Dynamic response characteristics of super high-rise buildings subjected to long-period ground motions

Spectrum characteristics of different types of seismic waves and dynamic response characteristics of super high-rise building structures under long-period ground motions were comparatively analyzed. First, the ground response wave （named LS-R wave） of a soft soil site with deep deposit, taking long-period bedrock seismic record as input, was calculated by wave propagation method. After that, a TOMAKOMAI station long-period seismic record from the Tokachi-Oki earthquake and conventional E1-Centro wave were also chosen. Spectrum characteristics of these waves were analyzed and compared. Then, a series of shaking table tests were performed on a 1：50 scale super high-rise structural model under these seismic waves. Furthermore, numerical simulation of the prototype structure under these excitations was conducted, and structure damages under different intensive ground motions were discussed. The results show that： 1） Spectrum characteristics of ground response wave are significantly influenced by soft soil site with deep deposit, and the predominant period has an increasing trend. 2） The maximum acceleration amplification factor of the structure under the TOM wave is two times that under the E1-Centro wave; while the maximum displacement response of the structure under the TOM wave is 4.4 times that under the E1-Centro wave. Long-period ground motions show greater influences on displacement responses than acceleration responses for super high-rise building structures. 3） Most inelastic damage occurs at the upper 1/3 part of the super high-rise building when subjected to long-period ground motions.

Effects of high modes on the wind-induced response of super high-rise buildings

For super high-rise buildings, the vibration period of the basic mode is several seconds, and it is very close to the period of the fluctuating wind. The damping of super high-rise buildings is low, so super high-rise buildings are very sensitive to fluctuating wind. The wind load is one of the key loads in the design of super high-rise buildings. It is known that only the basic mode is needed in the wind-response analysis of tall buildings. However, for super high-rise buildings, especially for the acceleration response, because of the frequency amplification of the high modes, the high modes and the mode coupling may need to be considered. Three typical super high-rise projects with the SMPSS in wind tunnel tests and the random vibration theory method were used to analyze the effect of high modes on the wind-induced response. The conclusions can be drawn as follows. First, for the displacement response, the basic mode is dominant, and the high modes can be neglected. Second, for the acceleration response, the high modes and the mode coupling should be considered. Lastly, the strain energy of modes can only give the vibration energy distribution of the high-rise building, and it cannot describe the local wind-induced vibration of high-rise buildings, especially for the top acceleration response.

Discussion on the Construction of Anti-smoke Construction Technology in Super High-rise Buildings

In recent years with the increasing number of super high-rise buildings and the ever-expanding scale the anti-smoke construction technology has attracted more and more attention.Based on this situation,this paper analyzes the smoke control technology of super high-rise buildings.The paper analyzes the importance of the application of anti-smoke construction technology in super high-rise buildings,analyzes the problems in the construction of smoke control and super high-rise buildings.The anti-smoke construction technology was studied and I hope that it can benefit the application of anti-smoke construction technology in high-rise buildings.

Research on ETABS Steel Tower atop Building Structural System

Equipping steel tower atop building structural system at the top of high-rise buildings is applied increasingly. However, the earthquake disasters indicate that under seismic effect, the tower on the roof reacts strongly to the earthquake, and the gazebo is damaged greatly under the condition that major structure has no earthquake damage. Based on analyzing the characteristics and application methods of ETABS software, for engineering projects, the paper uses ETABS software and simplified calculation method to calculate and make comparison analysis on steel tower atop building structure. The analysis results indicate that the method established in the paper has higher accuracy, which can meet the engineering requirements.

Collapse simulation of a super high-rise building subjected to extremely strong earthquakes

In recent years, super high-rise buildings (>500 m) are developing very quickly and become an important frontier of civil engineering. The collapse resistance of super high-rise buildings subjected to extremely strong earthquake is a critical problem that must be intensively studied. This paper builds up a nonlinear finite element model of the tallest building in China, Shang- hai Tower (632 m), and proposes the modeling method and failure criteria for different structural elements. The dynamic char- acters of this building are then analyzed, and the possible failure modes and collapse processes due to earthquakes are pre- dicted, as well as the corresponding collapse mechanism. This work will be helpful in collapse prevention and the seismic design of super high-rise buildings.

An improved ground motion intensity measure for super high-rise buildings

Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more reasonable IM for super high-rise buildings is proposed in this paper. This IM takes into account the significant characteristic that higher-order vibration modes play important roles in the seismic response of super high-rise buildings, as well as the advantages of some existing IMs. The key parameter of the proposed IM is calibrated using a series of time-history analyses. The collapse simulations of two super high-rise buildings are used to discuss the suitability of the proposed IM and some other existing IMs. The results indicate that the proposed IM yields a smaller coefficient of variation for the critical collapse status than other existing IMs and performs well in reflecting the contribution of higher-order vibration modes to the structural response. Hence, the proposed IM is more applicable to seismic design for super high-rise buildings than other IMs.

