低层装配式钢筋混凝土水平坐浆墙体抗震性能试验研究

为了研究低层装配式钢筋混凝土水平坐浆墙体的抗震性能,对3个不同剪跨比的低层装配式钢筋混凝土水平坐浆墙体进行了低周反复荷载试验。根据试验结果,分析了剪跨比对墙体的破坏形态、承载力、变形能力、刚度退化和耗能能力的影响。结果表明:随着剪跨比的减小,墙体的破坏形态由弯曲破坏转为剪切破坏;试件SW2和试件SW3的承载力相对于试件SW1分别提高68%和110%,延性分别降低21.8%和37.5%;试件SW1的耗能能力最好,刚度退化速度最缓慢;预制钢筋混凝土墙板与现浇边缘构件协同合作,连接处无竖向裂缝,墙体整体性较好,具有良好的抗震性能,可用于我国城镇建设中的低层住宅结构。     

Probabilistic development of shear strength model for reinforced concrete squat walls

In order to reconcile the larger scatter and avoid the biased estimate from deterministic predictions for the shear strength of reinforced concrete (RC) squat structural walls, a probabilistic shear strength model is developed in this paper based on the strut‐and‐tie model and the generalized likelihood uncertainty estimation (GLUE) method. The strut‐and‐tie model is used to derive an appropriate function form for the probabilistic shear strength model, where four unknown model parameters (e.g. k₁, k₂, k₃ and k₄) are defined carefully to guarantee them having a clear physical‐based meaning so that the corresponding prior distribution ranges can be specified reasonably. Then, the GLUE method is adopted to estimate the posterior cumulative distribution of k₁, k₂, k₃ and k₄ with an available experimental database. Furthermore, to demonstrate the stability of the estimated posterior cumulative distribution, the sensitivity of three major aspects in GLUE method is investigated. Finally, based on the estimated cumulative distribution of k₁, k₂, k₃ and k₄, the developed probabilistic shear strength model is simplified as a mean prediction model and a standard deviation prediction model for facilitate using in engineering practice. Therefore, with the developed probabilistic shear strength model, not only can the squat structural walls be designed in confidence, but the accuracy of those deterministic predictions can be evaluated in a probabilistic manner. Copyright © 2016 John Wiley & Sons, Ltd.     

In situ cyclic tests on existing stone masonry walls and strengthening solutions

The present work reports on an in situ experimental test campaign carried out on abandoned traditional masonry houses after the 9th July 1998 earthquake that seriously hit the Faial island of Azores. For the testing purposes, an experimental test setup was developed based on a self‐equilibrated scheme, which is herein described reporting on the advantages and drawbacks of this in situ test setup. Five specimens were tested aiming at characterizing the out‐of‐plane behavior of stone masonry walls and strengthening solutions recommended for post‐earthquake interventions. A detailed comparison between solutions' efficiency is presented including a cost vs benefit analysis. In order to assess the efficiency of the developed test setup for other applications on stone masonry walls, an in‐plane test on an existing URM panel is also presented. Several related issues are discussed, namely the advantages of dealing with the real boundary conditions and the capacity of providing valuable information of the response, as well as a detailed analysis of the obtained results. The authors believe that this work provides an increase in knowledge on the seismic behavior of the existing masonry constructions, resulting from the development of an in situ test setup and the efficiency quantification of strengthening solutions. Therefore, the work is thought to positively contribute for the preservation of architectural heritage and for its seismic vulnerability reduction. Copyright © 2010 John Wiley & Sons, Ltd.     

钢筋混凝土核心筒性态水平及性能指标限值研究

结合国内外对钢筋混凝土结构性能水平的划分标准并根据核心筒结构破坏特征及抗震性能要求,文中在现行规范基础上进一步细分,将钢筋混凝土核心筒结构的性能水准划分为良好使用、暂时使用、生命安全和接近倒塌4个水平;基于混凝土连梁及剪力墙构件的受力、变形及破坏特点,分别提出了连梁及剪力墙构件对应于4个性能水平的失效判别标准和变形限值...     

Response of infilled frames using pseudo-dynamic experimentation

An accurate and practical testing technique to study seismic performance of multi-storey infilled frames is formulated. This technique is based on the pseudo-dynamic method which can provide an acceptable approximation of the dynamic performance of structures under the influence of earthquake excitation. The pseudo-dynamic experimental technique is outlined and applied for testing a two-bay, two-storey gravity load designed steel frame infilled with unreinforced concrete block masonry walls. From the discussion of the results, the dynamic performance of the tested structure is assessed. © 1998 John Wiley & Sons, Ltd.     

