Bridge Type Research Articles

Mitigation mechanism of torsional vortex-induced vibrations using aerodynamic countermeasures: Case study on a typical closed-box girder

In this paper, a torsional simplified vortex model (SVM) framework is deduced from the time-frequency characteristics of the aerodynamic forces and related vortex drift patterns obtained by numerical flow visualization. With the SVM, the mechanism of torsional vortex-induced vibrations (VIVs) in a typical closed-box bridge girder is investigated, and then the mechanism for the mitigation of these VIVs with aerodynamic countermeasures, such as spoilers on handrails or guide vanes near maintenance rails, is analysed. The results reveal that large-amplitude torsional VIVs occur in the bridge girder at an initial angle of attack (AOA) of + 3°. The spoilers can almost eliminate VIVs, whereas the guide vanes can moderately suppress them. The contributions of distributed aerodynamic moment to the global vortex-excited moment (VEM) on the upper surface of both the original and guide vane girders are much larger than those on the lower surface, implying that the aerodynamic behaviour over the upper surface is predominant in exciting and sustaining VIVs. The contributions of distributed aerodynamic moment to the global VEM on the improved girder with spoilers are much smaller than those on the original girder, particularly on the upper surface, which cannot trigger VIVs. Thus, VIVs disappear when the spoilers are installed on handrails. Subsequently, the flow fields during VIVs are obtained by numerical flow visualization. For both the original and guide vane girders, the torsional VIVs are mainly excited by the separated vortices forming at the windward barriers over the upper surface, while the separated vortices over the lower surface also make slight contribution to VIVs. After the guide vanes are installed near the maintenance rails, the scales of vortices over both the upper and lower surfaces are reduced, resulting in a weaker impact on the girder, which is fundamentally responsible for the mitigation effect of the guide vanes.

Major Bridges of Bangladesh: Engineering Marvels and Infrastructural Icons

Bangladesh is a riverine nation in South Asia with a 580 km coastline on the northern littoral of the Bay of Bengal. Our country has 213 rivers, and 20 significant bridges have been built. As populations grow and urban and rural landscapes evolve, the demand for innovative and efficient bridge structures becomes increasingly apparent. With its numerous rivers and water bodies, Bangladesh has faced the challenge of providing efficient and safe transportation infrastructure. Over the years, the construction of significant bridges has become crucial for connecting regions, promoting economic growth, and enhancing accessibility. This paper explores the historical background, geographical challenges, and economic significance of major bridge projects in Bangladesh. This paper looks at how bridges in Bangladesh have changed over time, focusing on essential projects that helped shape the country's infrastructure. The paper studies explicitly main bridges like Padma Bridge, Jamuna Bridge, and Shah Amanat, Lalon Shah, and others in Bangladesh. It looks at their designs, how they were built, and how they contribute to the country's development. Factors including the span length, site conditions, aesthetics, and engineering considerations influence the choice of bridge type.

Experimental research on PPF anti-cracking effect in scale model of hollow rigid frame bridge

The hollow rigid frame bridge has many advantages, such as being lightweight, having strong spanning ability, and having slight deflection in span. This type of bridge has a broad potential for application in regions of many canyons and hills. While there has been less research into the application of this type of bridge, some of the bridges in early service have cracking problems. To satisfy the demand for cracking resistance of the Yunnanzhuang large-span hollow rigid frame bridge, our group proposed using Polypropylene Fibers (PPF) to enhance the strength of concrete against cracking. After analyzing the structure of the whole bridge, we gave the critical sections of the bridge and carried out a series of tests to give the PPF dosage that applies to the project. This paper focuses on the use of reduced-size bridge model tests to investigate the effect of PPF on the cracking resistance of hollow rigid frame bridges under bending.In this paper, the similarity criterion between the actual bridge and the model was calculated by the method of magnitude analysis, according to which scale-down model beams of the upper chord S4 segment and mid-span jointing segment of Yunnanzhuang Bridge were designed under the geometry of 1:5. We respectively made these models using the same C55 concrete as the actual bridge and Polypropylene Fibre Reinforced Concrete (PPFRC) with 0.3 % volumetric admixture of PPF in the same mix ratio, and three-point bending static load tests were performed on these models. To make up for the insufficiency of test groups, we performed a finite element analysis using ABAQUS and the CDP constitution, which led us to some reliable conclusions.Considering that concrete materials have size effect, directly using the results of model tests to predict the cracking stresses of the actual bridge is not accurate. In this paper, some theories on size effects were examined. Finally, the Size Effect Model (SEM), Boundary Effects Model (BEM), and Weibull's brittle strength theory were selected to correct the test results.The results show that PPF can increase the cracking load of the test beams, ranging from 11.22 % to 13.49 %. After using selected size effect theories to predict the cracking stresses in actual bridges, the results show that PPF can enhance the cracking strength of C55 concrete, with an increase ranging from 9.15 % to 18.75 %. Combined with the results of the structural analysis of the whole bridge, the critical section has a cracking stress between 2.6 MPa and 3.5 MPa when using C55 concrete, which has a certain risk of cracking. However, when using PPFRC, the cracking stress ranges from 3.1 MPa to 4.2 MPa, with no risk of cracking in most unfavorable cases, which can satisfy the demand for concrete cracking resistance of Yunnanzhuang Bridge.

