Monitoring Cultural Heritage in a Long-Term Project: The Norwegian Sequential Monitoring Programme

Abstract

A sequential monitoring programme for archaeological sites and monuments was started in Norway in 1997. The purpose of this ongoing monitoring was to produce more accurate figures for loss and damage and to detect long-term trends in loss/damage patterns. In this article we present the method used to document the sequential monitoring, the extent of and the most important causes of loss and damage to archaeological heritage, and we discuss both the strengths and weaknesses of the method used in this monitoring programme. The results so far point to agriculture as the single most important cause of loss, and together with housing and leisure it is also the most important cause of damage. In the large parts of Norway where agriculture is marginal and has been characterized by small farms and grass based livestock production, regrowth of fallow fields leads to cultural landscape change and the loss of archaeological sites.     

Numerical Modeling of a Church Nave Wall Subjected to Differential Settlements: Soil-Structure Interaction,Time-Dependence and Sensitivity Analysis

ABSTRACT

Historic masonry structures are particularly sensitive to differential soil settlements. These settlements may be caused by deformable soil, shallow or inadequate foundation, structural additions in the building and changes in the underground water table due to the large-scale land use change in urban areas.

This paper deals with the numerical modeling of a church nave wall subjected to differential settlement caused by a combination of the above factors. The building in question, the church of Saint Jacob in Leuven, has suffered extensive damage caused by centuries-long settlement. A numerical simulation campaign is carried out in order to reproduce and interpret the cracking damage observed in the building.

The numerical analyses are based on material and soil property determination, the monitoring of settlement in the church over an extended period of time and soil-structure interaction. A sensitivity study is carried out, focused on the effect of material parameters on the response in terms of settlement magnitude and crack width and extent. Soil consolidation over time is considered through an analytical approach. The numerical results are compared with the in-situ observed damage and with an analytical damage prediction model.     

Editorial Introduction

Abstract

International response to the problem of looting of archaeological sites has been hampered by the difficulty of quantifying the damage done. The scarcity of reliable information negatively impacts professional and public policy making, rendering consensus about the scale of the problem and the effectiveness of policy responses difficult to achieve. We report here on the use of publicly-available satellite imagery for quantifying the damage caused by looting of archaeological sites in Jordan. The ease of use and affordability of imagery such as that provided by Google Earth make the identification, quantification, and monitoring of archaeological site looting possible at a level previously unimagined. Our findings about looting at archaeological sites in Jordan shed light on the potential for a broader application of the method.     

Performance-based Seismic Risk Assessment of Urban Systems

ABSTRACT

Disaster risk mitigation has become a urgent global need. Similar to other natural hazards, earthquakes may cause significant damage on a large scale. In Europe and in other regions with dense urbanization, seismic events can heavily impact historical city centers due to the several structural fragilities. These centers are often part of the worldwide cultural heritage and their preservation is considered a strategic issue. Furthermore, earthquakes may have severe negative short-term economic effects on the impacted communities and adverse longer-term consequences for economic growth. For this reason, the development of an efficient approach for urban seismic risk assessment becomes essential. An original approach is proposed, based on performance concepts and multidisciplinary perspectives. The procedure is applied for validation to the city center of Concordia Sulla Secchia (Italy), damaged by the 2012 Pianura Padana Earthquake (PPE), comparing predicted damage scenarios with the actual post-seismic survey data.     

3D Digital Documentation,Assessment, and Damage Quantifi cation of the Al-Deir Monument in the Ancient City of Petra,Jordan

Abstract

The rock-cut monuments in the ancient city of Petra in Jordan form an outstanding tangible heritage site. Unfortunately, this important part of the world's cultural heritage is gradually being diminished due to weathering and erosion problems. In this research, an approach combining in situ surveying and laboratory analysis is applied in order to provide sufficient and comprehensive data regarding the documentation and evaluation of the status of the Al-Deir monument in Petra. The purpose was not only to quantify the damage, but also to make a first step towards creating a 3D monitoring programme of the deterioration rate. The approach presents a correlation study between the environmental condition and the surface weathering damage, using 2D mapping of the weathering form and accurate 3D realistic modelling from laser scanning and digital photogrammetry. The 2D mapping provides detailed weathering damage information for the entire stone surface of the monument, whereas the 3D modelling provides information on the spatial distribution and texture of the damage. Additionally, the 3D digital model can provide reference data as an exact guide to the restoration needed. In order to support the visual presentation of 3D surface details, a hybrid approach combining data from laser scanning and digital imagery was developed.

