Installation Effects Research Articles

Installation Effects and Behavior of a Driven Prestressed High-Strength Concrete Nodular Pile in Deep Saturated Soft Clay

This paper investigated the installation effects of a driven prestressed high-strength concrete (PHC) nodular pile in deep soft clay through full-scale tests, and the behavior of a driven PHC nodular pile is analyzed based on the field test results. The test results demonstrated that the driven PHC nodular pile installation process induced significant disturbance in the surrounding soil. The excess pore water pressures (Δu) that were induced by the installation of a driven PHC nodular pile were larger than the Δu that were induced by the installation of a driven PHC pipe pile. The driven PHC nodular pile installation caused significant Δu in the soil down to 2 m below the pile base, and the Δu became much smaller in the soil at 4 m below the pile base. The Δu dissipated slowly in the soft clay layers, and the Δu in the surficial soil layers dissipated faster than that in the deep soil layers. The nodules along the PHC nodular pile shaft could increase the pile shaft capacity. The measured shaft resistances of 350(400)-mm PHC nodular piles were 1.17–1.18 times the calculated shaft resistances of 350-mm PHC pipe piles in soft clay layers.

Evaluation of mechanical and electrical properties of a new sensor-enabled piezoelectric geocable for landslide monitoring

The embankment and slope are prone to internal deformation and progressive failure under the coupling action of water, heat and force. Therefore, scholars have attempted to reflect the coupled deformation of soil through deformation measurements of geosynthetics. However, all the current measurement methods are non-distributed methods, and there are problems such as a significant installation effect, small strain measurement range, and low survival rate. In view of these issues, this study used a sensor-enabled piezoelectric geocable (SPGC) based on the piezoelectric effect and impedance-strain effect. The laboratory in-isolation and in-soil tests were carried out, and the signals of the strain–stress-impedance-voltage of SPGC under different failure modes were tested. The results showed that the tensile strength and elongation at break of the SPGC reached 53.6 MPa and 45.46%, respectively. During the tensile failure process of the SPGC, the strain–stress curve was divided into five stages, the strain-normalized impedance curve was divided into three stages, the strain-voltage curve was divided into two stages, and there were three characteristic points that could be classified as level 3 warnings. Empirical calculation formulas for the strain-normalized impedance was established, and the strain of the SPGC within 10% could be qualitatively described and quantitatively calculated by monitoring the normalized impedance. During the clay drawing failure process of the SPGC, the normalized impedance increased and the voltage decreased with the increase of pulling displacement. During the clay shear failure process of the SPGC, a bilinear model could be used to describe the correlation between shear displacement and normalized impedance. The voltage increased with the increase of shear displacement. The research findings suggest that SPGC can realize soil disaster location, precursor identification, and graded early warning, and is expected to provide a distributed, real-time, and refined measurement method for the entire life cycle of geotechnical engineering operation and maintenance monitoring.

Numerical study on the influence of installation effect on laterally loaded piles in sand

Numerical study on the influence of installation effect on laterally loaded piles in sand

Voltage Stability Analysis of Power System with Photovoltaic Power Plant

Photovoltaic power plants usually do not provide reactive power output; hence the application of large photovoltaics in power systems will decrease the voltage stability level of the power system. Capacitor banks can provide reactive power to compensate the photovoltaic plants; therefore, capacitor banks can overcome the reactive power deficiency of photovoltaic plants. However, the effect of capacitor bank installation on the system’s voltage stability is unknown. Therefore, the research aims to investigate whether installing a capacitors bank can restore the level of system voltage stability. The study employs the method of Voltage Stability Margin and transient stability simulation to the IEEE 9 bus system. The IEEE 9 bus system is modified where one generator of the system is replaced with a photovoltaic plant, and a capacitor bank is also installed. The study results show that the modified system voltage stability level is lower than the original system. When the capacity of the capacitor bank is increased to the maximum allowable value, the voltage stability level rises. However, it is still unable to be restored to its original value.

Improved methods for source characterization on trains

One problem for railway noise predictions is to characterize noise from various auxiliary equipment, e.g., fans, compressors, transformers. The noise from such sources can be a dominating contribution under low-speed operation or stand still. To better handle this problem the EU-project TRANSIT investigates improved methods for acoustic source characterization. As a starting point it is assumed that an acoustic source is enclosed by a control surface. The surface is sub-divided into smaller areas and each area is assumed to act as an acoustic one-port coupled to all the other areas. The properties of each area can then be described by its volume flow and internal impedance. The resulting acoustic pressure at a receiving point, can finally be expressed as a product of the source volume flows and a matrix representing the acoustic installation effects ("source+radiation impedances"). To simplify the method one can assume uncorrelated sources and use an ISO procedure for sound power to determine the volume flows. The acoustic installation effects can be obtained using a monopole point source to measure or calculate the pressure at selected receiving positions.