Probabilistic curvature limit states of corroded circular RC bridge columns: Data-driven models and application to lifetime seismic fragility analyses

Reinforcement corrosion has been recognized as an influential factor in the seismic fragility, both demand and capacity models, of aging reinforced concrete (RC) bridges. For capacity models, accurate and applied prediction tools accounting for aging effects are yet to be well established. Current practices usually perform numerical analyses to obtain time-variant capacity models, which are time-consuming particularly when multi-source structural and environmental uncertainties are considered and sometimes even suffer computational non-convergence. To address these issues, this study leverages a rigorously optimized artificial neural network architecture to develop data-driven models for rapid estimates of probabilistic curvature capacity of corroded circular RC bridge columns with flexural failure modes. An extensive database of multi-level curvature limit states (i.e. slight, moderate, severe, and complete) is created through experimentally validated moment–curvature analyses. A new threshold for the moderate limit state is defined based on the strain of core concrete, rather than cover concrete, to account for the potential full erosion of the cover with drastic corrosion. The data-driven probabilistic capacity models are applied to aid the lifetime seismic fragility assessment of a typical highway bridge, where the spectral acceleration at 1.0 s (Sa-10), peak ground velocity (PGV), and Housner intensity (HI) are found consistently, for the first time, as optimal intensity measures for probabilistic demand modeling of RC columns with different extents of aging effects. For the ease of application, the database and code for the data-driven probabilistic capacity models are accessible at https://bit.ly/3uAa8EY .

Prediction of Pier Scour Depth under Extreme Typhoon Storm Tide

The Western Pacific region is highly vulnerable to typhoon storm surge disasters, with localized erosion posing a particularly prominent issue for coastal marine structures. The prevalence of extreme typhoon storm surges poses a significant threat to the safety of engineering projects in these areas. In this study, a parameterized wind field model with precise calculation of wind speed was employed to establish a numerical model for typhoon storm tides. Based on the Western Pacific typhoon data from 1949 to 2023, hydraulic simulations were conducted for Hangzhou Bay, Xiangshan Port, and Yueqing Bay, revealing maximum flow velocities of 4.5 m/s, 1.95 m/s, and 2.09 m/s, respectively. These velocities exceeded the maximum possible tidal flow by 0.47–1.17 m/s. Additionally, using Sun’s velocity formula, the initiation flow velocities were calculated to be 1.85 m/s, 1.81 m/s, and 2.06 m/s for the aforementioned locations. Through localized erosion tests conducted around typical bridge piers and the subsequent application of similarity criteria, the maximum depth of localized erosion in the study area was determined to range from 2.16 m to 16.1 m, which corresponds to 1.1–2.3 times the scour caused by the maximum tidal flow scenario. A comparison of the erosion test results with calculations based on several formulas demonstrated that the scour prediction formula proposed by Sun exhibited the highest accuracy. This study supplements the understanding of the impact of typhoon storm surges on bridge pier erosion and provides a scientific basis for the design of bridge foundations.