超高层建筑工程内爬塔式起重机附着提升拆除关键技术

内爬塔式起重机是适用于超高层建筑的一种大型设备,本研究介绍了内爬塔结构系统构造及爬升流程,通过设置支撑梁承受结构重力和塔式起重机设计荷载、设置液压油缸和内爬框架进行顶升操作,完成内爬塔结构提升。以小塔拆大塔为塔式起重机拆除原则,设计了两次屋面吊拆除过程,保障拆除工期和屋面结构安全。建立了支撑梁和内爬框架的三维实体有限元计算模型,优化支撑梁系统设计,得到了支撑梁和内爬框架在满载支撑状态下的应力和位移计算结果。结果表明,支撑系统安全可靠。

近断层地震动作用下多塔超高层建筑地震易损性分析

近断层地震动是一类含有高能速度脉冲的特殊地震动,其周期长、破坏性强、能量集中。多塔超高层建筑相比单塔超高层受力更加复杂,自振周期更长,速度脉冲能量更易输入结构,且可能对各塔造成较大的响应差异,但针对此类特殊情况抗震规范并未出台相应条文。对此,以一个三塔超高层建筑为例,以多种近断层、非近断层地震动,及高能速度脉冲为地震动输入,利用大型有限元软件进行地震时程分析,并以层间位移角和最大位移为主要分析对象,对主塔副塔结构进行地震易损性分析。结果表明:算例结构在各种地震动作用下,均可以满足“小震不坏、中震可修、大震不倒”要求;但近断层地震动对于结构产生的响应远大于非近断层地震动;比较各种损伤状态的损伤概率,近断层地震动较非近断层地震动平均上升11.79%。进一步分析其中高能速度脉冲发现:速度脉冲是造成近断层地震动对结构损伤的重要因素,较小的速度脉冲就有可能对主塔产生较为严重的结构损伤。

基于既有桩基承台的塔式起重机复合基础建造方法研究

在超高层基础施工时,需要同步施工塔式起重机基础。桩承台作为超高层常用基础形式,一般需要将塔式起重机基础预埋件布置在桩承台中心位置,以获得最优承载力。限于结构平面布置或塔式起重机作业安全距离的限制,无法将塔式起重机基础布置于承台中心,进而无法保证塔式起重机基础的受力安全性。针对上述问题,提出了基于既有桩基承台的塔式起重机建造方法,该方法可结合超高层原有桩基承台和筏板兼作塔式起重机基础,避免了塔式起重机基础的补桩等施工措施,显著节约了钢筋、混凝土等材料成本、人工成本和工期成本。

机场塔台液压爬模施工技术研究

通过液压爬模施工技术在兰州机场三期扩建工程空管工程北侧塔台中的应用,介绍了液压爬模系统的技术参数、构造、安装流程、施工工艺及施工关键要点等,并根据结构变化情况,探讨了液压爬模的施工技术措施,阐述了爬模系统对应的解决方法,制订了塔台核心筒爬模施工进度计划,保证了爬模提升工作的顺利进行,总体上协助了工期履约,有效解决了爬模施工过程中的各项具体问题。

超高层建筑动臂塔吊选型与定位研究

在超高层建筑施工中动臂塔吊是常见吊装机械,在施工中需要提前规划好动臂塔吊的选型和定位来进行研究,以提高其使用效能与合规性。本文以具体案例为依托,探讨动臂塔吊选型定位的主要原则与方式,从空间关系、结构影响以及吊运工况三个方面对其进行分析,旨在为后续施工实践提供必要参考。

某超高层建筑复杂塔冠结构设计分析

通过分析超高塔冠侧面开洞方案对框架-核心筒超高层结构的影响,并结合风洞试验结果,开洞方案能有效减小风荷载的体形系数。利用欧拉公式,确定空间扭转格构柱的长细比,最后通过SAUSAGE和MIDAS GEN有限元软件,对塔冠结构抗震性能和钢管结构的节点做细致分析。由于塔冠的风荷载直接影响到主体结构是否要增设加强层,目前对于此类项目造型,规范和现有研究均未明确风荷载取值。研究结果表明,通过对塔冠立面开洞处理,可以减小相应的风荷载,提高主体结构的经济性;复杂塔冠节点具有较高的安全性,整个塔冠结构具有更高的可靠度。

