Bridge Construction Research Articles

Oriented Molecular Bridge Constructs Homogeneous Buried Interface for Perovskite Solar Cells with Efficiency Over 25.3.

Buried interface optimization matters the efficiency improvement of planar perovskite solar cells (PSCs), and the molecular bridge is reported to be an effective approach. Herein, a molecular bridge is constructed at buried interface using 4-chloro-3-sulfamoylbenzoic acid (CSBA), and its preferred arrangement is systematically investigated. It is elucidated that the CSBA molecular is prone to be orientationally absorbed on TiO2 surface through COOH-Ti, and then connect with perovskite through S═O-Pb, resulting in a feasible oriented molecular bridge. Contributing to the passivated interfacial defects, optimized interfacial energy level, and released perovskite tensile stress, resulting from the oriented CSBA molecular bridge, the PSCs with an active area of 0.08 cm2 achieve a certified power conversion efficiency (PCE) of 25.32%, the highest among the TiO2-based planar PSCs. Encouragingly, the PSCs with an active area of 1 cm2 achieve a champion PCE of 24.20%, significantly promoting the efficiency progress of large-area PSCs. In addition, the PSCs with oriented CSBA molecular bridge possess enhanced stability, the unencapsulated PSCs can maintain ≈91% and ≈85% of their initial PCE after 3000 h aging under ambient condition and 1200 h aging under exposure to UV irradiation.

Laboratory studies of the soil erosion and alluvium processes in the area of bridge supports

The results of experimental studies of the process of bottom erosion during the construction of bridge supports under the protection of a sheet pile structure are presented. To protect the sheet piling box from the influence of ice floes during the period of ice drift, it is planned to install an ice-cutting protective device located upstream of the sheet piling box. In the process of conducting research, the principles of modeling the processes of river sediment transport taking into account the size of transported particles, non-erosive velocities and channel slopes are substantiated. Laboratory studies of the processes of forming erosion and alluvium are carried out for two cycles of parameters. At the same time, the influence of the ice-cutting device position relative to the sheet piling box on the amount of erosion and alluvium is studied. Experiments were carried out for various options of the ice cutter position relative to the sheet piling box; the ice cutter moved upstream along the axis of the tray with a step of 0.1 m (5 m for natural conditions). Based on measurements of bottom surface marks, two-dimensional erosion plans are constructed. For several options for the location of structures, the trajectories and directions of flow movement are determined by photographing the movement of surface floats, which makes it possible to create a grid of streamlines and determine the values of surface current velocities. An analysis of the velocity distribution over the surface and in the flow volume has shown that a horseshoe-shaped vortex is formed around the structure, with riffles and ridges appearing along its wings. A stagnation zone is established inside the “horseshoe”; in this zone the bottom remains relatively smooth. In the absence of an ice cutter, the main zones of soil erosion arise in the vicinity of the corners of the front face of the box, and alluviums form in the rear part of the structure. When installing an ice-cutting device in the shape of a triangle in front of the box, directed at an acute angle towards the oncoming flow, the erosion zones move to the vicinity of the corners lying at the base of the triangular ice cutter facing the box. The absolute values of erosion depth and alluvium height are reduced compared to the option without the ice cutter. When the ice cutter moves upstream relative to the box, a washout zone appears in the gap between the ice cutter and the box. The maximum values of erosion and alluvium occur in the absence of ice cutter and when placing the ice cutter at a distance of 200–300 mm from the box. The minimum values of erosion and alluvium are recorded when the ice cutter is placed close to the support box. With increasing flow rates and depths, the values of erosion and alluvium increase. Installing the ice-cutting device improves the hydraulic conditions of flow around the sheet piling box structure, which leads to a decrease in washout depths.

