单轴对称截面轴压构件弯扭失稳的换算长细比是计算其极限荷载的重要参数。基于单轴对称截面轴压构件弯扭失稳的平衡微分方程，采用Galerkin法推导了4种边界约束条件弯扭失稳临界荷载的一元二次方程，并进一步得到了基于荷载比、双长细比的弯扭失稳换算长细比理论式。基于理论式，分别对比了我国现行标准GB 50017—2017中双角钢组合T形截面轴压构件扭转失稳、弯扭失稳的换算长细比，揭示了其中存在的问题；提出了新的双角钢组合T形截面轴压构件扭转失稳、弯扭失稳换算长细比的计算式，并与理论式的计算结果进行对比。结果表明，对于不同边界约束条件的轴压构件，其弯扭失稳临界荷载或换算长细比的形式不尽相同；相较于GB 50017—2017中的公式，所建议的双角钢组合T形截面轴压构件扭转失稳、弯扭失稳的换算长细比具有更高的精度，且适用于4种边界约束条件和115个等边双角钢组合T形截面、71个长肢相并的不等边双角钢组合T形截面和71个短肢相并的不等边双角钢组合T形截面。

为研究标准化Z字形钢结构梁柱连接节点的转动刚度，对翼缘焊接和搭接两种形式的Z字形钢结构梁柱连接节点进行了单调和往复循环加载试验及有限元分析。研究了不同连接节点设计强度对Z字形钢结构梁柱连接节点转动刚度和循环刚度退化等力学性能的影响。结果表明，翼缘焊接和搭接两种形式的Z字形钢结构梁柱连接节点均具有良好的延性和滞回性能。翼缘焊接Z形节点转动刚度表现为刚性连接，翼缘搭接Z字形钢结构节点转动刚度表现为铰接。对于翼缘焊接Z字形钢结构梁柱连接节点，其转动刚度和循环刚度退化程度受焊缝连接强度影响显著。较小的强度设计倍数（0.2～0.4）时节点破坏模式为焊缝率先发生破坏，其节点转动性能表现为半刚性。较大节点强度设计倍数（0.7～1.1）时节点破坏模式转变为构件率先发生破坏，节点表现为刚性连接且其循环刚度退化程度（转角小于0.02 rad条件下）明显小于强度设计倍数较小的Z字形钢结构节点循环刚度退化程度。总体上看，可通过改变节点强度设计倍数来调节其转动刚度。

随着国内风电行业发展规模日益壮大，风机功率逐渐增大，对下部支撑结构的承载能力、稳定性能也提出了更高的要求，钢-混凝土混合结构塔筒（上部纯钢塔，下部混凝土塔）应运而生。然而，由于需要现场拼装、灌浆，因此其建造效率低且后期维护成本高。基于此，提出了一种新型预应力钢管混凝土格构式风电塔架代替原有的钢-混凝土混合结构塔筒，四角柱采用预应力中空夹层钢管混凝土，提升刚度的同时减少了钢材和混凝土的用量，便于运输和吊装。中空部分作为预应力孔道进行通长整体张拉，增加结构稳定性及轴向滞回性能。目前已有学者进行了钢管混凝土构件轴向拉-压性能的研究，但鲜少有针对预应力中空夹层钢管混凝土构件轴向复杂受力情况的研究报道。为了弥补现有研究的空白，针对预应力中空夹层钢管混凝土构件在轴拉、轴压及拉-压滞回荷载作用下的力学性能开展试验研究，为我国制定风电塔架的设计标准提供一定的理论基础和试验依据。

Autoclaved Lightweight Concrete （ALC） walls have become a commonly used wall form in prefabricated building structures， but wall cracking， which often occurs during normal use， adversely affects the aesthetics and durability of the building. In order to study the cracking resistance of embedded ALC wall panels and their effect on the stress performance of steel frames， this paper designs and completes the quasi-static full-scale tests of two single-story single-span rigidly-jointed steel frame specimens with embedded ALC walls which are connected to the steel frames with in-built anchors and pipe clips， respectively. Varying different wall finishes， the hysteresis curves， skeleton curves， stiffness degradation curves of the specimens are obtained from the actual measurements and the key experimental phenomena are observed. The test results show that the hysteretic curves of the two specimens are full hysteresis loops， the bearing capacity of the built-in anchor specimen is slightly higher than that of the pipe clip specimen， and the specimens have a good ability to work together. Considering the load capacity and stiffness， the lateral resistance of the built-in anchor specimen is better than that of the pipe clip specimen. The use of modified two-component MS adhesive as the connection material between ALC wall panels and steel frames results in later cracking compared to the use of polyurethane foam connection， which indicates that MS adhesive has a good deformation capacity， which helps to improve the cracking resistance of the wall.

