Composite active control system of roof and side truss cable for large section coal roadway in fold coal pillar area

In order to solve the surrounding rock control problem of large section gangue replacement roadway under complicated conditions, this paper analyzed the impact to the roadway controlling produced by the geological conditions such as high ground stress, folded structure tilted roof asymmetry and soft wall rock, and built the tilt layered roof structural mechanics model to clarify the increase span mechanism of the weak coal instability. Then, we proposed the combined control system including roof inclined truss cable, coal-side cable-channel steel and intensive bolt support. And then by building the structural mechanics model of roof inclined truss cable system, the support principle was described. Besides, according to this model, we deduced the calculation formula of cable anchoring force and its tensile stress. Finally surrounding rock control technology of large section roadway in fold coal pillar area was formed. Field practice shows that the greatest roof convergence of gangue replacement roadway is 158 mm and coal-side deformation is 243 mm. Roadway deformation is controlled effectively and technical support is provided for replacement mining.

Selection and modification of ground motion records using Newmark-Hall spectrum as target spectrum for long-period structures

Input ground motions have significant impacts on the uncertainty of structural responses in time-history analysis.In this study,records were selected and scaled for the evaluation of mean structural responses according to the target spectrum.The Newmark-Hall spectrum is closely related to seismic response of short,medium and long-period structures,so it was taken as the target spectrum here.The nonlinear time-history analyses of 9-story and 20-story steel moment-resisting frame structures were carried out as examples.They represent medium and long-period buildings,respectively.Three target spectra with risk of 50%,10%and 2%probabilities for exceedance in 50 years were calculated by the average Newmark-Hall spectrum method for three ground motion sets developed in the SAC Steel Project.The predicted structural mean responses of these Newmark-Hall spectra were compared with those calculated by the average spectral acceleration method for the same record set.It is found that both methods have similar accuracy for estimating the structural mean response.However,the method proposed herein is more effective in reducing the variability of the structural responses.Also,the proposed method is more advantageous for the time-history analysis of long-period structures or structures with more severe nonlinear responses under strong seismic excitations.

Lessons from the seismic behavior of a steel grid roof structure heavily damaged in Lushan earthquake

The seismic behavior of a school gymnasium, whose steel grid roof was heavily damaged during the Mw6.6 Lushan earthquake in 2013, is simulated through nonlinear dynamic analysis. The simulated damage is compared with field observations to validate the numerical model, based on which a parametric study was performed to provide insight into the failure process and damage patterns of steel grids. The results suggest that the grid damage is strongly related to roofsubstructure interactions. These include not only the substructure's amplification of the vibration, but the uncoordinated displacement of the substructure's columns which support the grid also play an equally important role. In particular, the latter effect may significantly alter the internal force distribution in the steel grid and lead to unexpected buckling of members that are proportioned as tension-only members. While such interactions are generally not accounted for in the design practice for grid structures in China, similar seismic damage may be expected for other existing grid roofs in future earthquakes. As is also demonstrated in this study, seismic isolation of the roof is a promising solution to protect grid roof structures by mitigating the detrimental effects of roof-substructure interactions.

Proposal of Stainless Steel Roof Structure and Tiles for Gymnasiums

This work proposed an architectural alternative project of a stainless steel roof structure that uses roof tiles also in stainless steel with emphasis on roofs for multi-sport gymnasiums.In the development of the work,two existing multi-sports gymnasiums are taken as a reference,but with ASTM(American Society for Testing and Materials)A36 steel roof structure.The proposed cover system uses cables and light gauge profiles,in commercial stainless steel,which reduces the weight and of course the final price of the roof structure.A structure that presents technical feasibility is obtained and analyzed by checking its behavior with respect to the efforts and displacements generated by the combinations of the acting loads,following the safety recommendations of the applicable standard.It is verified that using the stainless steel structure proposed in this work would cost 42%of the reference structure if this were in AISI(American Iron and Steel Institute)304 stainless steel.And this cost tends to be minimized due to greater durability and consequent reduction in maintenance costs of this type of steel.

