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为研究冷弯薄壁不等肢复杂卷边角钢屈曲性能和稳定承载力设计方法，对24根不同截面、长细比、宽厚比的不等肢复杂卷边角钢进行了轴压试验。试验结果表明，长细比较大且宽厚比较小的试件易发生弯扭屈曲，长细比较小而宽厚比较大的试件易发生局部屈曲或弯扭和局部相关屈曲。采用ABAQUS有限元软件对试件进行了有限元模拟，屈曲模式和承载力与试验结果吻合良好，表明建立的有限元分析模型是可行的。因此可采用经验证的有限元模型对不同长细比、卷边形式和卷边比的轴心受压不等肢复杂卷边角钢进行了参数化分析。结果表明，试件极限承载力受长细比的影响最为明显，将卷边比控制在一定范围内或改变卷边形式可提高试件极限承载力。最后将试验结果与直接强度法计算结果进行对比，表明直接强度法计算试件承载力较不安全。因此基于试验和数值分析结果提出轴心受压冷弯薄壁不等肢复杂卷边角钢构件考虑整体屈曲后强度的直接强度法修正公式，并通过对比试验结果和有限元分析结果验证了该修正公式的准确性和可行性。

为积极响应国家走绿色可持续发展道路的号召，北京冬奥会采用了大量支承架体用于临时看台或舞台的搭建。为研究赛后的临时看台支承架体能否安全合理地被再次使用，以索氏不锈钢插销式节点临时看台支承架体为研究对象，设计并制作了一个横纵均为2跨且跨度为2 m的足尺模型试件，共进行了两次试验，即在首次水平加载试验结束后，将该试验架体搭建在室外，经历长时间严寒风雪后再重复做一次试验，重点对比分析了其在4种不同恒载与水平荷载组合作用下的整体结构变形模式、力学性能及典型位置峰值应变等。研究结果表明：在恒载为0.0 kN∙m-2、0.5 kN∙m-2、2.0 kN∙m-2和3.5 kN∙m-2的工况下，两次试验中架体结构的试验现象及变形模式基本相同，力学性能差值在5%以内，典型位置处峰值应变差值在10%以内，累计损伤较小。两次试验结束后结构均未出现明显损伤，仍具有较大安全储备，所以在经历长时间的严寒风雪后，临时看台支承架体仍可以被重复使用。研究结果可为北京冬奥会临时设施架体的赛后利用等研究提供参考。

圆中空夹层钢管混凝土（concrete filled double-skin steel tube，CFDST）柱因其独特的结构形式与优异的力学性能，已成为现代工程结构中的主要受力构件。然而外钢管、内钢管与核心混凝土之间的相互约束作用导致其受力比较复杂。为此，采用PSO-BP混合神经网络算法对圆CFDST柱的轴压承载力进行了研究。收集了167组数据建立数据库，并选取8种影响因素作为输入层参数，轴压承载力作为输出层参数，分析了传统BP神经网络模型所存在的缺陷，建立了PSO-BP神经网络模型。此外，将机器学习模型与3种规范的结果进行比较，结果表明机器学习模型的精度比3种规范的精度更高。相较于BP神经网络模型，PSO-BP神经网络模型具有更好的预测能力，更有助于预测CFDST柱的轴压承载力，对工程上研究CFDST柱的力学性能有着重要意义。

为获得折叠装配式框架结构的静力性能，设计了两个折展框架榀足尺试件，通过开展结构静力加载试验对单榀折展框架在不同荷载工况下的变形特征、承载性能与破坏形态进行了研究。试验结果表明：对于正常使用状态，进行静力加载时，有支撑的单榀框架结构整体变形处于弹性范围，水平作用下受推和受拉位移变化趋势基本一致，且增设支撑对折展框架的刚度影响较大；水平极限荷载作用下，有支撑的单榀框架结构在支撑连接处首先出现不可逆的塑性变形，单榀框架在边柱下端与下部拉条连接处发生局部破坏；上、下层梁柱节点弯矩-转角曲线变化趋势一致，但上层节点初始刚度明显弱于下层节点初始刚度，同层梁柱节点初始刚度基本相同；单榀框架的各关键点处等效应力在往复加载过程中推拉对称，结构总体处于安全状态。

综合考虑桥梁系统灾变全过程，提出了一种适用于高地震烈度寒区的钢-混凝土组合梁桥抗震韧性评价方法。基于现有统计数据，综合考虑桩基沉降损伤、疲劳损伤以及冻融损伤，建立了高地震烈度寒区钢-混凝土组合梁桥震前功能损失函数；将地震易损性分析与桥梁抗震韧性评价相结合，建立了桥梁系统震后恢复函数；提出了震前临界维修加固年限和临时保通状态。结果表明：在高地震烈度冻土区的钢-混凝土组合梁桥系统的临界维修加固年限随地震动峰值加速度的增大而减小，当地震动峰值加速度分别为0.10g、0.15g、0.20g、0.30g时，桥梁系统的临界维修加固年限预计分别为27年、24年、19年、8年；当桥位在Ⅸ度及以上设防区时，必须在桥梁方案设计中考虑增设减隔震装置；桥梁系统的恢复时间随地震动峰值加速度的增大而增大，韧性指标随地震动峰值加速度的增大而减小；桥梁在运营20年后发生地震作用时，地震动峰值加速度为0.10g和0.15g的地震动预计不会影响桥梁通行，地震动峰值加速度为0.20g~0.40g的地震动需要进行维修加固实现临时保通，预计恢复时间为1~42天，韧性指标为0.647~0.578，恢复至临时保通状态的韧性指标最大值为0.650。