将普通C型钢截面翼缘段弯折形成折叠翼缘截面，可以降低翼缘宽厚比并增大截面高度，从而改善受弯构件的稳定性能并提高其抗弯承载力。为了研究折叠翼缘冷弯薄壁C型钢构件在纯弯状态下的抗弯性能，采用ABAQUS有限元软件建立了数值计算模型，分析了板件宽厚比、板件间角度和板件相对尺寸对构件极限承载力、屈曲破坏模式、变形特征及应力分布的影响，并与普通C型钢构件的抗弯性能进行对比分析。在此基础上，开展了抗弯承载力计算方法研究。数值分析结果表明：折叠翼缘构件发生了畸变屈曲以及局部和畸变的相关屈曲，并且翼缘与卷边的不同组合形成了两种不同类型的畸变屈曲变形。相同材料用量下，翼缘弯折角度取105°、卷边弯折角度取90°时构件承载力最大。当板件间角度不变时，随着弯折后翼缘段宽度比值的增加，折叠翼缘构件的抗弯承载力逐渐提高，提高幅度约为14%～49%。此外，采用AISI S100中的直接强度法公式计算了折叠翼缘构件的极限承载力，并与有限元分析结果进行了对比。对比结果表明，采用直接强度法计算的局部与整体相关屈曲的抗弯承载力离散程度较大，故基于参数分析结果对计算公式进行了修正。

With the advantages of standardization， integration and industrialization， modular steel building has quickly attracted the attention of academia and industry. In this paper， the authors summarize the semi-rigid and rigid connection of modular steel buildings and mainly focus on weak connection， poor cooperative performance of adjacent components and weak robustness. The advantages and disadvantages of existing modular connections are elaborated from mechanical mechanism and construction. The idea of "connected at both beam and column end" is proposed. For the cooperative performance of beam-beam and column-column between modules， the similarities and differences with steel-concrete composite beams and lattice columns are analyzed. Considering the decoration and construction， the solution of composite beam （column） with discontinuous connection is put forward. Additionally， the patterns influencing the robustness of modular steel buildings are summarized. Based on the existing research， it is recommended to conduct more in-depth research on rigid connections between modules， composite components with discontinuous connection， and system analysis.

Steel frame with the reactor is subjected to large and high-frequency dynamic load when the reactor is stirring. However， the design of this kind of steel frame structure usually adopts the static design method， and the static analysis cannot accurately describe the dynamic effect of the reactor acting on the structure. In order to efficiently research the dynamic effect of the steel frame supporting the reactor during the operation of reactor， a simplified modeling method is proposed in this paper to connect the reactor dynamic system with the steel frame using mass points and beam elements. Based on the current standard Vessel Supports—Part 4： Supporting Supports （NB/T 47065.4—2018）， the performance of the bottom joint of the reactor support， the overall structure， and the dynamic response of the reactor stirring blade under different rotation directions are studied， and the optimization design research on this type of structure is conducted. The results show that the vessel supports and joints designed according to the current standard are the weak parts of the structure， while the optimization design of the support based on the S-N fatigue curve of steel can ensure the structure remain within the elastic limit during normal operation. The method of "opposite of adjacent" used on setting the rotation direction of the reactor stirring can make the load-bearing structure have the minimum elastic deformation. This study provides some reference for the related design and research work.

Compared with block precast bridge deck， transverse full-width prestressed precast bridge deck has better integrity， faster construction， and a better application prospect in assembled composite beam bridge. The wet joint connection of the precast bridge deck under negative bending moment is the key part of the composite beam. Therefore， the mechanical properties of full-width prestressed precast bridge deck composite beam under negative bending moment are studied， the influence of the number of transverse prestressed bars， the arrangement of prestressed bars， the degree of shear connection and the materials at the joints on the mechanical properties such as structural failure mode， cracking load， bending bearing capacity and load-displacement curve is made clear， and the stress distribution at the joints of precast slabs is revealed. An improved effective moment of inertia superposition method for deflection calculation of precast bridge deck composite beams with complete shear connection is proposed， which considers the influence of longitudinal and transverse prestress and is in good agreement with the numerical results. For composite beams with partial shear connection， the domestic and foreign codes are compared， and it is concluded that the Standard for Design of Steel Structures in China is more applicable.

The application of ultra-high performance concrete （UHPC） to steel reinforced concrete structures can improve the load carrying capacity， reduce the cross-section size， and solve the problems of complex construction caused by the intensive configuration of stirrups and shear members. The current finite element simulation study of steel reinforced UHPC beams is mainly a parametric qualitative study of bending capacity， ignoring the bond-slip effect between steel and UHPC， which lacks the assessment of its interfacial bond performance and combination effect， as well as the in-depth discussion of the stress performance of the UHPC in tensile zone. In this paper， the finite element simulation analysis of the bending performance of steel reinforced UHPC beams was carried out based on ABAQUS， and the strength of UHPC， the strength of steel， the longitudinal reinforcement ratio and the steel ratio were parametrically investigated. The load-mid-span deflection curves， cross-section strain distribution， interface bond stress distribution， and tensile zone performance of the UHPC were analyzed. The main conclusions are as follows： （1） The loading process of the composite beam can be divided into four stages： the fully elastic stage， the damaged working stage， the plastic hardening stage， and the ductility development stage. （2） The UHPC in the tensile zone can still participate in the section bending resistance at the peak load， and suggestions for the value of the equivalent stress reduction factor for the tensile zone of UHPC are proposed based on parametric research. （3） The bond stress of the upper flange is mainly concentrated at the loading area， while the distribution of the bond stress on the lower flange is controlled by the development of cracks. The bond performance between the steel section and UHPC at the interface should be improved in the design by means of shear connectors or surface treatment of the steel profiles. （4） During the design process of composite beams， the strength and configuration rate of the steel profiles should be limited to ensure that the composite beams have good ductility and the UHPC in tensile zone exhibits good load-bearing performance.