Flyover noise evaluation of low-noise technologies applied to a blended wing body aircraft

In the frame of the European research project ARTEM (Aircraft noise Reduction Technologies and related Environmental iMpact), new aircraft architectures and alternative propulsion systems, e.g. Blended Wing Body (BWB) and geared turbofan engine concept, are investigated, as well as innovative noise reduction technologies such as metamaterials and low noise high-lift device systems. A noise impact assessment has been performed on a long-haul BWB concept developed by Roma Tre University, using the System Noise Prediction Tools of ONERA (CARMEN) and DLR (PANAM). First, shielding effects on the main noise sources are discussed, through installation effects hemi-spheres at chosen frequencies around the aircraft. Based on the shielding assessment, detailed take-off and landing procedures are simulated for several aircraft configurations. Two motorisations of the BWB are evaluated (BPR 8 and BPR 12), provided by RWTH Aachen. Finally, the most promising low noise technologies developed in the frame of ARTEM are applied, and their impact on noise levels on the ground is discussed. It can be demonstrated how the specific aircraft configuration, the engine type and the additional low-noise technology result in a significant overall noise reduction. A joint conference paper presents flyover auralisations based on these noise emission calculations.

Main sensitivity drivers in indoor acoustic comfort for autistic individuals

One challenge for railway noise predictions is to characterize noise from various auxiliary equipment, e.g., fans, compressors, transformers. The noise from such sources can be a dominating contribution under low speed operation or stand still. To better handle this problem the EU-project TRANSIT investigates improved methods for acoustic source characterization. As a starting point it is assumed that an acoustic source is enclosed by a control surface. The surface is sub-divided into smaller areas and each area is assumed to act as an acoustic one-port coupled to all the other areas. The properties of each area can then be described by its volume flow and internal impedance. The resulting acoustic pressure at a receiving point, can finally be expressed as a product of the source volume flows and a matrix representing the acoustic installation effects ("source+radiation impedances"). To simplify the method one can assume uncorrelated source surfaces and use an ISO procedure for sound power to determine the volume flows. The acoustic installation effects can be obtained using a monopole point source to measure or calculate the pressure at selected receiving positions. This simplified method has been validated under controlled laboratory conditions and tested on real equipment on trains.

Numerical modelling of laterally loaded piles driven in low-to-medium density fractured chalk

Chalk’s sensitive, variable nature poses difficulties for foundation designers. It can present as weak rock and yet be de-structured to very weak putty by dynamic or high-pressure loading. The development of multiple offshore wind farms at north European chalk sites led to the recent ALPACA Joint Industry Programme, which undertook intensive material characterisation and large-scale field testing at St Nicholas at Wade (SNW), Kent, UK to capture and better understand the behaviour of piles driven in fractured low-to-medium density chalk. Noting that lateral loading response is a vital design concern for monopile and jacket supported structures, this paper focuses on 3D Finite Element (FE) modelling of ALPACA’s monotonic lateral loading field tests on open-ended driven tubular steel piles. The brittle chalk is modelled with a strain-softening Mohr-Coulomb model combined with nonlocal regularisation, calibrated meticulously against the ALPACA characterisation dataset. A second, simpler modelling approach, adopting a perfectly-plastic Mohr-Coulomb model, is also explored as a simplified practical alternative. Both approaches can match field lateral capacity and bending moment distributions, after taking due account of pile installation and chalk fracturing effects. The analyses indicate how robust, accurate and cost-effective lateral loading design may be approached for low-to-medium density fractured chalks.

Haney Soil Health Test changes with season, not subsurface drainage

AbstractThe Haney Soil Health Test (HSHT) is used to quantify soil health using soil biological activity and water‐extractable C and N. However, suitability of the HSHT to measure soil health in subsurface drained fields remains unknown. Our goals were to use the HSHT in Minnesota cropand to (a) test the effect of recent tile drainage installation, (b) evaluate seasonal variability, and (c) calculate a potential N fertilizer credit. Three soil biological indices used in the HSHT were measured seasonally across 2 yr and used to calculate a soil health score and N credit. All metrics were unaffected by subsurface drainage, but all varied seasonally (greatest in spring) and annually (greater in 2020 than in 2021). Soil biological indicators did not change abruptly following subsurface drainage but may change gradually, and this needs to be tested further. Significant seasonal variability may pose challenges in tracking soil health over time.

