“3 Degrees and 8 Combinations” Teaching Mode of Anti-Seismic Design of Building Structures

Earthquakes pose a significant threat to people’s property and personal safety.Improving the teaching of civil engineering and building structure anti-seismic design courses can enable students to do a good job in anti-seismic design in the future and effectively reduce the damage on buildings caused by earthquakes.In this paper,we analyzed the basic characteristics of a course in civil engineering major,which is Anti-Seismic Design of Building Structures,and the shortcomings of traditional teaching.It is proposed that the 3-degrees and 8-combinations teaching mode of anti-seismic design of building structures can effectively improve students’autonomy and enthusiasm in learning,helps to cultivate professional ethics among students,and improve their ability to apply what they have learned.

The Ultimate Anti-Seismic Design Method

The design mechanisms and methods of the invention are intended to minimize problems related to the safety of structures in the event of natural phenomena such as earthquakes, tornadoes, and strong winds. It is achieved by controlling the deformations of the structure. Damage and deformation are closely related concepts since the control of deformations also controls the damage. The design method of applying artificial compression to the ends of all longitudinal reinforced concrete walls and, at the same time, connecting the ends of the walls to the ground using ground anchors placed at the depths of the boreholes, transfers the inertial stresses of the structure in the ground, which reacts as an external force in the structure’s response to seismic displacements. The wall with the artificial compression acquires dynamic, larger active cross-section and high axial and torsional stiffness, preventing all failures caused by inelastic deformation. By connecting the ends of all walls to the ground, we control the eigenfrequency of the structure and the ground during each seismic loading cycle, preventing inelastic displacements. At the same time, we ensure the strong bearing capacity of the foundation soil and the structure. By designing the walls correctly and placing them in proper locations, we prevent the torsional flexural buckling that occurs in asymmetrical floor plans, and metal and tall structures. Compression of the wall sections at the ends and their anchoring to the ground mitigates the transfer of deformations to the connection nodes, strengthens the wall section in terms of base shear force and shear stress of the sections, and increases the strength of the cross-sections to the tensile at the ends of the walls by introducing counteractive forces. The use of tendons within the ducts prevents longitudinal shear in the overlay concrete, while anchoring the walls to the foundation not only dissipates inertial forces to the ground but also prevents rotation of the walls, thus maintaining the structural integrity of the beams. The prestressing at the bilateral ends of the walls restores the structure to its original position even inelastic displacements by closing the opening of the developing cracks.

Construction of Teaching Case Base of Anti-Seismic Design of Building Structure

Anti-Seismic Design of Building Structures is an important course in civil engineering majors,and it is also a course that pays equal attention to theory and practice.Therefore,by establishing a case base for Anti-Seismic Design of Building Structures,the obscure theoretical knowledge can be taught to students in the form of examples,and the knowledge becomes intuitive.In this way,the students’understanding of anti-seismic design theory and the efficiency of teaching can be improved,and the students’interest in learning can be stimulated.

Anti-seismic Value of Watchtower-like Folk Residence on the Central Plain of China by the Insinuation of Typical Cases

Through the survey of ancient residences on the Central Plain of China, several ancient residences have been selected as typical cases. By combining with residential features of watchtower, characteristics of these residences have been analyzed carefully. In order to reasonably illustrate anti-seismic value of watchtower-like residences, their characteristics have been concluded in the perspective of plane form, structural arrangement, and anti-seismic construction measures. The plane form is of tower; the plane and vertical surfaces are regular and even; the wall's thickness is reasonable, and doors and windows are few and small; and bonded stone has been set in the wall, resisting compression.

