为研究玄武岩纤维增强复合筋(BFRP筋)与超高性能混凝土(UHPC)的破坏模式，对17组(共51个)试件开展中心拉拔试验，研究了筋材直径、筋材种类、UHPC纤维掺量、UHPC强度以及粘结剂等5个因素对破坏模式的影响。试验结果表明：随着BFRP筋直径的增加，破坏模式由筋材拉断破坏转变为筋材拔出破坏；仅添加单一钢纤维、PVA纤维的试块发生筋材拔出破坏；添加1%钢纤维、0.5%PVA纤维与添加0.5%钢纤维、1%PVA纤维的试件发生筋材拉断破坏；随着UHPC强度的变化，试件发生筋材拉断破坏与筋材拔出破坏；加入植筋胶后，试件破坏模式由筋材拔出破坏转变为混凝土劈裂破坏；由于筋材特性，钢筋-UHPC试件均发生筋材拉断破坏；该研究结果为工程中优化材料选型及提高结构粘结可靠性提供关键依据，完善了相关理论体系，推动复合材料在土木工程领域的高效应用。

为探究玄武岩纤维增强复合材料(BFRP)筋与玄武岩纤维再生混凝土(BFRAC)之间的黏结性能,开展中心拉拔试验,制备42个试件以研究筋材直径、筋材表面特征及再生混凝土粗骨料取代率对黏结强度的影响。并采用随机森林(RF)算法建立黏结强度预测模型。研究结果表明:黏结强度随着BFRP筋直径的增大逐渐增大;黏结强度随着再生粗骨料取代率的增加逐渐降低;BFRP筋表面特征对黏结强度有较大影响,经表面黏砂处理的BFRP筋的黏结强度高于经表面喷砂处理的BFRP筋。随机森林回归预测模型对黏结强度具有良好的预测能力,预测精度较高。进一步完善了BFRP筋与混凝土之间的黏结机理,为BFRP筋在混凝土结构中的应用提供了依据。

Four innovative mechanical connectors designed for improving the integrity of untopped flat diaphragms are proposed. Compared to traditional connectors, the innovative connectors avoid premature weld tearing, possess higher strength and ductility, which are not only suitable for double-tees but also applicable to untopped flat slabs with lower structural heights and smoother undersides. This allows for greater story heights or more stories within the same building height, which is important in driving the development of fully assembled structures. This paper summarizes the tensile performance of innovative connectors observed during the cyclic loading scenarios. Four sets of single-slab experiments were conducted, with each set consisting of a pair of connectors. Based on experimental findings, the theoretical formulas for connection strength and stiffness were provided. Connector optimization was performed in conjunction with the failure modes. Finally, using numerical simulation techniques, a parameter analysis was conducted on the influence of steel plate (or rebar) thickness (or diameter) and material strength on the resistance and deformability of innovative connectors. The results indicated that innovative connectors fully developed the ductility of steel and achieved a ductile failure mode. The strength and deformability of optimized connectors were improved due to the strong anchoring of L-shaped steel plate. The thickness (or diameter) of steel plate (or rebar) and the steel grade significantly impacted the tensile performance of the connectors. Design and application recommendation were proposed for innovative connectors. © 2024 Institution of Structural Engineers

为研究带预制混凝土（PC）填充墙的装配式RC联肢剪力墙在水平荷载作用下的受力性能，基于试验建立了无填充墙试件（CSW-N）和带PC填充墙试件（CSW-F和CSW-R）的有限元模型，并考察了轴压比、PC填充墙混凝土强度等级和刚性连接试件锚固钢筋布置等对装配式RC联肢剪力墙受力性能的影响。结果表明：轴压比由0.1增加至0.6时，试件CSW-F峰值承载力增加了约69.92%，延性系数下降了约40.68%；试件CSW-R的峰值承载力增加了约47.00%，延性系数下降了约42.06%。对于试件CSW-F，由于PC填充墙对剪力墙的约束作用较小，随PC填充墙混凝土强度等级增大，其峰值承载力增幅较小；对于试件CSW-R，当实心墙和夹心墙混凝土强度等级由C15增加至C30时，试件的峰值承载力分别提高了7.20%和4.32%，在相同混凝土强度下，实心墙的承载力高于夹心墙的承载力。对于试件CSW-R，锚固钢筋直径变化对剪力墙受力性能影响较小，但增加锚固钢筋数量可提高剪力墙峰值承载力。