Harnessing the joint effect of approach bridges in arch bridge construction: an analytical study on thrust stiffness and elevation error mitigation

Achieving full equilibrium for the horizontal component force of the backstay in cable-stayed arch bridges is challenging, and the stiffness of the buckle tower has a notable influence on the overall shape of the main arch structure. Increased stiffness in the buckle tower leads to reduced construction complexity. Therefore, this study proposed a method of enhancing the longitudinal thrust stiffness of the buckle tower using the joint effect of approach bridges. A sensitivity analysis was conducted on the approach bridge–composite buckle tower structure to determine the optimal combination method, resulting in the formulation of an analytical expression for the thrust stiffness of this structure. In this study, numerical analysis was performed to explore the composition mechanism of the thrust stiffness influenced by the pier–girder connection, and we discussed the applicability of the joint effect of approach bridges during the cantilever assembly process of arch ribs. The following conclusions were obtained: 1) prior to installing the main girder of the approach bridge, when the steel buckle tower and the junction pier have already been secured, the most effective approach is to form a “T” rigid structure by firmly connecting the main girder of the approach bridge with the composite buckle tower. This configuration provides self-weight deflection and pier–girder rotation restriction effects. 2) The study presents analytical formulas for the completely rigid pier–girder connection of the approach bridge–composite buckle tower structure, partially rigid pier–girder connection, and pre-deviation. Combined with the calculation program, this can guide structural design. 3) When a large downward elevation error of the arch ribs occurs in the middle and later stages, the cable force needed to install new arch segments becomes overly large. Therefore, the joint effect of approach bridges can be utilized to substitute for a portion of the cable force, effectively reducing potential elevation errors that might arise in subsequent arch ribs in the absence of this joint effect.

Interlayer Biatomic Pair Bridging the van der Waals Gap for 100% Activation of 2D Layered Material.

2D layered materials are regarded as prospective catalyst candidates due to their advantageous atomic exposure ratio. Nevertheless, the predominant population of atoms residing on the basal plane with saturated coordination, exhibit inert behavior, while a mere fraction of atoms located at the periphery display reactivity. Here, a novel approach is reported to attain complete atom activation in 2D layered materials through the construction of an interlayer biatomic pair bridge. The atoms in question have been strategically optimized to achieve a highly favorable state for the adsorption of intermediates. This optimization results from the introduction of new gap states around the Fermi level. Moreover, the presence of the interlayer bridge facilitates the electron transfer across the van der Waals gap, thereby enhancing the reaction kinetics. The hydrogen evolution reaction exhibits an impressive ultrahigh current density of 2000mA cm-2 at 397mV, surpassing the pristine MoS2 by approximately two orders of magnitude (26mA cm-2 at 397mV). This study provides new insights for enhancing the efficacy of 2D layered catalysts.

A Case Study for Stability Analysis of a Toppling Bank Slope with Fault Fracture Zones Developed under the Action of Bridge Loads and Reservoir Water

The mountainous areas of Southwest China have the characteristics of valley deep-cutting, a large topographic gradient, complex geological structures, etc. With the development of infrastructure construction in the area, the construction of bridges across valleys has gradually increased, and the phenomenon of slope failure occurs more and more frequently. As the weak interlayer, the fault fracture zones have a significant influence on the geological structure and stability of slopes, while the complexity of the mechanism of the deformation and failure of slopes increases with the combination of the development of the fracture zones and toppling deformation. This paper took the toppling bank slope of bridge foundations developed with fault fracture zones in Lancang River as the research object. Through an on-site field survey and geological survey technologies, it identified the distribution range of the fracture zones on the bank slope and determined the characteristics of the rock mass in the fracture zones. A stability evaluation model for the bank slope of the bridge foundations was established using the limit equilibrium method and discrete element method. Based on the two-dimensional limit equilibrium analysis, the potential failure modes of the bank slope were explored, and the stability of the bank slope under bridge loads was calculated. Through the three-dimensional geological model of the bank slope, including the fracture zones and toppling bodies, the three-dimensional discrete element numerical simulation method was adopted to simulate and calculate the deformation and failure process of the bank slope under different bridge loads and working conditions. According to the calculation results, the influence of bridge loads and reservoir water on the stability of the bank slope was analyzed from the perspectives of displacement, plastic zone, stability coefficient, and other factors. The formation process of the plastic zone and the development of the sliding surface were revealed, the incentive mechanism of bridge loads and reservoir water on the deformation and failure of the bank slope was analyzed, and the influence of fault fracture zones on the stability of the bank slope and the development of toppling deformation was determined. The results indicate that the fault fracture zones are important geological structures that affect the deformation and failure of the bank slope as a weak interlayer. Under the influence of bridge loads and reservoir water, the stability of the bank slope is affected by the quality of the rock mass and the development of the fault fracture zones, resulting in the unmet need for safety requirements and maybe leading to instability. Based on the calculation results of the stability evaluation prediction model for the bridge foundation bank slope and the engineering geological conditions, the bridge scheme has been selected.