为解决传统抗震支吊架采用“硬抗”的方式抵抗地震作用的问题，并减小传统抗震支吊架的震后残余变形，提出一种新型自复位耗能抗震支吊架。采用ABAQUS有限元软件分别对自复位耗能抗震支吊架和传统抗震支吊架进行有限元模拟，对比分析二者的应力及变形特性、滞回性能来验证所提自复位耗能抗震支吊架的抗震性能；通过建立不同参数的支吊架模型并对滞回性能进行参数分析，得到抗震斜撑复位比、刚度比和摩擦系数对自复位耗能抗震支吊架滞回性能的影响规律，并给出相应参数的取值建议；以支吊架响应峰值加速度作为工程需求参数，以支吊架破坏作为损伤极限状态，得到两种抗震支吊架的易损性曲线。结果表明：抗震斜撑复位比、刚度比和摩擦系数的取值范围分别为1.0~1.5、1.0~1.5和0.1~0.3时，自复位耗能抗震支吊架具有较好的滞回特性；新型自复位耗能抗震支吊架具有更强的鲁棒性，能够更好地保障管道系统的使用功能。

网架作为一种空间杆系结构，因其具有整体性和稳定性好、空间刚度大和抗震性能好的优点而被广泛应用在大跨度结构中。常规的网架安装方法主要有整体提升法、高空滑移法、分条吊装法及高空散装法等。但超高重型焊接球网架不同于一般螺栓球网架，其跨度及可承受的荷载更大，对应的施工安装难度及安全风险更高，如果仅采用单种常规安装方法，很难高效、顺利地实现结构成型。以上海临港冰雪之星项目室内滑雪场钢屋盖为背景，着重介绍“原位原姿态拼装后分块整体提升”的安装技术路线及对应施工过程分析和改进措施，并通过对胎架拼装、提升控制及卸载等关键工序的研究，为今后类似大跨度钢结构屋盖安装的施工方案提供参考。

为研究含H型钢的钢骨混凝土柱在压弯剪扭复合受力作用下的抗震性能，对7个含H型钢的钢骨混凝土柱和1个钢筋混凝土柱进行拟静力试验，探究了扭弯比、轴压比、配箍率等对试件抗震性能的影响，分析了试件在低周反复加载试验中裂缝产生和发展的规律及破坏特征，讨论了各试件的扭矩-扭率滞回曲线、骨架曲线、耗能能力、延性、刚度退化和损伤分析。结果表明：含H型钢的钢骨混凝土柱在复合受力状态下发生受扭破坏，其扭矩-扭率滞回曲线呈捏拢的S形，相较于普通钢筋混凝土试件，其承载能力和抗震性能更优。增大扭弯比、轴压比、配箍率以及采用箍筋焊接并配置栓钉能提高试件承载能力，但提高配箍率和配置栓钉会使试件刚度退化速率加快。

在北方寒冷地区，钢管混凝土结构因冻融作用侵蚀而造成钢管开裂以及钢管混凝土结构力学性能劣化从而导致结构破坏的事故时有发生。针对冻融侵蚀后钢管混凝土界面黏结性能问题，制作了钢管混凝土推出试件，考虑冻融循环次数、混凝土强度、钢管径厚比等不同参数，进行冻融试验和推出试验，分析了界面黏结力的分布规律和影响因素，研究了冻融循环作用后钢管混凝土界面黏结滑移本构关系，确定了界面平均黏结强度以及峰值黏结强度、残余黏结强度特征值。结果表明，随着冻融循环次数的增加，界面平均黏结强度减小，极限荷载对应的滑移逐渐增大，而残余黏结强度呈线性减小，稳定段起点滑移随着冻融循环次数的增加呈指数增长。峰值黏结强度、残余黏结强度随混凝土强度的增加而提高，随着径厚比的增大而降低。分析外钢管密布应变计所测出的应变分布规律可知界面黏结应力呈指数分布，对比分析由荷载、滑移结合能量法理论推导所得的黏结应力分布函数，结果表明其具有较高精度，为后期研究界面黏结性能提供了新思路。构建了冻融循环作用后界面黏结应力-滑移三段式本构模型，并提出了相应特征值计算公式和本构模型，可为该类构件设计时考虑冻融作用提供参考。

大跨度异形空间网架结构在大型公共建筑项目中广泛应用，但该类结构存在大量球形构件，传统全站仪监测的测量精度和效率较低，因此提出一种基于激光点云的大跨度异形空间网架球节点中心点坐标高效自动检测方法。利用三维激光扫描仪获取结构成形态的钢结构屋盖点云数据，然后对点云进行降噪处理，基于深化设计模型并根据后续工序的精度要求设置空间域，提取目标点云，最后采用编程算法对焊接球节点的中心点坐标实现自动化批量提取。为验证拟合球体中心点精度，对比了深化设计模型球节点与点云重构球节点的半径。以杭州西站大跨度异形空间网架焊接球节点为分析对象，结果表明，由该方法提取得到的大跨度异形空间网架球节点坐标精度高、效率大幅提升，具有良好的工程应用前景。

以云南红河综合交通枢纽单层曲面网壳为工程背景，对网壳结构、提升塔架的关键杆件布置测点进行施工过程监测研究，分析了结构在地面拼装及整体提升过程中内力的变化情况。通过对施工过程中网壳结构的温度效应进行研究，探讨了边界约束作用强弱对结构内力变化的影响程度，温度每变化1 ℃引起的网壳合拢后应力变化是合拢前应力变化的3倍；合拢后，温度每变化1 ℃引起网壳远离支座杆件的应力变化是靠近支座应力变化的2倍；对提升阶段监测数据进行分析，提升过程中实测应力波动范围在10 MPa以内，吊点提升同步性较好；此外，网壳结构卸载阶段监测数据表明，由于网壳提升状态与使用状态受力基本一致，网壳卸载前后应力变化较小，且卸载后支撑结构对温度敏感性较高。

输电塔是典型的风敏感结构，易受下击暴流极端强风的影响，导致输电塔倒塌、线路受损等风害故障频发，造成巨大的经济损失。为分析下击暴流作用下输电塔倒塌破坏的原因，根据马鞍山地区一次下击暴流事故中的实测气象数据，以事故中整体倒塌破坏的羊角型直线塔为典例，建立“一塔两线”有限元分析模型，分析下击暴流0°、45°、60°、90°风向角作用下输电塔体系的动力响应，探究下击暴流不同风向角作用下羊角型直线塔-线体系的受力特点、薄弱部位及破坏机理。研究结果表明：90°风向角是直线塔-线体系抗下击暴流作用的最不利工况，是导致直线塔-线体系倒塌破坏的主要原因。下击暴流作用下羊角型直线塔-线结构体系的倒塌破坏是塔腿主、斜材失稳所引起，在抗下击暴流设计时应加强塔腿部位。