Based on the lightweight steel-concrete framework system of modular wall structures， this study proposed a lightweight steel-concrete composite column-H-shaped steel beam joint suitable for this system. In order to study the mechanical properties of this joint， monotonic loading tests were carried out on three groups of beam-column joint specimens. The experimental results indicate that under monotonic loading at the beam end， the joint exhibits distinct semi-rigidity characteristics. The failure is characterized by yielding deformation of the flange of the combined steel column and concrete cracking， ultimately leading to joint failure due to excessive bending deformation of the top angle steel and the cracking of the stiffener weld. A refined simulation was conducted using ABAQUS finite element software. The deformation process and failure characteristics of the finite element model agree with the experimental results. The researchers consider three key parameters， namely， the height of the H-shaped steel beam section， the thickness of the C-shaped steel， and the thickness of the angle steel， a parametric analysis was performed. The results indicate that increasing the beam section height and the thickness of the angle steel connector significantly enhances the joint's flexural load-carrying capacity and initial rotational stiffness. In contrast， increasing the thickness of the C-shaped steel has a limited impact on the joint's flexural load-carrying capacity， with a minor effect on the initial rotational stiffness.

为研究GFRP-橡胶混凝土-钢双管组合柱（GFRP-rubber concrete-steel double-skin tubular columns,RCDSTCs）的轴压性能，对7个长柱试件进行了轴压试验。观察RC-DSTCs在轴压状态下的破坏模式，基于荷载-位移曲线、荷载-应变曲线和环向-轴向应变曲线分析了长细比、空心率对RC-DSTCs轴压性能的影响，提出了RC-DSTCs的轴压理论承载力计算式。结果表明：随着长细比的提高，RC-DSTCs的轴压破坏模式由材料破坏向弯曲失稳破坏转化，但所有RC-DSTCs的钢管均达到了屈服应变0.2%；同时，随着长细比的提高，RC-DSTCs的峰值荷载、GFRP管约束作用及延性显著降低；而随着空心率从0.3增加至0.4,RC-DSTCs的延性有明显提高；RC-DSTCs的轴压承载力计算结果与试验结果比较吻合，可为后续工程应用提供参考。

为研究螺栓连接梯形波纹腹板钢梁的受剪力学性能，设计并加工制作了6根螺栓连接梯形波纹腹板钢梁试件，开展钢梁受剪试验，试验结果表明所有试件的波纹腹板均发生了剪切屈曲破坏，并得到了波纹腹板的剪切屈曲临界荷载以及钢梁的受剪承载力指标。在考虑材料非线性、几何非线性以及几何初始缺陷的基础上，建立了螺栓连接梯形波纹腹板钢梁的有限元模型，并与钢梁受剪试验结果进行对比，验证了所建立有限元模型的准确性。进一步开展有限元参数分析，探究了波纹腹板高度和厚度、波纹宽度以及螺栓间距对钢梁受剪承载力的影响规律。根据试验数据、76个有限元算例的分析结果，以及目前关于焊接梯形波纹腹板钢梁受剪承载力的计算方法，综合考虑T型钢翼缘的抗剪贡献，提出了螺栓连接梯形波纹腹板钢梁受剪承载力计算公式。

In order to accurately evaluate the seismic damage of concrete-filled steel tubular （CFST） arch bridge， this paper regards the arch bridge system as a series-parallel system， that is， the key systems of the arch bridge system are connected in series， and the single components of different key systems are connected in series or in parallel. Taking a CFST arch bridge as the research object， the seismic response values of each component of the arch bridge are obtained by time-history analysis and neural network prediction. Based on the Copula function， the vulnerability of each key system and the overall system of the arch bridge are obtained respectively， and compared with the system vulnerability based on the first-order boundary method. The results show that the accurate seismic response value of arch bridge structure can be obtained by neural network prediction. When the peak ground acceleration A _PG=0.4g， the prediction accuracy rate exceeds 90%， and with the increase of A _PG， the accuracy rate gradually increases. Among the key component systems of the arch bridge， the failure probability of the arch column system is the highest， and the seismic isolation measures should be taken in the seismic design. The failure probability of the wind bracing system is the lowest， and the influence of the wind bracing system can be ignored in the vulnerability analysis of the arch bridge system. The vulnerability of the arch bridge system based on the series-parallel system is between the upper and lower bounds of the first-order boundary method. When the A _PG=0.3g， the failure probabilities of the series-parallel system under mild， moderate and severe damage conditions are 98%， 94% and 25%， respectively. The relative deviations from the upper bounds of the first-order boundary method are -1.4%， -3.1% and -16%， respectively， and the relative deviations from the lower bounds are 0.6%， 3% and 11%， respectively. It is obviously more reasonable to use the series-parallel system to analyze the vulnerability of the CFST arch bridge.