Failure investigation of a propped cantilever truss bridge

Propped cantilever truss is not a common bridge construction technique. The performance of such bridges under operational and extreme loading is not reported in the literature either. In this paper, failure mechanisms in a propped cantilever truss bridge are reported using field investigation. The field observations are supplemented by numerical analysis to identify the causes of failure. A a systematic account of damage mechanisms in bridge components is also reported. The failure of the Lamgadi Bridge over the Seti River in Nepal is used as a case study example. The loading and construction protocols are detailed, and numerical analysis results are juxtaposed with the field observations to explain the failure mechanisms. Field observations and numerical results show that lack in adequate design is the most likely cause of the bridge collapse. Numerical results also indicate that the roller support at the propped end, unlike the hinged pot bearing used in the as constructed bridge would have been a safer choice. The failure could have been easily prevented with proper numerical simulation of the bridge response during the design phase.

The effect of infrastructure development on increasing farmers’ income of main agricultural commodities in Serdang Bedagai Regency

Improving the quality and quantity of infrastructure leading to agricultural production centers will increase the economic activities of the community. The more stable infrastructure of agricultural centers will facilitate access to the location, more competitive prices, and more guaranteed quality so that it will increase agricultural production and productivity as well as the income and welfare of the community, especially farmers. The contribution of Serdang Bedagai’s agricultural and plantation sectors is so large that it is only natural that the priority of infrastructure development is the construction of roads and bridges to facilitate the mobility of agricultural products. This study was conducted to provide additional perspectives and references on the importance of infrastructure in improving the welfare and income of rice farmers in Serdang Bedagai regency. This study employs quantitative approaches. The investigation took place within Serdang Bedagai Regency, Sumatera Utara Province by distributing questionnaires to respondents, namely 96 farmers. Respondents were farmers representing 17 sub-districts. The findings indicated that infrastructure development positively and significantly influences the income of farmers producing the main commodities in the Serdang Bedagai area. Furthermore, it is shown that road conditions (X) have an impact of 47.4% on the income (Y) of major commodity farmers in the Serdang Bedagai regency.

Pengaruh Penambahan Variasi Limbah Serat Pelepah Pisang terhadap Kuat Lentur Beton

Concrete is a material that is often used for the construction of building structures, bridges and others. Concrete consists of a mixture of fine aggregate (sand), coarse aggregate (gravel), water and cement. In addition to these materials, concrete is usually also mixed with additional materials. In this study, stone banana stem fiber was used as an additional ingredient in the concrete mix. This study aims to determine the composition of the banana stem fiber mixture in concrete, as well as to determine the cracking behavior of the concrete during testing after the addition of banana stem fiber to the concrete mixture. The purpose of this study was to determine and analyze the results of the compressive strength test of concrete, normal concrete and banana fiber mixed concrete. The method used is an experimental method with variations of banana tree fiber, namely 0% (normal concrete); 0.25% and 0.5%. In this test, the specimen model was used, namely a test object measuring 60x15x15 cm. The tests carried out were the flexural strength of the concrete which was carried out after the concrete reached the age of 28 days and the shrinkage test which could be seen visually. From the results of the study it was found that the more the mixture of banana fiber waste, the flexural strength value of the concrete decreased, starting from normal concrete with a value of 49.73 MPa, a mixture of 0.25% with a value of 28.63 MPa, and a mixture of 0.5% with a value of 27.19 Mpa.

A Comprehensive Review of the Advances, Manufacturing, Properties, Innovations, Environmental Impact and Applications of Ultra-High-Performance Concrete (UHPC)

The article presents the progress and applications of ultra-high-performance concrete (UHPC), a revolutionary material in modern construction that offers unparalleled strength, durability, and sustainability. The overview includes the historical development of UHPC, covering its production and design aspects, including composition and design methodology. It describes the mechanical properties and durability of UHPC and highlights recent innovations and research breakthroughs. The potential integration of multifunctional properties such as self-heating, self-sensing, self-luminescence and superhydrophobicity, is explored. In addition, advances in nanotechnology related to UHPC are addressed. Beyond the actual material properties, the article presents an environmental impact assessment and a life-cycle cost analysis, providing an insight into the wider implications of using UHPC. To illustrate the environmental aspects, the determination of CO2 emissions is explained using three numerical examples. Finally, various applications of UHPC are presented, focusing on the construction of buildings and bridges. By synthesizing the above-mentioned aspects, this review paper captures the dynamic landscape of UHPC and serves as a valuable resource for researchers and engineers in the field of construction materials.