Experimental and numerical investigation on deck system of a 102 m simply supported prestressed UHPC box-girder highway bridge

To address two main challenges (excessive mid-span deflections and numerous cracks in the main girder) in long-span prestressed concrete (PC) box-girder bridges, this paper proposes a long-span simply-supported UHPC box-girder bridge. In comparison to conventional PC box-girder bridges with three-dimensional prestress, the proposed UHPC box-girder consists only one-dimensional (longitudinal) prestress, and the thickness of the bottom/top plate and web of the UHPC box-girder are relatively thin and are strengthened with dense diaphragms and stiffening ribs. The 4th Beijiang River Bridge adopts this type of bridge with a span of 102 m, which is the longest span simply supported prestressed UHPC box-girder highway bridge in the world. Considering the fact that the thickness of the top plate of the UHPC box-girder is relatively thin (only 20 cm) and the transverse prestress is removed from the top plate, thus, under the direct action of wheel loads, the risk of bridge deck cracking may correspondingly increase. To investigate the mechanical behavior of the deck system of UHPC box-girder bridges, a 1:2 scaled experimental specimen associated with the field bridge is tested. The mechanical behavior of the new deck system is investigated and discussed. It is found that because the support strength of the stiffening rib is significantly weaker than that of the web, the UHPC deck slab should still be regarded as a two-way slab rather than a one-way slab in the elastic stage. In addition, although the test load location is unfavorable to the UHPC deck slab and the first crack appears on the UHPC deck slab, this deck system finally suffers from bending failure of the transverse rib. Furthermore, finite element analysis is carried out to study the mechanical behavior of this new deck system. Parametric analysis considers some factors including the reinforcement ratio in the transverse rib, the height of the transverse rib, and the space between transverse ribs. The results provide a good reference for design and optimization in the new deck system of UHPC box-girder bridges.

Electronic Couplings versus Thermal Fluctuations in the Internal Conversion of Perylene Diimides: The Battle to Localize the Exciton.

Energy transfer processes among units of light-harvesting homo-oligomers impact the efficiency of these materials as components in organic optoelectronic devices such as solar cells. Perylene diimide (PDI), a prototypical dye, features exceptional light absorption and highly tunable optical and electronic properties. These properties can be modulated by varying the number of PDI units and linkers between them. Herein, atomistic nonadiabatic excited state molecular dynamics is used to explore the energy transfer during the internal conversion of acetylene and diacetylene bridged dimeric and trimeric PDIs. Our simulations reveal a significant impact of the bridge type on the transient exciton localization/delocalization between units of PDI dimers. After electronic relaxation, larger exciton delocalization occurs in the PDI dimer connected by the diacetylene bridge with respect to the one connected by the shorter acetylene bridge. These changes can be rationalized by the Frenkel exciton model. We outline a technique for deriving parameters for this model using inputs provided by nonadiabatic dynamics simulations. Frenkel exciton description reveals an interplay between the relative strengths of the diagonal and off-diagonal disorders. Moreover, atomistic simulations and the Frenkel exciton model of the PDI trimer systems corroborate in detail the localization properties of the exciton on the molecular units during the internal conversion to the lowest-energy excited state when the units become effectively decoupled. Overall, atomistic nonadiabatic simulations in combination with the Frenkel exciton model can serve as a predictive framework for analyzing and predicting desired exciton traps in PDI-based oligomers designed for organic electronics and photonic devices.

The Coexistence of Carotico-Clinoid Foramen and Interclinoidal Osseous Bridge: An Anatomo-Radiological Study With Surgical Implications.

