Bridge Connection Research Articles

Biomechanical evaluation of bridge span with three implant abutment designs and two connectors for tooth-implant supported prosthesis: A finite element analysis

Background/purposeBridge stability under loading was influenced by bridge span with the connector and implant abutment design. Thus, the purpose of this study was to evaluate the effects of rigid and non-rigid connector designs and pontic connections of different abutment systems in the tooth-implant supported prosthesis (TISP) at different span distances on the biomechanical stress distribution of the overall system components. Materials and methodsFor comparative analysis, rigid and non-rigid bridge connections were fitted with three implant abutment systems (one-piece, two-piece and three-piece), and five implant-to-natural tooth distance configurations (12 mm, 14 mm, 16 mm, 18 mm, and 20 mm) were provided. ResultsThe maximum stress between TISP components occurred at the distal side of crown margin of cement1 in rigid connector with one-piece group and the bottom of the crown3 in non-rigid connector with one-piece group, while the other groups were more concentrated at the junction between the mesial side of the implant collar and the abutment. In addition, neither the rigid nor non-rigid connector model showed that stress distribution increased proportionally with the bridge span distance. ConclusionIt was clinically recommended that if the implant with a shorter bridge distance of 12 mm from the natural tooth, the rigid connection of the three-piece abutment can be used as the TISP design. If the bridge distance was 18 mm longer, the non-rigid connection of the three-piece abutment could maintain the physiological movement of the natural tooth and avoid the excessive stress on the bone crest around the implant.

Measurement of Ground Vibration for Unpaved Bridge Approach Field Model on Soft Soil

The information and the data of the bridge approach condition is important because it allows designers to know the response of the soil once loaded with vehicles and respectable suggestion for correct engineering solutions to beat the matter. There are a few clarifications the reason of problem occurred at bridge approach was recently inspected by other researchers previously and one of the issues is a dissimilarity between the height of the bridge and road on the connection. The objective of this research is characterize and create techniques for field investigation to inspect the effect of vibration from vehicle loading at bridge approaches and this case might be referred to as a repetitive cyclic loading. The aim of this research is to investigate critical location of vibration at bridge approach model by the influence and effect from measurement tools. This research concentrated on constructed field model of the unpaved bridge approach model in Research Centre for Soft Soil Malaysia (RECESS), Universiti Tun Hussein Onn Malaysia (UTHM), Johor, Malaysia. A portable measurement equipment system with high sensitivity triaxial ICP accelerometer used to investigate and measure the effect of vibration loading at unpaved bridge approach field model. Piezoelectric (ICP) accelerometer is now preferable for researchers for the field surveillance or laboratory testing. From the analysis, it can be stated here that the vibration value increases as the speed and vibration level produced changes from L1 to L2. In the transverse direction, it is found that P1 values are larger than P2 to P6 values at both sites BAA and BAB. On the longitudinal direction, the farther away the plate compactor is from the bridge model connection, its value decreases and it is found that the D1 area has a higher vibration value compared to D2 to D5. It may be then, concluded that in this research it is similar to the previous research at the actual study site where the vibration value is high in the area 1m to 2m from the bridge connection.

Enhanced thermal conduction of hybrid filler/polydimethylsiloxane composites via a continuous spatial confining process

Owing to the rapid development of the electronics and aerospace industry toward high integration and power, the growing demand for heat dissipation management materials was urgent. However, the continuous fabrication of thin highly thermally conductive polymer composites at a large scale remains challenging, especially requiring control of the filling content of fillers. Herein, the continuous spatial confining forced network assembly (CSNA) method was applied to realize the continuous construction of thermally conductive networks of hexagonal boron nitride (h-BN) and multi-walled carbon nanotubes (MWCNT) in polydimethylsiloxane (PDMS) matrix. The thermal conductive composites presented thickness-dependent in-plane thermal conductivity (K), reaching 4.28 W m−1 K−1 for h-BN (30 wt%)/MWCNT(2 wt%)/PDMS in 0.15 mm thickness. The h-BN/MWCNT/PDMS composite represented a 1543.5% increase compared to the pure PDMS thanks to the CSNA method and the bridging connection of MWCNT. This work provided a facile method to prepare the thin high thermal conductive composites, which might promisingly advance the industrialization of thin thermosetting thermal conductive composite films.

