Rubble Stone Masonry Walls Strengthened by Three-Dimensional Steel Ties and Textile-Reinforced Mortar Render,Under Compression and Shear Loads

This article addresses the results of a structural strengthening solution for rubble stone masonry walls. The strengthening includes inserting three-dimensional steel ties across the thickness of the walls and a 30-mm layer of air-lime and cement mortar render reinforced with glass fiber mesh (textile-reinforced mortar), on both sides of the wall. The strengthening solution was found to be efficient for rehabilitating ancient rubble stone masonry walls due to the “three-dimensional” confinement, provided by the steel wires, by offsetting the low cohesive capacity of the mortar used in the walls and thus improving the mechanical resistance and delaying the collapse mechanisms. This study is part of an experimental research program carried out in Universidade Nova de Lisboa, to evaluate structural strengthening solutions for ancient rubble stone masonry buildings. To this end, three specimens of rubble stone masonry walls without strengthening (unreinforced masonry) and other three, with the mentioned strengthening solution, were subjected to compression and shear load tests. Building materials were also tested in order to characterize physical, chemical and mechanical properties.     

山东滕州市染山西汉画像石墓

2008年,对山东滕州市染山汉墓进行发掘。该墓系在山坡开凿斜坡式墓道和长方形墓坑。在墓坑内用石材砌筑并排的5座椁室,椁室前部有前室和南、北侧室。出土遗物500余件,包括陶器、原始瓷器、玉器等。该墓的年代应为西汉中期,墓主应是郁郎侯刘骄。该墓的发掘为研究西汉葬制、葬俗、画像石艺术等提供了新资料。     

ARTIFICIAL ACCELEROGRAMS REPRESENTATIVE OF THE DAMAGE DISTRIBUTION ON A LOW-RISE SHEAR WALL

This study attempts to reproduce in an artificial way, at a given magnitude-distance couple, the statistical characteristics of damage caused by real accelerograms. The structure adopted is a low-rise shear wall, modelled as a nonlinear, one degree of freedom system with a degrading frequency as a function of a non-cumulative damage variable. Strong-motion records, contained in a large database, are characterised in terms of seismological and seismic parameters. Artificial accelerograms are generated from response spectra representative of real accelerograms belonging to different magnitude-distance zones. Although the mean damage is consistent, the low dispersion of damage caused by the artificial accelerograms with respect to that caused by the real accelerograms is highlighted. In order to reproduce the damage dispersion in addition to the mean damage, a generation method of representative artificial accelerograms is proposed. This method introduces the standard deviation drawn from attenuation relationships into a dispersion pre-process with respect to the regressed spectrum at a given magnitude-distance point. The method turns out to be capable of reproducing the statistical features of damage produced by real strong-motion records.     

SHEAR MODULUS AND DAMPING OF CLAYEY SANDS

A series of cyclic triaxial tests on clayey sands was carried out and attempts were made to evaluate the strain dependency of shear modulus and damping. Although the strain dependency of the shear modulus of clayey sands was similar to that of clay in the low strain range, G/G ₀ became close to that of clean sand in the high strain range. The damping ratio was less for the clayey sand containing more fines, especially in the medium to large strain range. It was shown that the change in the effective confining stress with loading cycles in the undrained shear test needed to be considered, particularly in the large strain range. The consideration can be made by normalising G with G ₀' instead of using G ₀. When an initial shear stress was applied to the specimen, the amount of residual strain, which was induced with cycles, had to be added to the normal strain amplitude in order to determine the shear modulus. If the effects of excess pore pressure and the amount of residual strain were taken into account properly, it was suggested that the shear modulus of clayey sand in irregular loading could be evaluated reasonably well by using the average G/G ₀—γcurve obtained by cyclic loading tests on isotropically-consolidated specimens.     

Shear Modulus and Damping Ratio of Cohesive Soils

This article presents results from a laboratory investigation into the dynamic characteristics of reconstituted and undisturbed cohesive soils by means of resonant-column tests. In particular, results showing the influence of various soil parameters, such as confining stress, overconsolidation ratio, void ratio, plasticity index, calcium carbonate content, and time of confinement on shear modulus and damping ratio at small and high shear strains are presented and then discussed. Relationships for the small-strain shear modulus, the degradation of shear modulus at high strains, and the increase of damping ratio at high strains over its small-strain value are proposed. Finally, the practical implications of the results in the context of seismic site response analysis are discussed.     

