Rotational behavior of degraded traditional mortise-tenon joints: experimental tests and hysteretic model

This article presents the results of an experimental study on the rotational behavior of degraded Chinese traditional mortise-tenon joints with different degradation types and different degradation degrees. Six joint specimens degraded through artificially simulated method, were tested by reversed cyclic loading, from which the moment-rotation curves were obtained. The results indicated that the rotational behavior of these joints is semi-rigid, the hysteretic curve shapes of degraded joints are same to that of joint without degradation. The maximum moment, yield moment, and initial rotational stiffness of degraded joints decreases as the degraded degree increases, whose empirical degradation relationships were obtained based on the test data. A hysteretic model for degraded traditional mortise tenon joints was proposed. Experimental results were used to validate the proposed hysteretic model. Good agreement between predictions and tests was observed.     

In Situ Characterization of Rammed Earth Wall Renders

The Algarve region in southern Portugal has one of the most significant rammed earth construction legacies in the country. This construction method is characterized by its high susceptibility to water damage and external renderings are essential to the longevity of these constructions. This study collects and organizes data that provides the basis for the conservation and repair of renderings. Five earth buildings from western Algarve were selected to represent this heritage and its diversity of composition and susceptibility to water damage. Some of their commonest anomalies result from the interaction between the earth substrate and the traditional external renderings, given their distinct characteristics and behavior. The selected sample is described and the mechanical strength of the rammed earth walls and their renderings are evaluated through in situ tests. Samples of the external renderings and earth substrate of the five buildings comprising the sample were also collected and characterized in the laboratory. The characteristics of these two materials and their behavior as an assembly were analyzed. The results of the in situ and laboratory tests are compared and the viability of using a method based on in situ tests for the wider characterization of the type of construction under analysis evaluated.     

Hydraulic observations from a 1 year fluid production test in the 4000 m deep KTB pilot borehole

A long‐term pump test was conducted in the KTB pilot borehole (KTB‐VB), located in the Oberpfalz area, Germany. It produced 22 300 m³ of formation fluid. Initially, fluid production rate was 29 l min^?1 for 4 months, but was then raised to an average of 57 l min^?1 for eight more months. The aim of this study was to examine the fluid parameters and hydraulic properties of fractured, crystalline crusts as part of the new KTB programme ‘Energy and Fluid Transport in Continental Fault Systems’. KTB‐VB has an open‐hole section from 3850 to 4000 m depth that is in hydraulic contact with a prominent continental fault system in the area, called SE2. Salinity and temperature of the fluid inside the borehole, and consequently hydrostatic pressure, changed significantly throughout the test. Influence of these quantities on variations in fluid density had to be taken into account for interpretation of the pump test. Modelling of the pressure response related to the pumping was achieved assuming the validity of linear Darcy flow and permeability to be independent of the flow rate. Following the principle ‘minimum in model dimension’, we first examined whether the pressure response can be explained by an equivalent model where rock properties around the borehole are axially symmetric. Calculations show that the observed pressure data in KTB‐VB can in fact be reproduced through such a configuration. For the period of high pumping rate (57 l min^?1) and the following recovery phase, the resulting parameters are 2.4 × 10^?13 m³ in hydraulic transmissivity and 3.7 × 10^?9 m Pa^?1 in storativity for radial distances up to 187 m, and 4.7 × 10^?14 m³ and 6.0 × 10^?9 m Pa^?1, respectively, for radial distances between 187 and 1200 m. The former pair of values mainly reflect the hydraulic properties of the fault zone SE2. For a more realistic hydraulic study on a greater scale, program FEFLOW was used. Parameter values were obtained by matching the calculated induced pressure signal to fluid‐level variations observed in the KTB main hole (KTB‐HB) located at 200 m radial distance from KTB‐VB. KTB‐HB is uncased from 9031 to 9100 m and shows indications of leakage in the casing at depths 5200–5600 m. Analysis of the pressure record and hydraulic modelling suggest the existence of a weak hydraulic communication between the two boreholes, probably at depths around the leakage. Hydraulic modelling of a major slug‐test in KTB‐HB that was run during the pumping in KTB‐VB reveals the effective transmissivity of the connected formation to be 1 to 2 orders of magnitude lower than the one determined for the SE2 fault zone.     

Blind tests shed light on possibilities and limitations for identifying stone tool prehension and hafting

Prehensile wear has never formed the focus of a blind test in microwear studies and doubts remain about the formation, identification and interpretation of diagnostic prehension and hafting wear. The results of the presented blind tests demonstrate that prehension and hafting traces do form and that their formation is sufficiently systematic and patterned to allow valid and reliable interpretations. A combined approach, involving macroscopic, low power and high power analyses, is suggested as the most meaningful approach for consistent inferences.     

From Alloy Composition to Alloying Practice: Chinese Bronzes

We propose a new methodology based on standard statistical processes for displaying and rigorously comparing the alloy composition of archaeological bronze alloys. Although traditional approaches using visual comparisons of histograms of alloying elements in an assemblage of archaeological objects are adequate for observing differences between these distributions, we argue that differences in sample size cannot be adequately accounted for without using a statistical approach. We demonstrate this methodology by comparing the alloy composition of bronzes from the sequence of Bronze Age cultures in Central China—Erlitou, Erligang (Zhengzhou, or early Shang), Anyang (late Shang) and Western Zhou. We suggest that this approach allows the identification and rigorous comparison of ‘regional alloying practices’, which in turn enables us to link the alloy composition of the objects with the intentions and skills of foundry workers.     