以某奥体中心体育场钢结构屋盖为研究对象，对其加固及施工方案进行了分析。首先进行模型反建，并对该屋盖在施加新增荷载后的内力及变形进行分析，明确了需要加固的杆件范围。在此基础上，采用有限元软件对结构开展精细化分析，确定了包含加强节点、杆件和结构的加固方案，有效地改善了结构的传力体系，提高了结构的承载能力并降低了结构在使用荷载下的应力和变形。针对钢屋盖的不同部位，分别通过预应力锚索、增大截面和设置刚性圆管等方式进行加固，保证结构安全且满足建筑要求。除此之外，还对该加固方案对应的施工过程进行了有限元模拟，可为实际施工提供参考。经省运会工程实践验证，本项目的加固方法简单有效。

泰安体育场作为山东省泰安市的新地标，其钢结构屋盖采用轮辐式索承网格结构，通过68榀径向索和1道中央环索形成张拉结构体系，最大悬挑跨度为45 m。通过数值分析对施工过程进行了精细化稳定性分析，针对不规则构件吊装的工程技术难点，进行了吊装方案的设计与优化；考虑到成本控制与施工周期，极具创新性地采用了径向单道胎架作为屋盖施工过程中的临时支撑，结合工程实际情况设计了胎架转换结构，并对单道胎架整体在多种可能的荷载组合作用下进行验算与校核。通过对体育场屋盖施工全过程的模拟以及对安装过程中的重难点进行优化分析，为现场施工的安全顺利开展提供了技术保障，可为其他类似采用单道胎架施工方法的工程提供施工方案设计的新思路。

连体结构建造技术中，整体提升是一种经济、高效的施工方法，其在工程中应用广泛。然而实际提升施工中，连体与塔楼对接精度低，其中一个关键原因是提升荷载会使塔楼产生显著的水平变形。就此类问题，提出采用塔楼复位的方法解决，并详细介绍了塔楼复位的实施方案与设计优化分析方法。塔楼复位方法的核心思想为通过对塔楼施加水平荷载，消除塔楼附加水平变形从而使其回复至接近设计状态。此后，以杭州云门钢结构项目为例，结合结构形式与施工方案提出两种塔楼复位方案，完整分析塔楼复位的可行性、有效性并给出复位方案的优化方法。最后给出了实际实施后的塔楼复位效果。

鼓蜂窝四撑杆型索穹顶抛弃传统概念，结合了多撑杆构思，是构形最为丰富的一类索穹顶结构。为研究新型鼓蜂窝四撑杆Ⅲ型索穹顶结构静力性能，选取下弦节点布置方案1，建立跨度为120 m的有限元数值分析模型，研究该结构在不同荷载水平及分布方式下的变形和内力变化。并进一步对结构进行参数化分析，研究包括初始预应力水平、矢跨比、撑杆高度（厚跨比）及下弦节点布置方案等不同参数对于结构整体刚度与承载力的影响及变化规律。分析结果表明鼓蜂窝四撑杆Ⅲ型索穹顶具有良好的结构性能，各索杆均不容易发生破坏，结构整体刚度大。研究中给出了初始预应力水平与相关几何参数的合理取值范围，可为该结构索穹顶的实际工程设计与应用提供参考。

在万向减震球型钢支座的基础上对其弹簧元件进行耗能设计，提出了一种新型耗能减震球型钢支座，采用钢板弹簧叠加耗能钢作为耗能减震元件。通过单调拉伸加载试验和循环拉伸加载试验，研究了Q295钢材的耗能能力，采用拟静力试验和数值分析相结合的方法，分析了支座耗能减震元件的滞回性能和自复位性能；将该新型球型钢支座应用于网架结构中，考察其耗能减震能力。研究结果表明，Q295钢材的滞回曲线饱满，具有一定的耗能能力；减震元件的耗能减震性能较好，并且具有一定的复位能力；相较于一般的弹性减震支座，新型球型钢支座可以吸收部分地震能量，从而进一步降低结构的动力响应。

采用有限元模型研究内置型钢的圆形不锈钢管混凝土构件的纯弯力学性能，有限元计算结果与试验结果吻合良好。该类典型构件的抗弯承载力比不锈钢管混凝土对比构件的相应值高111.33%；混凝土承担的弯矩也比对比构件的相应值高23.31%，受压区混凝土的抗压承载力约提高了20%，原因是钢管和型钢翼缘对受压区混凝土形成了良好的约束作用。该类构件的抗弯刚度与抗弯承载力随着混凝土强度、不锈钢含钢率、型钢含钢率和回转半径比的增大而提高；其抗弯承载力随着不锈钢屈服强度或型钢屈服强度的增大而提高。最终给出了该类构件的抗弯刚度和抗弯承载力的简化计算方法。

为研究钢管高强混凝土叠合柱偏心受压性能，以混凝土类型和偏心距为参数，完成了6根叠合柱偏心受压试验，研究了不同参数对钢管高强混凝土叠合柱损伤发展过程、破坏特征、承载力和延性的影响，并基于《钢管混凝土叠合柱结构技术规程》（T/CECS 188—2019）和相关学者提出的公式对16根钢管混凝土叠合柱的偏压承载力进行了计算。研究结果表明：再生混凝土叠合柱与普通混凝土叠合柱的受力过程均经历了弹性、带裂缝工作和破坏3个阶段，表现出外围混凝土保护层被压碎脱落、纵筋鼓曲和箍筋外鼓等破坏特征；与普通混凝土叠合柱相比，再生混凝土叠合柱的初始刚度和变形能力有所降低，但承载力略高；随着偏心距的增加，钢管混凝土叠合柱的初始刚度和承载力迅速降低，而位移延性系数迅速增大，中和轴逐渐向受压区移动，与平截面假定的吻合度有所降低；钢管混凝土叠合柱偏压承载力计算应考虑钢管自身承载力以及钢管对核心混凝土约束效应的影响。

