Displacement‐based seismic analysis for out‐of‐plane bending of unreinforced masonry walls

This paper addresses the problem of assessing the seismic resistance of brick masonry walls subject to out‐of‐plane bending. A simplified linearized displacement‐based procedure is presented along with recommendations for the selection of an appropriate substitute structure in order to provide the most representative analytical results. A trilinear relationship is used to characterize the real nonlinear force–displacement relationship for unreinforced brick masonry walls. Predictions of the magnitude of support motion required to cause flexural failure of masonry walls using the linearized displacement‐based procedure and quasi‐static analysis procedures are compared with the results of experiments and non‐linear time‐history analyses. The displacement‐based procedure is shown to give significantly better predictions than the force‐based method. Copyright © 2002 John Wiley & Sons, Ltd.     

Preliminary Investigation of the Molise (Italy) Earthquakes of 31 October and 1 November 2002

On 31 October and 1 November 2002, two earthquakes took place in the Italian region of Molise. 29 deaths were reported, while many buildings collapsed or suffered major damage. The tectonics of the earthquakes and historic seismicity of the area are briefly described. The distribution of damage and macroseismic intensity are confronted with the current seismic zonation of the region. In particular, the paper deals with the damage suffered by different types of structures, namely masonry and RC buildings and historical churches. The observed damage is mainly attributed to the poor quality of the materials and execution of construction, lack of maintenance and protective devices (e.g., steel ties), as well as to structural interventions. Reference is made to the management of the post-earthquake emergency. This revised version was published online in July 2006 with corrections to the Cover Date.     

砌体结构房屋抗震加固设计方法探讨

对砌体结构房屋常用的加固技术手段进行了探讨。结合茂名石化公司抗震加固设计与施工经验，提出了砌体结构房屋抗震加固设计与施工时应注意的问题。     

新型混凝土空心砌块房屋抗震性能研究

本文介绍了一种集承重与保温于一体的新型混凝土砌块房屋的抗震性能的研究结果。文中采用具有负刚度的四折线恢复力模型，用Newmark数值积分法，选用代表I-Ⅳ类场地的10地震记录，分别对两栋典型的新型砌块房屋进行了非线性地震反应分析，研究了在抗震设防“三水准”情况下房屋的抗震能力。计算结果表明：新型砌块房屋具有良好的抗震性能，在7、8度地震区分别建造7层和6层的这种房屋可满足抗震设防三水准要求。文中还介绍了一个足尺新型砌块房屋模型的模拟振动台试验，用本文给出的非线性地震反应分析方法对模型进行了计算，且将振动台试验结果与计算结果做了比较，验证了本文选取的计算模型是合理的、计算方法是可靠的。     

Effect of earth tide on deep well water level

On the basis of the partial differential equations of the water level in a deep well that is affected by the bulk strain tide, the boundary conditions of permeating each other between aquifer and well are considered. The solutions of the equations have been obtained by the superposition principle, inpulse theorem and separation of the variations. Some suitable values are given to the parameters of well aquifer in the solutions. By means of the numerical calculation the relations among the well tide coefficients and phase lag phenomenon of response of the well level to earth tides is well interpreted. The parametric studies and the obtained graphs show that the more the radius of casing in a well, the porosity of an aquifer and the bulk compressibility for solid matrix of an aquifer, the less the transmissibility of an aquifer, then the less the tidal coefficient of well level, while the more the phase lag for well level to respond to the tide is. The response of the well level to the tide of longer period is better than the shorter period events. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 66–75, 1991.     

砌体结构工程抗震软件的结构隔震功能及算例分析

在砌体结构抗震软件开发过程中，为完善软件功能，添加了结构减震设计验算程序。作为首次应用性软件开发，暂只包含橡胶热隔震的设计与验算功能。本文主要介绍了软件应用时，橡胶垫隔震支座的设计过程，并通过对一个模拟的8层砌体建筑进行隔震设计与对比分析，给出了隔震设计后隔震效果的有关结论。     

软土地基上带圈梁构造柱砌体结构的非线性有限元分析

本文对软土地基上带圈梁构造柱的砌墙体进行了非线性有限元全过程分析。根据砌体、混凝土和钢筋各自的本构关系，采用八结点等参元有限元进行求解。在分析过程中，考虑砌体出现的开裂与开裂过程中的应力迁移，讨论了各种工况对墙体的内力分布带来的影响。     

Complex bedding geometries and facies associations of the turbiditic fill of a confined basin in a transpressive setting (Castagnola Fm., Tertiary Piedmont Basin, NW Italy)

