Number and plural semantics: Empirical evidence from Marori

This paper presents new empirical evidence from Marori (a Papuan language of Southern New Guinea) for the semantics of number in a complex number system. Marori has a basic three-way number system, singular/dual/plural. Marori is notable for showing distributed number exponence and constructed number strategies, in sharp contrast with familiar twoway, morphologically simpler number systems in languages such as English. Unlike in English, the reference of plurals in Marori in many contexts is to a group of three or more individuals. While Marori’s number system is typologically quite different from English, it shows an intriguing similarity in that in certain contexts, plural/nonsingular forms allow an inclusive reading (i.e. reference to any number of individuals, including one). The paper also presents evidence that all number types, including constructed dual, can be used for generic reference. The paper concludes with remarks on the theoretical significance of our findings

Determining the presence of scour around bridge foundations using vehicle-induced vibrations

Bridge scour is the number one cause of failure in bridges located over waterways. Scour leads to rapid losses in foundation stiffness and can cause sudden collapse. Previous research on bridge health monitoring has used changes in natural frequency to identify damage in bridge beams. The possibility of using a similar approach to identifying scour is investigated in this paper. To assess if this approach is feasible, it is necessary to establish how scour affects the natural frequency of a bridge, and if it is possible to measure changes in frequency using the bridge dynamic response to a passing vehicle. To address these questions, a novel vehicle–bridge–soil interaction (VBSI) model was developed. By carrying out a modal study in this model, it is shown that for a wide range of possible soil states, there is a clear reduction in the natural frequency of the first mode of the bridge with scour. Moreover, it is shown that the response signals on the bridge from vehicular loading are sufficient to allow these changes in frequency to be detected

Factors Influencing the Prediction of Pile Driveability Using CPT-Based Approaches

This paper investigates the applicability of Cone Penetration Test (CPT)-based axial capacity approaches, used for estimating pile static capacity, to the prediction of pile driveability. An investigation of the influence of various operational parameters in a driveability study is conducted. A variety of axial capacity approaches (IC-05, UWA-05 and Fugro-05) are assessed in unmodified and modified form to appraise their ability to be used in estimating the driveability of open-ended steel piles used to support, for example, offshore jackets or bridge piers. Modifications to the CPT-based design approaches include alterations to the proposed base resistance to account for the resistance mobilized under discrete hammer impacts and the presence of residual stresses, as well as accounting for the effects of static capacity increases over time, namely ageing. Furthermore, a study on the influence of various operational parameters within a wave equation solver is conducted to ascertain the relative impact of uncertain data in this respect. The purpose of the paper is not to suggest a new design procedure for estimating pile driveability, rather to investigate the influence of the various operating parameters in a driveability analysis and how they affect the magnitude of the resulting predictions. The study will be of interest to geotechnical design of piles using CPT data

Empirical Shaft Resistance of Driven Piles Penetrating Weak Rock

In this paper, an empirical relationship between the Unconfined Compressive Strength (UCS) of intact rock and the unit shaft resistance of piles penetrating rock is investigated. A growing number of civil engineering projects are utilizing steel piles driven into rock where a significant portion of the pile capacity is derived from the shaft resistance. Despite the growing number of projects utilizing the technology, little to no guidance is offered in the literature as to how the shaft resistance is to be calculated for such piles. A database has been created for driven piles that penetrate bedrock. The database consists of 42 pile load tests of which a majority are steel H-piles. The friction fatigue model is applied to 7 of the pile load tests for which sufficient UCS data exists in order to develop an empirical relation. The focus of this paper is on case histories that include driven pipe piles with at least 2 meters penetration into rock

Drive-by scour monitoring of railway bridges using a wavelet-based approach

This paper numerically investigates the feasibility of using bogie acceleration measurements from a passing train to detect the presence of bridge scour. The Continuous Wavelet Transform is used to process the simulated acceleration measurements for a number of train passages over a scoured bridge, with scour represented as a local reduction in stiffness at a given pier. Average Wavelet coefficients are calculated for a batch of train runs passing over the same bridge. A scour indicator is developed as the difference in average coefficients between batches from the healthy bridge and when the bridge is damaged by scour. The method is assessed using a blind test, whereby one author simulated trains passing over a bridge in various states of health. The remaining authors were provided only with the train accelerations and had to predict the state of scour without any prior knowledge. This scour indicator performed quite well in the blind test for normal vehicle operating conditions

Use of mode shape ratios for pier scour monitoring in two-span integral bridges under changing environmental conditions

In this paper, a novel pier scour indicator is introduced, which uses the ratio between mode shape amplitudes identified at two points on an integral bridge structure to monitor the progression of scour erosion. The Mode Shape Ratio (MSR) is investigated as an additional parameter to complement the use of changes in natural frequency as a scour indicator. The approach is demonstrated using numerical modelling and the MSR is extracted from acceleration signals arising in the structure due to modelled ambient and vehicle-induced vibrations. The MSR shows higher sensitivity to scour erosion than the more commonly researched natural frequency. Furthermore, the variation in MSR under temperature fluctuations is inversely related to that of frequency, in that it increases with increasing temperature whereas frequency decreases with increasing temperature. This inverse relationship potentially enables the separation of the scour effect from the temperature influence on the dynamics of the system