Adding composite truss to improve mechanical properties of reinforced concrete T-girder bridge

To solve the problem of insufficient transverse connection of T-girder bridges, this paper investigated the strengthening method of two composite trusses symmetrically installed in mid-span. The composite truss included two top plates, four diagonal braces, and one horizontal brace. An experimental investigation was carried out to study the mechanical properties of reinforced concrete T-girder using single-point loading method under four load cases. The experimental results showed that the maximum transverse stiffness of T-girder specimens strengthened with composite trusses improved by 12.4% compared with control beams. Simultaneously, it had an excellent restraining effect on the cracks development. The maximum percentage decrease in the deflection corresponding to the maximum load when the reinforced concrete T-girder strengthened with composite trusses over the control beam of up to 39.7 was observed. In addition, the load transverse distribution coefficient was investigated according to rigid-jointed slab (girder) method. The composite trusses were chosen as intermediate diaphragm to calculate moment of inertia. The analytical model was in an accurate with the experimental result under the same loading condition. The optimize spacing of composite trusses was given from 600 mm ( L/10) to 1200 mm ( L/5), and thickness of top plate was 30 mm when the load transverse distribution coefficient was homogeneously distributed. Finally, a three-dimensional finite element model was used to evaluate the effectiveness of composite trusses.

External torque sensor design providing wireless and real-time data customized for drivetrain

In this study, a torque sensor design that can be used in both laboratory and field tests simulating road conditions of drivetrain of the vehicles is explained. Mechanical design of the sensor has been carried out via finite element method (FEM). Material of the torque sensor and the relevant heat treatment were determined. Electronic measurement circuit design and its setup have been carried out including amplifier, filter, ADC and data transmission features which are suited for full bridge connection. Verification and calibration tests have been performed with respect to DIN-51309. As a result of the studies, it was determined that the measurement accuracy of the system in the torque range of 250 ÷ 2500 Nm was 0.5%. The effect of noise-induced deviations was found 0.05% for the precision value. Consequently, a verified universal torque sensor has been developed for any drivetrain application under torsional effect with the given specifications. It is hoped that this sensor might become a common feature on any and every drivetrain for advanced monitoring of the drive components.

Passionate Way to Creativity through the Power of Job Crafting and Sense of Calling

Creative employees are treasured assets for organizations to remain competitive in the market. However, we still know little about how to encourage employee creativity in an organization. Taking a motivational perspective, this study aims to examine the direct relationship between job crafting and creativity and the indirect relationship through sense of calling. We collected information from 359 Indonesian tour guides, then we analyzed it using WarpPLS 4. The results of the study revealed that job crafting was positively related to employee creativity. In addition, it shows that the sense of calling sense of calling is able to become a connecting bridge in efforts to increase employee creativity.

Experimental and numerical investigation on optimized ultra-high performance concrete shear key with shear reinforcement bars

Over the last decade, ultra-high performance concrete (UHPC) has been used in highway bridge connections between deck panels and girders due to its superior compressive and tensile strengths, significant tensile toughness, and excellent long-term durability. However, there are limited studies and discussions on the UHPC shear key's design with or without shear reinforcement bars (SRBs) applied for adjacent girder bridges. This study aimed to numerically and experimentally investigate the effectiveness and functionality of SRBs used in an optimized UHPC shear key connection (abbreviated as OPT-SK) developed by the authors in a previous study. To this end, a finite element (FE) direct shear model for Federal Highway Administration (FHWA) shaped shear key (abbreviated as FHWA-SK) was developed and calibrated first. Then, the validated FE model was extended to investigate the OPT-SK's shear behavior with SRBs. To experimentally measure the ultimate load capacity of the OPT-SK, a push-off direct shear (P-ODS) test was carried out on the OPT-SK with SRBs in both pre-crack and post-crack status. The results showed that the OPT-SK with SRBs exhibited a higher carrying load capacity, a more evenly distributed stress, and a lower stress magnitude than the FHWA-SK with SRBs. The cracks or damage mainly initiated and developed in the high strength concrete (HSC) components and the interface between the UHPC and HSC components. The P-ODS test's load-displacements or strains were reported to highlight the SRBs' effectiveness and functionality in the OPT-SK.