ABSTRACT This paper details the influence of syndepositional tectonics in controlling the architecture of a well‐exposed confined turbiditic sandbody, which crops out in the eastern part of the Tertiary Piedmont Basin (Castagnola Basin, northern Italy). The Castagnola Basin was tectonically active during sedimentation of the sandbody, and the lateral distribution of turbidity‐current deposits has been used to constrain both how the basin subsided and the impact of basin topography on flow behaviour and deposition. The sandbody occurs in the lower member of an Upper Oligocene–Lower Miocene turbidite system (the Castagnola Formation). The sandbody is ≈30 m thick and can be followed laterally for ≈1·8 km; it shows onlap terminations onto both northern and southern basin margins. The outcrop is sufficiently large to allow a detailed analysis of the facies and geometrical heterogeneity, as viewed approximately parallel to the average palaeocurrent trend (SW–NE). Correlation between 41 sedimentological logs reveals the diachronous development of a succession of sandstone packages (subunits). Nine vertically stacked and laterally juxtaposed packages have been recognized (subunits B to I from oldest to youngest), which reflect changes in basin floor accommodation as a result of synsedimentary tectonism. Each package shows the development of different vertical stacking patterns with thinning‐ and ‐fining‐upward small‐scale sequences and variable lateral facies arrangements, as a consequence of the position relative to the basin margins. The geometry, stratigraphic relationships, facies distribution and palaeocurrent directions indicate that turbidite deposition during accumulation of most of the sandbody was controlled by (1) synsedimentary tilting of the basin slopes; (2) the distribution of structural and depositional relief within the basin; (3) the thickness and volume of the turbidite flows; and (4) the angle of impingement of turbidity currents against the basin slopes.     

Hybrid event bed character and distribution linked to turbidite system sub‐environments: The North Apennine Gottero Sandstone (north‐west Italy)

This study documents the character and occurrence of hybrid event beds (HEBs) deposited across a range of deep‐water sub‐environments in the Cretaceous–Palaeocene Gottero system, north‐west Italy. Detailed fieldwork (>5200 m of sedimentary logs) has shown that hybrid event beds are most abundant in the distal confined basin‐plain domain (>31% of total thickness). In more proximal sectors, hybrid event beds occur within outer‐fan and mid‐fan lobes (up to 15% of total thickness), whereas they are not observed in the inner‐fan channelized area. Six hybrid event bed types (HEB‐1 to HEB‐6) were differentiated mainly on basis of the texture of their muddier and chaotic central division (H3). The confined basin‐plain sector is dominated by thick (maximum 9·57 m; average 2·15 m) and tabular hybrid event beds (HEB‐1 to HEB‐4). Their H3 division can include very large substrate slabs, evidence of extensive auto‐injection and clast break‐up, and abundant mudstone clasts set in a sandy matrix (dispersed clay ca 20%). These beds are thought to have been generated by highly energetic flows capable of delaminating the sea floor locally, and carrying large rip‐up clasts for relatively short distances before arresting. The unconfined lobes of the mid‐fan sector are dominated by thinner (average 0·38 m) hybrid event beds (HEB‐5 and HEB‐6). Their H3 divisions are characterized by floating mudstone clasts and clay‐enriched matrices (dispersed clay >25%) with hydraulically fractionated components (mica, organic matter and clay flocs). These hybrid event beds are thought to have been deposited by less energetic flows that underwent early turbulence damping following incorporation of mud at proximal locations and by segregation during transport. Although there is a tendency to look to external factors to account for hybrid event bed development, systems like the Gottero imply that intrabasinal factors can also be important; specifically, the type of substrate available (muddy or sandy) and where and how erosion is achieved across the system producing specific hybrid event bed expressions and facies tracts.     

CO2泄漏停止后天然条件下浅层含水层的自我修复能力评价

由于盖层中可能存在未知断层和裂隙或被废弃井穿透,储存于深部地层的CO₂会发生向上运移泄漏影响浅层地下水水质,在天然流场的作用下,受影响含水层在泄漏停止后,可能表现出一定的自我修复能力。以美国某野外试验场地为例,以TOUGHREACT软件为平台,模拟分析当CO₂泄漏停止后含水层的自我修复能力。结果表明：CO₂泄露进入含水层会降低地下水中的pH值,从而引起地下水中碳酸盐矿物（本次研究中为方解石矿物）的溶解发生;当泄漏停止后,在天然流场的作用下,地下水中pH值逐渐回升,说明天然条件下的含水层对pH值具有一定的自我修复能力,但在修复过程中,由于沿途方解石矿物的溶解,使得地下水中Ca的浓度值逐渐升高,研究区天然流场对地下水中的Ca修复效果不佳。