山西兴县红峪村元至大二年壁画墓

2008年5月,考古工作者在山西兴县康宁镇红峪村发掘了一座壁画墓。墓葬坐西朝东,由墓道、封门石、甬道、墓门及墓室组成,墓室为八角形,为夫妇合葬墓。墓顶和墓室皆绘有壁画,包括花卉、鞍马、墓主夫妇对坐图、备茶图及孝行故事等。西壁墓主夫妇之间有一牌位,题有墓主武庆及其妻景氏名字,其后座屏上题传马致远所作《天净沙.秋思》。西南壁上题记中有元代至大二年(1309年)纪年。     

Physical and Numerical Approaches for the Optimal Insertion of Seismic Viscous Dampers in Shear-Type Structures

This article presents the results of an exhaustive parametric analysis which compares the performances offered by various systems (which lead to both classical and non classical damping matrices) of added viscous dampers in shear-type structures. The aim of the research work here presented is the identification of the system of added viscous dampers which maximizes the dissipative properties under an equal “total size” constraint. The choice of the systems of added viscous dampers considered in the comparison is carried out both using a numerical approach (based upon the use of genetic algorithms) and a physically based approach (based upon the properties of classically damped systems). The comparison is carried out through the numerical evaluation of the dynamic response of representative shear-type structures to both stochastic and recorded earthquake inputs. The results obtained using both approaches indicate that a damping system based upon the mass proportional damping component of the Rayleigh viscous damping matrix (referred to as MPD system) is capable of optimizing simultaneously a number of different performance indexes, providing the best “overall” damping performances. The MPD system is characterised by viscous dampers (a) which connect each floor to a fixed point and (b) which are sized proportionally to the corresponding floor mass.     

试论南京地区明初功臣墓神道石刻

明早期功臣陵墓石刻制度主要参照了南宋时期的品官石刻制度,除了文献记载的石刻种类和数量明显反映了等级差异外,石刻的高度、石马障泥纹样、控马者的身份等都显示了等级差异。就是同一组石刻群中,文官武将石刻也是前后有序,左右有别,等级分明。     

The Effect of Stiffened Floor and Roof Diaphragms on the Experimental Seismic Response of a Full-Scale Unreinforced Stone Masonry Building

An extensive experimental program was carried out at EUCENTRE, within a research project on the evaluation and reduction of the seismic vulnerability of stone masonry structures. The main part of the experimental program has been devoted to the shaking table tests on three full-scale, two-story, single-room prototype buildings made of undressed double-leaf stone masonry. The first building tested was representative of existing unreinforced stone masonry structures with flexible wooden diaphragms, without any specific anti-seismic design nor detailing. In the second and third buildings, strengthening interventions were simulated on structures theoretically identical to the first one, improving wall-to-floor and wall-to-roof connections and increasing diaphragm stiffness. In particular, in the third specimen, steel and r.c. ring beams were used to improve the diaphragm connection to the walls and collaborating r.c. slab and multi-layer plywood panels were used to stiffen floor and roof diaphragms, respectively. This article describes the strengthening interventions applied to the third building prototype and presents the experimental results obtained during the shaking table tests. The results obtained permitted the calibration of a macroelement model representative of the nonlinear behavior of the structure.     

Castle Acre

This is the report of research excavations and salvage recording both inside and outside the standing Romanesque church. Evidence was seen of three pre-Conquest churches. The first was a ground standing timber building. The second was a Brixworth-type stone building. The third was a T-shaped church with a continuous transept and a tiny eastern apse. The evidence for these interpretations is presented. Documentary evidence is given and parallels are discussed. Additional information about the succeeding Romanesque church is presented. It had a rectangular crossing and tower, and evidence of a large added eastern chapel, reasoned to have been a new setting for the Holy Cross of Waltham, is discussed. Finds include floor tiles and stone. A burial close to the first church probably dates to the seventh century and suggests that Waltham was a minster church from the early years of the conversion. A herring-bone masonry wall is attributed to Harold.     

Floor Response Spectra for Bare and Infilled Reinforced Concrete Frames

The objective of this article is to study the effects of structural nonlinear behavior on Floor Response Spectra (FRS) of existing reinforced concrete frames. This study examines how the FRS vary with the level of post-elastic behavior in buildings of different number of stories and masonry infill wall configurations. The effect of damping modeling assumptions is also investigated. Differences and similarities with findings from the literature are discussed. On the basis of the obtained results, a commentary on the adequacy of basic assumptions used in predictive equations proposed by different seismic codes is offered.     

Inelastic Demand Spectra of Bi-Linear Models for Capacity Spectrum Method and Response of Simple Structures under Near-Source Records

A very useful tool for the preliminary design of structures is the elastic demand spectrum that can be used in the capacity spectrum method. A pseudo-acceleration relationship has to be assumed when constructing a demand spectrum. This assumption results in large errors for long period structures with large damping ratios and the conventional demand spectra require a substitute elastic structure. In the present study, the conventional demand spectra are extended to bi-linear models. Pseudo-acceleration is still assumed but results in acceptably small errors, when a constant viscous damping coefficient for a single-degree-of-freedom (SDF) structure is calculated from the tangent stiffness and the damping ratio is set at 5% in both elastic and yield phases. For nonlinear structures, tangent stiffness dependency of damping force could be acceptable because energy absorption is primarily the result of structural nonlinear deformation. To extend the conventional demand spectra to a bi-linear model, effective period calculated from the secant stiffness has to be used. The use of effective period introduces no approximation because the peak displacement of the SDF structure is computed from nonlinear analysis in the time domain. The method presented in this study is also valid if damping coefficient proportional to initial elastic spectra is used. In this case, the pseudo-acceleration is defined as the base shear coefficient that is required to produce the peak displacement of the SDF structure in a static manner. We present demand spectra of bi-linear models for a number of near-source records from large earthquakes, and spectral ratios of two horizontal components. The effects of different types of ground motion on the response reduction factor due to inelastic deformation are investigated.     