为实现模块化钢框架结构的高效装配，对所提出的新型模块化钢框架模块间全螺栓装配式内套筒连接节点进行了有限元与理论分析。采用经验证的ABAQUS有限元模型，分别对静力和拟静力作用下具有不同构造参数的新型模块间连接节点进行有限元参数分析，研究了内套筒长度和厚度、连接板厚度以及模块柱间距等参数对新型节点承载能力的影响。结果表明：新型模块间内套筒连接节点的承载力及抗震性能表现良好；在梁影响域内，增加内套筒长度可显著改善新型节点的受力性能。基于分析结果，给出了新型节点的优化与设计建议，并建立了适用于该新型节点的简化恢复力模型，可为模块化钢框架结构的进一步推广与应用，以及实现建筑工业化、产业化发展提供参考。

The large-span steel roof structure adopts a segmented and stepwise overall lifting construction technique. During the construction process， there are sudden changes in the structural system and boundary conditions， and the overall lifting is a dynamic process with abrupt variations in the structural force state. In response to the dynamic construction process， including the overall lifting， stress and deformation change rate indicators are proposed based on first-order differences of time series. A three-level early warning mechanism and thresholds for stress and deformation are introduced based on simulation results of the construction process and the 3σ criterion. A monitoring of component stress and structural deformation was conducted during a static loading test on a K6 reticulated shell， with the monitoring results analyzed and used for early warning. The results indicate that before the overall collapse of the shell structure， there are clear nonlinear characteristics in the structural force state. The proposed stress and deformation change rate indicators， along with the early warning mechanism， can effectively warn of nonlinear changes in the force state before an overall collapse， allowing personnel to take emergencymeasures in advance. The proposed change rate monitoring indicators and early warning mechanism were applied to the overall lifting process of the steel roof structure at Shanghai Songjiang South Station to verify the feasibility and effectiveness of the proposed method. The results show that the change rate indicators and their early warning mechanism can effectively warn of abrupt changes in the structural force state caused by load and boundary changes during the lifting process， validating the effectiveness of the proposed method.

To provide experimental data and recommendations for the application of high-strength steels in low-temperature environments， this paper focuses on two key influencing factors： welding heat input and different delivery conditions of base metals. Two types of high-strength steels， Q550D and Q690D with thicknesses of 20mm， were selected in thermo-mechanically controlled process （TMCP） and quenched and tempered （QT） conditions. Three commonly used gas shielded welding heat inputs of 1.0 kJ·mm^-1， 1.5 kJ·mm^-1， and 1.9 kJ·mm^-1 were applied to prepare the joints. The impact toughness tests were conducted， and the results were analyzed and compared. A systematic study was performed on the Charpy impact energy and transition temperature of the base metal， weld metal， and heat-affected zone （HAZ） in butt joints under different delivery conditions. The results indicate that the effect of welding heat input on the impact toughness of various regions of the joints is insignificant， while the delivery condition significantly affects the impact toughness. Specifically， the impact toughness of the HAZ in QT steel joints is superior to that of the base metal and weld metal， whereas in TMCP steel joints， the impact toughness of the HAZ is lower than that of the base metal and weld metal. The study on the ductile-to-brittle transition temperature under controlled conditions suggests that the high-strength steels used in this study exhibit good low-temperature sensitivity.

为实现建筑和工业废弃物的再利用，采用镍铁渣代替部分水泥、再生粗骨料代替天然骨料制备镍铁渣再生混凝土（RFC）。进一步地，将RFC填入圆钢管中形成钢管掺镍铁渣再生混凝土（RFCFST）柱。对11根RFCFST柱进行水平低周往复抗震性能试验研究。试验变量包括再生粗骨料取代率、轴压比、约束水平和剪跨比。试验结果表明，RFCFST柱与传统钢管混凝土柱的破坏模式相似。P-Δ效应会显著降低柱的抗侧能力和变形能力，尤其是在大轴压比和大剪跨比情况下。骨料取代率对RFCFST柱的承载力、变形能力和耗能能力几乎无影响。随着轴压比的增大，柱的变形能力降低，但单圈耗能能力增强。试件的水平承载力和延性随着套箍水平的提高而提高，随着剪跨比的增大而降低。基于试验结果和理论分析，提出了RFCFST柱水平力-位移角恢复力模型。

为使大跨钢屋盖结构抗火设计同时满足安全可靠、功能适用和经济合理的要求，对合肥新桥机场T2航站楼钢屋盖进行了基于仿真模拟的抗火设计。首先对典型的钢管混凝土柱、钢柱进行了基于构件的抗火性能仿真模拟，分析和比较了无防火保护和在不同等效热阻防火涂料保护下的温度场分布和构件耐火极限；对屋盖桁架和钢梁进行了基于整体结构的抗火性能仿真模拟，得到了考虑热膨胀效应下的屋盖构件耐火极限。最后基于分析结果，提出了抗火设计方案如下：支承钢屋盖的钢管混凝土柱和钢柱采用膨胀型防火涂料保护以实现3 h耐火极限；离楼面9 m以上钢屋盖构件不采用防火保护措施。

The novel T-head one-side bolt can effectively solve the problem that the traditional high-strength bolt cannot be directly applied to the bolted beam to tubular column joints. However， the bearing mechanism of each component in the beam-column joint with this novel bolt is still unclear and needs to be further explored. The T-head one-side bolt is characterized by the shape of the bolt hole on the endplate and tubular column. To explore the mechanical response and bearing mechanism of the endplate and beam components in this novel bolted connection， the finite element analysis software ABAQUS was used to carry out a systematic numerical analysis on the tensile performance of the T-stub connections based on the component method. The main research contents and conclusions are as follows： an accurate three-dimensional finite element model of the connection was established， and five yield line patterns on the T-stub flange in T-head one-side bolted joint was studied. Finally， the calculation formula for the yield strength of T-stub joints with T-head one-side bolts is given based on the principle of virtual work and the yield line theory.