The coexistence of complete carotico-clinoid bridge (CCB), an ossification between the anterior (ACP) and the middle clinoid (MCP), and an interclinoidal osseous bridge (ICB), between the ACP and the posterior clinoid (PCP), represents an uncommonly reported anatomic variant. If not adequately recognized, osseous bridges may complicate open or endoscopic surgery, along with the pneumatization of the ACP, especially when performing anterior or middle clinoidectomies. According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews guidelines, a systematic scoping review was conducted up to June 5, 2023. PubMed, Scopus, Web of Science databases, and additional citations were searched. Two hundred high-resolution noncontrast computed tomography (CT) scans (400 sides) and 41 dry skulls (82 sides) were analyzed to identify the different morphology of sellar bridges, focusing on the coexistence of complete CCF and ICB. Two embalmed latex-injected heads with coexisting CCF and ICB were dissected step-by-step to show the anatomic relationship with the surrounding structures from an endoscopic and microscopic perspective. A total of 19 articles were included. The review identified a complete CCF and ICB rate ranging from 4.92% to 6.3%. The analysis of 200 CT scans revealed a rate of coexistence in 4% of the cases, all encountered in White women. Two different types of interclinoid bridges were identified based on the degree of bone mineralization. Both endoscopic and macroscopic step-by-step dissections highlighted variability in morphology and consistency of the sellar bridges and the close relationship with the cavernous sinus neurovascular structures. The coexistence of CCF and ICB is an anatomic variation found in 4% of cases. Preoperative knowledge of the degree of mineralization and its relationship with surrounding structures is essential to performing safe surgery and minimizing cranial nerve and vascular injuries. Preoperative high-resolution CT scans can adequately identify these anatomic variations.

Research on Long-span Bridge Point Cloud Morphology Identification

With the rapid development of 3D laser scanning technology and the trend of accurate and convenient acquisition of 3D point cloud data, the 3D point cloud data that was challenging to acquire in the past has also become one of the main ways to represent the 3D form of bridges. Among several bridge types, suspension bridges have high research value due to their widespread use in long-span bridges. The main cable, as the main load-bearing member of the suspension bridge, exhibits characteristics such as a large span, heavy components, and numerous influencing factors in long-span bridges. Thus, controlling the formation of the main cables is a problem frequently encountered in bridge engineering. Using 3D point cloud scanning data, this paper constructs an overall 3D point cloud model of the bridge and proposes an automatic extraction algorithm for bridge components based on this model. Subsequently, the paper illustrates the integration of the algorithm analysis and control of user interaction platform building, aiming to build up long span bridge digital base, therefore realizing variation recognition and digital tracking of long bridge space form.

Development of Modified Rhombus Amplifier of Positioning Stage Compliant Mechanisms

Abstract This paper presents a modified design of rhombus-type amplifier used in positioning stage compliant mechanism. The new rhombus design is introduced to enhance the performance of rhombus and the results are promising. The new approach of rhombus amplifier is based on mixing the concept of rhombus type with the idea of hinges (reduced section portions) existed in bridge type. The performance of the proposed design is investigated by the pseudo rigid body model and validated by the finite element analysis. The new rhombus design improves displacement amplification ratio by (22.3%) with slightly change in master mode natural frequency (1.3%). The pseudo rigid body model for new rhombus design is consistent with the ANSYS results, and hence can be used in modelling and analysis of the new rhombus design.

Development of Guo Tourism Village through the Restoration of Ba Atok Bridge as an Effort to Preserve Minangkabau Cultural Wisdom

Bridge infrastructure is critical in connecting one region with other areas separated by rivers or ravines. In Minangkabau, a type of bridge is built using the Ba Atok Bridge roof. This bridge structure is characterised by pointed roof-like buffalo horns, where the Minangkabau people are known as Gonjong. The remaining Ba Atok Bridge is located in Padang City, specifically in Guo Village, Jalan Lubuak Tampuruang, Kuranji Village, Kuranji District, Padang City, with a bridge length of 16 meters. The community needs the Ba Atok Bridge as a bridge to cross the river to gardens, schools, madrasas, mosques, and other villages. Its unique shape has charm, and this is one of the cultural heritage assets that must be maintained as a characteristic bridge between the nuances of traditional Minangkabau culture. Therefore, the Community Service Team of the Faculty of Engineering, Andalas University, is also collaborating with the Tourism Awareness Group (POKDARWIS), which also has the same initiative, namely carrying out bridge restoration with traditional Minangkabau cultural nuances. Restoration begins with identifying damage, discussing it with community groups, making an architectural design, submitting a proposal to Bank Nagari, and repairing the bridge's upper frame. The Ba Atokini bridge restoration activities impact crossing access and have become characteristic of the Guo Tourism Village, which POKDARWIS manages.