Slotted Hole Effect on Damage Mechanism of Gymnasium Building with RC Frame and Steel Roof

On the 2011 off the Pacific Coast of Tohoku Earthquake, gymnasium buildings exhibited the unexpected structural damages, which prevented a use as evacuation shelters in during- and post-disaster periods. The major failure occurring on the connection between the RC column top and steel roof as well as the cracks in the RC column base was observed during the emergent inspection. According to the earlier studies, it was implied that the presence of the slotted hole possibly deteriorates the seismic capacity;however, the length of slotted hole was fixed at a certain value. Facing this concern, this research attempts to clarify the influence of the slotted hole length through a comprehensive parametric study by pushover and seismic response analyses. In conclusion, it has been discovered that the slotted hole deteriorates the seismic capacity for the connection failure up to almost 50% of that without slotted hole. Moreover, the discrepancy of characteristics obtained by the static and dynamic analyses is originated by means of the presence of slotted hole. This slotted hole effect should be noted by structural engineers and researchers to provide the adequate seismic diagnosis and strengthening.

三星堆古蜀文化遗址博物馆大型螺旋坡道结构设计与分析

三星堆古蜀文化遗址博物馆中庭的螺旋坡道采用钢箱梁结构体系,最大半径28.7m,水平投影长度118.5m。介绍了大型螺旋坡道结构体系选型和边界条件的对比过程,采用通用计算软件MIDAS Gen建立多尺度整体模型考虑螺旋坡道和主体结构的相互作用,通过静力分析和反应谱分析考察螺旋坡道在不同荷载作用下的承载能力和变形,并采用有限元软件ANSYS建立分析模型进行连续倒塌分析。结果表明,螺旋坡道采用钢箱梁结构具有较好的整体刚度,静力荷载和地震作用下坡道的应力和变形均满足规范要求,并具有较好的抗连续倒塌能力。

水滴形大跨钢屋盖结构风洞试验和风振分析

自然风经过大跨结构时,由于结构屋顶形状不规则,通常会引起柔性屋面的振动,因此针对大跨屋面结构抗风设计需要考虑风压分布和风振响应。以陕西省水务集团矿泉水生产车间为工程背景,制作了1∶200的刚性模型,通过刚性模型风洞试验测得该水滴型大跨钢屋盖结构的表面风压,研究了屋盖表面典型测点及整体的风压分布规律。基于风洞试验数据,对结构进行风振时程分析,得到了屋盖表面的风振响应和风振系数。结合刚性模型风洞试验和风振分析,深入研究了水滴形大跨屋盖结构的风压分布规律和风致振动特性,并总结了其共性规律。

杭州电竞中心车辐式索承网格屋盖结构设计

索承网格结构是一种新型空间结构形式,广泛应用于大跨度空间结构中。针对杭州电竞中心车辐式索承网格屋盖结构进行分析和设计,采用MIDAS有限元软件进行索张拉施工方案设计与仿真,采用ABAQUS有限元软件进行稳定性分析和大震动力弹塑性分析。分析结果表明:在施工过程各个阶段,屋盖钢结构构件应力比始终小于1,索拉力小于索破断力的30%;施工完成时,与设计值相比,屋盖结构最大竖向位移和索内拉力的误差分别为6%和4%;屋盖结构稳定安全系数为9.63,单层网壳结构稳定安全系数为31.2,均大于规范规定的2.0,屋盖结构稳定性满足要求;初始缺陷对本工程单层网壳的影响很小;在大震作用下,屋盖结构构件均未出现塑性变形,且预应力拉索不退张。

重庆江北机场T3B航站楼大厅屋盖钢结构提升施工技术

重庆江北机场T3B航站楼大厅屋盖钢结构为异形三维曲面造型焊接球网架。由于周边飞机不停航,且由于构造复杂、结构高差大、跨度大、杆件数量多,给屋盖钢结构施工带来很大挑战。基于方案探讨和专家论证,提出一种优化施工方案:大厅钢屋盖划为7个提升分区,每个分区在楼面拼装为提升小分块,通过二次及多次累积提升进行施工。施工前运用BIM技术进行工序预演,并采用3D3S,MIDAS Gen软件进行数值模拟分析,为施工的准确性和安全性提供有力支撑。