为研究薄壁型钢混凝土（thin-walled steel reinforced concrete，TSRC）梁试件的抗弯性能，设计制作了5根TSRC梁并进行四点弯曲试验，探究不同抗剪螺杆布置方式、截面形式、剪跨比以及混凝土保护层厚度对TSRC梁试件抗弯性能的影响。研究结果表明：TSRC梁的失效模式为薄壁钢管加载点处发生局部屈曲，外围混凝土保护层出现贯通斜裂缝，混凝土保护层沿抗剪螺杆开裂；TSRC梁试件在加载过程中未发生脆性破坏，表现出较好的延性；TSRC梁开裂荷载较小，在0.11Pu ~ 0.15Pu之间，裂缝总数较少，稳定在6~10条；满跨布置螺杆、增大钢管截面尺寸、减小剪跨比以及增加保护层厚度均可提高TSRC梁试件的承载力。基于试验结果，建立适用于TSRC梁的极限抗弯承载力和抗弯刚度计算公式，可为该构件在实际工程中的应用提供参考。

建立Levy型索穹顶结构有限元分析模型，给出有限元结果合理性的判定准则，提出冲击失效准则。进行大量冲击工况下的动力响应全过程分析，给出杆件破坏分布规律和失效模式，揭示结构在竖向冲击荷载作用下的失效机理。依据冲击失效机理及参数分析，提出抗冲击措施。研究结果表明：所有冲击工况均符合冲击判定准则，在所选竖向冲击荷载范围内，Levy型索穹顶结构的失效模式可分为4种，即结构轻度损伤、结构局部1级失效、结构局部2级失效和结构整体破坏。随着冲击动能的增加，结构的动力响应模式逐渐呈模式1→模式2→模式3→模式4的发展趋势。通过分析可知，结构的动力响应模式由结构的能量吸收值及构件两端速度差决定。

基于复合钢本构模型，明确了复合比β对不锈钢复合钢应力-应变性能的影响。通过试验结果的承载曲线和破坏模式验证了数值模拟方法的准确性，进而以β、腹板宽高比a/hw和腹板高厚比hw/tw为变量开展300个数值模型的参数分析，系统分析了各变量对不锈钢复合钢H形截面钢梁受剪承载曲线和极限承载力的影响。研究结果表明：随着β的增加，不锈钢复合钢应力-应变曲线中的屈服平台逐渐消失，复合钢应力-应变性能逐渐由碳钢转变为不锈钢。当β较小时，不锈钢复合钢应力-应变曲线存在明显的屈服平台，这削弱了复合钢的应变强化对H形截面钢梁受剪承载性能的有利影响。随着β的增加，不锈钢复合钢的非线性应变强化性能逐渐增强，导致H形截面钢梁的延性性能逐渐提高，强度性能逐渐降低。经过验证，既有的欧洲规范设计公式对不锈钢复合钢H形截面钢梁受剪极限承载力的预测过于保守。基于参数分析结果，建立了考虑β影响的腹板贡献系数计算方法。研究结论有助于推广不锈钢复合钢的工程应用。

索塔锚固区的受力分析通常采用实体有限元单元进行，然而由于其结构复杂、种类繁多，不易被一般工程设计人员使用。为此，结合某斜拉桥的实际工程案例，分析了内置式钢锚箱锚固体系的传力特点，提出了一种基于平面框架理论的简化计算方法，并利用非线性的分析方法建立了锚固区ANSYS有限元模型以修正公式。结果表明修正前简化公式计算结果与有限元模型计算结果之间的误差在10%左右；考虑到塔壁厚度、索塔计算高度以及锚箱侧板厚度的影响，使用折减混凝土弹性模量的方法来补偿和修正桥塔应力分布，具体的混凝土折减系数使用非线性回归的方法确定。最终将修正公计算式结果与有限元模型计算结果重新进行对比，结果表明，修正后的计算公式与有限元模型计算结果的误差在2%以内，可以较好地分析索塔锚固区的索力分配情况，具有实际工程意义。

冷弯薄壁型钢（CFS）全螺栓垫板连接T形拼合柱是一种新型拼合截面柱，在全螺栓连接框架结构中承受集中荷载。目前关于全螺栓连接T形CFS拼合柱轴心受力性能的研究报道较少。基于已有的试验研究成果，建立准确可靠的T形CFS拼合柱数值分析模型，选取构件长细比、板材厚度、垫板的纵向间距等参数，研究在轴压作用下各重要参数对T形CFS拼合柱极限承载力和屈曲模态的影响。结果表明：随着长细比的增大，T形CFS拼合柱的屈曲模式由局部与畸变相关屈曲逐渐转变为整体屈曲，当长细比

安徽省池州段长江大跨越345 m超高杆塔是国家“西电东送”工程中白鹤滩-浙江±800 kV特高压直流输电线线路的重点工程。在超高杆塔施工中对摇臂抱杆高空吊装全过程受力分析是保证施工安全、保障西电东送工程顺利竣工的重要手段。开展了模拟施工过程的摇臂抱杆调幅加载试验，明确了分级加载下摇臂抱杆的全过程受力特征，建立了考虑动力特性的摇臂抱杆高空吊装有限元分析模型，明晰了在实际荷载工况下结构重要杆件与节点的应力分布规律，并基于诸多关键工况分析优化了高空摇臂抱杆的设计方案。研究成果可为超高杆塔的摇臂抱杆吊装施工提供理论支撑。

钢-混凝土组合结构兼具钢筋混凝土结构与钢结构的共同优点，具有承载力高、刚度大、延性和抗震性能好及节约材料等优点，符合土木工程的发展方向。处于复杂受力状态下的梁-柱节点区域是建筑结构中需要特别关注的部位，既是整体结构安全性和可靠性的重要基础，又是建筑结构抗震设计中的薄弱环节，因此节点部位的设计至关重要。在综合介绍钢管混凝土柱、型钢混凝土柱及钢柱与钢筋混凝土梁的连接节点研究背景的基础上，分析了上述节点连接的构造形式及受力性能等方面的研究现状，指出了该类节点连接方式及受力性能方面有待进一步解决的问题，为该领域的深入研究及该类节点连接的设计提供参考。

