Characterization of bricks and tiles from the 17th-century brick Chapel,St. Mary's City,Maryland

The brick Chapel at St. Mary's City, Maryland, built around 1667, would have been an impressive structure on a colonial frontier where all the other buildings were built only of wood. While the building is no longer extant, the bricks remaining in the buried foundations hold information about the technologies and materials used by brickmakers in the 17th-century Chesapeake region. Instrumental neutron activation analysis (INAA) and petrographic analysis of thin sections were used to compare the Chapel bricks and other 17th-century bricks and tiles from several Chesapeake contexts to locally available clay sources. While the composition of the Chapel bricks is generally consistent with that of clays available in southern Maryland, these historic materials could not be linked to any one deposit, and may reflect the mixing of clays from multiple sources. In contrast, building materials from other 17th-century buildings at St. Mary's City could be more precisely “matched” to specific local clay deposits. This paper reports on our initial investigations toward understanding the technology of the Chapel bricks and their relationship to other bricks from St. Mary's City.     

明初城墙包砖问题试析

本文通过统计明初南直隶、湖广、江西三省的城墙包砖情况,考察了明初城墙包砖的基本面貌,并根据明代各级城市所用城砖的烧造与征调情况,探讨包砖的相对成本,指出明初城市包砖与城市的等级、所处地区的军事战争形势密切相关。     

High-performance enrichment of casein and ovalbumin in wall painting with immunomagnetic beads

The detection of trace binding medium in wall paintings is usually challenging due to the aging and degradation of proteinaceous binding medium in a long time. Therefore, immunomagnetic beads (IMBs) with specific enrichment ability for casein and ovalbumin were prepared, and then the beads were applied for capturing target proteinaceous binding medium from ancient Chinese wall paintings. After optimization of experimental conditions, the enrichment performance of magnetic beads was confirmed by enzyme-linked immunosorbent assay (ELISA) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In this experiment, archaeological wall painting samples were used to verify the accuracy of the construction enrichment method. The results showed that the OD_450nm value of archaeological samples containing binding medium has increased to varying degrees after IMBs enrichment, effectively avoiding the occurrence of false negative results, indicating that the IMBs enrichment method developed in this work could be successfully applied for enriching ovalbumin and casein binding medium from ancient wall paintings for subsequently immunoassay detection.     

The ‘Triple R’ Approach on the Restoration of Archaeological Dry Stone City Walls: Procedures and Application to a UNESCO World Heritage Site in Oman

The ‘Triple R’ approach on the restoration of dry stone walls, using recognizable, reversible and respectful constructive techniques is here illustrated. A set of restoration procedures are explained and applied to a UNESCO World Heritage site in Al-Baleed (Salalah, Sultanate of Oman) in the ‘Land of Frankincense’. The procedures were adapted in an innovative way to take into account the climate features of the Indian Ocean area (specifically, the effects of the monsoon season). All the restoration procedures aimed at conserving the site’s original architectural features by using only suitable stones and materials found on-site. Specific procedures have been adopted to consolidate walls, gates, foundations and sloping surfaces. Simple on-site mechanical tests and evaluation methods have been developed for a quick assessment of the safety level of the restored walls to ease future archaeological excavations. The application is related to a waterfront side of the ancient city built around the ninth century and added to over the next five centuries. These restoration procedures allowed for further archaeological excavations with new findings is here described.     

Simulation of Shake Table Tests on Out-of-Plane Masonry Buildings. Part (III): Two-Step FEM Approach

ABSTRACT

This article presents numerical simulations of two full-scale masonry structures which were tested on the shaking table within the scope of the workshop “Methods and challenges on the out-of-plane assessment of existing masonry buildings”. The numerical models have been developed on the basis of the blind-prediction models which have been improved after the publication of the test results. The solution procedure is divided into two steps with separate numerical simulations for each one. In the first step the collapse mechanism of the structure is determined by means of pushover analysis using a continuum, plasticity-based model. In the second step the dynamic response of the structure is simulated using a multibody model approach and frictional contacts. Results of the tests show reasonable, yet far from perfect predictive capabilities of the used numerical methods.     