Shock absorber lateral and impact force measurement using a column-type sensor

A novel method for the lateral and impact force measurement of shock absorbers using a three-component column-type sensor is proposed in this study. The strain gauge configuration and the bridge connection were designed, and the outputs of each designed measuring bridge under both alignment and eccentric loading were theoretically analyzed. Simulations and experimental tests were conducted to validate the measuring bridge output of the theoretical analysis; the results from the theoretical analysis, simulation, and experiments agree well with one another. In accordance with the specifications put forth in the SAE J2570 standard, the designed sensor was calibrated to obtain its performance parameters and calibration coefficients, which were then applied to acquire the lateral and impact force of a shock absorber. The calibration results demonstrate that the maximum nonlinearity and hysteresis were 0.51% and 0.87% (full-scale), respectively, and the sensor had good linearity and weak coupling between dimensional characteristics.

Effect of MWCNTs on microstructure and properties of WC-9Co gradient cemented carbides

WC-9Co-xMWCNTs (Multiwalled carbon nanotubes) gradient cemented carbides with cubic carbides free layer (CCFL) were prepared by powder metallurgy method. The effect of different MWCNTs content on the microstructure and mechanical properties of WC-9Co gradient cemented carbides have been studied. The microstructure and phase composition of WC-9Co-xMWCNTs composites were characterized by means of optical microscope, scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, the hardness, fracture toughness, bending strength and friction coefficients were tested by Vickers indenter, universal testing machine and tribometer. The results showed that the MWCNTs could promote the growth of CCFL. The minimum grain size of WC was obtained in the WC-9Co-0.08 wt% MWCNTs composites and the sample possessed the highest hardness and bending strength, the lowest friction coefficient and the best wear resistance at the same time. The fracture toughness and relative density increased steadily together with the addition of MWCNTs. Besides, the mechanism of MWCNTs enhancing the alloys include bridge connection, crack deflection, pull-out and strengthening effect of the network structure.

Practice-Accessible Methodology for Nonlinear Refined Analysis of Gusset Plate Connections for Steel Truss Bridges

A new approach is proposed for estimating structural capacity of gusset plate connections of steel truss bridges. The approach involves nonlinear refined analysis of a truss model, consisting of a single truss made of shell elements for two gusset plates at a subject connection and frame elements for truss members. Connectors (bolts or rivets) are excluded from the proposed model in order to simplify the model, with the knowledge that their associated failure modes can be addressed by simplified design calculations. Only yielding and buckling failure modes of gusset plates are considered. The new approach is calibrated by comparison with laboratory test data from NCHRP Project 12-84. The primary intent of this paper’s approach is to reduce the complexity of the refined analysis developed under this National Cooperation Highway Research Program project and make it more user-friendly to load rating engineers seeking accurate estimation of gusset plate capacity. Further, an imperfection sensitivity curve characterizing reduction in capacity as a function of lateral imperfection (gusset plate out-of-flatness) in gusset plate geometry is introduced as an added tool for the load rating engineer, providing more confidence in capacity estimation. Based on a limited case study, the proposed refined analysis provides an estimate of gusset plate capacity that is approximately equal to capacity calculated by the truncated Whitmore method of the AASHTO Manual for Bridge Evaluation (2018). In other words, the proposed approach validates the truncated Whitmore method as compared to the more conservative partial shear method of the AASHTO Manual.