现有站房的规模和设施与实际客运需求的矛盾日益突出，因此全国掀起了铁路站房改扩建的浪潮。其中，将原站改扩建为高架候车厅站房的施工工况最为复杂，给施工单位带来非常大的挑战。基于株洲站改扩建工程，研究不停运营业线上盖高架候车厅改扩建施工关键技术，首先剖析了该类铁路改扩建工程的特点及难点，提出了平行于既有站台的大平行、小流水改扩建模式，解决了站厅施工与车站服务同步运营的关键性难题；然后提出了营业线钢柱施工技术、不停运营业线上盖混凝土结构支护体系的模块化技术和高架候车厅屋盖分区提升技术，为高架候车厅下中上3层立体结构提供了成套技术解决方案，可为今后同类工程施工提供参考和必要的技术储备。

矩形钢管-波折钢板组合墙是一种新型剪力墙，通过横置波折钢板连接两侧钢管形成预制钢构件，然后在钢管内及双波折钢板间填充混凝土形成组合墙。为研究矩形钢管-波折钢板组合墙在竖向荷载作用下的承载性能，以管间墙肢长度和栓钉间距为变化参数，完成了5个仅在墙端钢管混凝土柱顶加载的组合剪力墙试件抗压静力试验。在试验过程中，主要对加载端柱的竖向位移和组合墙三个不同高度截面应变进行了测量。试验结果表明，竖向荷载由组合墙边缘构件矩形钢管混凝土柱传递至剪力墙整体截面，需要一定的传力长度。管间墙肢长度以及栓钉间距是影响荷载传递路径长短和截面竖向应变分布平截面程度的主要因素。当管间墙肢长度不大于5倍墙厚以及栓钉间距小于200 mm时，在组合墙边缘构件破坏前，荷载经过1.07倍墙宽的传递长度可以传递至组合墙全截面。研究结果为进一步提出矩形钢管-波折钢板组合墙在竖向荷载下的承载力计算方法提供了基础性试验依据。

海洋工程平台塔架结构中，圆形截面中空双钢管是主要受力构件，工程界十分关注其受压性能和耐腐蚀性能。为研究圆中空夹层不锈钢管水泥砂浆短柱的轴压力学性能，以外不锈钢管壁厚、内碳素钢管直径和是否含夹层水泥砂浆为试验变量，共设计了12个短柱试件。分析各试件的破坏情况、荷载-位移曲线、承载力、变形能力及应变特征，研究不同变量对极限承载力的影响规律。结果表明：试件破坏形态为外钢管端部或中部局部屈曲破坏；随着不锈钢管壁厚的增大，试件的轴压承载力近似呈线性增长；夹层水泥砂浆对试件力学性能影响较大，可有效提高试件承载力，抑制外不锈钢管的变形，提高试件延性；对于含夹层水泥砂浆的试件，承载力随空心率增大而减小，不含夹层水泥砂浆的试件，承载力随空心率增大而增大。根据国内外规范以及相关学者提出的理论公式，计算了试件的极限承载力，并与试验承载力进行了对比分析，给出了设计建议。

型钢混凝土（steel reinforced concrete，SRC）柱因承载力高、刚度大和耐久性能好等优点而被广泛应用于高层结构中。然而，现阶段SRC结构设计普遍基于承载力设计法，基于性能的抗震设计法在SRC结构方面的应用仍待完善。作为基于性能（位移）的抗震设计方法中最重要的一环，现阶段SRC构件的侧力-位移关系评估缺乏规范指导。基于美国现行规范ASCE/SEI 41-17中针对钢筋混凝土构件的相关规定，结合SRC构件的受力与变形特征，提出了发生弯曲破坏的SRC柱在地震作用下的侧力-位移曲线建模方法。该曲线采用约束混凝土强度计算SRC构件的峰值承载力；使用刚度折减法考虑型钢与混凝土之间的黏结滑移；基于SRC构件的变形特征考虑了纵向受力钢材端部滑移对柱顶侧移的贡献。最后，通过与28根SRC柱试验结果的比较证明了曲线的适用性。计算结果表明：所提出的曲线能合理预测发生弯曲破坏的SRC柱的开裂荷载、开裂位移、峰值荷载、峰值位移和强度退化，可为SRC结构的性能化抗震设计提供参考。

北京未来城学校教学楼的地上部分采用钢框架结构，并设置2道结构缝将造型奇特的教学楼分为3个部分。教学楼地下部分不设缝连为整体，采用钢筋混凝土框架结构。钢连廊跨度为33 m，采用2层通高桁架结构。钢连廊与两侧主体结构采用弱连接，通过对比3种支座方案，选用布置金属摩擦摆隔震支座+黏滞阻尼器的方案。对钢连廊与两侧主体结构整体模型进行动力弹塑性时程分析，连廊整体作为刚体随3层主楼楼面发生地震响应，隔震支座的隔震效果显著。此外，介绍了本项目中钢筋混凝土梁与钢骨混凝土柱连接节点及梁配筋的注意事项，为后续相关工程设计提供参考。

以钢管混凝土叠合柱为研究对象，设计了一种高强对穿螺栓连接的外套筒式梁柱节点。为了研究该新型节点的抗震性能和破坏机理，对3个缩尺比为1∶2的节点进行了拟静力试验。观察节点损伤过程及破坏模式，分析了梁端荷载-位移滞回曲线、骨架曲线、节点延性及耗能能力，采用ABAQUS软件建立有限元模型，研究套筒宽厚比和加强肋板厚度对节点抗震性能影响。试验及有限元研究结果表明：节点滞回曲线饱满，延性系数介于3.13~4.19之间，等效黏滞阻尼系数介于0.211~0.296之间，节点域的变形较大且耗能能力较强；随着套筒厚度增大，核心区混凝土开裂减少，破坏位置由节点外移至梁端截面；减小套筒宽厚比和增大加强肋板厚度可以有效提高节点刚度。为保证外套筒式节点达到刚性节点要求，建议套筒宽厚比不大于25，加强肋板厚度不小于梁翼缘厚度。

