Rapid Repair of Earthquake Damaged RC Interior Beam-wide Column Joints and Beam-wall Joints Using FRP Composites

This paper studies the seismic performance of FRP-strengthened RC interior non-seismically detailed beam-wide columns and beam-wall joints after limited seismic damage.Four eccentric and concentric beam-wide column joints and two beam-wall joints,initially damaged in a previous study,were repaired and tested under constant axial loads(0.1fc′Ag and 0.35fc′Ag) and lateral cyclic loading.The rapid repair technique developed,aimed to restore the original strength and to provide minimum drift capacity.The repair schemes were characterized by the use of:(a) epoxy injections and polymer modified cementitious mortar to seal the cracks and replace spalled concrete;and(b) glass(GFRP) and carbon(CFRP) sheets to enhance the joint performance.The FRP sheets were effectively prevented against possible debonding through the use of fiber anchors.Comparison between responses of specimens before and after repair clearly indicated reasonable restoration in strength,drift capacity,stiffness and cumulative energy dissipation capacity.All specimens failed with delamination of FRP sheets at beam-column joint interfaces.The rapid repair technique developed in this study is recommended for mass upgrading or repair of earthquake damaged beam-column joints.

Seismic behavior and mechanism analysis of innovative precast shear wall involving vertical joints

To study the seismic performance and load-transferring mechanism of an innovative precast shear wall(IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted on two test walls. The test results confirm the feasibility of the novel joints as well as the favorable seismic performance of the walls, even though certain optimization measures should be taken to improve the ductility. The load-transferring mechanism subsequently is theoretically investigated based on the experimental study. The theoretical results show the load-transferring route of the novel joints is concise and definite. During the elastic stage, the vertical shear stress in the connecting steel frame(CSF) distributes uniformly; and each high-strength bolt(HSB)primarily delivers vertical shear force. However, the stress in the CSF redistributes when the walls develop into the elastic-plastic stage. At the ultimate state, the vertical shear stress and horizontal normal stress in the CSF distribute linearly; and the HSBs at both ends of the CSF transfer the maximum shear forces.

装配式混凝土剪力墙结构接缝连接研究进展

装配式剪力墙结构拼装时存在大量的水平接缝和竖向接缝,由于剪力墙的刚度较大,接缝连接处易存在刚度不足引起的损伤集聚问题,成为影响结构整体性和抗震性能的决定性因素。总结了国内外正在发展的预制装配式剪力墙结构水平和竖向接缝的连接形式,并对各类连接形式的构造特点、抗震性能、应用优势和技术瓶颈进行了系统阐述和分析,在此基础上探讨了装配式剪力墙结构接缝连接技术的发展方向。结果表明:目前湿式连接技术已较为成熟且被广泛应用,但仍存在现场湿作业量大、质量不易检测和控制等问题;干式连接技术工业化程度高,但对施工精度的要求也高,可能产生的螺栓松动、锈蚀以及磨损问题限制了其工程应用;将消能减震技术融入竖向接缝连接,利用超高性能混凝土实现水平接缝连接,并结合可恢复功能防震技术,是未来装配式剪力墙结构高质量发展的新增长点。

一种新型结构与保温一体化复合墙板节点试验

为解决复合墙板节点常见的保温板易燃、易脱落等棘手问题,并使其抗震性能良好。给出了一种新型的结构与保温一体化陶粒混凝土T型复合墙板节点。该复合墙板节点具有夹芯独特构造优势,主要表现在绿色节能,轻质高强,力学性能好,保温系统连接可靠,还能杜绝火灾的发生。通过对T型复合墙板节点进行抗震试验,分别研究了其滞回性能、破坏机理、承载及变形能力、延性、耗能、损伤等。结果表明:一体化复合墙板节点的破坏顺序为腹板-翼缘-节点核心区;薄弱位置主要发生在腹板脚部,混凝土被拉裂或压碎,钢筋被拉长或压弯等;节点核心区受力相对良好,安全储备充足;符合“强节点,弱构件”设计要求和墙板革新发展政策。延性系数大于3,墙板节点安全性能良好。通过损伤指标评估分析,了解了试件各阶段工作状态。