基于美标的某海外散货仓库大跨钢结构选型

随着近年来“一带一路”持续推进,大跨钢结构在海外应用越来越广泛,如何在海外工程背景下采用美标进行钢结构选型成为了行业难点。本文基于某海外散货仓库项目,介绍了美标设计的主要结构分析过程,并给出了在全生命周期经济性下的结构选型。通过结构比选提出了一种新型自稳型门式钢架结构体系,其具有较好的经济性和极大的增加了仓库使用空间,为类似项目提供了参考。

西安咸阳国际机场T5航站楼钢屋盖旋转提升施工技术

西安咸阳国际机场T5航站楼钢屋盖采用大跨异形空间网架结构体系,结构造型独特,场地条件复杂,工期紧,施工难度大,质量要求高。介绍项目施工的重难点及方案选择,同时对施工过程中涉及的关键技术进行重点说明,主要包括异速等比同步旋转提升施工技术、大面积异形网架屋盖提升措施、旋转提升分区檩托及马道安装定位技术、全过程施工模拟计算分析技术、施工健康监测技术等。

马鞍山长江公铁大桥主航道桥桥塔设计

马鞍山长江公铁大桥主航道桥为双主跨1 120 m的三塔钢桁梁斜拉桥,桥梁跨度大、受力复杂,桥塔设计要求高。桥塔设计过程中对边中塔比例、结构形式、结构尺寸等进行比选分析,基于提高结构整体刚度、优化中塔受力和控制中塔基础工程规模的考虑,最终确定采用中塔塔顶高程高于边塔,边塔、中塔均为钢-混组合结构的方案。边塔塔高308 m和306 m,采用平面A形塔;中塔塔高345 m,采用空间A形塔。桥塔分为上塔柱、中塔柱、下塔柱3个区段。上塔柱为钢结构,采用钢锚箱式索塔锚固结构。中、上塔柱交界处设钢-混结合段,结合段外壁板布置PBL剪力键和剪力钉,结合段内设有一圈锚杆,钢塔柱竖向压应力通过结合段的承压板和剪力连接件传递至混凝土塔柱,拉应力通过锚杆传递至混凝土塔柱。中、下塔柱为混凝土结构,五边形截面。中、下塔柱交界位置设置横梁,边塔布置1道下横梁,中塔布置2道下横梁,中塔2道下横梁之间通过3道系梁连接。横梁均为预应力混凝土结构,系梁为钢筋混凝土结构。经计算,桥塔受力满足设计要求,桥塔各构件受力明确、安全合理。

预应力倒三角管桁架钢屋盖滑移施工技术

广交会展馆四期展馆扩建工程地处城市核心区,环境复杂,铁、隧、馆多重结构交互。工程体量大,结构复杂,施工难度大,总工期仅644d,在同类工程中工期最短,工期履约压力大。其中展厅屋盖钢结构为预应力倒三角管桁架结构,钢构体量大。针对此屋盖钢结构特点、难点,从缩短工期、高效建造方面开展研究,创新提出超长大跨度钢桁架分段等节奏滑移施工技术,即展馆两侧附属混凝土结构先行施工,提供滑移支撑体系,屋盖钢结构滑移与展厅下部2层主体混凝土结构同步施工,实现了展厅屋盖钢结构提前插入安装,各专业平面、立面穿插施工,缩短了关键线路工期;研发了基于装配式、自稳定高空平台的大跨度钢桁架拼装技术,实现超长大跨度重型钢桁架分单元快速拼装;针对主体结构作为滑移支撑体系两侧异标高的特点,设计双向滑移轨道,并研制滚针式滑靴及动力系统,确保滑移安全稳定;应用倒三角预应力钢绞线快速穿束和张拉技术,解决了超长预应力筋穿束张拉与高空滑移技术难题;液压同步控制系统与智能施工监测确保了大跨超重钢桁架屋盖滑移的应力、应变可控,按方案模拟过程平稳进行。

厦门翔安国际机场航站楼三重檐屋盖提升施工技术

在厦门翔安国际机场航站楼建设项目中,屋盖钢结构分上中下3层,上下重叠部分面积大、屋檐高,施工难度大。综合土建施工工艺、施工场地条件、工期等要求,选用满堂脚手架进行安装,并将上层屋檐与船形桁架相连。为保证整体稳定性和施工精度,上层屋檐采用液压提升,中层、下层屋檐安装选用分块吊装或全部分块液压提升方案,控制结构稳定提升。在保证安装质量和精度的前提下,减少施工成本、缩短工期。