Development of large-scale synthetic 3D point cloud datasets for vision-based bridge structural condition assessment

Visual recognition of 3D point cloud data of bridge inspection scenes is a key step in automating the visual inspection process, which is currently largely manual and inefficient. To alleviate the lack of large-scale annotated point cloud datasets for training such 3D visual recognition algorithms, this research investigates an approach for developing large-scale synthetic point cloud datasets. The proposed approach proceeds in four steps: (1) random generation of different types of bridges in computer graphics environments; (2) sampling of camera trajectories that represent data collection scenarios during bridge inspection; (3) 3D reconstruction using Structure from Motion (SfM) applied to rendered synthetic images; (4) automated annotation of the reconstructed point cloud using ground truth masks obtained with synthetic images. Besides, this research proposes to store point uncertainty information defined by the error between the ground truth depth and the depth calculated from the SfM results. Prior to training, thresholds can be applied to this uncertainty information to control the levels of outliers in the dataset. This research demonstrates the proposed approach by generating point cloud datasets for two data collection scenarios. The effectiveness of the generated datasets is investigated by training 3D semantic segmentation algorithms and evaluating the performance on real and synthetic point cloud data. The proposed approach for point cloud dataset generation will facilitate the development of generalizable and high level-of-detail 3D recognition algorithms toward autonomous bridge inspection.

Quantitative analysis of debonding gaps in concrete-filled steel tubes on the Qinghai-Tibet Plateau under severely harsh conditions

In recent years, the maximum span of concrete-filled steel tube (CFST) arch bridges has substantially increased to nearly 700 m, rendering it a preferred bridge type for traffic nodes located in mountainous regions and deep canyons owing to its robust earthquake resistance and adaptability to varying terrain. Construction defects, particularly debonding gaps, significantly diminish the structural bearing capacity of these bridges. This study aims to realize the accurate quantitative calculation of debonding gaps in CFSTs through ultrasonic non-destructive testing. The first wave's acoustic time and overall ultrasonic pulse velocity (UPV) were employed as the state variables of ultrasonic pulse propagation in CFSTs with debonding gaps. Ultrasonic non-destructive tests were conducted on CFST specimens produced in the Qinghai-Tibet Plateau and Guangxi. An approximate calculation path of ultrasonic propagation in CFSTs was proposed, and the differences in the UPVs of CFSTs produced at different air pressures were analyzed. A calculation model of the UPVs of CFSTs was formulated using different air pressure influence coefficients. Additionally, a numerical simulation of the ultrasonic energy transfer in CFSTs with diverse debonding gaps was performed, elucidating the propagation mechanism of ultrasonic energy across the three-phase steel-concrete-air interface in CFSTs. The propagation law of ultrasonic waves in CFSTs was verified through dynamic ultrasonic energy snapshots and the state variable calculation results. Based on the experimental and numerical findings, a quantitative analysis method and correlation model for CFST debonding gaps were proposed, based on their UPVs at different air pressures. The quantitative calculation model was modified by analyzing the values measured at an actual CFST bridge, enabling the accurate quantitative analysis and calculation of the degree and scope of debonding gaps in CFSTs.

Refinement and Validation of the Minimal Information Data-Modelling (MID) Method for Bridge Management.

Various approaches have been proposed for bridge structural health monitoring. One of the earliest approaches proposed was tracking a bridge's natural frequency over time to look for abnormal shifts in frequency that might indicate a change in stiffness. However, bridge frequencies change naturally as the structure's temperature changes. Data models can be used to overcome this problem by predicting normal changes to a structure's natural frequency and comparing it to the historical normal behaviour of the bridge and, therefore, identifying abnormal behaviour. Most of the proposed data modelling work has been from long-span bridges where you generally have large datasets to work with. A more limited body of research has been conducted where there is a sparse amount of data, but even this has only been demonstrated on single bridges. Therefore, the novelty of this work is that it expands on previous work using sparse instrumentation across a network of bridges. The data collected from four in-operation bridges were used to validate data models and test the capabilities of the data models across a range of bridge types/sizes. The MID approach was found to be able to detect an average frequency shift of 0.021 Hz across all of the data models. The significance of this demonstration across different bridge types is the practical utility of these data models to be used across entire bridge networks, enabling accurate and informed decision making in bridge maintenance and management.

