lower than rigid foundation, and the mode shape distribution is different from them.

Buried pipelines, such as water supply and power transmission systems, play a vital role in daily life. Seismic resistance of the pipeline systems is a very important research topic because of its tremendous impact during and after earthquake. This paper reviewed the investigations from the last several decades of the dynamic behavior of underground pipelines. Nine topics were included: theoretical evaluation of seismic response of buried pipelines, modeling for soil-structure interaction/fluid-soil-pipe interaction for buried pipelines, analysis of pipeline seismic response due to permanent ground deformation, seismic response of pipelines passing through liquefication areas, finite-element analysis of buried pipelines, experimental studies of seismic response of underground pipelines, seismic damage assessment, seismic behavior of pipeline networks, and seismic performance of joints and bend regions. It was found that more and more studies have been based on finite-element analysis considering that the computer technology has been well developed and finite-element analysis is much less expensive than experiments. Although common damages during earthquakes are caused by the wave propagation effect, the most severe damages are caused by permanent ground displacement, such as fault movement. The studies of pipelines subjected to fault movement were reviewed, but few seismic damage assessments were found that focused on the damage caused by fault movement. (C) 2020 American Society of Civil Engineers.

In order to study seismic behavior of half-speed turbine-generator foundation under horizontal earthquake loading in different directions, the 1/10 scaled model was designed and fabricated. The rigid foundation of half-speed turbine-generator sets can be seen as a complex space frame system. The tests were conducted under eight earthquake waves in two directions separately. The loading directions were along the axis of longitudinal and transverse. The seismic response of displacement and story drift was investigated by a pseudodynamic test. The hysteresis behavior and crack propagation were analyzed. From the research, it is shown that the maximum displacement of the foundation under the earthquake of intensity 7 is 15.20 mm (longitudinal), basically in the range of elastic deformation. The seismic response of earthquake input in different directions is obviously different. Under the same earthquake input, the seismic displacement along the axis of longitudinal is larger than that of transverse. Under the rarely earthquake of intensity 8, the foundation still keeps good working condition. The maximum elastic-plastic story drift is 1/191 under the limit value 1/50 provided in the Code for Seismic Design of Buildings. The deformation capacity of the structure meets the requirements of the current seismic design code of China.

对设置不同厚度微孔混凝土保温层复合板的热工性能和200mm厚微孔混凝土砌块墙体的隔声性能进行试验研究.结果表明,表观密度为766kg/m3的微孔混凝土的导热系数为0.223W/(m·K);承载层厚度为60mm,保温层厚度分别为150,200mm复合板的平均传热系数分别为1.35,0.94W/(m2·K),满足JGJ134—2010《夏热冬冷地区居住建筑节能设计标准》中外墙的热工性能指标限值要求;200mm厚微孔混凝土砌块墙体的计权隔声量RW为45dB,满足GB50118—2010《民用建筑隔声设计规范》中相邻两户房间之间的隔声性能要求.

为推广落实再生混凝土在实际工程中的应用,在使用4～8 mm小粒径再生粗骨料的条件下,基于Bolomey理想级配曲线,通过6组试验,得出强度等级C35、坍落度180 mm再生混凝土配合比为:水泥:水:砂:RCA:SP=1:0.6:3.75:1.81:0.005,实现了再生混凝土在小截面混凝土构件上的工程应用.并通过与欧洲规范对比,修正了普通混凝土早期抗压强度模型应用于再生混凝土时的系数,即s=0.44.

The basic mechanical properties of ceramsite cellular concrete (CCC) with spherical and cylindrical ceramsite as coarse aggregate were studied respectively,and the relationship between apparent density and mechanical properties is discussed,the quantitative relationship between axial compressive strength,tensile strength,deformation properties and cube compressive strength was analyzed as well.The results show that the apparent density of CCC is from 600 kg/m3 to 1 200 kg/m3,the compressive and hydraulic ratio is 7%~15%, the flexural ratio is 5%~13% ,the elastic modulus is 6×102~7.5×103N/mm2 and Poisson's ratio is 0.18~0.31.Under this experimental condition,CCC with spherical aggregate is superior to that with the cylindrical ceramsite in mechanical performance.

Based on a large turbine-generator foundation in the actual project, dynamic characteristics of 1:10 model of this foundation are obtained from modal analysis of the random excitation method. Natural frequency, mode shapes and damping ratio of the structure are acquired. The results of basic vibrating displacement under operation condition are obtained according to the the vibration analysis of response prediction. Besides, using hammer pulse method to actually measure the support dynamic stiffness of bearing pedestal of this turbine-generator, to examine whether the support dynamic stiffness of this foundation meet the requirements of the current specifications. Finally, the results shows that dynamic characteristics of the foundation perform well and the structural design is safe and reasonable.

为评价实际工程中的1000MW汽轮发电机组基础的振动特性,本文采用模型模态试验方法进行研究.首先以该基础为原型基于相似原理制作1/10缩尺模型,并使用激振器空间激振方法对模型进行模态测试.然后采用LMS Test Lab系统进行模态分析,得到原型在0～70Hz范围内的各阶振型、自振频率、阻尼比,最后通过振动理论预测出原型强迫振动动力响应.试验结果表明,该基础整体振动的振型占主体地位,在机组工作转速范围内最大振动速度均方根值远小于3.8mm/s的限值,最大振动线位移中间平台部分测点超出0.20mm的限值,因而建议加强中间平台的振动控制.

