摘要：混凝土3D打印技术作为一种新兴的高效自动化建造技术,在实现建筑领域低碳化方面具有重要的应用潜力。针对混凝土3D打印技术目前在低碳性方面的优势和面临的挑战进行系统性介绍。相较于传统建造方式,3D打印技术省人工、免模板的特点带来了建造人员结构以及成型工艺的改变,使得建筑施工阶段碳排放量大幅下降,同时减少了现场建筑垃圾排放;高设计自由度为多种低碳化建筑结构设计提供了新的选择;拓扑优化、节能-增材制造一体化、可拆卸再建造等结构设计策略有助于节约原材料、降低运行能耗以及实现资源循环利用。此外,材料低碳是目前3D打印低碳混凝土所面临的重要挑战之一,3D打印技术与固废利用、轻质、地聚物、纤维增强等低碳化混凝土体系的结合是进一步创新优化低碳性的有效途径。未来,混凝土3D打印技术将依赖于工艺优化、结构设计、材料研发等多方面的协同发展,助力建筑领域实现自动化和绿色低碳化转型。

摘要：To improve the seismic performance of columns, engineered cementitious composite （ECC） is introduced to partially substitute concrete at the base of the columns to form ECC,/reinforced concrete （ RC） composite columns. The mechanical behaviors of the ECC/RC composite columns are numerically studied under low-cyclic loading with the finite element analysis softwareof MSC. MARC. It is found that the ECC/RC composite columns can significantly enhance the load capacity, the ductility ad energy dissipation of columns. Then, the effects of the height of the ECC, the axial compression ratio and the longitudinal reinforcement ratio on the seismic behaviors of the composite columns are parametrically studied. The results show that the ECC/RC composite column with a height of the ECC layer of 0. Sh（h is the height to the cross-section） can achieve similar seismic performance of a full ECC column. The peak load of the composite column increases significantly while the ductility decreases with the increase of the axial compression ratio. Increasing the longitudinal reinforcement ratio within a certain range can improve the ductility and energy dissipation capacity and almost has no effect on load capacity. The aalysis results ae instructive and valuable for reference in designing ECC structures.

摘要：In order to investigate the flexural behaviors of engineered cementitious composites （ECC）, theoretical and experimental researches are done on flexural doublereinforced ECC beams. Based on the assumption of the plane section remaining plane in bending and simplified constitutive models of materials, the calculation methods of load carrying capacities for different critical stages are obtained. Then, these calculation methods are demonstrated by comparing the test results with the calculation results. Finally, based on the proposed theoretical formulae, the effects of the compression strength, compression strain and tension strength of ECC, and the reinforcement ratio on the flexural behaviors of double-reinforced ECC beams are analyzed. The calculated and measured results are in good agreement, which indicates that the theoretical model can be used to predict the momentcurvature response of steel reinforced ECC beams. And the results of parametric studies show that the increase in the compression strength of ECC can greatly improve the flexural performance of beams; the increase in the ultimate compression strain can significantly improve the ultimate curvature and ductility, but has little effect on the load bearing capacity of beams. little effect on the flexural The tensile strength of ECC has behaviors of ECC beams. The increase in the steel reinforcement ratio can lead to significant improvement of the load bearing capacity and the stiffness of beams, but a degradation of the ductility of beams. The theoretical model and parameter analysis results in this paper are instructive for the design of steel reinforced ECC beams.

摘要：An engineered cementitious composite （ECC） is introduced to partially substitute concrete in the tension zone of a reinforced concrete beam to form an ECC/reinforced concrete （RC） composite beam, which can increase the ductility and crack resisting ability of the beam. Based on the assumption of the plane remaining plane and the simplified constitutive models of materials, the stress and strain distributions along the depth of the composite beam in different loading stages are comprehensively investigated to obtain calculation methods of the load-carrying capacities for different stages. Also, a simplified formula for the ultimate load carrying capacity is proposed according to the Chinese code for the design of concrete structures. The relationship between the moment and curvature for the composite beam is also proposed together with a simplified calculation method for ductility of the ECC/RC composite beam. Finally, the calculation method is demonstrated with the test results of a composite beam. Comparison results show that the calculation results have good consistency with the test results, proving that the proposed calculation methods are reliable with a certain theoretical significance and reference value.

摘要：为解决产品改造升级复杂度高、拆卸难度大等问题,在机电产品设计阶段引入影响产品改造升级相关因素,提出一种考虑改造升级风险的复杂产品模块智能聚类方法。从产品零部件的功能相关性、结构相关性、关联更改概率、拆卸相关性等方面定义零部件关联属性,建立产品零部件间综合关联矩阵;采用结合改进人工蜂群算法的密度峰值聚类算法求解模块划分方案,以模块划分质量为优化目标,实现截断距离的优选。以某型号升降电梯的零部件模块划分为例,验证了所提方法的可行性和有效性。