某大底盘多塔超高层结构分析与设计

某项目为1栋带3座塔楼的大底盘多塔超高层结构,塔楼均匀分布于裙房北侧,分别为部分框支剪力墙和剪力墙结构体系。针对塔楼偏置问题进行了分析,并采用盈建科、PERFORM3D、ETABS等软件对结构进行了多塔模型和单塔模型的整体计算对比、罕遇地震下的动力弹塑性分析及温度效应分析。多塔与单塔模型整体指标吻合较好,内力接近,同时根据分析结果对结构构件采取相应的构造加强以满足性能目标。结果表明,项目结构形式及构件截面合理,具有良好的抗震性能。

深圳某超高层结构设计重点及难点分析

深圳某超B级高度的超高层塔楼,采用钢管混凝土框架柱+钢筋混凝土框架梁+钢筋混凝土核心筒结构。塔楼相对于裙房部分有较大的偏心,同时因为建筑功能要求存在有多处跃层透空空间。采用盈建科、ETABS等软件对项目进行了整体计算、构件设计及楼板应力分析。针对塔楼偏置、楼板不连续、核心筒收进等不规则项,对于结构构件采取适当的构造加强,以满足抗震性能目标。对于外框梁不闭合的问题,采取对比分析,确保水平地震剪力可有效传递。结果表明,项目结构体系选择恰当,结构布置、构件截面取值合理,具有良好的抗震性能。

武汉某商业综合体空调系统设计

本文介绍了某商业综合体的空调系统设计,包括空调冷热源、空调水系统、空调末端设计等,并对酒店裙房内区过热、超高层建筑空调水系统分区、变风量空调系统新风设计几个重难点问题进行了分析,采用多种技术措施降低空调系统运行能耗。

内爬式塔机附着装置倒运技术研究

超高层建筑核心筒内安装的内爬式塔机附着装置一般通过塔机自身吊装或拖运到核心筒外框吊运实现倒运,易受空间限制或核心筒外框施工进度较慢的影响。以上海张江中区单元57-01地块项目为背景,介绍了一种内爬式塔机附着装置倒运的方法。实践证明,该方法安全可靠,节省了施工工期和成本,可为类似超高层建筑核心筒内爬式塔机附着装置的倒运施工提供借鉴。

集中型多标段群塔作业技术与安全管理研究

超大型公共建筑往往由不同单体建筑组合成一个整体,建筑在平面上占地面积大且造型复杂,在立面上又包含不同层高的单体。在此大型公共建筑由不同施工标段组成情况下,要保障场地垂直运输的覆盖率,塔吊的布置往往密集而集中,因此对塔吊的技术与安全管理提出了更高的要求。本文基于岳阳市中心医院项目的塔吊布置,阐述了不同施工单位组成的集中型群塔作业的安全管理,并提出了安全管控措施,以期可为类似项目提供借鉴。

湾区中心总部综合体高层塔楼结构抗震超限设计

位于广州番禺的湾区中心总部大型综合体,包含1栋超高层办公公寓塔楼、2栋超高层住宅塔楼及商业裙房,结构采用不分缝处理,整体形成大底盘多塔结构。重点对1#主塔楼的主要结构特点进行了详细阐述,介绍了其结构设计的主要过程以及相关抗震设计方法,重点分析了抗震设计过程中的概念设计,解决了斜柱设计、大底盘超长裙楼设计等重点问题,通过不同的计算程序进行对比分析,对关键构件及重点部位采取了加强措施,分析结果表明,该超高层塔楼可满足预定的抗震性能目标,各项分析指标均能满足现行规范要求。

新型承重梁的内爬塔吊在超高层建筑工程中的应用

以深圳星河雅宝双子塔西塔工程为背景,介绍了新型承重梁的内爬塔吊在星河雅宝双子塔西塔中应用的关键技术。针对内爬塔吊爬升占用工期长、下部作业人员物体打击风险大、薄壁核心筒超前施工对塔吊附着不利、塔吊拆除环境复杂等难点进行了研究,通过一系列技术的综合运用,有效减少了工期并降低了施工安全风险。总结的经验可供类似工程借鉴。

超高层建筑内爬塔吊底部防护平台设计与应用

以星河雅宝高科创新园三地块施工总承包工程为背景,针对超高层建筑内爬塔吊底部安全防护这一难题,设计并应用了可随内爬塔吊同步爬升的防护平台。平台主要结构为“井”字形钢梁,通过钢丝绳悬挂在塔吊内爬基节下并可随塔吊同步爬升。当平台爬升时,与墙体保持一定距离,而当平台工作时,与墙体之间的间隙被完全封闭。该平台具有安全可靠、质量轻等优点,并减少了内爬升塔式起重机对下部结构施工安全的影响,取得了良好的效果,可为同类项目提供参考。