A field study of temperature field distribution characteristics of flat steel box girder and its influential environmental factors

As one of the mainstream girder types of long-span bridges, the flat steel box girder (FSBG) under thermal action has been one primary concern for bridge engineers and researchers. This research presents a field study of the temperature field distribution characteristics of FSBG and its influential environmental factors. To achieve this, an acquisition equipment that comprises of thermometers and environmental sensors is applied to a prototype cable-stayed bridge under construction, in which the structural temperature field of FSBG and the surrounding environmental data are collected and analyzed thoroughly. The results indicate that the vertical temperature distribution (VTD) in certain time instants exhibits significant variations and the maximum vertical temperature gradient can reach up to 27.9 °C. Despite of this, it is found that the VTD of FSBG can be covered by several current standards such as AASHTO standard and New Zealand standard. As for the transverse temperature distribution (TTD), it is found that both the variation and temperature difference of TTD in certain time instants are considerable, especially at the deck surface, which far exceed those of the TTD prescribed in current standards. This indicates that the TTD of FSBG should be seriously considered during the bridge design phase. Furthermore, the field study reveals that the wind speed has negative effect on the structural temperature of FSBG (when the air temperature is less than that of FSBG), while the solar radiation exerts positive effect on the structural temperature of FSBG. The outcome of this study can provide valuable references for thermal design, monitoring and control of long-span bridges employing FSBGs as bridge main girder.

Comparative Study on the Seismic Vulnerability of Continuous Bridges with Steel–Concrete Composite Girder and Reinforced Concrete Girder

For medium- and small-span bridges, the weight of the superstructure in steel–concrete composite girder bridges is lighter than that of a reinforced concrete girder bridge. However, it is still uncertain whether steel–concrete composite girder bridges exhibit superior seismic performance compared to reinforced concrete girder bridges. This study quantitatively compared the seismic performance of the two types of bridges. Using the theory of probabilistic seismic demand analysis, the seismic vulnerability curves of bridges were derived. To conduct seismic demand analysis for probabilistic analysis on the OpenSEES platform, bridge samples were generated using the Latin hypercube stratified sampling method, which considers the uncertainties associated with the two types of bridges. The vulnerability curves of the piers, bearings, abutments, and the system of the two bridges were established using probabilistic analysis of the time history analyses. The results showed that the seismic vulnerabilities of components and the overall system of the steel–concrete composite girder bridge were both lower than those of the reinforced concrete girder bridge. When the peak ground acceleration (PGA) of the ground motion was 0.3 g, the moderate and serious damage probabilities of the piers in the steel–concrete composite bridge were only 54.61% and 60.89%, respectively, of those of the reinforced concrete bridge. Consequently, replacing the upper reinforced concrete girders with steel–concrete composite girders can significantly improve the seismic performance of a large number of existing bridges.

Combined concrete and cable restrainers to prevent longitudinal unseating of highway bridges during earthquakes

Numerous irregular highway bridges with laminated rubber bearings are constructed in Southwest China, which are likely to suffer from unseating failure of girders during earthquakes. Due to the shortcomings of existing unseating prevention devices, a novel system composed of concrete restrainer and steel cable, termed as CCCR, is proposed to prevent longitudinal unseating at the flexible transition piers of irregular highway bridges. The configuration and mechanical properties of the proposed CCCR is first elaborated. To verify the efficiency of the proposed system, a refined finite element model is developed for a typical highway bridge, in which the nonlinear behaviors of rubber bearings, concrete restrainers, steel cables, bridge piers, abutments, as well as pounding between adjacent segments are simulated in detail. Incremental dynamic analysis (IDA) is then conducted using this model considering three scenarios, namely the bridge system (1) without restrainer (Prototype), (2) with concrete restrainer (CR), and (3) with combined concrete and cable restrainers (CCCR). Additionally, extensive parametric analyses are also carried out to further investigate the influence of the critical parameters of CCCR on the unseating prevention performance and the damage of pier. The results show that the proposed CCCR system can effectively prevent unseating even under most catastrophic earthquakes with the pier still maintaining slight damage. Besides, design values of the critical parameters are recommended based on the parametric analysis, including the capacity and initial gap of the concrete restrainer, as well as the length and slack of the steel cable.