对于大型复杂空间钢结构，可靠的施工过程分析对保障施工安全性和钢结构安装质量具有重要意义。在传统施工过程分析与钢结构直接分析的基础上，提出一种考虑构件和安装模块初始缺陷以及变形累积的钢结构非线性施工过程分析方法。利用NIDA软件将该方法应用于成都某大悬挑钢桁架结构的施工过程分析中，确保了施工方案的可行性。同时，对比分析了非线性施工过程分析、一次成型分析和线性施工过程分析3种分析工况下结构关键节点位移及构件应力情况，并与施工实测值进行了比对。结果表明，一次成型分析与线性施工过程分析的位移较实测值偏小，而基于直接分析法的非线性施工过程分析结果与实测值更加吻合，验证了该方法的准确性及适用性。

乌鲁木齐国际儿童医院由门诊医技楼、病房楼等部分组成，总建筑面积为240 000 ㎡。主要介绍了门诊医技楼主体结构设计、入口雨棚设计、大厅屋盖、分叉柱、倒梯形截面设计等多个施工技术问题。通过结构选型对比分析，主体结构采用减震框架结构，雨棚和大厅屋盖均采用单层网壳结构，经济合理的同时保证了建筑效果。通过传力路径分析和有限元计算，对网壳结构进行了单体模型和总装模型的对比研究，重点分析了结构的变形问题，对整体网壳进行了几何非线性和材料非线性的整体稳定性分析，对倒梯形截面采用截面替换的方式进行了补充分析，对支座等关键部位进行有限元分析以满足受力和稳定性的要求。

This study explores how ageing temperature and the volume percentage of Al2O3+B4C nanoparticles influence the machinability and hardness of stir-cast Al-7075 Metal Matrix Composite (MMC). Using liquid metallurgy techniques, hybrid materials were created by reinforcing Al7075 metal matrix with varying weight percentages of nanosized B4C (1.5%, 3%, and 4.5%) and Al2O3 (1%, 1.5%, and 2%). After fabrication, the samples were subjected to five-hour ageing process at temperatures of 100, 120, and 140 degrees Celsius, followed by cooling to ambient temperature (27 degrees Celsius). Hybrid nano composites that had been heat treated were tested for wear, tensile strength, and hardness. Results shows that, the addition of nanoparticles and heat treatment considerably improves the tensile strength, hardness, and wear resistance of hybrid composites by 3%, 17%, and 10%, respectively, for samples reinforced with 4.5% B4C + 2% Al2O3. SEM analysis was used to investigate the type of wear and the tensile fracture mode of nano composite samples by analyzing the wornout surface and the surface where tensile fracture occurred. Machinability was assessed using L27 orthogonal array tests, focusing on three key process parameters: feed rate (0.1 mm/min), depth of cut (0.2 mm/min), and spindle speed (1000 rpm). Outcomes show that, increasing the wt. % of nano-Al2O3/B4C leads to higher machining force and surface roughness (Ra) of MMCs. Conversely, higher ageing temperatures result in decreased machining force and surface roughness. Optimal surface roughness and machining force were achieved with 1% Al2O3 + 1.5% B4C and an ageing temperature of 140�C. These findings offer valuable insights into the ease of machining of composite metal alloys, emphasizing the importance of parameter selection and optimization for desired machining outcomes

The flexural behavior of lightweight concrete two-way slabs is investigated in this work, with a focus on the strengthening or repairing method of externally attaching carbon fiber-reinforced polymer (CFRP) sheets. Five 1000 mm by 1000 mm by 120 mm reinforced lightweight concrete slab slabs were used in the experiment. Tested one specimen with no strengthening and another with CFRP sheet strengthening and repaired the rest with a single layer of CFRP at damage ratios of 50%, 60%, or 70% of the ultimate load, consciously making each slab crack under bending loads while keeping the exact measurements. As to the experiment findings, the ultimate load capacity increased by 30.3% at the strengthened specimen, 17.7% at the 50% damage level, 12.6% at the 60% damage level, and 10.9% at the 70% damage level. As degradation increases, so does the carrying capacity of LWC slabs. The amount of damage LWC slabs sustain influences their stiffness and flexibility. Effectively repairing the sample, CFRP sheets raised the reinforced concrete slabs� failure stress and stopped the fractures from growing. Reinforced concrete slab failure was increased, and CFRP sheet repairs of the specimens successfully stopped crack propagation.

Overall structural integrity and load transfer between concrete and reinforcement enabling composite action relies on the bond between concrete and reinforcement. Bond strength determination of reinforced concrete is an essential task that a pullout test can determine. Experimental pullout behaviour can be affected by various parameters, such as concrete and steel strength, boundary conditions, etc. Therefore, a parametric study on pullout tests is time-consuming. In addition, measurements of internal stress-strain components and damages of constitutive materials are also difficult in experimental endeavours. In this context, finite element (FE) models should be developed to perform a parametric study with cost and time-saving. This study proposes a finite element modeling strategy of reinforced concrete under pullout force by using the expected failure mechanism to predict bond-slip behaviour in ABAQUS. In FE models, surface-to-surface cohesive interaction behaviour was used to assign interaction between reinforcement and concrete. The proposed modelling strategy was validated with available experimental data from four reference specimens, having all possible failures (i.e., pullout, splitting, and splitting-pullout) under pullout loading. The finite element analysis showed that the proposed FE modeling strategy performed well in predicting bond-slip behaviour in elastic regions. Additionally, maximum bond stresses were predicted satisfactorily, except for the splitting failure pattern, using the proposed FE modelling strategy.