Injection Grouts for the Re-Attachment of Architectural Surfaces with Historic Value—Measures to Improve the Properties of Hydrated Lime Grouts in Slovenia

In the described studies with the aim of optimizing hydrated lime grout composition, the first measure was to reduce the water content of the grout using a highly efficient polycarboxylate ether-based superplasticizer, whereas the second measure was to increase the content of the inert limestone filler with an adequate grain size distribution. In this way, an attempt was made to achieve the best possible volume stability and strength properties of the hydrated lime grout, while continuing to fulfill the other necessary requirements regarding non-structural grouting works which are reported in the literature.

The results of the tests showed that a non-structural grout consisting of 1 volume part of hydrated lime CL 90-S and 3 volume parts of inert limestone filler, with 0.5% of the polycarboxylate ether based superplasticizer, fulfilled most of the established requirements, so that it is thus potentially suitable for re-attachment interventions on architectural surfaces.     

SOIL-STRUCTURE AND SOIL-STRUCTURE-SOIL INTERACTION: EXPERIMENTAL EVIDENCE AT THE VOLVI TEST SITE

This paper shows the results of two passive experiments carried out at the European Volvi test site where a scaled building has been constructed. The first experiment was performed to study the motion of the structure excited by two small earthquakes. For one month, six strong-motion recorders were installed within the structure, at the top and at the basement. The analysis of the deformation of the structure has been assessed by computing the spectral ratio between the top and the bottom, with a special focus on soil-structure interaction. An analytical model was then proposed to reproduce the structure and soil-structure system behaviour. The soil-structure interaction was accounted for by using impedance functions. During the second experiment, we concentrated our efforts on the effect of the building vibration on the surface ground motion. An explosive shot was fired and several strong-motion recorders were installed on the ground close to the structure that allowed us to clearly identify a monochromatic wave coming from the building, in the time and frequency domains. This experiment allows us to demonstrate the non-negligible effect of the soil-structure-soil interaction that may disturb the surrounding ground motion.     

Laboratory Research on the Effects of Heavy Equipment Compaction on the in situ Preserved Archaeological Remains

Following the Malta Convention/Valletta Treaty the preferable way for the physical protection of archaeological sites is in situ preservation. When planning in situ preservation, in addition to other issues, it is also necessary to consider changes in physical environment and their impact on in situ preserved remains. This is especially important when human interaction takes place. Recently, an increase in construction on the top of archaeological sites has occurred, thus the effects of heavy equipment compaction need to be studied in more detail.

This paper presents research on the effects of the use of heavy equipment (e.g. rammers and rollers) compaction on archaeological remains. For the purpose of our research, laboratory testing has been performed. In a custom-made steel box, artificial archaeological sites were created using layers of sandy silt and gravel. A variety of archaeological and modern artefacts were placed in these created environments. Some of them were equipped with strain gauges for deformation recording. Through a series of tests a servo-hydraulic piston was used, which simulated the dynamic loading of the artificial sites. Humidity and temperature were recorded before, during, and after each test. Since layers and artefacts were three-dimensionally recorded before and after each test, compaction of layers and movements of artefacts could be studied. With attached strain gauges and visual inspection following each test, deformations and thus damage to artefacts during different stages of loadings was recorded.

The goals of our laboratory tests were the development of a new methodological approach to study the effects of heavy equipment compaction to the archaeological sites, getting an insight into the problems of such tests, and the estimation of the applicability of their results. With the presented results, our research has been a step towards better understanding the effects of heavy equipment compaction on archaeological remains and thus to the preservation of archaeological sites in situ.     

The upper continental crust, an aquifer and its fluid: hydaulic and chemical data from 4 km depth in fractured crystalline basement rocks at the KTB test site

Detailed information on the hydrogeologic and hydraulic properties of the deeper parts of the upper continental crust is scarce. The pilot hole of the deep research drillhole (KTB) in crystalline basement of central Germany provided access to the crust for an exceptional pumping experiment of 1‐year duration. The hydraulic properties of fractured crystalline rocks at 4 km depth were derived from the well test and a total of 23100 m³ of saline fluid was pumped from the crustal reservoir. The experiment shows that the water‐saturated fracture pore space of the brittle upper crust is highly connected, hence, the continental upper crust is an aquifer. The pressure–time data from the well tests showed three distinct flow periods: the first period relates to wellbore storage and skin effects, the second flow period shows the typical characteristics of the homogeneous isotropic basement rock aquifer and the third flow period relates to the influence of a distant hydraulic border, probably an effect of the Franconian lineament, a steep dipping major thrust fault known from surface geology. The data analysis provided a transmissivity of the pumped aquifer T = 6.1 × 10^?6 m² sec^?1, the corresponding hydraulic conductivity (permeability) is K = 4.07 × 10^?8 m sec^?1 and the computed storage coefficient (storativity) of the aquifer of about S = 5 × 10^?6. This unexpected high permeability of the continental upper crust is well within the conditions of possible advective flow. The average flow porosity of the fractured basement aquifer is 0.6–0.7% and this range can be taken as a representative and characteristic values for the continental upper crust in general. The chemical composition of the pumped fluid was nearly constant during the 1‐year test. The total of dissolved solids amounts to 62 g l^?1 and comprise mainly a mixture of CaCl₂ and NaCl; all other dissolved components amount to about 2 g l^?1. The cation proportions of the fluid (X_Ca approximately 0.6) reflects the mineralogical composition of the reservoir rock and the high salinity results from desiccation (H₂O‐loss) due to the formation of abundant hydrate minerals during water–rock interaction. The constant fluid composition suggests that the fluid has been pumped from a rather homogeneous reservoir lithology dominated by metagabbros and amphibolites containing abundant Ca‐rich plagioclase.