大跨度钢结构空间造型丰富，施工阶段结构的传力路径与最不利受力位置动态变化。为解决施工过程结构分析与安全复核时建模计算流程繁琐的问题，基于AutoCAD与ANSYS软件开发了大跨度钢结构一键式建模、计算与结果读取的插件。该插件采用C#语言调用AutoCAD. NET框架，读取并输出大跨度钢结构图纸文件中的模型信息，自动生成结构有限元建模、计算与结果读取的APDL命令流，可用于大跨度钢结构施工过程的数值模拟与安全评估。以某单层球面网壳结构为例验证了所开发的大跨度钢结构建模分析插件的有效性，使用该插件快速建立了有限元分析模型，并复核了结构在施工阶段的内力和变形。研究结果表明，单层球面网壳结构在施工全过程中满足强度和稳定性要求，内力和变形在安全范围内且满足设计要求。该插件能够高效、准确地将大跨度钢结构信息由CAD软件传递至CAE软件，完成施工过程的数值模拟与安全评估。

对于局部火灾，需要考虑建筑物构件在不均匀受热情况下的热学与力学响应。以方钢管梁为研究对象，模拟其不同高度处承受底部火羽流冲击作用的热力学现象。不同于应用绝热表面温度概念来实现流固传热的单向迭代耦合，提出一种新的计算流体力学-有限元数值（computational fluid dynamics-finite element method,CFD-FEM）模拟手段，通过采用CFD方法统一分析火灾模块与热模块来实现流固传热界面的双向直接耦合。首先通过典型局部火灾试验验证了该数值方法的准确性。继而在火灾模块中探究了空间速度场与温度场的分布规律，在热模块中探究了不同高度处钢梁壁面热流的变化规律，以及辐射与对流热流随时间的变化规律。最后以固体温度为边界条件完成了结构模块分析，实现了固体域热力耦合，探讨了在此局部火灾场景下不同高度处钢梁的力学响应，探讨了其在受热后出现的屈服强度退化现象。

The complex structural behaviors in steel spiral staircases， due to their unique and irregular structures， render traditional linear analysis methods inadequate for accurate prediction of structural responses and stability design， particularly in determining effective lengths. This study employs the direct analysis method （DAM） to overcome these limitations， taking into account the overall structural and member initial imperfections， thus providing an efficient and safe approach for the analysis and design of such structures. A specific engineering project is presented as a case study， utilizing NIDA software to perform a stability investigation via DAM， with results compared against those obtained through linear analysis. The research examines the mechanical responses under full-span loading， left and right half-span loading， and various live load distributions across different sectors， as well as the impact of varying support conditions on the staircase structure. The findings indicate that the maximum component stress determined by DAM exceeds that of first-order linear analysis， with a maximum utilization factor reaching 0.993， and a corresponding vertical displacement that is even more significant， peaking at 0.348 m， confirming the importance of second-order effects. In the design of steel spiral staircases， adverse distributions of live loads， especially under left half-span loading conditions， should be given special consideration. For live load distributions， the impact is greatest in sectors 3 and 4， located at the mid-span of the staircase. Moreover， increasing the stiffness of the top support contributes to a reduced stress ratio while also leading to an increase in bending moments due to second-order effects. This research plays a significant role in guiding the analysis and design of steel spiral staircases.

In order to investigate the axial compression bearing capacity of 7075-T6 aluminum alloy square tubes， nine specimens were fabricated and subjected to axial compression tests. The study obtained the ultimate bearing capacity， failure modes， and load-axial displacement curves of the specimens. Finite element models of the specimens were established for numerical analysis， and the effectiveness of finite element numerical analysis was validated by comparison with experimental data. Parametric analysis was conducted using finite element numerical analysis， proposing a overall stability coefficient-relative slenderness ratio curve suitable for 7075-T6 aluminum alloy square tubes. The paper discussed the influence of local buckling on bearing capacity as the relative slenderness ratio varied. The results indicate that 7075-T6 aluminum alloy square tubes exhibit certain ductility. The established finite element models accurately simulate the entire loading process and ultimate bearing capacity of the specimens. The proposed overall stability coefficient-relative slenderness ratio curve has better accuracy than the softening curve. For members with the same cross-section but different relative slenderness ratios， the influence of local initial geometric defect on the ultimate bearing capacity varies.

As an independent energy-dissipating component designed separately from the eccentrically braced steel frame， the replaceable shear links not only confine the plastic deformation of the structure to the region of the energy-dissipating links during large earthquakes， but also， more importantly， facilitate the repair of the structure after the earthquake. In this paper， three scaled models of this steel frame structure were fabricated and unidirectional shaking table tests were conducted to obtain the dynamic characteristics， plastic development and damage mechanism of the structure， and the stress distribution， displacement response and acceleration response of the model were analysed and studied. The results show that the specimen has good energy dissipation performance， and the sequential energy dissipation of shear links and buckling-restrained brace members makes the structure have good seismic performance under earthquake. The maximum inter-story drift angle of the buckling-restrained eccentrically braced steel frame specimen with replaceable shear links meets the requirements of the code， and it has a good safety as well as strength reserve. The structural deformation is mainly dominated by shear deformation， and the increase of shear force in each layer is relatively balanced， and it has excellent seismic performance. The acceleration amplification factor of the multi-story structure can be reduced under large earthquakes to effectively reduce the dynamic response of the structure.