The pseudo-dynamic test was conducted on the turbine-generator spring vibration isolation foundation to study the spring deformation under action of horizontal earthquake. The test model is 1:8 according to the similarity relation conversion. By experimental results, the story drift of spring vibration vibrating foundation is under the limit value provided in Code for seismic design of buildings. With the existing of spring vibration isolation, the foundation has good performance in the horizontal earthquake. The displacements of columns are no longer equal because of the spring vibration isolation. The earthquake force is redistributed to the columns so that each one can fully play its role.

For the study of the equivalent elastic modulus of reinforced concrete members under different stress states,based on the e-quivalent stiffness principle,the equivalent elastic modulus of the Axial compression member,the bending member and four kinds of ec-centric compression members with different eccentricity were calculated.The results show that the equivalent elastic modulus of the mem-bers are different owing to different stress states,but there is a linear relationship between the equivalent elastic modulus and the reinforce-ment ratio no matter what member.

The 1:8 modal tests were conducted on 1000MW turbine generator spring vibration isolation foundation. According to the similarity relation conversion, the displacement response and spring deformation of the model were investigated by pseudo-dynamic test. In the pseudo-dynamic tests, 7 degree frequent and rarely earthquake tests were carried out respectively. By experimental results, the foundation has good working performance, and the story drift is under the limit value provided in Code for seismic design of buildings.

采用热流计法在相同条件下,同步测试了内保温、外保温和夹层保温轻质复合板的温度变化和热流,计算了各自的传热系数并进行了对比分析.结果表明,内保温和外保温复合板的传热系数相当,而夹层保温复合板的传热系数相对较大.其中,60mm厚结构层+100mm厚保温层的复合板传热系数约为1.0W/(m2·K),基本满足公共建筑节能设计标准有关夏热冬冷地区的限值要求.

The pseudo-dynamic seismic tests and lateral cyclic load tests for tie-columns and ring-beams confined masonry structure according to the seismic requirements and masonry structure strengthened with reinforced concrete beams and columns have been carried out. Cracks propagation pattern, hysteretic curves, skeleton curves and stiffness degradation curves were compared and analyzed. The results from tests show that the brick masonry building with tie-columns and ring-beams has good ductility. The brick masonry building strengthened by RC beam-column can keep bearing capacity after serious cracking of masonry wall. The brick building strengthened by RC beam-column can satisfy the requirements of the seismic fortification criterion. The RC beam and column can be used as reinforcement measure to improve the seismic performance of brick buildings.

A 1:2 reduced scale ordinary masonry structure model with no seismic fortification measures was designed in this paper. After 6 degree rare earthquake, this model has been reinforced by additional concrete beams. Comparedwithresilience, displacement, acceleration and other characteristic in the case of before and after the reinforcement in 6 degrees rareof seismic action. By undertaking quasi-static test with the masonry structure after reinforcement, studied the ultimate bearing capacity, hysteretic curves, skeleton curves, stiffness degradation curve and carry out cracks, then compared with the skeleton curve in the previous studies.

In this paper, the model tests of 7 degree frequent earthquake, 7 degree fortification earthquake and 7 degree rarely met earthquake are carried out by using the seismic ground motion parameters of a design reference period of 60 years. Displacement of platen and columns, restoring force of foundation and reinforcement strain are obtained, as well as the position and development of cracks. The research shows that the spring vibration isolation foundation has good working performance under earthquake, and the vibration springs has certain effect of decreasing vibration.

A 1:8 foundation model was designed and fabricated based on a spring vibration isolation steam-turbine generator foundation. The gravity was simulated through the hydraulic servo loading system, and the pseudo dynamic tests were carried out under the action of two different 7th intensity medium earthquakes and a 8th intensity rare earthquake. The results indicate that, under the action of different earthquakes, the acceleration amplification factors are all smaller, the inter-story drift angles of each story are in accordance with the specification requirements. Cracks appeared under the action of 8th intensity rare earthquake, but no penetrating cracks. Springs have played a good role in vibration isolation, and no relative slippages between the spring vibration isolator and the capital of columns.

针对多自由度弹簧隔振基础的隔振效率计算方法存在的缺陷,提出了一种隔振效率的测试方法,设计制作了1∶8的汽轮发电机基础的试验模型.将测试结果与简化计算方法进行了对比,分析了两者存在差异的原因,并对汽轮发电机基础的弹簧隔振效率进行了评价.

For investigating the influence of reinforcement ratio on the elastic modulus of reinforced concrete component,6 groups rein-forced concrete components and 2 groups specimens with different reinforcement ratio were made. The deformation was measured under a specified load,then the elastic modulus was determined by the finite element analysis software based on the known deformation. The relationship between the reinforced ratio and the elastic modulus was obtained through the regression. The results show a linear relation-ship between the reinforcement ratio and elastic modulus. Under economic and frequently used reinforcement ratio,different reinforce-ment ratios have different influence to various basic components of reinforced concrete. According to the actual situation,the effect of re-inforcement ratio should be considered in the value of elastic modulus.

A natural vibration characteristics test on a physical model(scale is 1:10) of 660MW turbo-generator foundation of a power plant is made by using modal analysis. The structural dynamic characteristic parameters of this foundation, such as natural frequency, vibration mode and damping ratio, are obtained through the test. The results show that no resonance will happen between turbo-generator foundation and each rotor of turbo-generator unit during the run-up or run-down periods. It occurred many times local vibration during the frame column of the condensers and the midspan of the beam at the bottom column, this article makes suggestions that using a short column connects the upper and lower beams. Local vibration occurred on the middle platform of the generatior in 50Hz± 5%frequency range, so it is suggested vibration reduction treatments on the middle platform. This research provides areference for the dynamic modificationand optimization design of the turbo-generator foundation in the future.