Anti-seismic behavior of HRB400 reinforced steel bars

The properties of anti-seismic HRB400 steel bars with 25 mm diameter were systematically investigated. The results showed that the properties of the HRB400 reinforced steel bars had been greatly enhanced comparing with HRB335 steel bars, i.e. coordination of strength and ductility, strain-aging sensibility, low temperature impact toughness, weld ability and high strain low cycle fatigue. The ductile-brittle transit temperatures of hot-rolled and strain-aged steel bars were evaluated as –17 °C and ?8 °C respectively, and the low temperature impact toughness of HRB400 steel bars remains to be improved. Transmission electron microscopy (TEM) and electron diffraction showed little vanadium existed in ferrite as VN, most of which existed in pearlite as alloy cementite which resulted in the declination of impact toughness. Methods were suggested to improve the anti- seismic properties of steel bars.

The Ultimate Anti-Seismic System

In general, of construction projects, utility anti-seismic technologies, such as hydraulic tie rod or tie rod structural vibration control system, assess efficiency and safety in node structures from earthquakes risk. According the building construction framework, we exanimate, with experiments, the mechanism of reaction and a patent idea of anti-seismic system with potential conclusions, through using different methods, such as of horizontal seismic insulation, design with elongated rigid columns and design columns without ductility. We provide that we made strong foundation in earthquakes, solar-wind and utility power structural systems and tornados effects in lightweight constructions. We suggest that may fix to existing or under design construction like bridges.

Anti-seismic research on nuclear engineering siting

Nuclear engineering belongs to significant project;there is higher requirement on sitings.The study has discussed basic factors of selecting sites,anti-seismic research on sitings including the seismic ground motion,probability methods of seismic hazard analysis as well as interaction about structure and foundation,meanwhile provide the reason for nuclear engineering selecting sites.

Optimization design of anti-seismic engineering measures for intake tower based on non-dominated sorting genetic algorithm-Ⅱ

High-rise intake towers in high-intensity seismic areas are prone to structural safety problems under vibration.Therefore,effective and low-cost anti-seismic engineering measures must be designed for protection.An intake tower in northwest China was considered the research object,and its natural vibration characteristics and dynamic response were first analyzed using the mode decomposition response spectrum method based on a three-dimensional finite element model.The non-dominated sorting genetic algorithm-II(NSGA-II)was adopted to optimize the anti-seismic scheme combination by comprehensively considering the dynamic tower response and variable project cost.Finally,the rationality of the original intake tower antiseismic design scheme was evaluated according to the obtained optimal solution set,and recommendations for improvement were proposed.The method adopted in this study may provide significant references for designing anti-seismic measures for high-rise structures such as intake towers located in high-intensity earthquake areas.

Tensile deformation behavior of high strength anti-seismic steel with multi-phase microstructure

To investigate the tensile deformation behavior of high strength anti-seismic steel with multi-phase microstructure,tensile tests with strains of 0.05,0.12 and 0.22 were performed at room temperature.Microstructure of tested steels was observed by means of optical microscopy（OM）,transmission electron microscopy（TEM）and scanning electron microscopy（SEM）.Tensile mechanical properties of tested steels were obtained,and the influence of bainite content on deformation behavior was also discussed.Meanwhile,the deformation mechanism of steel with three kinds of microstructures of bainite,pearlite and ferrite was analyzed.Results show that tested steel with high volume fraction of bainite exhibits a continuous deformation behavior,and this may be attributed to a higher bainite volume fraction and a lower mobile dislocation density.The morphology of microstructure will influence the mechanical properties of tested steels.An increasing content of bainite can improve the tensile strength,but reduce the plasticity and toughness of the tested steels.In the deformation process of 0.039 Nb steel,the ferrite and bainite have priorities to deform,and the deformation exhibits co-deformation of all microstructures in the later stage of deformation.In the deformation process of 0.024Nb-0.032 Vsteel,the ferrite and pearlite have priorities to deform,and the deformation exhibits co-deformation of all microstructures in the later stage of deformation.