装配式混凝土剪力墙-梁钢套筒节点性能试验研究

为研究螺栓连接的装配式剪力墙-梁节点的抗震性能,提出了一种在剪力墙内预埋高强螺杆,然后通过钢端板与混凝土梁连接的节点,设计了3组缩尺装配式试件与1组缩尺现浇试件,并对其进行了拟静力试验,研究分析了节点的破坏形态、滞回曲线、骨架曲线、刚度退化、耗能能力等。结果表明:3组装配式试件的滞回曲线呈“弓形”,且装配式试件的峰值承载力比现浇试件提升了8.42%~21.05%,位移延性系数在4.28~4.66之间,等效黏滞阻尼系数均在0.18~0.24之间,证明了该装配式节点具有良好的抗震能力和变形能力。

一种填料优化改性的建筑外墙密封胶性能研究

密封胶的质量与性能对装配式建筑外墙接缝处理具有直接影响,利用密封胶填补接缝,可以防止水分渗透,避免结构材料的破坏,从而延长建筑物的使用寿命。研究制备一种装配式建筑外墙接缝用改性密封胶,将其用于装配式建筑外墙接缝过程,为装配式建筑外墙提供加固支撑。通过进行装配式建筑伸缩缝的嵌缝处理,完成装配式建筑伸缩缝的养护后,对伸缩缝粘接性能、硬度性能、拉伸性能进行测试。实验发现,在碳酸钙填料的质量分数占比2.5%时,制备得到的改性密封胶具有最佳的力学性能和加固性能等,更适用于装配式建筑外墙接缝的实际应用。

装配式地连墙接缝变形特性研究

为了研究接缝对装配式地连墙变形特性的影响并采取合理的改进措施,采用现场试验的方法将局部现浇地连墙替换为装配式地连墙,并对其实测的变形数据进行了对比分析;在实测数据分析的基础上,通过PLAXIS2D有限元软件模拟分析了不同深度横向接缝对装配式地连墙变形特性的影响规律;通过PLAXIS3D有限元软件对比了现浇墙与装配式地连墙水平方向及竖直方向变形形态,分析了竖向接缝对装配式地连墙变形特性的影响规律;最后,针对实测数据显示出的变形偏大问题,提出了改变冠梁刚度、围檩刚度、墙幅宽度、支撑位置4种改进措施,并通过PLAXIS3D有限元软件进行了验证。结果表明:装配式地连墙的接缝对墙体的刚度存在弱化作用,增大了其变形程度;位于坑底以上的横向接头失效时,墙体水平位移会显著增大,位于坑底以下的横向接头失效时,不会引起墙体水平位移的显著增大;竖向接头会显著减小装配式墙体的整体刚度,使其协同变形能力变差,变形更加难以控制;适当调节支撑位置可有效缓解墙幅间的错动和减小墙体变形。

地下连续墙新型刚性接头设计与研究

城市建设的快速发展促使对地下空间的需求日益增加,地下连续墙作为深大基坑的支护或结构外墙的应用也越来越多。针对“两墙合一”的地下连续墙,提出了一种新型刚性接头、防绕流接头板及施工工艺,能有效预防混凝土绕流问题,进而提高地下连续墙的整体刚度、强度以及接头的止水能力。通过数值模拟计算了刚性接头的承载力与延性,并与普通工字钢接头进行了对比。结果表明,采用新型刚性接头的地下连续墙,具有较好的刚度和受力性能,施工可行性高,具有较好的应用和推广前景。总结的经验可供今后类似工程借鉴。

Static behavior of semi-rigid thin-walled steel-concrete composite beam-to-column joints with bolted partial-depth flush end plate:experimental study

A new type of semi-rigid thin-walled steel-concrete composite beam-to-column joint has been proposed in this paper.Five semi-rigid composite beam-to-column joint specimens subjected to hogging moments under monotonic loading were tested to study the static behavior of this new type of joint.The main variable parameters for the five joint specimens were the longitudinal reinforcement ratio and the joint type.The experimental results designated that the magnitude of extension of the longitudinal reinforcement is the most important factor that influenced the moment-rotation characteristic of the new type of joint.The concrete slabs could resist 3.8%-19.1% of the total shear load applied to the cross-sections near the beam-to-column connection.The edge stiffened elements,such as the flange of the lipped I-section thin-walled steel beam,were capable of having considerable inelastic deformation capacity although they had comparatively large width-to-thickness ratios.The shear failure of the concrete cantilever edge strip must be taken into account in practical design because it has significant influence on the anchorage of the longitudinal reinforcement in the new type of external joints.