Intraperitoneal instillation of levobupivacaine plus dexmedetomidine versus ropivacaine plus dexmedetomidine for post-operative analgesia in patients undergoing laparoscopic cholecystectomy

Introduction: Laparoscopic procedures have many advantages over open procedures, such as less haemorrhage, better cosmetic results, less post-operative pain and shorter recovery time, leading to a shorter hospital stay and less expenditure. Hence, the present study was undertaken for comparing the effect of intraperitoneal installation of levobupivacaine (L-B) plus dexmedetomidine versus ropivacaine plus dexmedetomidine for post-operative analgesia in patients undergoing laparoscopic cholecystectomy (LC). Materials and Methods: This was a prospective randomized study conducted in our hospital on 60 American Society of Anaesthesiologists grade I or II patients of either sex, aged 18–55 years, scheduled to undergo LC surgery under general anaesthesia. All patients were randomly divided into two groups of 30 each: Group 1: Patients were given 20 ml of 0.5% L-B plus 0.25-μg/kg dexmedetomidine intraperitoneally after gallbladder removal, and Group 2: Patients were given 20 ml of 0.5% ropivacaine plus 0.25-mg/kg dexmedetomidine intraperitoneally after gallbladder removal. Post-operatively, the patients were assessed for pain utilizing a visual analogue scale (VAS). VAS was graded on a scale of 0–10. VAS was recorded at 0, 1, 8, 12 and 24 h post-operatively and compared. Results: Mean time to first analgesic requirement among patients of Group 1 and Group 2 was 365.1 min and 297.2 min, respectively, which shows a statistically significant longer post-operative analgesic effect in Group 1 patients. While comparing VAS at different time intervals in between the two study groups, all the readings were comparable. The difference was found to be non-significant in the two groups (P > 0.05). Nausea and vomiting were seen in two patients in Group 1 and three patients in Group 2. Complications were noted in <10% of the patients in both groups. Conclusion: Intraperitoneal instillation of local anaesthetic solution in LC provides effective post-operative analgesia, and analgesia provided by L-B plus dexmedetomidine is better than ropivacaine plus dexmedetomidine.

Effect of Multi-SVC Installation for Loss Control in Power System using Multi-Computational Techniques

Effect of Multi-SVC Installation for Loss Control in Power System using Multi-Computational Techniques

The TRANSIT project: innovation towards train pass-by noise source characterisation and separation tools

In TRANSIT, experimental methods are developed to separate and characterise noise sources on moving trains. Improved microphone array techniques allow quantification of sound power and directivity. Source separation methods based on the Pass-By Analysis method, Advanced Transfer Path Analysis and the TWINS model are also developed. For trains at standstill, new test methods are developed to quantify noise transmission paths from sources to the standard microphone positions accounting for installation effects. Several measurement campaigns are used to demonstrate and verify these methods. In addition, innovative materials and methods are investigated for improved sound comfort in trains. Approaches considered include optimal sound absorption at the source, attenuation along ducts for air conditioning systems and innovative meta-structure designs for the car-body parts.

Five Year Analyses of Vegetation Response to Restoration using Rock Detention Structures in Southeastern Arizona, United States

Rock detention structures (RDS) are used in restoration of riparian areas around the world. The purpose of this study was to analyze the effect of RDS installation on vegetation in terms of species abundance and composition. We present the results from 5 years of annual vegetation sampling which focused on short term non-woody vegetation response within the riparian channel at 3 restoration sites across southeastern Arizona. We examined the potential ways that RDS can preserve native species, encourage wetland species, and/or introduce nonnative species using a Control-Impact-Paired-Series study design. Species composition and frequency were measured within quadrats and zones on an annual basis. Multivariate bootstrap analyses were performed, including Bray-Curtis dissimilarity index and non-metric multidimensional scaling ordination. We found that response to RDS was variable and could be related to the level of degradation or proximity to groundwater. The non-degraded site did not show a response to RDS and the severely degraded site showed a slight increase in vegetation frequency, but the moderately degraded site experienced a significant increase. At the moderately degraded site, located between two historic ciénegas (desert wetlands), species composition shifted and nonnative species invaded, dominating the vegetation increase at this location. At the severely degraded site, pre-existing wetland species frequency increased in response to the installation of RDS. These findings extend the understanding of RDS effects on vegetation, provide scenarios to help land and water resource managers understand potential outcomes, and can assist in optimizing success for restoration projects.

