This study presents a comprehensive investigation into a novel prefabricated reinforced concrete column-steel beam eccentrically braced frame hybrid system incorporating replaceable energydissipating links. A cyclic loading test was conducted on a two-story, single-bay substructure to evaluate its mechanical behavior, deformation characteristics, and failure modes. The results revealed that the energy-dissipating links yielded, buckled, and fractured in sequence after full plastic development, effectively concentrating damage and preserving the elastic behavior of primary structural components. The structure exhibited uniform inter-story stiffness, good deformation compatibility, and superior drift capacity exceeding seismic code limits. A refined finite element model based on Abaqus was developed and validated against experimental data, showing strong agreement in terms of stress distribution, deformation patterns, failure modes, and hysteretic response, with a maximum load prediction error below 13%. The findings demonstrate the proposed system's favorable seismic performance and damage-controllability, offering a promising direction for performance-based seismic design of prefabricated hybrid structures.

Reinforced concrete column-steel beam (RCS) hybrid frames are an innovative structural system that integrates steel beams and reinforced concrete columns, thereby offering an efficient structural system for modern buildings. However, the influence of the composite effect of the slab on the seismic behaviour has not been fully investigated in current designs. This study introduces a novel prefabricated RCS hybrid frame that explicitly considers slab composite effects and evaluates its seismic performance. A 1/2-scale one-bay two-storey precast composite column-steel hybrid frame is designed and tested under cyclic loading. The crack propagation, damage progression, failure modes, hysteresis performance, load-bearing capacity, stiffness, deformation, and energy dissipation, among other seismic performance metrics, are analysed. Experimental results indicate that the hybrid frame remains elastic under an overall drift ratio of 0.25 % and achieves an ultimate overall drift ratio of 3.76 %. Additionally, the panel zone remains in an elastic state during loading, with the structure demonstrating favourable plastic deformation and energy dissipation. Results of finite-element analysis indicate that considering the slab composite effects resulted in a 74 % increase in the lateral stiffness and a 44 % increase in the maximum load-bearing capacity. These findings validate the favourable seismic performance of the proposed RCS hybrid frame system and provide valuable scientific and technical insights for optimising such structural designs.

The K-type eccentrically braced hybrid frame system is a novel structural system composed of prefabricated concrete columns, steel beams, energy-dissipating beam segments, and diagonal steel braces. To investigate the seismic performance of K-type eccentrically braced hybrid frame and its post-earthquake repair capability, low-cycle reversed loading tests were conducted on one two-story single-span K-type eccentrically braced hybrid structure specimen and one single-story post-damage repaired specimen. The mechanical behavior, deformation capacity, and failure modes of the two-story specimen at different loading stages were analyzed. The mechanical behavior, deformation capacity, and repair capability of the single-story damaged specimen after replacing the energy-dissipating beam segments were also studied. Results indicate that for the single-story specimen, before and after replacing the energy-dissipating beam segments, the energy-dissipating beam segments develops plastic deformation well and dissipates energy sufficiently, and the overall structure exhibits excellent seismic capacity and post-earthquake repair capability; For the two-story single-span specimens, the overall structure of each floor maintains good consistency, with uniform stiffness distribution and basically consistent force-bearing characteristics, its energy-dissipating beam segments on each floor exhibit good deformation coordination performance and seismic capacity.

With how fast highways are developing in China, road cracks are becoming a bigger and bigger issue. Especially when it rains, the cracks get worse and the soil gets damaged, which leads to more problems for the roads. In this paper, we look at how rainfall soaking and dry-wet cycles affect soil cracks in the road base through lab tests. We also talk about how well polymer materials work for fixing those cracks. The test results show that: (1) If the pavement structure is intact, water seeps in horizontally in a ring-like pattern. But when cracks are present, the water moves in a V-shape, creating a clear preferential flow. (2) The dry-wet cycles really lower the soil's compressive and shear strength, and make crack spreading worse. (3) By tweaking the polymer material formula with an orthogonal test, a solution of acrylamide and magnesium acrylate can slow down crack spreading and boost the soil's shear strength. Among these, the 10 % acrylamide solution works the best. It really slows down how fast the samples break apart and boosts their shear strength. The way polymer materials fix cracks includes: changing the physical properties of the soil around the cracks to slow down their growth, and filling in the cracks to create a water barrier that keeps the water balance on both sides. This study provides effective materials and technical support for subgrade crack repair.