Experimental and numerical study on mechanical behavior of high-strength lockbolted friction grip connections

Despite the wide application of high-strength bolts joint in steel bridges, there are still some issues with this jointing technology such as large variation in the bolt preload, looseness of the joint as well as the fatigue problem. In this study, the high-strength lockbolted friction grip (HSLFG) connections were proposed as an alternative and the experimental results indicated that HSLFG connections have comparable mechanical behavior and strength to that of high-strength bolted friction grip (HSBFG) connections. First, the experiments were carried out on four HSLFG connections and four conventional HSBFG connections, in which the mechanical properties of both connections such as the failure modes, load-bearing behavior, and load-strain relationships were obtained and compared. The experimentally results indicate that the preload of the high-strength lockbolts satisfy the requirements of Eurocode3 and JTG D64-2015. Refined finite element (FE) models were established and were verified against the experimental results which proved the FE models could effectively predict the elastic-plastic behavior and positions of rupture of the HSLFG connections. Furthermore, the parametric analysis of FE model was conducted to investigate the effect of element types, friction coefficients on the mechanical property of the HSLFG connections. This research provided a promising strategy for the development requirements of HSLFG connections in steel bridges.

Politicizing the polycentric urban region: bridge connection negotiations in the Pearl River Delta, China

ABSTRACT This study extends the literature on polycentric urban regions through a situated account of the politicized nature of polycentric city-regional development. This is achieved through an analysis of the uneven development of bridge connections within the Pearl River Delta, China. By analysing the region’s polycentric development from the prism of the politics of transport connections and by viewing bridge alignment negotiations as government-led efforts to shape physical and functional polycentricity, we highlight the importance of a governance framework. This governance framework can complement large-scale quantitative analyses of polycentric urban regions.

Understanding Trauma-Informed Care in the PALTC Setting

Understanding Trauma-Informed Care in the PALTC Setting

Steel-reinforced resin for bolted shear connectors: Confined behaviour under quasi-static cyclic loading

Injections bolts were initially conceptualized to repair riveted connections in bridges with long service lifetime and now they are widely used in steel and composite structures. Injecting steel-reinforced epoxy resin in bolted connections with oversized holes is a novel approach to enable fast and easy assembly of composite structures while limiting slip between the components. The performance of these bolted shear connectors is mainly dependent on the injected material. In this paper, short-term mechanical properties of an epoxy-based resin mixed with steel shots (steel-reinforced resin) are evaluated to consider it for bolted shear connectors. Uniaxial static tests allowed to compare the stiffness and ductility of resin and steel-reinforced resin and to define a hardening law, while multiaxial tests were conducted under quasi-static cyclic loading in order to characterize the material behaviour under confined conditions. Steel-reinforced resin specimens showed a stiffness under confined conditions 2.6 times higher compared to the bare resin specimens. This increase of stiffness is fundamental to achieve slip resistant behaviour when resin-injected shear connectors are used in significantly oversized holes. The linear Drucker-Prager plastic model was used to define the material behaviour. The good agreement observed indicates that future investigations on numerical and experimental performance of bolted shear connectors can be implemented with the parameters proposed in this paper.

Identification of extraocular extension in uveal melanoma by ophthalmological ultrasound.