摘要：基于3D打印技术的自动化和智能化优势,将其应用于建筑业,成为当前工程领域研究的热点之一。但是,这种技术在设计方法、打印材料、打印设备以及施工工艺等方面还存在诸多问题,这在一定程度上限制了其大规模的推广应用。与其他应用领域相比,3D打印技术在建筑行业中的应用目前还处于初级阶段。相较于传统的建筑施工,3D打印技术具有如下潜在优势:(1)机械化程度高,施工快,成本低;(2)无模板施工,资源消耗少;(3)劳动强度低,节省人力;(4)施工过程安全、清洁、精确;(5)设计自由,实现轻质高强及多功能;(6)高度定制化,实现标准化与个性化的统一。然而,由于3D打印技术与传统施工技术的不同,导致传统的普通混凝土无法直接应用于3D打印。而以层层堆叠方式打印的材料则普遍存在结构强度较低、层间形成施工冷缝等问题。因此,近年来研究者们在材料配合比、结构优化设计、评价标准以及施工工艺等方面不断探索,并取得了丰硕的成果。最近,已有不少3D打印技术成功应用于个性化住宅、桥梁建造等的案例报道。在建筑业大尺度3D打印技术中已取得成功应用的包括轮廓成型工艺、混凝土打印工艺、D型打印工艺和数字建造工艺,其中轮廓成型工艺现已成为主流的建筑3D打印技术。建筑业3D打印建造技术的主要特征可概括为:基于挤出工艺分层打印混凝土、粉末台面配合使用粘结技术以及增强网格。为了满足3D打印的要求,在打印过程中,打印材料需要保持一定的可挤出性、可建造性、粘结性、可工作时间以及高强度。同时,混凝土结构需要一定的增强措施以确保结构的安全可靠性。此外,随着不同技术之间的相互融合,涉及到具体的项目应用时,可以采用某几个技术的联合。本文系统总结了大尺度3D打印建造技术的发展过程和研究进展。以纤维增强水泥基材料为打印材料,综述了3D打印技术中原材料选择、材料特性、结构增强措施等关键问题。最后,对建筑3D打印技术的发展方向做了展望,以期为3D打印技术在建筑业中的应用推广提供借鉴。

摘要：采用同样尺寸的钢梁和混凝土梁,通过中间绞结和底面粘贴FRP布而形成的组合梁,对其进行抗弯试验来研究钢筋混凝土梁弯曲或弯剪裂缝所导致的FRP剥离破坏.试验共设计了7组21根组合梁,通过2个对称的集中荷载进行抗弯试验,重点研究了组合梁破坏过程和形态、FRP布在加载过程中应变分布的规律、不同的裂缝开展程度对组合梁初裂荷载和极限承载能力的影响以及混凝土强度对FRP与混凝土粘结强度的影响.试验结果表明:组合梁的初裂荷载与FRP的长度没有关系,主要取决于裂缝的竖向位移;裂缝的竖向位移和FRP的长度对梁的极限荷载具有较大的影响,特别是在FRP锚固长度较小的情况下.针对梁中弯曲及弯剪裂缝引起的FRP剥离破坏进行了深入的试验研究,为工程结构加固提供了一定的参考依据.

摘要：为综合评价现浇剪力墙预制框架半装配式框架-剪力墙结构的抗震性能,设计制作了2榀1∶2的2层2跨混凝土框架-剪力墙结构模型试件,并对其进行了低周反复荷载试验.对比研究了这2榀试件的破坏机制、破坏过程、滞回性能、位移延性和耗能能力等抗震特性.试验结果表明,半装配试件与现浇试件具有相近的开裂位移、裂缝开展形态、破坏模式、耗能能力和侧向承载能力,但半装配试件的延性略低,在不同承载状态下的水平荷载也略低.现浇剪力墙预制框架半装配式框架-剪力墙结构的整体性较好,在地震中具有可靠的抗倒塌能力.

摘要：针对现有的高架火炬附塔蒸汽管线支架采用大量焊接作业的施工方法,产生的安装偏差较大,高空焊接量多,高空作业难度大,用工成本高,检修时难以拆卸等问题,从设计、机加工、安装等方面对支架的要点和难点进行解析,研究并应用新型的高架火炬附塔蒸汽管线可拆卸式支架。新型式的支架可增加支架的可靠性,减少高空作业难度,降低项目实施成本,同时具备可拆卸功能。

摘要：X65钢注水海管介质含有溶解氧,导致管道内发生严重腐蚀。针对该问题,基于现场注水海管基础数据,考虑流速、温度、溶解氧浓度和Cl^(-)浓度对X65钢腐蚀行为的影响,设计9组正交试验,采用高温高压反应釜、扫描电子显微镜和X射线衍射仪进行失重测试和腐蚀产物表征;结合多元线性回归法,建立腐蚀预测模型。结果表明:4种影响因素对腐蚀速率的影响程度由大到小排序为:溶解氧浓度>温度>流速>Cl^(-)浓度,溶解氧浓度是腐蚀主控因素;随着流速、温度、溶解氧浓度和Cl^(-)浓度的增大,腐蚀速率增大;腐蚀产物表征结果表明,腐蚀产物主要为Fe3O4和Fe2O3;考虑上述4个因素的影响,基于7组均匀腐蚀速率值,建立腐蚀预测模型;采用剩余2组均匀腐蚀速率值对腐蚀预测模型进行验证,误差最大为8.9%,表明该腐蚀速率预测模型的准确性较高。