Rain and snow seepage into the cracks of the soil wall is the leading cause of its surface weathering, and the key to crack repair lies in developing reasonable repair materials. Based on the carbonation principle and mineralization mechanism of quicklime, this study focuses on the cracks in the city wall of Kaifeng as the research subject. Urea urease solution, quicklime, sodium methylsilicate, styrene-acrylic emulsion, waterborne polyurethane, and soil were selected to prepare 27 groups of high-fluidity repair materials with varying proportions. The surface strength, water absorption, surface strength after water absorption, consistency and freeze-thaw cycle tests of crack repair samples were carried out to explore the repair effects of different proportions of repair materials on crack diseases. The results demonstrated that the urease urea solution, along with its mineralization reaction with quicklime and sodium methylsilicate, significantly accelerated the chemical interaction between quicklime and sodium methylsilicate, thereby enhancing the mechanical and waterproofing properties of the repair materials. The group composed of 7.5% quicklime and 7% sodium methylsilicate exhibited a total efficacy coefficient of 96.25, indicating superior mechanical strength and waterproofing performance. Among the tested waterproofing agents-sodium methylsilicate, styrene-acrylic emulsion, and waterborne polyurethane-the effectiveness was ranked as follows: waterborne polyurethane > sodium methylsilicate > styrene-acrylic emulsion. Notably, the group containing 5% sodium methylsilicate combined with 7.5% quicklime achieved the lowest water absorption rate of 3.9%. Thirty cycles of crack-filling experiments revealed that the crack resistance of the filling material surpassed that of the original sample, while maintaining excellent integrity with the earthen structure even after freeze-thaw cycles (Fig 1).

An innovative precast eccentrically braced hybrid frame, featuring replaceable links, was developed to overcome limitations observed in traditional hybrid frames. These limitations primarily arise from the inefficient lateral resisting system in traditional hybrid frames and difficulty in post-earthquake repairs. To investigate the cyclic behavior of this structure, the braced hybrid frame was tested under cyclic loads. Various aspects, including the failure patterns, hysteretic characteristics, skeleton curves, ductility, and energy dissipation capacity, were thoroughly examined. Earthquake-damaged specimens were tested for the cyclic behavior after replacing the links. Comparing test results revealed that the specimens maintained good performance, indicating excellent repairability of the structure. Furthermore, a reliable nonlinear finite element model of the hybrid frame was developed, encompassing material nonlinearities of concrete, steel beams, rebars, and shear links, to explore the behavior of the new structure. An extensive parametric investigation was conducted to assess the impact of column rebar ratio, link yield capacity, link length, and brace stiffness on the frame's cyclic behavior, aiming to clarify the mechanical matching relationship between different structural components.

Taking the arch and corridor project of Xiangyu tourist and sightseeing place in Linyi,Shandong province as the background,the composite structure system of large rise-span ratio cross steel arch and hec-tometre corridor was analyzed and designed.The overview of the project was introduced,and the structural design features of the system were discussed.The core content of the design of corridor,arch and pedestri-an bridge in the structural system was expounded.The structural form of cross steel arch support with large rise-span ratio was presented.The design characteristics of the corridor with weak connections was pointed out.It was defined that TMD device was used to control the vibration of the corridor and pedestrian bridge under the excitation of walking load.The ANSYS finite element software was used to analyze the mechani-cal characteristics of the composite structure.The results showed that the structural performance was safe and reliable,and the indexes conformed to the design specifications.The key technical issues needing fur-ther study were put forward.