Uveal melanoma is the most common primary malignant intraocular tumour in the adult population, with a survival rate of 50% despite advances in treatment and knowledge of this disease. The presence of extraocular extension (EE) worsens the prognosis of these patients, so its proper identification can ensure its management and early intervention. Ophthalmological ultrasound is the technique of choice for the diagnosis and follow-up of these patients, both of the anterior EE using ultrasonic biomicroscopy (UBM), and the posterior EE using A and B ultrasound. The aim of this study is to describe the ultrasound characteristics of the BMU and the A and B ultrasound. A descriptive and retrospective study is carried out on patients diagnosed with uveal melanoma (UM) and EE from 2003 to 2019. The ultrasound characteristics of the local disease and the follow-up after treatment were recorded completely and at each visit. In the case of anterior EE, photographs of the anterior segment and UBM were taken, while those involving the posterior segment were explored under A and B mode ultrasound. All enucleated eyes were sent for anatomopathological study. Ten patients with an average age of 72.3 years were included. The largest proportion of them were medium-sized tumours, followed by large and small ones. The most frequent morphology of the primary tumour was cupuliform. All the EE presented lower internal reflectivity compared to the primary tumour. No trans-scleral connection bridges were found between the primary tumour and the EE in the ultrasound studies. 50% of patients underwent primary enucleation at the time of diagnosis of intraocular MU due to the presence of the EE, and the remaining 50% presented the EE after initial treatment of the primary tumour with I125 brachytherapy. Sixty percent of the patients presented with posterior EE, and were therefore diagnosed with ultrasound A and B. The most frequent histopathological pattern with 87.5% of patients was the epithelioid pattern. Ultrasound scanning in patients with MU is mandatory for diagnosis and follow-up of EE. BMU and A and B ultrasound are the test of choice for anterior and posterior EE, respectively. EE have particular ultrasound characteristics such as low internal reflectivity, regularity of their contour and their location usually adjacent to the base of the primary intraocular tumor.

Structural and buckling behavior of full-scale slender UHPC columns

Ultra-high performance concrete (UHPC) is a relatively new class of concrete and cementitious materials with much higher strength and durability than conventional concretes. The use of UHPC is currently expanding worldwide from bridge deck joints and connections to full components and larger applications. With the superior mechanical properties of UHPC, future UHPC columns in buildings and bridges will have compact cross-sections and smaller footprint. The main goal of this study is to provide experimental demonstration and reliable datasets of slender UHPC columns to validate current analytical procedures and inform future designs. This paper presents results and discussions from five full-scale UHPC columns (largest set of axially-tested UHPC columns to-date) at a 4 million-lb [∼18,000 kN] testing facility. The specific objectives are to investigate the structural and buckling behavior of slender UHPC columns under concentric axial loading, and assess the current ACI procedure for slenderness effects using the moment magnification method. When the actual material properties of UHPC and longitudinal bars are used for assessment, the ACI equations were found to overestimate the axial load capacity of slender columns by approximately 9%, on average. The study is concluded by design guidance and several recommendations for applying the moment magnification method for slender UHPC columns, which can be readily incorporated into future design codes.

Reinforcement detailing effects on axial behavior of full-scale UHPC columns

Ultra-high performance concrete (UHPC) applications are currently expanding worldwide from bridge deck joints and connections to full components and larger applications. UHPC has superior structural properties relative to other cementitious materials with multiple times the compressive and tensile strength, durability, and ductility. These outstanding mechanical properties of UHPC make it a strong candidate for full structural columns. The goal of this study is to provide experimental demonstration and reliable datasets of UHPC columns to validate current analytical procedures and inform future designs. This paper presents results and discussions from five full-scale UHPC columns tested at a 4 million-lb machine. The first objective is to analyze the experimental behavior of long UHPC columns with negligible slenderness effects and varying reinforcement details, i.e. different longitudinal, transverse, and fiber reinforcement ratios, under concentric axial loading. The second objective is to inspect the validity of ACI 318 equations for estimating the UHPC columns axial compressive strength. The results indicated that using the actual material properties of UHPC and longitudinal bars for ACI 318 equations overestimates the axial load capacity of columns with different reinforcement details by approximately 13% on average. Furthermore, a new strength reduction factor of 0.75 is suggested (instead of 0.85) for estimating axial capacity of UHPC columns with slenderness limit less than 30.

Biphasic mineralized collagen-based composite scaffold for cranial bone regeneration in developing sheep.