A CPT-based multi-spring model for lateral monopile analysis under SLS conditions in sand

Monopiles are the most common Offshore Wind Turbine (OWT) foundations due to their simplicity in design, fabrication, and installation. However, large new-generation turbines have led to significant changes in monopile dimensions, necessitating extensive finite element analyses and ground investigations to meet design requirements. While Cone Penetration Test (CPT)-based p - y methods can analyse slender pile lateral behaviour, they often miss additional resistance mechanisms relevant to rigid monopiles. This paper introduces CPT-informed resistance mechanisms for monopiles to incorporate additional lateral resistances beyond p - y modelling capabilities. Distributed moment–rotation ( m - θ ) springs are defined by repurposing CPT-based axial capacity estimation methods for piles; and pile tip shear and moment springs are informed by approximating a residual bearing stress post-installation using local CPT q c values. The performance of the multi-spring model is appraised against data reported from monotonic pile pushover tests conducted at two sand sites. Results show that the multi-spring model is capable of predicting pile head deflections reasonably well within serviceability deflection limits against the reported test data, but ultimate failure loads cannot be predicted using the proposed model. A clear sensitivity in pile response to local variations in CPT q c is demonstrated

Experimental Demonstration of a Mode Shape-Based Scour-Monitoring Method for Multispan Bridges with Shallow Foundations

A vibration-based scour monitoring approach applicable to bridges with multiple simply supported spans on shallow foundations is experimentally investigated in this paper. A monitoring strategy based on the relative changes in pier mode shape amplitudes due to scour is postulated. The first global mode shape of a bridge structure with multiple spans is extracted from acceleration measurements using an output-only approach, Frequency Domain Decomposition (FDD). The relative changes of the pier mode shape amplitudes under scour are then tracked. Here, each pier mode shape value is compared with the mean values of the remaining piers in a process that creates a Mean-Normalised Mode Shape (MNMS). The approach is demonstrated on a scaled model of a bridge with four spans, supported on sprung foundations, where scour is simulated by the replacement of springs with springs of lower stiffness corresponding to a reduction in foundation stiffness. It is shown that at a given ‘scoured’ pier, significant increases in the MNMS value occur, suggesting that the location of the scour can be identified. The magnitude of the MNMS at a given pier also increases with an increase in stiffness loss due to scour. In practice, the approach would work best by carrying out a visual inspection of the bridge to establish the initial health condition at the time of sensor installation. After this initial process, the bridge can be monitored remotely for scour on an ongoing basis

A Review of Numerical Models for Slab-Asphalt Track Railways

Higher train speeds and heavier axle loads trigger elevated stresses and vibrations in the track, potentially increasing track deterioration rates and maintenance costs. Alternative track forms made of combinations of reinforced concrete and asphalt layers have been developed. A thorough understanding of the slab and asphalt tracks is needed to investigate track performance. Thus, analytical and numerical models have been developed and validated by many researchers. This paper reviews numerical models developed to investigate railway track performance. The synthesis of major finite element models is described in detail, highlighting the main components and their outputs. For slab track models, the use of a structural asphalt layer within the railway track remains an active research topic and firm conclusions on its efficacy are not yet available. It can be expected that slab track structures will also be affected by train-induced ground vibrations. There is thus a gap in the literature regarding the measurement of dynamic effects on high-speed railway lines, and further research is needed to investigate the dynamic behaviour of slab–asphalt track systems. In this review, novel solutions for mitigating the vibrations in high-speed rail are discussed and compared. The use of asphalt material in railways appears to have beneficial effects, such as increasing the bearing capacity and stiffness of the structure and improving its dynamic performance and responses, particularly under high-speed train loads

Wavelet-based operating deflection shapes for locating scour-related stiffness losses in multi-span bridges

Scour erosion poses a significant risk to bridge safety worldwide and remains among the top causes of failure. Scour at bridge foundations changes the stiffness of the soil-foundation system, resulting in global changes in the dynamic behavior of the bridge. In this paper, a new approach to detect the loss in foundation stiffness resulting from scour at multiple foundation locations is proposed, using wavelet-based Operating Deflection Shape (ODS) amplitudes. A numerical model of a bridge with four simply supported spans resting on piers is used to introduce and test the approach. Scour erosion is modelled as a reduction in vertical foundation stiffness under one or multiple bridge piers. A fleet of passing trucks, modelled as half-car vehicles, are used to excite the bridge to enable structural accelerations be calculated at an ‘accelerometer’ (sensor node) located at each support. The proposed method is shown to be effective with only one accelerometer at each support location in a multi-span bridge. Using a statistical population of passing vehicles, the temporal accelerations measured at each support are averaged and transformed into the frequency–spatial domain, in order to estimate the wavelet-based ODS for a given scour case. A damage indicator is postulated based on differences between the ODS of healthy and scoured bridge cases. The damage indicator enables visual identification of the location of scoured piers considering a range of natural frequencies of the system