Research on the seismic performance of eccentrically braced hybrid frames indicates that utilizing very short links can enhance structural stiffness and load capacity. However, there is limited investigation into their effectiveness within eccentrically braced substructures featuring flush end plate bolted connections. This study involves an experimental and numerical investigation to understand the behavior of very short shear links with flush endplates bolted connections in the substructure. An experimental study of 8 specimens was carried out, and the variables studied included loading protocol, links length ratio, flange thickness, and end plate thickness. The experimental results showed that the co-design methodology for flush endplates and bolts of very short links exhibited acceptable performance. Very short shear links bolted with flush endplates demonstrated an average overstrength coefficient of about 1.8 and an ultimate plastic rotation angle above 0.12 rad. Numerical analysis explored the effects of length ratio, web height-to-thickness ratio, and flange width-to-thickness ratio on overstrength behaviors and yield capacity of very short links. The analysis indicated that the length ratio was crucial in determining overstrength coefficients and the yield capacity of very short links. The study established modified formulas that consider the impact of different variables to more accurately determine overstrength behaviors and yield capacity based on formulas in the Chinese code.

为了解决传统箱形截面柱法兰连接节点对结构空间占用的问题,提出了一种箱形截面柱剪力键式全螺栓连接节点,并对2个全螺栓连接箱形截面柱和1个整体式箱形截面柱进行拟静力试验研究.观察了全螺栓连接箱形截面柱的破坏现象,分析了全螺栓连接箱形柱的滞回性能、承载力、刚度退化、延性以及耗能能力等受力特性.结果表明:整体式箱形截面柱和剪力键式全螺栓连接箱形截面柱均发生塑性铰破坏;滞回曲线饱满,具有良好耗能能力;剪力键和水平单向螺栓的设置可使全螺栓连接箱形截面柱承载力提高24.64％,竖向高强螺栓拉力降低29.44％;节点处钢连接件的设置约束了箱形截面柱的屈曲变形,与整体式箱形截面柱相比,全螺栓连接箱形截面柱的位移延性系数提高了 26.47％;钢连接件间无滑移,剪力键式全螺栓连接节点连接可靠.通过剪力键式全螺栓连接节点与刚接节点有限元分析结果对比,表明在工程应用中箱形截面柱剪力键式全螺栓连接节点可等效刚接.采用GB 50011-2010《建筑抗震设计规范》对箱形截面柱剪力键式全螺栓连接节点进行承载力验算,计算结果与试验结果吻合.

基于离心预制混凝土组合柱抗震性能试验,采用ABAQUS软件对该类型组合柱在轴压及水平往复荷载作用下的受力性能进行了非线性有限元分析,研究了轴压比、预制管及芯部混凝土强度、体积配箍率和预制管空心率对柱承载力及变形能力的影响.并采用拟合法建立了适用于该类型组合柱的恢复力模型.研究结果表明:有限元结果与试验结果吻合较好,在轴压及水平往复荷载作用下,柱的破坏模式为压弯破坏,耗能能力较好.柱承载力随轴压比增加而提高,但变形能力降低,当轴压比超过临界值时,柱的受力状态转为小偏心受压,承载力降低;提高预制管或芯部混凝土强度可提高柱承载力,但会降低柱的变形性能;提高体积配箍率及降低预制管空心率可改善柱的变形能力,当空心率降低至 20%后,其影响可忽略.本文所建立的恢复力模型与试验结果吻合较好,能够较为准确地模拟该类型组合柱的滞回特性.

为提高装配式钢筋混凝土框架抗震能力,提出带竖缝混凝土墙的装配式消能减震框架结构体系.通过1个消能子结构试件的低周反复加载试验,考察消能子结构和竖缝混凝土墙设计方法的合理性,分析试件破坏模式、滞回性能、承载力、延性、抗侧刚度及变形特征等.通过有限元分析竖缝混凝土墙的抗震性能,研究带竖缝混凝土墙的装配式框架消能子结构的受力机理.结果表明:罕遇地震作用下,消能子结构中梁柱轻微损伤,梁柱节点及齿槽连接区钢筋基本保持弹性,结构损伤主要集中于竖缝混凝土墙;消能子结构的极限位移角为1/30,位移延性系数为3.25,变形和耗能能力良好;消能子结构弹性抗侧刚度理论值与试验值相对误差为10.4％;竖缝混凝土墙模拟和规范计算得到的极限位移和特征点荷载吻合较好;竖缝混凝土墙对实体墙两端梁截面产生附加阻尼力,缝间墙斜撑作用使其外侧和中间墙肢发生差异性破坏.建议带竖缝混凝土墙的装配式框架消能子结构在多遇和罕遇地震作用下的层间位移角限值分别按1/800和1/100控制;竖缝混凝土墙设计时应考虑斜撑作用,按压弯剪复合受力进行设计,并加强外侧缝间墙墙肢抗剪配筋构造.