北京近代建筑砖石墙体的病害分析

为了尽量减少在修复工作时对历史建筑造成不可预估的破坏,修复前对建筑的病害分析是必不可少的。本文以北京近代建筑砖石墙面为研究对象,针对近代建筑的砖石墙面病害进行了调查研究,结合每类建筑病害特征,对其病害成因进行了简要分析,即病害分析。研究砖石墙面的病害成因,对寻求适宜的砌体病害保护修复方法有着重要的意义。     

Seismic Resistance Evaluation of Unreinforced Masonry Buildings

The article presents seismic resistance evaluation study of unreinforced brick masonry buildings. The study was carried out as part of the Ph.D. research work of the first author. As part of the study, in addition to the standard laboratory tests, a dynamic field test was carried out on single-story, single-room unreinforced masonry structure. The model structure was tested in actual ground conditions against simulated earthquake vibrations produced through controlled explosions, especially designed for this purpose. Based on masonry properties accrued from lab and field tests, finite element models of the brickwork system were also studied. Finally, the software named, “Shear Damage Index (SDI),” developed as part of this study, was used to plot contours of shear demand (shear stress) to shear capacity (shear strength) ratio on the numerical model and hence to identify potential weak zones in the model for possible strengthening of those locations.     

便携式X射线荧光现场分析壁画颜料适用性研究——以西藏拉萨大昭寺壁画为例

便携式X射线荧光光谱仪作为快捷的无损分析技术,广泛应用于壁画文物的现场分析中.本文利用便携式X射线荧光光谱仪分析了西藏拉萨大昭寺转经廊壁画,选取部分样品,利用实验室X射线荧光分析,发现所分析颜料的主要显色元素具有一致性,并利用拉曼光谱确定了壁画颜料的成分.通过比较研究,发现便携式X射线荧光光谱仪可确定大部分色彩较为纯正的颜料的成分,同时,由于西藏拉萨大昭寺壁画颜料的杂多性,对于含砷的橙色颜料、含砷或含铅与含铁的黄色颜料、含铜砷的绿色颜料、含钙硫的白色颜料、群青与孔雀石的混合颜料则需结合拉曼光谱确定之.本研究工作显示,利用便携式X射线荧光光谱仪开展现场检测,可极大地减少实验室分析样品的取样数量,有利于壁画颜料的无损分析与微损分析.     

江苏丹阳葛城遗址勘探试掘简报

江苏丹阳葛城吴文化遗址,经勘探试掘,确认其为一座吴国城址.城址内分布有窖穴、房基、水井、水沟,城址外分布有土墩墓.遗址中出土有较丰富的陶器、石器、青铜器等吴文化遗物.通过对出土陶器分析,可将该文化遗存分为三期:早期为西周中晚期,中期为春秋前期,晚期为春秋后期,三者之间连续无缺环.经与江、浙、皖地区同类吴文化遗存对比,可推知丹阳葛城古城是目前所发现的最早、延续使用时间最长、保存状况较为完好的吴国城址.     

Effectiveness of FRCM Reinforcement Applied to Masonry Walls Subject to Axial Force and Out-Of-Plane Loads Evaluated by Experimental and Numerical Studies

ABSTRACT

An experimental campaign and a numerical analysis devoted to the investigation of the out-of-plane behavior of masonry walls reinforced with Fiber Reinforced Cementitious Matrix (FRCM) are presented here. The main goal of this study is to analyze and evaluate the effectiveness of the strengthening system, by discussing failure modes and capacity of strengthened masonry walls, in order to assess their behavior under out-of-plane horizontal actions, such as, for example, seismic actions. A purposely designed experimental set-up, able to separately and independently apply an axial force and out-of-plane horizontal actions on masonry walls, was used. Experimental results are discussed and compared with the outcomes of nonlinear analyses performed on simplified finite element models of the walls. A proper evaluation of the flexural capacity of FRCM strengthened walls is the first step of the ongoing process of drawing reliable code guidelines leading to a safe design of strengthened masonry structures.