Analisis Biaya dan Waktu pada Proyek Jembatan (Studi Kasus Proyek Pembangunan Jembatan Candisari Sambeng Kabupaten Lamongan) dengan Menggunakan Metode Earned Value

Project management has three main objectives when carrying out construction projects including cost, quality, and time. If a project can be completed with a predetermined level of quality or quality, then the project has been successfully managed. This research uses earned value method. That is a method of knowing costs based on the work that has been done. Thus we can find out whether the Candisari Sambeng bridge construction project in Lamongan Regency is faster or longer than the schedule that has been made. CV value has a negative value in the 15th period, namely -Rp 18,078,304 SV value there is a negative value until the 18th period with a value of -Rp 494,817,905 CPI value found in the 15th week period with a value of 0.995. The SPI value in the 18th period with a final SPI value of 0.903 estimated cost (EAC) is. IDR 5,166,992,802 estimated EAS time for the jembata replacement project of 21,320 weeks. If the performance is considered the same project, the cost required to complete the construction of the bridge is Rp 5,166,992,802 from the total project budget of Rp 5,346,534,000 so that it gets a profit of Rp 179,541,198, and the time needed to complete the construction work is 21,320 weeks from the specified time of 21 weeks so that the project implementation is delayed for 0,320 weeks.y.

Inovasi Metoda Pekerjaan Jembatan Rangka Baja Studi Kasus: Pembangunan Jembatan Ujung Tanah Ii, Kota Padang, November 1993

The bridge is one of the most important means of transportation for humans. The bridge also serves as a link between one area and another. Seeing the importance of the function of a bridge, the construction of a bridge must meet various existing standards. One of the requirements that must be met in making a bridge is the resilience of the bridge in accept the load of both humans and vehicles that cross the bridge and the static equilibrium conditions on the bridge. The construction of a Truss bridge is usually carried out at the place where the bridge will stand. But now the construction of the bridge can be done outside that location, to then be shifted to the actual location. And, that's not only for short bridges, but also for long bridges. But sometimes a condition does not allow conventional bridge construction, while on the other hand the construction of the bridge is something very important. For that we need an innovation, an alternative method so that the construction of the Truss bridge can be carried out. The 100 meter span Australian Truss bridge was assembled above the maintenance bridge at the Batang Arau flood control structure and then shifted downstream to the new bridge location which is 10 meters away. Before the shifting was carried out, rails were prepared as the shifting path and two bridgeheads as the placement of the Truss bridge on the left and right of the Batang Arau river. Currently the Ujung Tanah II Truss bridge has been functioning for 30 years with good maintenance.

Slip-Resistant Pretensioned Connections in Hot-Dip Galvanized Steel Bridge Constructions under Fatigue Loading

Slip-Resistant Pretensioned Connections in Hot-Dip Galvanized Steel Bridge Constructions under Fatigue Loading

Detection of Traffic Control Devices during Bridge Construction Projects Using Deep Learning

Recent days during the time of road construction so many accidents may occur due to the objects in the construction area cannot capture during travel. Some method must be implemented to classify and locate instances in the image. In deep learning area it extends its application to this field for object detection. Even though a method is identified it has risk factors such as real-time detection, changeable weather, and complex lighting conditions. In this paper we are discussing the algorithm used for detection and a next version of that algorithm to detect the object with more precision. And also the number frames capture during driving is also more than other algorithm. Here we discussed about YOLO algorithm, and which is the best algorithm that applies different aspects such as key generic object detection frameworks, categorized object detection applications in traffic scenario, evaluation metrics, and classified datasets are included. The idea in YOLO v7 is to avoid that there is an identity connection when a convolutional layer with residual or concatenation is replaced by re-parameterized convolution.