To promote the seismic performance of reinforced concrete column-steel beam (RCS) frame, eccentric braces were creatively introduced into it. An improved plastic design method considering the differences in the combination of concrete and steel was proposed for the structure. The plastic design method not only adopts the energy-balance criterion considering the pinch effect of the concrete column and the influence of damping to accurately determine the base shear force but also considers the reasonable value of the story shear distributions along the height and the shear-sharing ratio between MRF and EBF substructures in detail. By considering cases with different heights, this paper verifies the effectiveness of the proposed method with a refined finite element model based on Sap2000. Meanwhile, a case based on the elastic design method was also presented for comparison. To prove its practicability in real engineering, the results of extensive nonlinear static and dynamic analyses of the 6-story and 9-story frames were conducted in terms of base shear, yield mechanisms, link plastic rotations, and inter-story drifts. The results show that the elastoplastic base shear and yield mechanisms predicted by the plastic design method have an acceptable agreement with the numerical simulation results under nonlinear analysis conditions. In addition, average inter-story drifts obtained by the nonlinear time history analysis met the calculation expectation, and the distribution coefficient adopted in this paper has good applicability to the eccentrically braced RCS frames, demonstrating that the structural elastoplastic response could be controlled by the proposed design procedure.

为提升装配式剪力墙结构的质量与施工效率,降低建造成本,提出了预制墙板间竖向连接不使用灌浆套筒的装配式复合齿槽连接剪力墙结构体系,结合某高层住宅项目的应用,介绍了该新型装配式结构技术体系的优势和实施要点.

地震是我国高层建筑面临的最主要威胁之一,高层建筑依靠主体结构自身的延性损伤来耗散地震能量,尚不能有效引导损伤发展和控制震损模式,难以保全高层建筑的震后使用功能.项目组以提升试验仿真还原度、创新结构控制新理念和研发关键新构件为目标,深入开展了高层建筑"地震致损机理"剖析、"可控减震体系"创新和"高效消能构件"研发三个方面工作,取得了一系列技术突破,推动了高层建筑地震损伤控制技术的发展.

为探索高效合理的暗柱预制空心剪力墙连接方式,解决连接施工和质量检验困难的问题,提出了3种水平接缝连接方式:暗柱通过竖向附加钢筋贯通连接、U形钢筋间接搭接及钢节点连接.通过3个暗柱预制空心剪力墙和1个现浇空心剪力墙的拟静力试验,研究了各试件的抗震性能与水平缝工作性能.结果表明,各试件均呈现压弯破坏特征,实现了预期的强剪弱弯目标.预制试件的延性系数在4左右,与现浇试件相比,各预制试件耗能与变形能力稍弱.各预制试件极限位移角为1/56～1/67,弹塑性变形能力满足现行规范要求.试件水平接缝处易形成贯通裂缝,但水平抗剪构造可满足抗剪需求.分析了基于规范计算试件抗弯承载力的适用性,并提出了考虑水平缝影响的抗弯承载力计算方法.

An innovative hybrid frame with high stiffness steel connection was developed to overcome the limitations of a conventional hybrid beam system, which has been proved to have an adverse impact on the reliability of bolted or welded connections due to plastic hinge development in the steel joint section. To examine the cyclic behavior of this structural system with innovative connections, the hybrid frame has been tested under reversed cyclic loads. The mechanical process, failure patterns, hysteretic characteristics, skeleton curves, ductility, and energy dissipation capacity were considered. In addition, a reliable nonlinear finite element model of the hybrid frame, including the material nonlinearities of concrete, steel beam, stud, rebar, and tendon, has been developed to investigate the behavior of the new type connection. An enhancement coefficient α for the flexural bearing capacity of steel beams to the demand flexural capacity of hybrid beams was proposed. Specimens with different α were analyzed, and a conservative suggestion of α⩾1.5 was given. An extensive parametric study with the changes in axial load ratio, slab width, and beam-to-column stiffness ratio was conducted.