Appropriate mechanical support and excellent osteogenic capability are two essential prerequisites of customized implants for regenerating large-sized cranial bone defect. Although porous bone scaffolds have been widely proven to promote bone regeneration, their weak mechanical properties limit the clinical applications in cranioplasty. Herein, we applied two previously developed mineralized collagen-based bone scaffolds (MC), porous MC (pMC) and compact MC (cMC) to construct a biphasic MC composite bone scaffold (bMC) to repair the large-sized cranial bone defect in developing sheep. A supporting frame composed of cMC phase in the shape of tic–tac–toe structure was fabricated first and then embedded in pMC phase. The two phases had good interfacial bond, attributing to the formation of an interfacial zone. The in vivo performance of the bMC scaffold was evaluated by using a cranial bone defect model in 1-month-old sheep. The computed tomography imaging, X-ray scanning and histological evaluation showed that the pMC phase in the bMC scaffold, similar to the pMC scaffold, was gradually replaced by the regenerative bone tissues with comprehensively increased bone mineral density and complete connection of bone bridge in the whole region. The cMC frame promoted new bone formation beneath the frame without obvious degradation, thus providing appropriate mechanical protection and ensuring the structural integrity of the implant. In general, the sheep with bMC implantation exhibited the best status of survival, growth and the repair effect. The biphasic structural design may be a prospective strategy for developing new generation of cranioplasty materials to regenerate cranial bone defect in clinic.

Does Palapa Ring Project Infrastructure Bridging Connectivity and Economic Activity?

This study examines the impact of existence of the Indonesian Palapa Ring Project (PRP) infrastructure on connectivity and economic activities in 46 districts in the West, Central, and East package of PRP in 2015-2020. Connectivity is an internet activity that measured by using percentage of internet use and economic activity is measured by using Gross Regional Domestic Product (GRDP). The fixed effect staggered difference-in-difference is utilized to analyze the panel data obtained from Badan Pusat Statistik (BPS)-Statistics Indonesia. An examination of parallel trend assumptions, robustness check, and heterogeneity analysis are also presented. The results show that PRP infrastructure has a positive and significant impact on connectivity; yet has no significant effect on economic activity. In response to the findings, the policy should be designed by intensifying coverage and quality of the internet; proliferating Information Communication Technology (ICT) facilities in rural areas; and expanding education and digital literacy programs.

Consciousness and Near-Death Experiences: Access to a Known World

Near-death or death-like experiences are a natural, albeit uncommon, phenomenon due to the temporary and reversible decoupling or dissociation of the Psychosoma from its material counterpart, the physical body. Indeed, these “psychophysical events” are fundamental in clinical conditions that lead to unconsciousness in individuals declared clinically dead or who have come very close to physical death. In addition, Consciousness is fundamental in the occurrence of these experiences. In fact, Consciousness, a higher order field, is the entity that vibrationally dissociates from the physical body and is also the protagonist of the entire chain of events of near-death experiences, as well as out-of-body experiences. Undoubtedly, matter is a creation of the Universal Intelligent Principle and the primary cause of all things. Thus, Consciousness is the basis of all existence, of primordial reality. Vehicle of manifestation of Consciousness, the Psychosoma is a morphogenetic, vaporous, translucent, luminous body which is also made up of all organs, including the immaterial brain [mind] and the other electromagnetic systems of the human body. The Psychosoma is, therefore, the connection bridge between Consciousness, a complex subtle field, non-electromagnetic, responsible for all phenomena of near-death experiences in connection with the dense field of gross matter, the physical body. For example, the Consciousness is the one who sees, feels pain and welcomes its family members on the verge of death during the near-death experience in any vibrational dimension, even being perceived by the Psychosoma. Here it is important to remember that dimension is not a place. It’s a vibration. It’s a frequency. The main objective of this article is to approach innovative and comprehensive concepts about the role of Consciousness in near-death experiences as well as to try to overcome limiting paradigms that prevents the progress of science. In addition, concepts based on quantum holography and information theory were raised here. Following this reasoning, I start with the formulation of a hypothesis about the role of Consciousness in near-death and out-of-body experiences. Thus, we propose a new and unique approach to Consciousness in order to investigate the role of Mind and its relationship with life and death. In this way, we intend to introduce new concepts for discussion and not give the last word to the currently unanswered questions of Consciousness regarding its interaction with the environment; with death and life and finally with respect to its origin. Finally, a selective bibliographic research was carried out in English language databases with the purpose of making the study design compatible, which presents specific concepts of a subject that had been little studied until then.