Numerical Analysis of Behavior of Geo-Synthetically Reinforced Slopes Under Seismically Active Conditions

Slopes are the unsupported inclined soil mass. Stability of slopes has always been a governing factor for carrying out construction on slopes. Both static and dynamic loads can cause failure to a slope yet there are considerate methods to determine the bearing capacity and factor of safety for slopes under static loads while as dynamic loads specifically earthquake loads are generally unpredictable. This paper checks effect of installation of geogrid layers in soil slopes under seismic loads. This study has been carried out using Finite Element Based Software PLAXIS incorporating CD-ROM (SMC) file of WNW OF FERNDALE, CA on 10th March 2014.The model was scaled as 1x .5 x .5 m with slope angle of 32? and a model footing of 50 mm which was loaded suitably. During the study numerical results of deformation compared with experimental results. It was found that addition of geogrid layers enhanced the factor of safety upto appreciable extent. Optimum depth and optimum number of geogrid layers were also determined. The percentage increase in factor of safety at different levels of installation was also recorded.

Testing pile foundations at the ETH Zurich drum centrifuge: recent developments

Motivated by the need to develop rational design methods for the retrofit of existing bridges on pile groups, this paper introduces recent experimental developments at the ETH Zurich drum centrifuge in Switzerland. Four set-ups are developed for vertical, pushover, combined and vibration testing. Their capabilities and limitations are demonstrated using as an example a 2 × 1 pile group on dense saturated sand. Single piles are subjected to vertical loading, exploring the role of installation effects and interface roughness. Pushover loading is employed to measure the moment capacity [Formula: see text] of a lightly and a heavily loaded group. In contrast to intuitive expectations, the heavily loaded system mobilises larger [Formula: see text]. The developed combined loading apparatus is proof-tested for a shallow foundation. Combined loading under constant vertical load is conducted to derive failure envelopes, revealing significant coupling between lateral and moment loading, and confirming the expansion of the failure envelope with increasing static vertical load. The vibration testing set-up is proof-tested, confirming the possibility of identifying the natural frequency of the system and the small-strain stiffness of the foundation through non-destructive testing. Although the study is fuelled by the ongoing work on pile groups, the developed experimental set-ups are of general applicability for the study of deep and shallow foundation systems.

Numerical simulations of displacement piles in a tropical soil

The behavior of pile foundations under axial loading is directly influenced by the effects that its installation process induces in the surrounding soil. Consequently, the consideration of these effects is essential for the correct numerical modeling of these geotechnical structures. In the present study, numerical simulations of driven cast-in-situ piles under axial loading have been carried out using finite element analysis. Three 3.5 m long piles with diameters ranging from 114.3 to 219.1 mm were analyzed. The pile installation effects have been considered indirectly by employing two distinct approaches, both based on the concepts of cylindrical cavity expansion. The behavior of the tropical soil profile is described with the Hardening Soil constitutive model. The load-displacement response and load distribution along the pile obtained with the numerical simulations have been analyzed and compared with in-situ load tests results. In the failure conditions, both approaches accurately predicted the bearing capacity of the piles, with an average error of only 2% compared to the measured values. The results in terms of load distribution over depth were also satisfactory. The difference between measured and numerical ultimate base resistance values ranged from 0% to 30%. The good agreement between the numerical and experimental results indicates that the proposed numerical approaches have been effective in simulating the piles installation process and reinforces the importance of considering the installation effects in the numerical modeling of these geotechnical structures. Both approaches can also be used to predict the bearing capacity of displacement piles.

Estimation of impact sound reduction by wood flooring installation in a wooden building in Korea

Multi-family homes have been constructed traditionally using heavy materials like concrete/steel and bricks. Wooden structures are a promising substitute for typical heavyweight constructions. However, floor impact noise has been identified as the most annoying noise source in South Korea. Here, we have studied the effect of floorboard installation on impact sound changes before and after installing the floorboard on the floor of a wooden building. We used standard tapping and bang machines in this study to generate lightweight and heavyweight impact sounds. The changes in noise from lightweight and heavyweight impact sounds were estimated on the upper layer (UL) and lower layer (LL) floors before and after the installation of the plywood floorboard (PFB). The average of the octave band center frequencies at 125, 250, 500, 1000, and 2000 Hz from the lightweight impact before installation of PFB was 84.08 dB (UL) and 50.54 dB (LL), respectively, while 84.04 dB (UL) and 41.90 dB (LL) after the installation of the surface decorated PFB. Similarly, the heavyweight impact sound before installing PFB was 73.26 dB (UL) and 42.16 dB (LL), respectively, while after installation of PFB, impact sound appeared at 71.58 dB (UL) and 42.48 dB (LL). The results exhibited that lightweight impact sound could be reduced by about 8.6 dB on the LL. These results could entice the researcher or building engineer to design wooden floorboards for a comfortable building environment. This study is new because it compares the impact sound of the floor before and after it has been constructed.