中国海洋大学船形钢结构及采光顶施工关键技术

介绍了中国海洋大学海洋科教创新园区(西海岸校区)一期工程船形钢结构及采光顶的施工方案,解决了钢结构安装复杂的技术难题,并取得了速度快、质量好、低消耗的效果。通过有限元分析,得到了每步张拉的钢索张拉力大小,为实际张拉提供理论依据。合理的张拉顺序和适当的工具选择确保了安装的顺利进行。经过船形钢结构安装及吊索张拉、采光顶安装及吊索张拉、船形钢结构稳定索张拉等步骤,最终实现了预期的结构状态。该施工技术具有可行性和可靠性。

广交会展馆四期扩建工程展厅钢结构屋盖设计

广交会展馆四期扩建工程项目展厅的钢结构屋盖由珠江散步道、标准展厅和卡车通道组成。为了满足业主对标准展厅跨度及净高的功能要求,对5种钢结构屋盖的结构体系进行比选,最终采用了下弦设置穿心式预应力钢绞线的倒三角形立体桁架的结构体系。对所采用的结构体系的基本设计信息进行介绍,并对其进行了荷载分析、施工模拟分析及屋盖抗连续倒塌分析。结果表明所采用的结构方案在满足业主需求的情况下是安全可靠且经济合理的,各项指标均满足规范要求。

单层网壳屋盖整体滑移施工关键技术

北京星火站枢纽区屋盖采用单层菱形网格结构,采用异位拼装、整体滑移施工方案,支撑体系主要由网格巨柱及V形撑组成。基于此,主要介绍钢结构施工关键技术,包括菱形网格屋盖拼装单元吊装、拼装,屋盖整体滑移,双螺栓扭转网格巨柱拼装单元吊装、拼装。基于施工全过程分析,验证施工方案,确定施工方案的可行性。

机场复杂空间曲面钢网格结构屋盖施工关键技术

针对乌鲁木齐地窝堡国际机场换乘中心屋盖钢结构造型复杂、用钢量大、施工精度要求高、支撑结构形式多样等特征,提出复杂空间曲面钢网格结构施工技术与控制方法。综合开发超大型整体提升技术、分段拼装技术、数字化预拼装与管理技术等,高效解决了复杂异形钢结构施工难题。利用有限元软件MIDAS与ANSYS进行了施工全过程数值分析,对提升施工全过程中各构件内力与变形进行了验证,结果表明,各构件内力与变形均满足设计要求,成功完成了复杂空间曲面钢网格结构施工。

广州南沙国际金融论坛永久会址主体结构设计

广州南沙国际金融论坛永久会址属于大型复杂会议类建筑,具有大底盘双塔、钢屋盖连体、大开洞、竖向质心偏移、大跨结构等多项不规则项。介绍了结构重力体系和抗侧体系的选型思路,主体结构选用混凝土框架+屈曲约束支撑体系,外表皮采用空间钢结构。重点分析了单塔与整体结构的差异以及钢屋盖对下部双塔的影响。通过弹塑性分析,对大震作用下各个时程点的损伤水平进行评估,对大开洞的楼板进行了地震及温度作用下的楼板应力分析;对大跨桁架进行了抗连续倒塌分析。结果表明结构可满足大震不倒的要求,支撑承载力能充分发挥,大底盘结构具有良好的基座支撑特性。

某博物馆大跨钢空腹夹层板屋盖设计

以湖北省天门市某博物馆的大跨度钢空腹夹层板楼盖为实例设计,介绍了钢空腹夹层板的设计方法和结构布置,基于YJK模型和SAP2000模型分析了实用计算方法和壳单元有限元模型计算结果的变形和受力的差异及其原因,对比研究了传统方管剪力键和新型十字剪力键在空腹夹层板结构中的受力表现。结果表明,本工程中实用方法与壳单元有限元模型计算得到的挠度结果吻合性较好,实用方法难以考虑次弯矩,会导致受压板件的计算应力较壳单元有限元模型明显偏小;剪力键的构造对结构受力有一定影响,新型十字剪力键连接的弦杆应力较方管剪力键略小,应力集中情况在一定条件下更缓和;通过增加部分加劲肋板,可以减小支座端应力。