基于已完成的5个齿槽式连接预制剪力墙试件进行的单调推覆加载试验,采用通用有限元分析软件ABAQUS建立了15个齿槽式连接剪力墙模型,对其受剪性能进行有限元分析.通过与试验结果对比,有限元分析得到的试件破坏模式、开裂形态、承载力和试验结果吻合较好,验证了材料本构模型、单元类型、接触关系和边界条件等建模方法的可靠性.利用验证的有限元模型研究了剪跨比、分布筋直径及加载方式对受剪性能的影响.结果 表明,随着剪跨比的增大,受剪承载力降低;往复荷载作用下的受剪承载力较单调加载下降约10％,试件后期刚度退化迅速;随着分布筋直径增大,受剪承载力增大.

通过5榀全尺寸承重保温一体化预制墙板竖向轴压试验,研究了洞口、高厚比及加载方式对轴压作用下墙板的破坏模态、承载力、裂缝发展等受压性能的影响,分析蒸压砂加气混凝土砌块与混凝土框格的整体协同受力性能.试验研究表明:集中荷载作用下,肋柱局部发生受压破坏,墙板中肋柱、肋梁和砌块整体协同受力性能较好;均布荷载作用下,在试验高厚比范围内,墙板平面外侧向位移均小于6 mm,无面外失稳破坏,随着墙体高厚比增加承载力有所减小,洞口的存在可改变墙板的破坏模态;蒸压砂加气混凝土砌块与混凝土框格相互约束形成受力整体,肋柱承担主要荷载;给出承重保温一体化预制墙板轴心受压承载力计算式,算式计算结果与试验值吻合较好.

Rectangular hollow reinforced concrete (RC) columns have been used extensively for bridge structures. Inadequate transverse confinement and thin wall thickness lead to brittle shear failure, whilst limited studies have reported on the shear model. A hollow high-strength concrete and high-strength stirrups (HHSCS) column, which consisted of high-strength materials, were developed in this paper. The prior monotonic loading tests were conducted to investigate the shear performance on eight specimens. The test variables included aspect ratio, axial compression ratio, and transverse reinforcement ratio. The results revealed that all specimens experienced typical shear failure. On the basis of the modified truss-arch model, a theoretical formula was developed for estimating the shear strength of rectangular hollow RC columns. Also, six existing shear strength models were reviewed and compared with the proposed model using the test data including 37 shear-critical rectangular hollow RC columns. The comparison results showed that the proposed model provided high accuracy of shear strength whether shear-critical rectangular hollow RC columns with high-strength or normal-strength materials.

建立了预制混凝土管组合柱-钢梁节点在往复荷载作用下受力性能分析的精细化有限元计算模型.根据已完成的6个"弱节点"试验结果,对比分析试验与模拟试件的破坏模式、梁端荷载-位移骨架曲线和特征点荷载,验证了有限元模型的准确性.研究了预制混凝土管组合柱-钢梁节点核心区受力全过程工作机理,并对各关键组件的应力、应变发展规律及其相互作用进行分析.通过有限元模型参数化分析,研究了轴压比、钢套箍厚度、钢套箍延伸高度、预制混凝土管强度及芯部混凝土强度等因素对节点承载力和变形能力的影响.分析结果表明:在梁端往复荷载作用下,钢套箍屈服"拉力带"和核心区混凝土"斜压杆"机构共同抵抗节点剪力;峰值荷载时钢套箍以刚体变形为主,极限荷载时钢套箍腹板大面积屈服;芯部混凝土、钢套箍与预制混凝土管之间界面接触相互作用力分布不均匀;轴压比、钢套箍厚度、预制混凝土管和芯部混凝土强度对节点承载力及变形能力影响较大,增大钢套箍厚度可以显著提高节点承载力及变形能力;钢套箍延伸高度增加可以提高节点变形能力,但对承载力影响不明显.建立了预制混凝土管组合柱-钢梁节点受剪计算模型,理论值与模拟值吻合较好且偏于安全.