黑龙江大兴安岭呼中北山洞遗址2016年发掘简报

2016年对北山洞遗址的发掘,共清理灰坑3座、灶址16处,出土陶器、石器、玉器等遗物1800余件。依据层位关系及出土遗物特征分析,该遗址可分为六个时期文化遗存。第一期文化遗存属旧石器时代晚期,石器加工包含石片工业和石叶工业两种类型,剥片技术以锤击法为主,工具加工多采用打制修理技术。第二至第五期文化遗存属新石器时代,石器加工以细石核、细石叶等细石器工艺为主,剥片技术包括锤击法和间接压制法,工具加工多采用较为精细的压制修理技术。第六期文化遗存应与早期鲜卑遗存有密切关系,年代为东汉时期。北山洞遗址的发掘对大兴安岭东麓山区考古学文化编年体系的构建在一定程度上具有填补空白的意义。     

Excavations at Bamburgh: New Revelations in Light of Recent Investigations at the Core of the Castle Complex

The article documents the results of a series of investigations undertaken by the Bamburgh Research Project (BRP) within the Inner Ward of Bamburgh Castle, Northumberland between 1997 and 2010, using resistivity, ground penetrating radar survey, and limited excavation. Throughout the course of the investigation around the ruins of the medieval chapel, material evidence was found of Romano-British activity. Furthermore, stone structures of pre-twelfth-century date were revealed. Two phases of a possible early medieval defensive wall were identified beneath the north wall of the current chapel structure, and a stone building was found beneath the main body of the church which may represent part of the church of St Peter, mentioned by Bede.     

Experimental analysis of rubble stone masonry walls strengthened by transverse confinement under compression and compression-shear loadings

Stone masonry walls of ancient buildings have reasonable resistance to vertical loads but lower resistance to shear forces and reduced tensile strength. However, to achieve such compressive strength the masonry must not disaggregate when subjected to loading. This can be achieved if during the construction of the walls larger stones, usually referred as “through stones”, are used, spanning the thickness of the wall, making it possible to improve the transverse confinement of the masonry. For rehabilitation projects and structural reinforcement of such buildings, the transverse confinement can be achieved by fixing steel elements perpendicular to the wall. This confinement technique is often part of a more comprehensive rehabilitation solution, which includes the application of mortar or concrete reinforced layers applied to the wall surface.

This article presents results of an experimental research on material properties and mechanical characterisation of stone masonry specimens strengthened by two transverse confinement solutions (independent steel reinforcing rods and continuous steel ribbons wrapping the specimen). Specimens were tested under compression and compression and shear loadings.

This experimental work is part of a major research project to study the mechanical behavior of URM and strengthened walls, and the characteristics of the building materials of such specimens.     

东汉铜镜和画像石的图像比较

东汉时期的铜镜和画像石是两种不同质地、不同用途,分别处在阴阳两间的文物资料,然而,两者却有着相同的图案装饰,其创作设计的出发点都是为人生服务的。     

Shake-Table Tests of Confined-Masonry Rocking Walls with Supplementary Hysteretic Damping

A shake-table investigation is conducted on a 40% scale model frame-wall system to validate the concept of rocking walls as primary seismic systems. The rocking wall concept was implemented on confined masonry walls, but the findings can be extended to any rocking wall system. As the inherent damping of this system is low, a pair of supplemental steel hysteretic energy dissipating dampers is used at the base of the wall. It is concluded that with careful detailing, damage is not only eliminated but the structure re-centers itself following a large earthquake.     

近代江南地区工商业会馆、公所碑刻述论

在现有的行会制度史研究中,尚无专文对碑刻本身进行探讨.本文认为:刻石立碑是行会活动的一项重要内容,是工商业会馆、公所从社会合法性到政治合法性的一个重要标志,是行会受到封建官府保护的象征.在会馆、公所等行会组织的发展中,碑刻具有传承后世的记忆功能、惩戒违规的警示功能、颂扬美德的激励功能、公布官府法令的告示功能以及征信与佐证功能,有助于形成行业的凝聚力和从业者的自豪感,增强会馆、公所的权威性和同业商人对行业的归属感及维护行业利益的责任感,约束违规违法行为,对会馆、公所的变迁与发展具有不可替代的作用.     

Smart Lead Rubber Bearings Equipped with Ferrous Shape Memory Alloy Wires for Seismically Isolating Highway Bridges

Shape memory alloys (SMA) can substantially improve the damping capacity and re-centering capability of elastomeric isolators. The objective of this study is to assess the seismic performance of smart lead rubber bearings (LRBs) equipped with double cross ferrous SMA wires. Hysteretic shear response of SMA wire-based LRB is determined using finite element method. The seismic response of a multispan continuous steel girder bridge isolated by SMA-LRB is evaluated. Hybrid SMA-LRB bearing exhibits a significantly lower shear strain demand (up to 46% reduction) and a higher energy dissipation capacity (up to 31% increase) compared to the LRB.