Studies of stone texture and spatial distribution of soluble salts were carried out at the monument in order to explain the mechanism of the weathering problem. Relative humidity, temperature, and wind are the main factors in the salt damage process. In order to study the effect of these conditions in the salt crystallization process a series of fieldwork investigations and laboratory work were undertaken. The results show that visible zoning of weathering damage is correlated to different salt concentrations.     

Valuing visitor benefits at Maehu Picchu

Abstract

This paper shows how the application of economic valuation techniques could assist decisionmakers in managing the unique archaeological site of Machu Picchu in a more efficient way. These techniques demonstrate that the current admission fee is very low compared with the typical tourist's willingness to pay. Raising the admission charge to 40 would not reduce the revenue raised and would, at the same time, reduce maintenance costs and damage to the site caused by high visitor numbers. Site managers should consider practising price discrimination whereby foreign tourists pay a fee substantially higher than that charged to Peruvian nationals.     

The Mechanical Farm of 2030

Abstract

After introducing influences which will affect mechanization of agriculture over the next 50 years, the review deals separately with three aspects of equipment on farms. These are machinery for arable farming, equipment used in livestock husbandry, and the hardware and software likely to assist farm management. The bulk of crop production is predicted to be carried out by a system of field gantries which will replace today's tractor and implements. The gantries will be fitted with automatic guidance but will still carry an operator who will be provided with extensive monitoring instrumentation. Second, monitoring of livestock growth or yield will be computer based. Health and breeding will also be automatically monitored and controlled, and farm staff will be aided by a robot, whose functions will include remote viewing and sensing, routine animal and feed handling operations, and assistance with animal herding. Computers will be used extensively in farm management with on-farm machines linked permanently to national information data banks, to suppliers and organizations who purchase from the farm and to consultant organizations. Computers will also be used for planning decisions based on operational research predictive methods and particularly for daily work planning.     

Study on Damage Assessment of Earthen Sites of the Ming Great Wall in Qinghai Province Based on Fuzzy-AHP and AHP-TOPSIS

ABSTRACT

As a world-renowned heritage site, the Ming Great Wall in Qinghai Province, is an example of an earthen site that is seriously threatened by a series of deterioration. Its damage assessment is the precondition for further protection planning and implementation, but related research was found to be scant. To fill this gap, we explore to study its damage assessment by applying Fuzzy-AHP and AHP-TOPSIS to determine the damage assessment levels for 18 earthen sites selected from Qinghai Province, combined with their occurrence environment, engineering properties of rammed earth, deterioration characteristics, and building technologies. After obtaining and comparing results, the AHP-TOPSIS is indicated to be much closer to the real damage conditions. Therefore, this method is proved to be more suitable for the damage assessment of earthen sites in Qinghai Province. This study also holds the potential application of the AHP-TOPSIS in the damage assessment for other earthen sites in Northwest China.     

Artifact Visibility at Open Sites in Western New South Wales,Australia

Abstract

Surface visibility is a significant constraint in archaeological survey, and estimates of surface visibility are a common addition to cultural resource management reports. Despite this, relatively few studies have attempted to identify the factors affecting visibility and quantify their effects. We report the results of such a study based on analysis of surface stone artifacts deposited by prehistoric hunter-gatherers from the Stud Creek area in what is now Sturt National Park, western New South Wales, Australia. While we are able to demonstrate and quantify relationships between high artifact visibility and erosional surfaces, and low visibility and vegetated or depositional surfaces, our findings also indicate a high degree of local variability. This variability sometimes obscures the predicted relationships. The outcome of this research leads us to question the way some sampling designs for archaeological survey are constructed.     

Preservation Status and Priorities for In Situ Monitoring of the Weapon Sacrifice in Illerup Ådal,Denmark

Abstract

Excavations of the southern part of a very rich sacri?cial bog in Illerup Ådal, Denmark between 1950 and 1985 recovered approximately 15,000 Iron Age artefacts. At the time, 60 per cent of the area was left unexcavated and thousands of objects are now preserved in situ, but the present preservation status has not been investigated for approximately twenty-?ve years. Extensive in situ monitoring was carried out for one year in order to present a prioritized plan for further monitoring of the unexcavated areas, producing documentation of groundwater table variations, water quality and vegetation in the area. Results show that the remaining artefacts are generally well preserved in a waterlogged and anaerobic environment. However, in the north-eastern part of the bog, the groundwater table is too low even in a year when net precipitation and hydrological conditions were near normal. In the centre of the bog elevated salt concentrations have been measured in the groundwater.     