This paper proposes a methodology to evaluate and optimize the dynamic response of tall buildings under wind loading, controlled through semi-active Magneto-Rheological dampers (MR dampers). For this, a tall building, modeled as a 2D frame, is taken as case study and three structural control configurations are proposed. The original structural configuration of the building is the first configuration analyzed, called Uncontrolled Original (C1). In the second configuration, called Uncontrolled Optimized (C2), the fundamental frequency of the building is optimized via PSO algorithm as a function of its mass. Then, in the third configuration, Controlled Optimized (C3), a set of MR dampers with behavior formulated via the modified Bouc-Wen rheological model and controlled through the Linear Quadratic Regulator associated with the Clipped Optimal control strategy (LQR-CO) is applied to the structure. Finally, the dynamic response of the three scenarios under wind action is analyzed and compared to performance criteria established in the literature. The results demonstrate that the C3 configuration is the only one able of satisfying all the established performance criteria, proving that the proposed methodology y that combines structural optimization with MR dampers is a powerful tool for vibration control.

Mechanical processing of hole edges in large-size hull structures of single and double curvature for welding saturation parts into them is an urgent task of shipbuilding. A considerable amount of such machining has to be performed directly on the slipway on a fully assembled structure. To perform such works non-stationary technological machining complexes are used, which have reduced rigidity in comparison with stationary equipment. The article summarizes the results of mathematical modeling of cutting forces during face milling of a workpiece made of high-strength high-viscosity shipbuilding steel. The application of high-speed face milling in order to reduce the value and non-uniformity of cutting forces is theoretically substantiated. Recommendations for selection of technological cutting modes and tool geometry are determined. The obtained experimental data confirm the possibility and expediency of high-speed face milling of hull structures made of hard-to-machine materials under conditions of a low-rigid technological system.

The article describes the results of laboratory studies on the unfrozen water content and ultimate long-term strength of frozen clay and chalk samples in the temperature range from -10 to -25 �C. The soil samples contained dissolved salt in the pore space, with three types of salts (NaCl, KCl, and CaCl2) being considered. The findings indicate that the influence of the content and type of dissolved salt on the ultimate long-term strength of soils is realized indirectly through the unfrozen water content. In this case, the soil freezing characteristic curve in the region of negative temperatures significantly depends on both the type of dissolved salt and its quantity. The experimental data obtained were used to parameterize the model and calculate the maximum bearing capacity of the frozen wall (FW) in the presence of dissolved salts in the volume of frozen soils. It has been demonstrated that the decrease in the maximum FW bearing capacity is substantial with the appearance of dissolved salt in the pore space of the soils. This decrease is at-tributed to the combined effects of two factors: 1) a reduction in the FW thickness and 2) a decrease in the frozen soil strength due to an increase in the amount of unfrozen water content in the soil pore space. The second factor is deemed more significant.

This work is devoted to an experimental investigation of fatigue behavior of pultruded fiberglass tubes under uniaxial tension, compression and torsion. Static tests were carried out; a presence of postcritical deformation stage during torsion is noted. Regularities of inhomogeneous strain fields evolution are analyzed using digital image correlation method. Fatigue curves are built for four cyclic loading modes: tension-tension, compression-compression, tension-compression and torsion. An analysis of specimens' fractures is carried out, typical damaging mechanisms are revealed. Residual dynamic stiffness data is obtained and studied using a previously proposed fitting model. Results demonstrate model's high descriptive capability and its flexibility to describe two-staged and three-staged stiffness degradation curves. An influence of loading mode on a shape of these curves is found out. Model parameters' dependence on maximum stress value during the loading cycle is studied using the Pearson's correlation coefficient. The necessity of multiaxial fatigue behavior investigation of pultruded fiberglass tubes is concluded.

This study reports an experimental investigation of the fatigue and fracture resistance of R350HT, a heat-treated pearlitic rail steel with refined microstructure used in rails. Monotonic tensile, rotating bending, linear elastic plane strain fracture toughness, and fatigue crack growth rate tests are presented. The results are used to outline the basic properties and are corroborated by fractographic investigation. This enables the identification of the dominant type of fracture. Regarding fatigue and fracture resistance, the investigated material shows similar properties as other pearlitic rail steels, such as R260. At room temperature, the dominating fracture is of brittle cleavage type, showing some ductile regions associated with pro-eutectoid.

The research focuses on examining the impact of technological defects, specifically "dry-spot" and "wrinkles," on the mechanical behavior and buckling resistance of structural composites. The investigation of the buckling phenomenon was carried out through a compression test on a thin plate fabricated from carbon-fiber-reinforced polymer (CFRP) laminate. This test was performed using a specialized fixture designed in accordance with ASTM 3410 standard. For the analysis, the study employed a three-dimensional digital optical system, Vic-3D, in conjunction with the AMSY-6 acoustic emission system. The research showcases findings from acoustic emission signals that verify the shear-based mechanism of buckling in plates constructed from CFRP featuring "dry-spot" type defects. In the case of "wrinkles" defects, it was observed that transverse shear transpires at the stress concentration points created by the "excess" layers.

Partial confinement can provide sufficient reinforcement to enhance the compressive strength and ductility of concrete with lesser confining material. This paper presents the results of an axial compression test conducted on eighteen plain concrete cylinders of 150 mm diameter and 300 mm height partially confined with a Stainless-Steel Wire Mesh (SSWM) strip of different widths. The study included two specimens without wrapping, two fully wrapped specimens, and others wrapped with two SSWM strips of varying widths at both the ends of concrete cylinder. The strain on SSWM up to failure is measured to understand the effectiveness of lateral confining pressure on the behaviour of concrete cylinders. The peak axial compressive strength and corresponding strain of unconfined and SSWM-confined concrete cylinders are compared. The result shows a significant increase in peak confined compressive stress as compared to an unconfined concrete cylinder. However, the confinement efficiency is reduced when the height of the unconfined region exceeds the diameter of the cylinder, and significant strain localisation is detected within the unwrapped region. Based on experimental investigation, a confinement coefficient is suggested for a partial wrapping of SSWM on the concrete cylinder.