挡土墙设计绘图系统的开发

介绍在ＡｕｔｏＣＡＤ系统下开发挡土设计绘图系统的原理，方法及实施过程，对程序设计技巧也作了讨论。     

Numerical analysis of deformation behaviour of quay walls under earthquake loading

In the last 50 years, there have been many incidences of failure of gravity quay walls. These failures are often associated with significant deformation of liquefiable soil deposits. Gravity quay wall failures have stimulated great progress in the development of deformation-based design methods for geotechnical structures. In this paper, the effective-stress analysis method has been used in conjunction with a generalised elasto-plasticity constitutive model implemented into a finite element procedure. Various monotonic and cyclic triaxial paths are simulated in order to demonstrate the capabilities of the constitutive model. The FEM is validated by back analysis of a typical Port Island PC1 caisson type quay wall, which was damaged during the 1995 Hyogoken-Nanbu earthquake. The numerical results are compared with the observed data obtained consisting of seaward displacement, settlement and tilting. In addition, both the influence of permeability, on the generation of pore water pressure and the influence of the relative density of the backfill and foundation layers, on the residual deformation of gravity quay walls are investigated.     

Dynamic pressures on a pair of rigid walls retaining poroelastic soil

This work deals with the evaluation of the dynamic pressures and the associated forces on a pair of rigid vertical cantilever walls retaining a uniform, fully saturated poroelastic layer of soil. Hysteretic damping in the soil skeleton may also be present. Wall pressures and forces are induced by horizontal ground shaking harmonically varying with time and spatially invariant. The problem is solved analytically under conditions of plane strain. The governing partial differential equations of motion, after separation of variables and the simplifying assumptions of zero vertical normal stresses and zero horizontal variation of vertical displacements, reduce to a system of two ordinary differential equations for the amplitudes of the solid skeleton horizontal displacement and the pore water pressure, which are easily solved. The parameters examined include the ratio of the distance between walls to the height of the retained soil material and the soil material properties such as porosity, permeability and damping. The comprehensive numerical data presented indicate that the displacements, wall pressures and resultant forces are highly dependent on the distance between the walls for any values of porosity and permeability.     

预制空心保温剪力墙试验研究及延性分析

为解决传统的预制实心剪力墙结构自重大以及运输不便等不足,并避免预制夹心剪力墙内外页墙板的连接问题,提出一种预制空心保温剪力墙（PHISW）结构。为研究PHISW的抗震性能,对2个剪力墙试件进行低周反复荷载试验。试验结果表明:PHISW破坏模式以弯曲破坏为主,承载力与现浇实心剪力墙相近,但延性系数略低。基于此采用ABAQUS建立数值分析模型,并分析了轴压比、暗柱箍筋直径和间距、暗柱纵筋配筋率以及空心率这四个参数对PHISW延性的影响。数值模拟结果表明:模拟分析的滞回曲线与试验结果吻合较好,轴压比、暗柱纵筋配筋率以及空心率对PHISW延性影响显著,暗柱配箍对PHISW延性的影响较小。建议轴压比设计值不大于0.4,暗柱箍筋直径不宜小于8 mm,箍筋间距不宜大于150 mm。暗柱纵筋配筋率建议取值为1.49%～3%,墙体空心率不宜大于25%。     

考虑SSI效应的核电厂直立翼墙与排水沉管交叉体系静动力响应分析

某核电厂的联合泵房两侧直立翼墙以及排水沉管为交叉设计,且属抗震I类物项,因此,考虑土-交叉体系结构动力相互作用是抗震安全性评价的关键技术问题。以实际核电厂条件为背景,基于ANSYS分析平台建立了翼墙-沉管交叉体系-地基静动力分析模型,运用UPFs创建的粘弹性边界单元考虑无限地基辐射阻尼影响及地震动的输入,并精细化模拟地基材料的力学特性及交叉体系的空间分布形态,开展了静动力荷载联合作用下翼墙-沉管交叉体系的响应分析,探究交叉体系结构的应力、变形及加速度峰值等响应的变化规律。计算结果表明：直立翼墙与排水沉管交叉部位出现了应力集中现象,翼墙结构的竖向加速度响应与竖向及顺沉管水平向位移变形有较大变化,沉管在交叉部位的响应也有显著增加。研究成果可为核电厂取水工程构筑物的类似交叉体系设计提供技术参考。