基于新型耗能板提升钢框架节点抗震和抗连续倒塌能力

针对全焊节点在地震和连续倒塌条件下有限的抗倒塌能力,该文基于新型耗能板对其进行改进提升。首先通过试验、数值模拟和理论分析相结合的方法揭示了新型耗能板在单调荷载和循环荷载作用下的力学性能;进而通过新型耗能板与节点在地震作用和连续倒塌条件下的协同作用,给出了新型耗能板节点的设计方法。结果表明:新型耗能板在单调和循环荷载作用下的力学性能不同,在单调荷载作用下表现为受拉破坏,在循环荷载作用下表现为剪切破坏;通过算例分析表明,新型耗能板节点的抗震与抗连续倒塌设计方法是合理的;新型耗能板全焊节点在地震和连续倒塌条件下主要经历双塑性区域形成阶段和硬化阶段,其中新型耗能板全焊节点的抗震和抗连续倒塌性能的差异主要体现在硬化阶段;新型耗能板的增加可同时有效提高全焊节点在地震和连续倒塌条件下的承载力、变形和耗能能力。

电气化铁路接触网地震作用与抗震性能分析

研究目的:高地震烈度区域电气化铁路沿线途经多条地震断裂带,接触网系统在地震作用下易出现损坏,影响列车的正常运行。本文结合高地震烈度区电气化铁路,基于接触网系统服役特性,开展了4柱3跨原型足尺振动台试验,建立并验证地震响应下的接触网系统有限元模型,开展地震作用下接触网系统的地震响应仿真计算,对比分析接触网导线、腕臂、定位器、支柱等关键装备的抗震性能,并比较分析不同的接触网导线工作张力、跨距以及锚段长度对接触网系统抗震性能的影响,提出高地震烈度区接触网系统的抗震设计原则及措施,全面分析与研究地震作用下接触网系统响应规律和抗震性能。本文提出的关于接触网系统抗震性能分析数据及研究结论,能有效补充和完善接触网抗震设计规范及标准,有力支撑铁路工程建设,提升电气化铁路防灾抗灾能力。研究结论:(1)地震激励对接触网腕臂装置的影响较小,定位器出现受压,导致钩环结构易脱落;(2)地震激励对接触网支柱、接触线具有十分明显的影响,可造成支柱柱底应力增大和接触线跨中位移增大;(3)锚段长度对抗震性能无明显影响,适当增大接触线工作张力、减小跨距可有效降低接触网系统的地震响应;(4)本研究成果可为轨道交通领域防灾减灾设计提供指导。

设置侧向限位阻尼器的层间隔震结构减震性能研究

对在隔震层设置侧向限位黏弹性阻尼器组成混合耗能结构随机激励下的减震性能进行了系统研究.首先,建立混合耗能结构的地震动方程,利用双过滤白噪声激励地震动的滤波方程,将该类激励下混合耗能结构的动力学问题精确转化为基于易于获得简明封闭解的白噪声激励问题.其次,基于复模态法和白噪声激励的Dirac函数性质推导了混合耗能结构系列响应(结构位移、层间位移和阻尼器阻尼力)的方差和0~2阶谱矩的简明封闭解.最后,通过算例在验证所提封闭解正确的基础上研究了混合耗能结构减震性能的影响因素.研究表明:层间隔震层以上楼层的结构响应量随着隔震层刚度的增大而增大;黏弹性阻尼器阻尼参数对隔震层以上楼层的影响特征为,结构位移在一定阻尼参数下可达到最小,而层间位移则随着阻尼参数的增大而增大.该研究可为层间隔震混合耗能结构的设计提供参考.