To know is to accept. Uncovering the perception of renewables as a behavioural trigger of rural energy transition

Abstract Our research aims to reflect on rural communities’ awareness and perceptions of various energy sources, particularly focusing on renewable energies. We argue that there is an urgent need to expand the knowledge base on the perspectives of rural communities directly and indirectly affected by renewable energy installations. From an empirical point of view, our study focuses on the Lipno county in the Kuyavian-Pomeranian Voivodeship (Poland), where a relatively unique constellation of renewable energy and local community is emerging. Our findings indicate a wide awareness about renewable energies in the community, but a rather shallow, imbalanced, and outdated knowledge on potentials, advantages and disadvantages of individual locally available renewable energy sources was detected. To break deeply rooted carbon dependency and lock-in and to trigger mechanisms of change leading to more sustainable futures, practical, contextual, and place-based knowledge is essentially needed to shape responsive attitudes. We claim that personal experience of the effects of renewable energy installation (especially small-scale ones) can be a proxy for the change and scaling up. This is a key because it proves the leading role of an inclusive approach to developing renewable energy in rural areas. Locals undertake new energy investments, which is the basis of spatial (territorial) distribution justice – they not only bear the costs of operating new energy installations but also derive tangible benefits from renewables.

Low-frequency amplification of propeller tonal noise due to the scattering by a compact rigid cylinder

The present work addresses the scattering of the tonal noise of a low-speed propeller by a rigid cylinder, as a generic configuration representative of installed marine propellers. Both propeller and cylinder axes are parallel to each other. The diameters of the propeller and of the cylinder are much smaller than the acoustic wavelengths, as well as the propeller-cylinder distance. This corresponds to a compact regime of diffraction. Only the hydrodynamic tonal noise of the propeller at the first multiples of the blade-passing frequency is considered, assuming rigid blades, in a two-dimensional formulation. The direct and scattered sound fields are expressed in terms of spinning modes, with respect to the propeller and cylinder axes, respectively. Use is made of the exact Green’s function of the cylinder for the Helmholtz equation. The modes of orders ±1 are found the only efficient ones in the direct field, whereas higher-order modes rapidly decay. Yet, in the presence of the cylinder, higher-order modes are scattered into the contra-rotating mode of order 1 in the reference frame of the cylinder, with a strong amplification. A simple experiment, performed in air but with Helmholtz numbers typical of marine applications, confirms these results as key features of the asymptotic Green’s function of the cylinder. The same modal behavior is reproduced as closed-form simple expressions from a low-frequency approximation of the Green’s function. The results show that the installation effect is crucial for the tonal noise of marine propellers at very low frequencies.

Cross-story installation of viscous dampers in timber frame houses for earthquake damage reduction

Timber frame structures are commonly used in housing construction that use squared-off timber beams, columns, and walls as lateral load-bearing members. A small-size viscous damper can be applied to timber frame houses to reduce damage caused by major earthquakes. Dampers are normally installed inter-story (between adjacent floors) to absorb vibration energy and reduce seismic response. Another method is the cross-story installation wherein a damper is installed between the rooftop and base of the structure across intermediate floors. This study investigated the effectiveness of cross-story installation of a viscous damper by conducting eigenvalue analyses of 2DOF models and earthquake response analyses of a two-story timber frame house subjected to the 2016 Kumamoto earthquake and other major earthquakes. We compared the damping factors and response reduction effects of the cross-story installation with those of conventional inter-story installations. The results showed that the cross-story installation of dampers was more effective than the inter-story installation in terms of reducing story drift. Furthermore, the cross-story installation reduced the number of dampers required for preventing severe damage by half. Finally, the cross-story installation allowed the viscous damper in the first story to absorb vibration energy nearly twice as much as that of the inter-story installation. Therefore, while the cross-story damper is typically installed on an outer frame fixed to the house, our results conclude that it can be applied to an existing house as a seismic retrofitting measure.