An innovative discretely connected precast concrete floor (DCPCF) was presented, in which the adjacent precast concrete hollow or sandwich flat slabs were connected by mechanical connectors embedded in the precast concrete slabs and beams. This paper summarized the seismic performance observed during the shaking table test of a precast frame-shear wall structure adopting DCPCF. A 1/4-scale model of a 4-storey 2-bay single-span frameshear wall structure was designed and tested on the shaking table to evaluate the dynamic characteristics and seismic responses of building structures adopting DCPCF. In addition, a finite element model, including detailed modeling of beam-column joint and slab joint connections, was established using nonlinear dynamic modeling program. The predictions on the seismic performance using the finite element model agreed well with the test results for the designed frame-shear wall structure. The precast concrete frame-shear wall structure adopting DCPCF had satisfactory seismic performance during the test process. The in-plane deformation of DCPCF was observed under the horizontal earthquakes, and DCPCF could not satisfy the requirements of rigid diaphragm assumption in most cases under design basis seismic intensity. The seismic design method based on semi-rigid floor diaphragm had large error and safety risk in calculating the seismic shear force of building structure adopting DCPCF. Additionally, design suggestions for multi-storey and high-rise building structures using DCPCF were proposed based on the observed seismic responses.

Mechanical connectors are commonly employed in precast concrete diaphragm floors to stiffen the diaphragmatic action and bolster construction robustness. This paper introduced four innovative mechanical connectors for untopped concrete diaphragms following a thorough investigation into the application scope and physical attributes of existing connectors. Additionally, this study summarized the tension behavior of the innovative slab joint connections observed during cyclic loading experiment, along with two secondary optimized types through numerical simulations. Various aspects including failure characteristics, force-displacement relationships, strength and stiffness degradation laws, energy dissipation capacity, strain states, and ductility of the specimens were analyzed and compared. The results indicated that the butterfly connector (BFC), innovative chord connector (ICC), optimized L-shaped steel & cover plate connector (LCPC), and butterfly-cover hybrid connector (BCHC) effectively harnessed the malleability of steel materials to provide tensile resistance for joint connections. Among these, ICC exhibited the most reliable strength and energy dissipation capacity, while BFC demonstrated superior ductility, albeit with a slightly lower strength. LCPC and BCHC, with strengthened anchorage of the L-shaped steel plate, exhibited substantial strength and deformability. Based on the experimental and simulated findings, it was recommended to consider the yield force as the service load limit for all untopped diaphragm joint connectors.

为探究玄武岩纤维增强复合材料（BFRP）筋与超高性能纤维混凝土（UHPFRC）之间的粘结性能，通过中心拉拔试验，对BFRP-UHPFRC试件破坏模式、粘结-滑移曲线进行分析，且探讨了筋材直径、单一纤维及钢-PVA混杂纤维对粘结强度的影响。结果表明，试件破坏模式包括BFRP筋拔出破坏与拉断破坏。BFRP筋直径的增大将导致粘结强度降低。随着单一纤维掺量增加，粘结强度呈先增大后减小的趋势。而相较于单一纤维，钢-PVA混杂纤维显著提高了试件的粘结强度，当掺入1%钢纤维和0.5%PVA纤维时，粘结强度最高（25.35 MPa）。此外，通过灰狼算法优化的支持向量回归模型实现对粘结强度的预测，预测值与实际值拟合较好。