The Reduction of Fire Damage in Southern England, 1650-1850

Abstract

The incidence of fire damage in southern England fell off steeply about 1780. This is traced to a spreading movement to build or rebuild in brick-and-tile instead of ‘mud’, timber and thatch, reinforced by improvements in fire-fighting. It resulted in the predominantly Georgian central buildings of southern market towns.     

Structural Assessment of Ancient Masonries before and during a Rehabilitation Process

ABSTRACT

The rehabilitation of old buildings requires detailed knowledge of the mechanical characteristics and stress state of the structural elements, which play an important role in the intervention process. In this sense, non-slightly destructive tests can estimate structural characteristics with good precision at relatively low costs. Consequently, this article presents a device, based on the flat jack technique, applied to continuous stress monitoring over time. It also focuses on the onsite determination of service stresses and its continuous monitoring in several masonry buttresses of a historic building, as well as the assessment of the structural safety before, during, and after an intervention process. A brief analysis of the research is performed, and the motivation and the methodology adopted are described. Finally, the evolution of the measurements recorded and the analysis of the results achieved are detailed. The study enabled recommendations to be made to the intervening agents that guarantee structural safety.     

Thirty Years of Monitoring in England — What Have We Learnt?

Abstract

Over the last thirty years, over sixty separate episodes of monitoring waterlogged archaeological sites have been carried out in England. This paper lists these projects, summarizes basic information about them, and reviews what we have learnt over these last thirty years. Recommendations are given to help improve future monitoring projects. In particular, it is suggested that more work is needed on assessing the state of preservation of a site before monitoring is considered; that a proper project design needs to be developed at the outset of the work; and that more thought should go into deciding why monitoring is needed for a given site, including identifying mitigation options that can be initiated if monitoring data suggest optimum conditions for survival are no longer being maintained.     

They did not Live by Grass Alone: the Politics and Palaeoecology of Animal Fodder in the North Atlantic Region

Abstract

A five year research project was set up to monitor soil moisture and groundwater levels of an extensive buried, mainly alluviated landscape located at the interface between the lower Great Ouse valley and the fen-edge in western Cambridgeshire. The intention was to monitor changes in hydrology, soil structure and geochemical status before, during and after large scale gravel extraction. The results presented here concern the pre-extraction monitoring period over three years. The project has identified three major landscape zones – shallowly buried former dryland, several sets of relict palaeochannel systems which still remain waterlogged, and a marginal zone between these where the monitored parameters fluctuate on a seasonal basis. The moisture levels of the alluvial overburden, buried soils and infills of the palaeochannel systems appear to act independently of each other, controlled by a combination of rainfall, agricultural land management, height above sea level and depth of burial. It is predicted that the removal of 1–3m of overburden accompanied by water abstraction when gravel extraction commences will lead to changes in the moisture regime of the immediate area and therefore of any contained archaeological contexts and the superficial sediments in this river valley/fen-edge landscape.     

Quantification and Visualization of In Situ Degradation at the World Heritage Site Bryggen in Bergen,Norway

Abstract

Environmental monitoring at the World Heritage Site of Bryggen in Bergen, Norway, has shown damaging settling rates caused by degradation of underlying archaeological deposits. Measurements of piezometric head, oxygen, and soil moisture content, as well as chemical analyses of water and soil samples are key elements of the environmental monitoring.

Groundwater monitoring and geochemical analyses reveal a complex and dynamic flow through the natural and anthropogenic stratigraphy. The preservation conditions within the organic archaeological deposits are strongly correlated with oxygen and soil moisture content, that are controlled by the groundwater flow conditions at the site. To quantify decay rates, it is thus essential to understand the wider hydrogeological context of the site. This paper presents recent advancements in quantifying decay rates in the saturated zone at Bryggen. The paper also shows that 3D geo-archaeological modelling can contribute to preservation management by visually combining results of geological, archaeological, geochemical, and hydrological investigations. This opens up for improved multidisciplinary understanding of preservation potential, thereby contributing to an improved protection of archaeological deposits in situ.     