加快钢结构制造智能化升级，发展新型建造方式，不仅是推动建筑业高质量发展的重点任务，也是我国向制造强国目标迈进的主攻方向。建筑钢结构制造属于典型的离散制造生产方式，具有标准化程度低、生产批量小和种类多样的特点，目前多采用人工辅助的机械化生产，制造生产方式仍然比较落后，因此解决建筑钢结构制造的关键技术问题对实现建筑工业化和智能化具有重要意义。针对建筑钢结构智能制造存在的装备智能化程度低、制造工艺较传统及生产管控数字化不足等问题，研究了建筑钢结构智能制造生产线规划设计、智能装备和先进制造工艺技术以及生产过程数字化管控等诸多内容，并通过数字孪生模型和微型生产线联调联动测试实验对智能生产线的可行性进行了技术验证，为钢结构智能生产线设计和既有生产线升级改造提供了很好的应用示例。

金属消能构件进入屈服状态后产生阻尼，从而达到消能的作用，通常采用等效阻尼系数来度量消能的效果，而等效阻尼系数由滞回曲线形状、屈服承载力、屈服后刚度等因素决定。基于双线性滞回模型，推导了屈服后刚度比与等效阻尼系数的关系式。研究结果表明，随着屈服后刚度比的增大，等效阻尼系数减小，且减小幅度随着消能构件延性系数的增大而逐渐增大。为研究防屈曲钢板墙这种金属消能构件的屈服后刚度特征，设计了网状分布加劲肋夹板的防屈曲钢板墙试件，通过试验确定其滞回特性，并通过试验结果校核有限元模型。通过有限元分析芯板材料类型、芯板高厚比、高宽比对防屈曲钢板墙屈服后刚度的影响。分析结果表明，防屈曲钢板墙芯板材料类型、高宽比对屈服后刚度的影响较为显著。对于高宽比为1.2的试件，在变形幅值为1/100的墙高时，相较于芯板材料为Q235的钢板墙，芯板材料为LYP100和LYP160的钢板墙屈服后刚度比分别下降了80.23%和72.77%。而对于芯板材料同样为Q235钢板墙但高宽比为2.0的试件，其屈服后刚度比是高宽比为1.0试件的2倍。通过参数分析拟合得到了不同芯板材料类型的防屈曲钢板墙屈服后刚度比的计算式。

In order to explore the determination of the number of strengthened stories and the arrangement of strengthened story components for super high-rise frame-tube structures with large aspect ratios， and to obtain a strengthened story layout plan that can meet the structural needs while minimizing the adverse effects of vertical stiffness and internal force mutations caused by the strengthened story， the T2 tower of Qingdao Haitian Center is taken as the research object， and a three-dimensional structural model is established based on ETABS software for analysis. After comparing the traditional scheme of arranging strengthened stories with improved schemes， a setting principle of strengthened story of super high-rise frame-tube structure with large aspect ratio based on this structure is proposed.The outrigger trusses and waist trusses are arranged in the direction with low stiffness， while the outrigger trusses are not arranged in the direction with high stiffness， and waist trusses are only set within the end spans. This approach not only can meet the structural demands of lateral displacement and inter-story drift， but also can reduce the abrupt change of inter-story drift and internal force. At the same time， the stiffness difference between the two main axes at the strengthened story is reduced， which is most beneficial to the structure.

In order to study the behavior of cold-formed thin-walled stainless steel built-up box section stub columns， a total of 25 fixed-ended stub columns including 14 built-up section specimens without holes， 6 unstiffened channel or edge-stiffened channel section specimens and 5 built-up section specimens with circular web holes were tested under axial compression. The material of specimens was S30408 austenitic stainless steel. The experimental results involving failure modes， ultimate capacities and responses of load versus axial shortening were obtained and fully documented. The experimental results show that the type of built-up section has a significant effect on the ultimate bearing capacity of the built-up section column， in which the test specimens of CC-section and UU-section exhibit the largest and smallest bearing capacity respectively. The ultimate bearing capacity of built-up UU-section specimens is larger than the sum of the bearing capacity of the single channel section specimens. The holes on the web have almost no weakening effect on the ultimate bearing capacity of the specimens when the hole diameter-to-web height ratio is less than 0.5. The test results were compared with predictions calculated by the design method as per the current American Specification ASCE/SEI 8-22. It is found that the test strengths were lower than the predicted values， indicating that the current codified provision in ASCE/SEI 8-22 is not applicable to be directly used for ultimate bearing capacity predictions of the cold-formed thin-walled stainless steel built-up box section stub columns.

A light steel-steel fiber recycled concrete composite column （SFRC composite column） was proposed. In order to study the axial compression performance of the composite column， five groups of short column specimens with varying configuration were tested， including one group of steel column specimens and four groups of composite column specimens. The effects on the failure characteristics， load-displacement curves， bearing capacity， stiffness and ductility of composite columns were studied with the parameters of section configuration， steel fiber content and recycled concrete strength. The results indicate that the SFRC composite column enhances the stability of the light steel column and substantially increases its bearing capacity. The bearing capacity of SFRC composite column increases with the addition of steel fiber. Steel fiber can restrain the crack development of recycled concrete and reduce the damage and stiffness degradation of specimens. The bearing capacity of composite column increases with the increase of recycled concrete strength， but the ductility decreases accordingly. A formula for calculating the compressive bearing capacity of SFRC composite short column has been established based on the code.