装配式建筑具有良好的经济、环境和社会效益,符合国家大力倡导智能建造和建筑工业化的要求。楼（屋）盖作为建筑结构中重要的水平承重构件,是建筑结构的重要组成部分,因此展开全装配式楼盖的研究具有重要的理论意义和应用价值。叠合式楼盖整体性好,但自重大,存在大量现场湿作业,不利于预制混凝土和预应力技术的高效利用,不利于节能减排。课题组提出的分布式连接全装配RC楼盖（DCPCD）施工便捷、效率高,无现场浇筑,减轻楼盖自重的同时减少了空气污染。由于板缝的存在,楼盖横板向和顺板向具有不同的受力特点,且横板向刚度受板缝和连接件的影响,对楼盖整体刚度影响较大。为研究DCPCD楼盖横板向承载机理,进行了6个DCPCD试件和2个整浇楼盖试件竖向承载性能试验及有限元模拟,并结合试验,提出了DCPCD楼盖横板向抗弯刚度理论计算方法。本文主要工作和研究内容具体如下:（1）进行了竖向荷载下DCPCD横板向受力性能试验,研究了楼盖的破坏形式、裂缝发展、挠曲变形等力学性能。结果表明:DCPCD楼盖板缝连接件受力性能良好,可有效传递横板向弯矩;抗弯刚度小于整浇试件,没有明显的塑性工作阶段;横板向挠曲变形呈现出由多段直线在板缝位置处连接而成的特点;板缝数增多会降低楼盖横板向刚度,连接件个数增多对横板向刚度有提高作用,板缝位置位于受力较大的跨中时对横板向刚度影响较大。（2）通过建立DCPCD横板向受力性能有限元分析模型并开展数值模拟分析,进一步揭示了DCPCD楼盖横板向受力特征。根据楼盖有限元模型,分析了混凝土、钢筋和连接件的应力,揭示了楼盖横板向受力特征。结合楼盖竖向受力性能试验,验证了有限元建模方法的正确性;改变连接件中钢板强度,从Q235到Q345对DCPCD楼盖加载后期承载力提高较明显。（3）基于最小截面刚度原则、折线变形理论和共轭梁理论,提出了DCPCD楼盖横板向刚度计算方法。分别将理论值与试验值进行对比,验证理论计算方法的准确性和可行性;采用MATLAB对横板向抗弯刚度较为精确的共轭法进行运算,研究了板缝位置、板厚、跨厚比和连接件个数等敏感性参数对楼盖横板向刚度的影响,研究发现:连接件个数较少时,板缝远离跨中有利于楼盖承载力的提高;相邻两条板缝的间距对楼盖横板向刚度有较大影响,应在合理范围内;板厚和跨厚比的增大均能提高楼盖抗弯刚度;当板厚和跨厚比一定,随着连接件个数增多,对楼盖承载能力的提高程度逐渐减小。本文通过进行竖向荷载下DCPCD横板向受力性能试验、建立适用于DCPCD楼盖的横板向受力性能有限元分析模型,并提出了DCPCD楼盖横板向刚度计算方法,全面揭示了DCPCD楼盖横板向承载机理,系统分析了板缝构造等因素对楼盖横板向刚度的影响,对竖向荷载下楼盖横板向受力性能研究有重要意义,研究成果可为分布式连接全装配RC楼盖的工程应用和设计提供参考。

为研究分布式连接全装配RC楼盖（DCPCD）横板向传力性能，完成了8个对边简支试件的竖向静载试验。基于共轭法提出了DCPCD横板向刚度的计算方法，并研究了板缝数量、板缝连接件数量、楼盖跨度和横板向与顺板向刚度比等参数对DCPCD横板向传力性能的影响。结果表明：DCPCD试件的板缝连接件受力性能良好，可有效地传递横板向弯矩和剪力，并能较好地协调相邻预制板的变形；基于共轭法的DCPCD横板向刚度计算方法的精度比最小截面刚度法和折线变形法高；减少板缝数量、增加板缝连接件数量均可有效改善楼盖横板向的传力性能，提高楼盖的竖向承载力和刚度；基于楼盖承载力与振动舒适度的要求，建议四边简支楼盖横纵向刚度比的取值范围为0.3～0.75。

针对工程水泥基复合材料（ECC）用于板柱结构柱周围局部实心区域形成的ECC/RC空心楼盖板柱节点,可减少结构本身自重,充分发挥ECC材料高强度、高延性和抗剪性能好等特点,以ECC强度、ECC面积、暗梁为参数,对ECC/RC空心楼盖板柱节点进行抗冲切性能数值分析研究。结果表明:ECC材料可显著提高空心楼盖板柱节点的抗冲切承载力和刚度,改善节点的变形能力和耗能能力,但未改变节点的破坏形态,节点仍发生冲切破坏;节点的抗冲切承载力随着ECC强度和ECC面积的提高而增大;当节点仅使用一种增强方式时,暗梁和ECC材料的抗冲切承载力分别为普通混凝土的1.26倍和1.15倍;与暗梁相比,ECC材料对节点抗冲切承载力的提高效果更明显;与同时使用ECC材料和暗梁的节点相比,当节点仅使用ECC材料时,增大ECC面积对节点抗冲切承载力的提高效果更为明显;在进行空心楼盖板柱结构设计时,建议同时使用暗梁和ECC材料,保证节点有较高极限承载力的同时,兼顾良好的变形能力和耗能能力。