Finite Element Analysis of soft Foundation Strengthening by Vacuum Loading from Lower Position

Strengthening soft foundation by vacuum loading from lower position is a new method of ac-celerating the consolidation of dredger fill.This paper presents the mechanism of soft foundation strength-ening by vacuum loading from lower position and evaluates the effectiveness of this method under variousboundary conditions by means of finite element method(FEM)on the basis of Biot's consolidationtheory.     

Evaluation of the seismic response of masonry buildings based on energy functions

This work is based on energies evaluated from the responses of 12 stone and brick masonry systems subjected to 58 shaking table tests. The evolution of input energy during a damaging base excitation is correlated to the change of the damage patterns of the considered buildings. The comparison among energies dissipated and absorbed by the buildings during the various shocks gives some hints on strengthening strategies. It is found that damage to spandrel beams produces a more significant energy absorption than other types of damage. Copyright © 2001 John Wiley & Sons, Ltd.     

福州台段316国道某大桥地质灾害成因分析研究

316国道某大桥自1990年通车以来长期运行，于1999年安全检查中发现大桥病害严重，后经修复加固后重新通车运行。文章以该大桥北岸(福州台)段的病害情况为例，分析其病害的成因．并着重从地质条件出发，在分析考虑场地土层类型与结构等地质条件的基础上，从地基稳定性和斜坡面的稳定性两方面进行相应的计算分析，并结合大桥发生损伤破坏地段范围和北岸(福州台)段深层位移监测成果资料进行综合分析评价。分析结果表明：北岸(福州台)段的不良地质条件及其对高填桥台方案的不适宜，是导致该大桥产生严重病害的重要原因；同时，通过加重补桩以阻止和控制桥台滑移的加固措施，其效果也并非最佳。因此，该大桥病害的修复加固方案设计和施工设计应充分考虑不良地质条件的主要控制作用因素。     

Strengthening of moment‐resisting frame structures against near‐fault ground motion effects

Near‐fault ground motions with forward directivity are characterized by a large pulse. This pulse‐like motion may cause a highly non‐uniform distribution of story ductility demands for code‐compliant frame structures, with maximum demands that may considerably exceed the level of code expectations. Strengthening techniques for multi‐story frame structures are explored with the objective of reducing maximum drift demands. One option is to modify the code‐based SRSS distribution of story shear strength over the height by strengthening of the lower stories of the frame. The modified distribution reduces the maximum story ductility demand, particularly for weak and flexible structures. However, this strengthening technique is less effective for stiff structures, and is almost ineffective in cases in which the maximum demand occurs in the upper stories, i.e. strong and flexible structures. As an alternative, the benefits of strengthening frames with elastic and inelastic walls are evaluated. The effects of adding walls that are either fixed or hinged at the base are investigated. It is demonstrated that strengthening with hinged walls is very effective in reducing drift demands for structures with a wide range of periods and at various performance levels. Wall inelastic behavior only slightly reduces the benefits of strengthening with hinged walls.Copyright © 2004 John Wiley & Sons, Ltd.     

石粉灌浆石砌体的抗震抗剪强度及其应用研究

基于灌浆石砌墙体的拟动力试验、工程实践和震害经验，经分析研究，首次提出灌浆石砌体的抗震抗剪强度及抗震加固验算方法。经对工程实例验算，验证了本研究的可靠性和实用性。     

碳纤维布增强钢筋混凝土柱延性性能的评估与分析

在试验研究的基础上，对碳纤维布提高钢筋混凝土柱延性的机理进行了分析，确定了碳纤维布用量、轴压比、剪跨比、矩形截面柱转角部位的形状等试验因素对碳纤维布加固钢筋混凝土柱延性的影响规律。在此基础上，重点对碳纤维布加固钢筋混凝土柱延性性能的评估与分析方法进行了研究，提出了碳纤维布加固矩形截面钢筋混凝土柱位移延性比的理论计算方法和简化计算公式。计算结果与试验数据能较好地吻合。工程技术人员可以应用上述方法，对碳纤维布增强钢筋混凝土柱延性性能进行合理的评估与分析。     

地下排水与观测廊道加固方案的现场试验论证

华东天荒坪抽水蓄能电站上水库库底的地下排水与观测廊道为城门洞型,拱体为预制混凝土,边墙与底板现浇。运行期间发现廊道拱顶沿纵向开裂。电厂曾采用外加钢结构支撑混凝土拱顶的方案进行了加固处理,但裂缝开裂并没有得到有效控制。为弄清拱顶开裂原因,提出有效的改造加固方案,为此,进行了现场试验,结果表明:预制混凝土拱脚相对现浇边墙发生向外侧的滑动,是导致开裂的主要原因,因此,阻止其相对滑动,是加固处理的关键。     

Determination of mechanical properties of traditional masonry walls in dwellings of Faial Island,Azores

The determination of mechanical properties of masonry walls is a fundamental pre‐requisite for the characterization of the seismic response of traditional buildings, which helps on the definition of adequate rehabilitation and strengthening procedures. This paper presents a testing campaign carried out in the Cedros region of Faial Island, Azores, hit by the July 98 earthquake, aiming at the determination of physical and mechanical properties of stone masonry walls, namely the mass density and Young's modulus. The paper describes the developed testing techniques as a contribution to the study and the preservation of traditional masonry buildings. Copyright © 2002 John Wiley & Sons, Ltd.     

快速加固吹填泥浆的试验研究与分析

为了研究利用外掺剂加快吹填泥浆的沉积落淤问题,找到能够使吹填土尽快地从泥浆状态转变为具有一定承载力的地基方法,将吹填泥浆中分别加入水泥、生石灰、水泥和生石灰混合剂,通过沉降柱试验模拟了外掺剂作用下吹填泥浆的落淤、自重固结、预压下强度增长等过程,并从粒度成分、矿物成分、和微观结构方面进行了加固机理的分析,从而在吹填的同时对吹填泥浆进行加固。结合处理前后相关试验结果的对比分析发现,外掺剂能够加速吹填泥浆的落淤、固结及强度增长。     

真空和堆载两种预压法的室内试验研究

通过室内试验模拟真空预压法和堆载预压法加固不同深度的土体,对两种预压法下土体前后的物理力学性质指标、土体的沉降量、排水量等进行了分析,认为两种方法均能使土体的物理力学性质改善,就渗透性而言,真空预压优于堆载预压,但就压缩性而言,堆载预压优于真空预压;堆载预压下试样的轴向位移远大于真空预压下的轴向位移,且比真空预压下的沉降收敛慢;真空预压下的排水量大约是堆载预压下排水量的1.8倍;在真空预压和堆载预压下,浅层土体的排水量均大于深层土体的排水量。