基于实地抽样调查的区域农村民居抗震性能评价

针对目前农村民居抗震性能研究主要面向单体房屋而非区域这一现状和不足,本文以四川省德阳市为研究区域,基于实地抽样调查数据、谷歌影像和影响农村民居抗震性能的其他相关数据建模,得到了一种乡镇区域尺度农村民居抗震性能指数的计算方法。具体方法为:(1)选取研究区6个县(市、区)119个乡镇中30个乡镇的代表性农村民居作为抽样调查点,进行逐户实地查看、现场仪器测量及询问当地村民。调查内容包括房屋结构类型、建造时有无采取抗震措施以及所处的场地条件等。(2)以抽样乡镇的人口密度、人均社会消费品零售总额为自变量,砖混结构房屋面积占比为因变量,构建农村民居砖混结构面积占比模型。(3)以抽样乡镇的砖混结构房屋面积占比、平均坡度、地质灾害点密度为自变量,农村民居抗震性能指数为因变量,构建农村民居抗震性能指数模型。(4)根据抗震性能指数模型计算整个研究区119个乡镇的抗震性能指数。计算结果显示:(1)构建的砖混结构面积占比模型和农村民居抗震性能指数模型均具有较高的精度。(2)研究区抗震性能计算结果直观反映了农村民居的抗震性能。相较于前人的工作,本文的方法大大减少了大面积调查所需的时间和经济成本。

双曲面球型减隔震支座与普通支座在成昆铁路典型桥梁上的抗震性能对比分析

以成昆铁路典型桥梁为研究背景,讨论了双曲面球形减隔震支座的抗震性能,对比分析了不同桥型对减隔震效果的影响。进一步地,讨论了桥墩的高度、形式以及位置对减隔震效率的影响。结果表明,双曲面球形减隔震支座对于简支T梁桥、简支桁架梁桥以及连续梁桥均有良好的减隔震效果。整体而言,双曲面球形减隔震支座对墩顶的载荷优化大于墩底,对弯矩的优化大于剪力;桥墩墩高、桥墩位置以及桥墩形式都会影响抗震支座的减隔震率。

预制系梁刚度对双柱式桥墩抗震性能影响分析

为探究预制系梁刚度对双柱式桥墩抗震性能的影响,利用ABAQUS软件建立小碑村大桥带装配式系梁的下部结构模型,改变系梁的材质与系梁截面内尺寸,建立了9个有限元模型,用位移加载的形式对其进行拟静力分析,发现其刚度变化对于结构抗震性能的影响较小,当尺寸变化达203%时,结构抗震性能的变化仍不显著,说明本结构对于预制系梁的刚度变化不敏感。结果表明进行预制系梁材质及尺寸设计时,有较宽的可行范围,应考虑成本、构造要求及施工方法等因素综合选取。

金阳河特大桥超高桥墩设计关键技术

金阳河特大桥主桥为(106+2×200+115+40)m连续刚构桥,位于高山峡谷地带,桥址处50年超越概率10%地震烈度7.7度,5~7号主墩分别高113、196、182 m。针对横桥向抗震响应突出且墩高差异大的特点,主墩采用钢管混凝土组合墩,对墩高较大的6号、7号主墩横桥向双侧放坡,各主墩顺桥向尺寸保持恒定以方便施工,梁端设置粘滞阻尼器以实现顺桥向耗能减震;各主墩刚度经匹配设计,控制截面的地震响应达到合理比例。主墩为外包混凝土的四肢钢管混凝土柱及柱间腹板形成的箱形构造,竖向每间隔12 m设置1道钢筋混凝土横隔板;墩梁固结采用钢管混凝土柱置于主梁0号块腹板外侧的连接构造,钢管混凝土柱与承台连接采用承压板+PBL剪力键的构造。大桥整体结构计算结果表明:持久状况和E2地震作用下,钢管混凝土组合墩满足承载能力极限状态要求,主墩墩顶水平位移小于规范规定的变形容许值。主墩施工先安装钢管骨架,再采用液压爬模工艺施工钢管外包层和柱间腹板,研发了多点同步重型提升系统代替大型塔吊,以降低高空作业安全风险,节省施工费用。