Performance-based assessment of the novel prefabricated CFST bridge pier by numerical approach

This study aims to profoundly investigate the seismic performance and application prospect of the typical continuous beam bridge with the novel prefabricated concrete-filled steel tubular (CFST) piers, with advantages in simple on-site assembly, convenient transportation of prefabricated components, good seismic performance, and low construction cost. According to two prototype continuous beam bridges respectively equipped with low and tall typical reinforced concrete (RC) piers, 7 bridge cases with prefabricated CFST piers featuring various configurations of the tie beams are designed. Three-dimensional numerical models of these bridge cases are established and verified with the previous experimental studies, and numerical simulations of all the bridge cases are conducted to assess and compare the seismic responses and fragility curves. The results show that the bridges with prefabricated CFST piers exhibit a reduction in top pier transversal displacement and maximum curvature along the pier height, which are 43 % and 138 % lower than those of the prototype RC piers, respectively. Besides, the bridges with prefabricated CFST piers generally present lower probabilities of being damaged compared to those of the prototype bridges with RC piers.

Islamic faith-based organisations and their role in building social capital for post-disaster recovery in Indonesia.

This paper investigates the role of Islamic faith-based organisations (FBOs) in Indonesia and examines the way in which their disaster recovery aid can be successful or less successful depending on social capital formation in communities affected by a disaster. The paper argues that Islamic FBOs play a prominent role in disaster-affected communities by building new social capital or strengthening existing social capital. Failure to do so may affect a community's recovery and its long-term resilience. Applying a framework that considers three types of social capital-bonding, bridging, and linking-from a comparative perspective, the paper discusses two cases of disaster recovery: one following the earthquake that struck Aceh in 2013; and the other after the Mount Kelud volcanic eruptions in East Java in 2014. In both instances, the findings highlight the importance of the village facilitator, cultural sensitivity, and understanding of local indigenous and religious practices for successful disaster recovery.

Modification of the N-methyl-4,5-diazacarbazole D-π-A with a π-conjugated bridge to enhance excited-state properties for superior utilization in green energy applications: A theoretical approach

In organic photovoltaic technology, tailoring the acceptor or donor unit to enhance intramolecular charge transfer is a well-known approach, however, the effect of modifying conjugated bridge units is an underdeveloped phenomenon. In this study, this approach has been focused, where a series of conjugated bridges including, a) electron-excessive heterocycles, b) electron-deficient heterocycles, and c) short-chain unsaturated hydrocarbons have been substituted from thiophene bridge-containing D-π-A; N-methyl-4,5-diazacarbazole (donor) and bay-annulated indigo (acceptor) molecule. This quantum chemical study aims to investigate the effect of various types of π-conjugated bridges on the electronic structure and solar cell activity of already reported material. The selected π-conjugated bridges include electron-excessive (furan, pyrrole, & thiophene) and electro-deficient (diazine, tetrazine, & pyridine) heterocycles, and short-chain hydrocarbons (ethylene & ethyne). The optimized structural parameters e.g., dihedral angles (θ), distortion energies (Edis), & bond distances (d), and electronic behaviour i.e., Frontier Molecular Orbitals (FMO), Electrostatic Potentials (ESP), Density of States (DOS) spectra, dipole moments (μ), and absorption spectra of the hypothetically designed molecules are estimated using density functional theory calculations. The solar cell proficiency is investigated with transition dipole moment (μT), reorganization energy (RE), Transition density matrix (TDM), exciton binding energy (Eb), and open circuit voltage (Voc). Our finding encompassed that our designed D-π-A molecules show significant improvement in their electronic behaviour, especially when the thiophene bridge of the reference molecule is substituted with the excess electron heterocycles, especially pyrrole. The HOMO-LUMO gap of this particular molecule (MPy) is reduced to 2.07 eV, resulting in the significant charge transfer between donor and acceptor units (0.15 e-). Moreover, the results of RE, TDM, Eb, and Voc also support the high solar cell efficiency of pyrrole-containing molecules.