南昌东站插接离缝式双曲铝板幕墙施工技术

南昌东站高架层候车厅外侧28个幕墙铝板开花柱造型,是南昌东站标志性建筑造型结构,全部由双曲异型铝板拼接组合而成,加工及施工难度高。针对该结构造型的龙骨、饰面及细部做法进行详细拆解剖析,通过全流程要点控制,最终实现高品质的外观效果。该工程在既有BIM技术支持下,充分挖掘提升联合下单潜力,有效指导双曲铝板加工、安装,以实现设计效果。同时,通过预焊接、装配式等措施方法,显著提升标准化模块复制施工效率,并保障施工效果整齐划一。预组装龙骨、插接离缝式铝板插接工艺、全异型石材柱脚等工艺做法均可为类似工程提供参考。

“两墙合一”深基坑工程设计与技术创新

北京CBD核心区某项目基坑深度36m,因受场地空间限制,采用“两墙合一”+内支撑支护体系,在实现基坑挡土、止水功能的同时完成了地下结构外墙施工。为提高工程质量和施工效率,针对地连墙与主体结构的连接、槽段接头处理方式、有限空间导墙结合近接建筑物预换撑等方面进行了技术创新,取得了较好的工程效果,可供类似工程参考。

超高层单元幕墙弹出式插芯节点设计及应用

单元幕墙已经成为超高层建筑外围护结构的主流形式,采用插接节点,在安装过程中必须按楼层逐层插接安装,为此提出超高层建筑单元幕墙多段同步施工技术。该技术通过将分段施工收口楼层单元板块的插接式节点设计为弹出式插芯节点,解决了单元幕墙必须按楼层逐层插接安装的工序问题,实现单元幕墙的分段同步施工。分析了超高层单元幕墙弹出式插芯节点设计、技术原理、工艺流程和安装要点,并结合工程案例,对采用弹出式插芯节点的超高层建筑单元幕墙多段同步施工技术和工程应用进行探讨。

建筑外墙保温板接缝专用改性聚醚密封胶制备及特性研究

为提升建筑外墙保温板的使用寿命,制备装配式建筑外墙保温板接缝用改性聚醚密封胶,并通过试验分析该密封胶性能。以封端硅烷偶联剂和异腈酸酯基硅烷作为改性剂,聚醚元醇作为基料制备改性聚醚密封胶,应用在装配式建筑外墙保温板接缝中。依据标准测试该密封胶的表观性能,研究养护时间、紫外光照对该密封胶的粘接强度影响,分析催化剂和填料用量对于该密封胶表观性能与拉伸性能影响。试验结果表明,该密封胶表观性能符合标准,养护7 d后粘接性能基本稳定,催化剂用量20%,填料用料30%时表观性与拉伸性能最好。

型钢混合连接装配式混凝土剪力墙结构受力机理研究

结合钢筋混凝土结构和钢结构的优势,设计一种型钢-螺栓-后浇混凝土装配式剪力墙型钢混合连接。基于ABAQUS有限元软件建立混合连接的剪力墙模型,探究低周往复荷载作用下该混合连接预制剪力墙的受力性能,主要分析模型的破坏形态、受力机制、变形曲线、特征承载力等,并扩展分析了材料强度、轴压比、连接件数量、型钢截面高度等参数对模型受力性能影响。结果表明:装配式剪力墙破坏形态为压弯破坏,破坏时钢连接件仍保持完整,符合“强连接,弱墙肢”的基本设计理念;装配式剪力墙具有较好的承载力、延性和刚度;轴压比对结构承载力影响显著,型钢混合连接间距的增大能有效提升剪力墙延性。建立了型钢混合连接抗剪需求承载力计算模型和公式,并与国内外规范计算值对比分析,公式计算值和BS EN 1992欧洲规范计算值分别与模拟值的误差在15%和20%以内,均可用于型钢混合连接剪力墙竖缝受剪承载力设计参考。

苏州某大型复杂商业连体结构设计

苏州某大型商业综合体项目位于7度抗震设防烈度区,为体型重叠建筑。通过5道防震缝将建筑整体划分为购物中心A区、购物中心B区、停车楼、商业街A区、商业街B区五个独立结构单元。购物中心A区为复杂连体高层建筑,1~5层采用框架-剪力墙结构,两个单体在3~5层中区由钢桁架相连,顶部(6层)钢桁架结构与两个单体通过成品球铰支座连接,形成强连体结构。充分考虑了周期比、位移比双指标平衡后对购物中心A区剪力墙布置进行了优化;屋顶钢桁架结构支座采用变刚度设计,局部设置滑动支座解决恒载下杆件应力比较高的问题。通过性能化设计,该复杂结构连体部位可以满足中震弹性、大震不屈服的性能目标要求。性能化设计及专项分析表明,影院钢结构具有良好的抗震性能、楼盖舒适度及防倒塌性能。