建筑结构火灾事故频发，火灾可能对建筑物造成严重损伤，甚至引起建筑物倒塌，导致人民生命和财产的巨大损失。对于遭受火灾但未倒塌的建筑物，通过修复加固后可实现再利用。修复加固前，需要对受火损伤的建筑结构进行科学、详细、准确的检测和鉴定，确定建筑结构材料的剩余强度和构件的损伤程度，为建筑结构的修复加固提供依据，从而达到经济且安全地恢复建筑结构使用功能的目的。归纳了火灾后建筑钢结构检测与评估的研究进展，介绍了建筑结构火灾后现场调查分析的步骤和方法，分析了构件及火场经历的最高温度的判定方法及其适用性，指出了火灾后钢材力学性能推断与检测的方法及其优缺点，论述了构件及结构火灾后残余变形的测量内容和方法，总结了火灾后构件及结构剩余承载力的相关研究及验算方法。同时指出了有待进一步研究的问题，为建筑钢结构火灾后检测与评估的理论研究和工程应用提供参考。

连体结构在连体与塔楼间采用刚性连接时，该连接段受力复杂，特别是在考虑提升施工的影响后，连接段杆件受力与设计一次成型的杆件受力有显著区别。由此提出可通过分阶段卸载的方式使连接段内力与设计状态对应内力接近。分阶段卸载的分析可归纳为3个关键步骤：首先根据施工方案、现场环境等客观因素确定卸载方案；再采用有限元软件获取每个阶段（含多次卸载及拆杆）的杆件内力变化情况；最后通过优化理论可获得单次阶段最佳的卸载量分析。以杭州云门钢结构为例，进行分阶段卸载的方案探讨、计算假定的验证以及结构空间效应分析，结果表明分阶段卸载极大提高了施工后与设计一体成型的连接段结构内力的一致性。

为了实现房屋的折叠与展开并满足其受力需求，在传统剪支铰折叠结构的基础上，提出一种新型杆式折叠结构。首先，对新型杆式折叠结构进行设计和优化，采用螺旋理论对其进行自由度分析。同时，建立高度为2.2 m的ABAQUS有限元模型，对其施加平面内竖向荷载，获得不同铰接约束次数、钢材强度等级、销轴孔径、槽钢立柱壁厚、杆件宽度条件下折叠结构的初始刚度、极限承载力和破坏模式。最后，对折叠结构进行稳定性分析，提出了设计建议。结果表明：当折叠结构展开后高宽比为1/2^1/2时，可以达到最大折叠率；折叠结构展开过程中机构自由度为1，当折叠结构完全展开并施加一定铰接约束后结构自由度为负值；次要受力杆件、销轴孔径对结构初始刚度和极限承载力影响不大；提高钢材强度等级、槽钢立柱壁厚、主要受力构件宽度可提高结构初始刚度和极限承载力，但是其值过高时会导致结构发生失稳破坏；为避免结构失稳，可通过促进塑性铰形成和将特定杆件改为箱形截面两种途径来实现。

为促进建筑节能减排和全过程减碳，建筑拆除及回用关键技术成为了当前研究的重点。螺栓球节点作为建筑结构中的一种关键节点，其循环利用过程对受拉承载能力的影响却鲜少被研究。因此，对螺栓球节点开展了考虑循环利用损伤的轴拉力学性能试验研究。研究结果表明：当持荷水平不大于高强螺栓承载力设计值的90%、拆装次数不大于10次且锤击损伤程度不大于80%时，反复拆装损伤对节点抗拉承载力的影响可忽略不计，锤击损伤对反复拆装节点的受拉极限承载力的影响可采用0.95的安全系数来考虑；无论是否发生锤击或打磨损伤，节点抗拉承载力随拧入缺陷损伤的增加几乎呈线性下降；在拧入缺陷损伤的基础上，锤击或打磨损伤对节点承载力的影响在20%范围内；其余条件相同时，双侧锤击或打磨损伤比单侧损伤对节点抗拉承载力的影响小，打磨损伤比锤击损伤对节点抗拉承载力的影响小。工程中对该类节点进行拆除及回收利用时，须严格控制拧入缺陷造成的螺纹损伤并注意单侧锤击损伤。

为提高钢桁框体系的抗震可恢复性，提出了自复位钢桁框体系的概念，并研究了其在脉冲地震下的强度折减系数。以等效单自由度体系表征具有三折线滞回特征的钢桁框体系，选取182条脉冲型地震动对等效单自由度体系进行非线性动力分析，得到一个包含约6 022万个强度折减系数的数据库，揭示了不同滞回参数和脉冲型地震动对强度折减系数的影响规律。此外，借助BP神经网络拟合强度折减系数在地震下的对数正态分布模型参数，并建立了基于概率的钢桁框体系强度折减系数模型。结果表明所提出的模型具有较高的准确性。

This paper proposes a new type of steel-bars truss deck with permanent bottom form （PFCB-steel-bars truss deck）， which is an assembled floor deck consisting of steel-bars truss and permanent fiber cement bottom （PFCB） prefabricated with self-tapping screws and connectors. In order to study the structural performance of PFCB-steel-bars truss deck in the construction stage and to consider the influence of moisture in concrete mortar or precipitation weather on fiber cement bottom form during construction， a compressive capacity test of PFCB-steel-bars truss deck was conducted under water-saturated condition. A parametric analysis of the steel-bars truss deck structure was carried out using finite element software simulation， and the change rule of ultimate bearing capacity and stiffness was obtained. The results demonstrate that the PFCB-steel-bars truss deck has good performance under uniform design combination load and concentrated load， and the deflection of the specimens with a span of 3 600 mm is controlled to be between 6-8 mm under the ultimate load. Moreover， the change of the self-tapping screws spacing and the height of the steel trusses has a more obvious effect on the load bearing capacity of specimens.