In the past five years, the implementation of machine learning (ML) techniques has surged in civil engineering applications, particularly for optimizing and predicting solutions to various challenges. More robust prediction models may be produced by combining test data collected in the laboratory or field with ML. These models may be used to estimate the compressive strength of masonry or repair mortars, probable damage scenarios in buildings, concrete models, beams, and columns for determining the mechanical characteristics of materials, damage detection in civil structures, and so on. This comprehensive review aims to clarify the array of ML-based methods employed in civil engineering, specifically focusing on their efficacy in strengthening energy efficiency and cost-effectiveness. In combination with ML, the review explores corresponding soft computing methodologies such as fuzzy logic (FL) and design of experiments (DOE). A variety of case examples that highlight the versatility of these approaches, particularly in applications linked to structural reinforcement, enhance the story. The review navigates difficulties associated with the integration of soft computing in civil engineering and expands its scope to include emerging research directions. This synthesis of advanced artificial intelligence (AI) serves as a guide, providing new researchers with knowledge about a developing field. These methods could revolutionize the current situation by providing creative answers to complex problems that arise in civil structural applications.

The present study aims to develop a novel hybrid composite by incorporating clamshell as a secondary reinforcing filler into a bamboo-epoxy composite. The primary objective of this hybridization is to optimize the synergistic benefits of each component, harnessing the strength of bamboo fibres, the durability of epoxy, and the cost-effective repurposing of the waste clamshell. Compression moulding was employed to develop composites with varying filler content (0- 9 wt%). The effect of filler on the physical and mechanical properties of bamboo-epoxy composites was evaluated by conducting tests as per ASTM standards. Experimental results show that the addition of clamshell filler significantly improved composites' properties, but there was a limitation to the addition. Hardness, tensile, and flexural properties were increased, whereas impact strength was reduced. Composites with 6 wt% clamshell exhibited optimum properties, enhancing tensile strength by 20.5% and flexural strength by 24.4 % compared to composites without filler. SEM analysis of fractured tensile and bending specimens revealed an enhanced fibre-matrix bonding with the inclusion of filler and supported the experimental results obtained. The outcome of this study contributes to sustainable development by using natural resources like bamboo fibre and repurposing seashell waste to create cost-effective composite material with enhanced properties.

Adopting novel sandwich structures with FRP (Fibre Reinforced Polymer) skins and a metallic lattice core, both of which have high specific strength and stiffness, is one way to achieve better mechanical performance while remaining lightweight. Flexural stress is a load pattern that frequently occurs in the structural frame components of automobiles; nonetheless, while the in-plane load scheme has scarcely been examined, the out-of-plane load one has. As a result, the former configuration received consideration in this work. Moreover, short beam specimens were taken into account. The mechanical response of specimens with three different kinds of composite materials as skin material was analysed. The skins were made of CFRP (Carbon Fiber Reinforced Polymer), with two different weaving styles, and AFRP (Aramid Fiber Reinforced Polymer). All-titanium specimens were studied, too. Similar maximum loads and maximum displacement at break were recorded for both CFRP and AFRP specimens, while the all-titanium one resulted stronger. In terms of the load-displacement curves, the first section featured an initial linear phase, followed by a minor load drop, likely attributed to the breakage of fibres. The CFRP specimens showed a sharp fracture of the skin fibres, while for the AFRP, a fraying was observed.

Most techniques of measuring the stress intensity factor (SIF) in the cracking process assume a crack in a planar medium. Currently, there is no effective approach for curved brittle shells, particularly for non-developable cases, i.e., shapes with non-vanishing Gaussian curvature. This paper introduces a novel approach to obtaining material properties related to fracture by experimentally observing weakly curved surfaces. Based on the DIC record of the displacement field around the crack tip, the truncated Williams expansion is fitted to the data adjusted according to the shallow shell equations. The convergence properties of the method are investigated by comparing experimental data of PMMA cylinders to theoretical and numerical predictions. The applicability of the technique to non-developable surfaces is verified. It is demonstrated that robust convergence requires the number of terms in the Williams expansion exceeding 6. For different geometries, the ratio of the data selection radius and the length of the crack should exceed 0.3.

The determination of residual stresses by combining blind hole drilling and optical interferometric measurement of relief deformation is re-visited to evaluate its applicability to aerospace structures. The experimental methodology involves drilling a deep blind hole and evaluating the hole diameter increments in the principal strain directions using electronic speckle-pattern interferometry (ESPI). This is followed by the determination of the principal residual stress components via the solution of the inverse correlation problem. The study presents the pathway to overcoming one of the primary obstacles in residual stress determination, namely, the optimization of the measurement and interpretation procedures to obtain reliable results. It can be concluded from the analysis of the problem that the formulae connecting the raw experimental data and to the sought residual stress component values lead to a well-posed inverse problem. This makes it possible to obtain estimations of the measurement uncertainty. High density fringe patterns from ESPI provide a rapid and reliable method for residual stress determination, as illustrated using examples of approximately 160 MPa stresses in irregular zones of thick-walled structures.

南郭寺南山佛法身舍利塔是一幢新建于高设防烈度地区山坡平地上的仿古塔建筑，设计使用年限为100年，其建筑造型和结构体系比常规建筑稍复杂。首先通过动力特性分析得到塔的自振周期和振动模态，而后基于振型分解反应谱法和时程分析法，采用有限元软件midas Gen对结构在小震、中震和大震作用下的地震响应进行了数值分析。因为在结构总说明中，只用到了设计使用年限为50年的地震作用，而未将其调整为100年，所以分析中均取2组地震动参数，即设计使用年限50年和100年。小震和中震的地震响应计算均采用弹性法，分析结果满足结构抗震性能要求。大震响应计算时，振型分解反应谱法中将特征周期提高了0.05 s，弹塑性时程分析采用塑性铰滞回模型，最大层间位移角均小于限值1/100。弹塑性时程分析还表明，内核心筒剪力墙的塑性铰发展和屈服程度均比外框架严重，但结构总体处于存在明显塑性变形至不严重破坏的状态，满足“大震不倒”的抗震性能要求。总的来说，南郭寺南山佛法身舍利塔抗震性能安全可靠，其结构体系对于类似仿古塔建筑的结构选型和设计富有借鉴意义。