装配整体式齿槽剪力墙结构密拼接技术研究

装配整体式齿槽剪力墙结构是一种新型不出筋全预制混凝土剪力墙结构,具有标准化程度高、运输安装便捷、场内工作量少的优点。预制构件间通过密拼接技术实现水平连接,连接接缝内钢筋的布置限制了齿槽剪力墙的施工效率。基于装配整体式齿槽剪力墙的构造特征,提出了一种钢筋整体推拉连接技术,有效解决了钢筋连接问题,为装配整体式齿槽剪力墙结构的推广应用奠定了基础。

钢筋混凝土水池壁板水平施工缝抗渗性能试验研究

钢筋混凝土水池壁板因混凝土浇筑施工间断形成水平施工缝,造成新旧混凝土无法形成良好连接,在高水压作用下易出现渗漏。本文对不同混凝土材料及模拟水平施工缝试块进行了抗渗试验,对比分析了其抗渗性能,试验结果表明,添加聚丙烯纤维和内掺水泥基渗透结晶防水材料均能一定程度提高混凝土抗渗性能,而施工缝处的抗渗性能远低于混凝土自防水性能,对水平施工缝迎水面涂抹水泥基渗透结晶防水材料能有效提高该处的抗渗性能。对2片比例为1∶2的缩尺钢筋混凝土水池壁板进行了一次成型和考虑施工缝的二次成型局部渗透性能试验,试验结果表明,施工缝处混凝土因浇筑、振捣和养护不充分,池壁容易形成贯通裂缝,难以达到混凝土自防水目标要求。采用改性混凝土材料及在相关部位进行表面处理,能有效提高关键部位抗渗性能,进而提高整体抗渗性能。采用BP神经网络,建立了混凝土抗渗性能与其材料参数和施工工艺之间的非线性预测模型。

装配式混凝土剪力墙竖缝连接技术研究进展

概括了装配式混凝土剪力墙的几种竖缝连接方式,着重从连接机理、适用范围、主要特点等方面进行了介绍;归纳了国内外装配式混凝土剪力墙竖缝连接试验研究概况,分别从剪切性能试验研究和抗震性能试验研究两个方面进行探讨;介绍了一种新型榫卯连接装配整体式剪力墙结构;最后,针对装配式混凝土剪力墙竖缝连接技术提出几点建议。

沈阳北站深基坑地下连续墙渗漏原因分析及处理措施

地下连续墙被广泛应用于深基坑围护结构,受水文地质等因素的影响,墙体的局部结构会发生渗漏,届时需要对渗漏部位进行堵漏处理,增强地下连续墙的安全强度。文章结合沈阳北站地下连续墙渗漏情况,从渗漏原因分析、堵漏方案对比、处理措施等方面进行研究。经检验,堵漏施工方法应用效果良好,可为类似工程提供参考。

Experimental investigation on shear strength deterioration at the interface between different rock types under cyclic loading

The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake;however,rare work has been devoted to this subject due to lack of attention.In this study,experimental investigations on shear strength weakening of discontinuities with different joint wall material(DDJM)under cyclic loading were conducted by taking the interface between siltstone and mudstone in the Shaba slope of Yunnan Province,China as research objects.A total of 99 pairs of similar material samples of DDJM(81 pairs)and discontinuities with identical joint wall material(DIJM)(18 pairs)were fabricated by inserting plates,engraved with typical surface morphology obtained by performing three-dimensional laser scanning on natural DDJMs sampled from field,into mold boxes.Cyclic shear tests were conducted on these samples to study their shear strength changes with the cyclic number considering the effects of normal stress,joint surface morphology,shear displacement amplitude and shear rate.The results indicate that the shear stress vs.shear displacement curves under each shear cycle and the peak shear strength vs.cyclic number curves of the studied DDJMs are between those of DIJMs with siltstone and mudstone,while closer to those of DIJMs with mudstone.The peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number and the decrease rate varies from 6%to 55.9%for samples with varied surface morphology under different testing conditions.The normal stress,joint surface morphology,shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading,with the degree of influence being greater for larger normal stress,rougher surface morphology,larger shear displacement amplitude and faster shear rate.