预制系梁不同连接方案下对双柱式桥墩抗震性能影响研究

为研究装配式系梁不同连接方案下对双柱式桥墩抗震性能的影响,研究采用ABAQUS软件建立小碑村大桥带预制系梁的下部结构模型,改变预制系梁的断面形式和节点连接方式,建立3个有限元模型,用位移加载的形式对其进行拟静力分析,研究从3个方面分析了预制系梁的受力性能和抗震性能。结果表明:装配式系梁采用不同断面形式和节点连接方式,其结构抗震性能具有一定差异,其中采用“焊接—双H型钢”的连接方案具有较好的抗震性能和抗变形能力,实际工程中应考虑成本、构造要求及施工方法等因素综合选取性能最优方案。

基于显示器安装技术的核电站抗震屏风式OWP盘台的设计

根据操作员在C项目主控室盘台Mock Up验证过程中,针对OWP盘台提出的关于实现显示器密集安装和避免显示器之间缝隙漏光的新要求,本项目研发了抗震屏风式OWP盘台。核电站抗震屏风式OWP盘台利用屏风和显示器支架的相互配合可实现上述新要求:屏风具有足够高的固有频率和贯穿宽度方向的滑道结构,作为显示器支架载体的同时还可实现显示器支架的左右移动,即实现显示器的左右移动;显示器支架自身可实现显示器前后移动及万向角度调整,且各自由度均可可靠锁紧,二者配合可实现显示器的密集安装要求;屏风作为一道物理屏障可实现避免显示器与显示器之间缝隙漏光的要求。通过验证,核电站抗震屏风式OWP盘台可避免显示器与显示器之间的缝隙漏光,可实现显示器的均匀分布且最小间距可达到10mm,并满足相关核电站的抗震要求。

强震区抗滑桩加固碎石土边坡动力响应特征与桩身损伤识别:以川青铁路九寨沟双线大桥附近工点为例

为掌握西南强震区服役抗滑桩的地震响应特征与损伤状态,基于川青铁路位于强震区典型工点,构建了地震作用下不同损伤状态抗滑桩加固碎石土边坡三维有限差分模型,研究了坡体的加速度响应、抗滑桩结构内力变化以及桩身初始损伤对坡体动力响应的影响;引入小波包能量谱法,基于桩身加速度响应数据,构建能量损伤判别指标对桩身进行损伤状态、损伤位置以及损伤程度的识别。结果表明,抗滑桩能有效降低桩身周围土体的加速度响应,坡体加速度总体表现为高程放大效应,滑面附近是桩身受力集中区域且桩身损伤会导致其抗弯、抗剪承载力下降,侧向水平位移增大,进而加剧坡体加速度响应。损伤判别指标D PERV沿桩身的分布特征能够有效识别抗滑桩的损伤位置和损伤程度,建立的桩顶残余位移、桩顶损伤指标D PERV与损伤程度三者之间的定量关系能够评估桩身相对损伤程度,为边坡工程中抗滑桩服役性能评价提供新的思路和方法。

高烈度地震区倾斜隧道洞口段抗减震技术研究

为提升高烈度地震区倾斜隧道洞口段的抗震性能,依托某隧道工程,利用有限差分数值软件FLAC3D研究了注浆加固和减震层的抗减震效果。结果表明:(1)隧道纵向应力极值和位移最大值出现在洞口中间过渡段,监测面内应力极值和位移最大值均出现在衬砌结构拱脚;(2)与无抗减震措施相比,注浆加固与施作减震层均能减少隧道二次衬砌位移差,施作减震层后隧道竖向位移差减少最多,减震效果达到74.83%;(3)工况1(无措施)最小主应力峰值最大,为-28.64 MPa,施作减震层后为-20.05 MPa,减震效果达到29.99%;(4)随着隧道纵向长度的增加,最小安全系数先减小后增大,最小值出现在中间过渡段监测面S3处;工况1安全系数为1.95,工况2为2.24,但仍低于安全阀值,工况3为2.56,符合安全要求。综合位移、应力和安全系数,采用减震层的抗减震效果优于注浆加固。研究成果可为倾斜隧道洞口段抗减震设防设计提供参考。