The mechanical properties of the axial compression members of the double-shear splicing main members were studied through 10 sets of axial compression tests. The effects of different bolt connection lengths （120 mm， 180 mm and 240mm） and steel-clad area ratios （1.08， 1.22 and 1.31） were investigated. The ultimate failure mode， ultimate bearing capacity and load-displacement curve of the test members were compared and analyzed. The experimental results show that the ultimate failure mode of the angle steel main members without splicing joints is the flexural-torsional buckling failure around the main axis at the mid-span section， and the out-of-plane deformation is the largest and the torsional deformation is small. When the angle steel main member adopts the double-shear splicing joint， the axial compression ultimate failure mode is divided into two cases： when the bolt connection length at the double-shear splicing joint is not more than 120 mm or the steel-clad area ratio is 1.08， the compression failure mode of the main member is mainly mid-span cross-section flexural-torsional buckling， accompanied by the failure of the splicing joint. When the bolt connection length is greater than 120 mm and steel-clad area ratio is greater than 1.08， the compression failure mode of the splicing main member is the coupling failure of the flexural-torsional buckling at the mid-span near the joint and the local buckling at the inclined member. Combined with the test results， the existing calculation methods of the standards are demonstrated and analyzed， and the structural design suggestions of L125×10 angle steel main member are given. The research conclusions are conducive to promoting the development of transmission line structure design technology and laying a technical foundation for the compilation and improvement of transmission line structure design specifications.

为研究钢框架-覆竹木碳纤维板轻钢剪力墙结构的抗震性能，利用有限元软件ABAQUS对低周往复荷载作用下的冷弯薄壁型钢骨架墙体试件、覆竹木碳纤维板冷弯薄壁型钢墙体试件和钢框架-冷弯薄壁型钢骨架墙体试件进行分析，并通过试验验证了分析的合理性。对钢框架-覆竹木碳纤维板轻钢剪力墙结构进行全过程非线性分析，揭示其不同应力阶段的发展过程及破坏模式，研究冷弯薄壁型钢骨架壁厚、竹木碳纤维板厚度、竖向荷载和斜撑布置等因素对该类框剪结构抗震性能的影响。结果表明，结构的抗剪承载力和抗侧刚度随着冷弯薄壁型钢骨架壁厚、竹木碳纤维板厚度的增加而增大。提出了该类框剪结构的多拉杆简化模型，可为整体结构抗震分析提供参考。

为研究矩形管翼缘开孔波纹腹板钢梁的抗剪性能，设计完成了4个试件的受剪试验。通过分析试件的破坏模式、荷载-位移曲线和关键区域的应变发展规律，研究了试件的抗剪性能、极限承载力及波纹腹板在开孔后分担的剪力比例。利用ABAQUS软件进行了数值模拟，并将模拟结果与试验结果进行对比，验证了有限元模型的准确性。研究了腹板几何初始缺陷和开孔偏移对抗剪承载力的影响。结果表明：矩形管翼缘开孔波纹腹板梁具有较好的延性性能，其抗剪承载力会随着开孔孔径的增大而降低，腹板波纹越密集，抗剪承载力越高；开孔横向偏移对抗剪承载力的影响不明显；提出了针对该梁的波纹腹板剪力分配比例近似计算公式；腹板的几何初始缺陷对抗剪承载力的影响可忽略不计。

超高层框架-核心筒结构的施工周期长，施工过程中结构的刚度、荷载、材性等不断变化，外框架与核心筒之间将出现竖向变形差，从而改变结构和构件的受力状态，可能对结构产生不利影响。以某一正在施工的超高层框架-核心筒结构工程为研究对象，进行了施工过程模拟，首先介绍了结构竖向变形的基本规律，验证了施工模拟结果的一致性。然后根据模拟结果给出了找平值的确定方法，分析了不同阶段下结构外框架与核心筒间的竖向变形差及发展规律，最后基于分析结果提出了竖向变形差值补偿、核心筒超前施工、框架梁延迟刚接等控制措施及建议，减小了框筒间的竖向变形差，可为类似工程施工提供指导依据。

钢管塔在我国特高压输电线路中得到广泛应用。在微风作用下圆形截面构件会形成稳定的卡门旋涡，导致构件发生微风振动，极易造成螺栓松动、连接疲劳等问题，危及特高压钢管塔结构安全。针对特高压钢管塔，建立了斜材的力学模型，得到了斜材微风振动的弯曲振动微分方程，提出了其固有频率的计算方法，研究了轴力和连接刚度对斜材横向弯曲振动频率的影响。运用能量平衡法，考虑风输入能量和螺栓滑移耗能，提出了斜材稳态振幅计算方法。针对SJ3021型特高压钢管塔斜材，研究了风速和连接刚度对斜材振动稳态幅值的影响，提出了减少斜材微风振动影响的建议，为保障特高压输电线路安全提供理论基础。研究成果有利于特高压钢管塔斜材微风振动防控工作，对提高输电杆塔的安全性与可靠性具有重要意义。