Rehabilitation Techniques for Walls during the 18th Century in Cartagena de Indias (Colombia)

ABSTRACT

Although it may be thought that the rehabilitation of historical structures is a concern of modern engineering, studies on intervention processes from the past allow us to understand that this is a work carried out frequently and sometimes as a solution to low budgets for the construction of new buildings, or the need to offer quick practical solutions. The objective of this article is to show the way in which during the second half of the 18th century several important architectural and structural rehabilitation works were carried out in the walls of Cartagena de Indias, in view of the damage caused by the enemy attacks to the city as well as continuous impact by nature. By making use of primary sources (plans and original reports), the way in which two of the interventions were executed can be reconstructed: one on the Muralla Real, and another on the San José bastion, gathering information that helps explain their current state of conservation.     

A Qualitative Approach for Assessment of the Burial Environment by Interpreting Soil Characteristics; A Necessity for Archaeological Monitoring

Abstract

Modern-day archaeological monitoring is often hampered by lack of money, lack of time, inadequate measuring equipment, and lack of insight in the conservation potential of a site.

Although in modern archaeological excavations soil characteristics are noted (colour, texture, groundwater level, and sometimes mineralogy), these characteristics are mainly used for the interpretation of a site. However, by looking to these characteristics from a conservational view eventually combined with the conservation status of the archaeological objects, much can be learned about the burial environment. This is essential for optimizing archaeological monitoring.

Degradation processes result from the change of reactive phases in the soil or the site. Reactive phases are soil components such as organic matter, sulfides, iron(hydr)oxides and carbonates (chalk, shells), and, if present, components in the ground or interstitial water such as hydrogen ions and sulphate. The presence of these phases can easily be established by the archaeologist or soil scientist in the field. We propose a simple field-based method for assessing degradation processes essential for in situ preservation and monitoring.     

An assessment of attributing public healthcare infrastructure damage in the Donbas five years after Euromaidan: implications for Ukrainian state legitimacy

ABSTRACT

From the onset of the conflict in Eastern Ukraine in 2014, significant damage has been wrought to the public health infrastructure of the Donbas region. To date however, the full extent of that damage which is substantial, has not been documented: attribution of blame for that damage has not been attempted; and the implications for the region’s residents in terms of access to clinics and hospitals has been difficult to assess. This paper presents a spatial database of damaged facilities and relates that to the fighting to assess whether the damage incurred was collateral or targeted. The concept of state capacity is used to frame a discussion of what the consequences are for those residents remaining and for the challenges this crisis presents to the legitimacy of the Ukrainian government.     

Material Characterization and Micro-Modeling of a Historic Brick Masonry Pillar

A masonry pillar composed of solid clay bricks, cement mortar and infill is extracted from a historical structure and tested in concentric compression. It is subjected to cyclic and monotonic loads up to compressive failure.

In parallel, samples are extracted from the pillar and are subjected to destructive tests. Non-destructive tests are performed on the pillar, as well. The properties of the constituent materials are critically examined and their role in the maximum load reached and the failure mode obtained are discussed.

Finally, a finite element micro-model of the pillar is used for the simulation of the pillar test. The influence of the existing damage on the pillar is investigated using the model, resulting in a fair approximation of the global Young’s modulus, maximum load and the failure mode.

Highlights

●?A brick masonry pillar extracted from a historical building is tested in compression.

●?Material samples extracted from the pillar are characterized by mechanical tests.

●?A finite element micro-model of the pillar is used for the simulation of the compressive test.

●?The effect of damage on the compressive strength of the pillar is numerically investigated.     

Experimental Study on Seismic Performance of Through-Tenon Joints with Looseness in Ancient Timber Structures

ABSTRACT

In order to study the influence of looseness on seismic performance of through-tenon joints, six through-tenon joints specimens in 1:3.2 scale, including one tight-fitted joint and five loose joints, were fabricated according to the Engineering Fabrication Methods of Qing dynasty. The failure modes, mechanical behaviors such as the hysteresis and envelope curves, strength and stiffness degradations, energy dissipation, and deformation of the specimens under low cyclic reversed loading tests were analyzed. Results show that the failure modes of theses joints under positive and negative loadings are bending damage on the big tenon head and tearing damage on the variable cross-section, respectively. The hysteresis curves of joints appear to be anti-Z shape and present typical pinching effect. The greater the degree of looseness is, the more obvious the slippage is. The bending moment, stiffness and energy dissipation of loose joints are lower than those of the tight-fitted joint under the same rotation angle, and the increase in the loose degree cause them to gradually decrease. Meanwhile, the behavior of the through-tenon joints is further simulated by the nonlinear finite element analysis program, and the test results agree well with the numerical analysis results.