Experimental investigation of seismic behavior of precast pier‐footing socket connection with different design parameters

AbstractAccelerated bridge construction, with innovative connection details and construction technologies, has been extensively investigated and put into practical application for years. Nowadays, there are three commonly used connection methods of accelerated bridge construction technology, namely, lap‐spliced connection, sleeve connection, and socket connection. Due to the convenience of construction and lower requirements of construction accuracy, the socket connection is more suitable for reconstruction and expansion projects of traffic infrastructure, which could minimize the impact on traffic and accelerate construction progress. According to the structural characteristics of the socket connection, there are some design parameters that may significantly affect the seismic resistance of the structure, such as socket embedment length, fabrication of the shear key, and grouting material strength. To fully study the influence of different design parameters on structural performance, an experiment was carried out to investigate the seismic behavior of the precast pier‐footing socket connections with different design parameters. Five 1:2 scale reinforced concrete precast pier‐footing socket connection specimens with different design parameters were designed and tested under cyclically reversed horizontal loads. The development of hysteresis features, failure mode, load‐bearing capacity, stiffness degradation, structural ductility, energy dissipation capacity, and residual drift are analyzed to reveal the influence of the different design parameters on the seismic behavior of the precast pier‐footing socket connection. The seismic behavior of the precast pier‐footing socket connection was significantly influenced by the embedment length especially when the embedment length was less than 1.0bc. When the embedment length was 0.5bc, the failure mode changed from bending damage at the bottom of the precast pier to the anchorage failure of the precast pier‐footing socket connection. When the embedment length was 1.5bc, the fabrication of the shear key had limited improvement on the seismic performance of the specimen, while reducing the ductility of the specimen. When the embedment length was 1.0bc, the grouting material with a strength grade of C60 could be used in the socket connection between the precast pier and footing. The research presented in this paper provides some design suggestions and a technical basis for evaluating the seismic behavior of precast pier‐footing structures with socket connection.

ANALYSIS OF COST CALCULATION IN THE CONSTRUCTION PROJECT OF KAPAS – GLENDENG 8 BRIDGE IN BOJONEGORO DISTRICT DUE TO TIME ACCELERATION USING THE CRASHING METHOD WITH ALTERNATIVE ADDITION OF WORKING HOURS

Infrastructure development plays a very important role as capital in efforts to stimulate increased economic productivity, both at the national and regional levels, as well as reducing unemployment, alleviating people from poverty and of course improving the standard of living of the community at large. Delays in completing a project are a problem that often arises and can have an impact on the entire work, especially with time delays resulting in increased costs which can be detrimental to many parties. This delay also occurred in the Kapas-Glendeng 8 bridge construction project, Bojonegoro Regency. In anticipation of these delays, it is necessary to accelerate time and costs. In this research the author uses the crashing method with the alternative of increasing working hours. The crashing method is a way of estimating cost variables to determine the maximum and most economical reduction in the duration of an activity that is still possible to reduce. The research results showed that the total time and cost of the project required after crashing was 174 calendar days with a cost under accelerated conditions of Rp. 2,555,189,555.98 with a difference of 6 calendar days from the normal duration of 180 calendar days and a fee under normal conditions of Rp. 2,548,581,990.63.

Automated flatness assessment for large quantities of full‐scale precast beams using laser scanning

AbstractPrefabrication has been widely used in bridge construction, for which precast beams are produced from a beam yard and constructed with a cast‐in‐suit bridge deck. The developments recently are focusing on large dimensions or large quantities of beam units, which leads to the inevitable challenge of beam quality control. Among them, beam surface flatness as one of the important indicators for manufacturing quality needs to be strictly controlled to ensure structural performance. However, the commonly used methods still rely heavily on manually contact‐based inspection, which is not only time‐consuming but also error‐prone. This paper presents an automated flatness assessment for large quantities of full‐scale precast beams by using terrestrial laser scanning techniques. Through axis calibration, target surface segmentation, and flatness deviation calculation, flatness deviations of the segmented surfaces from the point cloud of the entire beam are calculated, and colored maps are generated to visually assess the flatness quality. The proposed approach was applied to numerical simulated models as well as laboratory‐scale specimens for accuracy validation. Besides, its processing time was also compared to conventional contact‐based inspection during a field test. Moreover, efforts are devoted to applying the proposed method on nearly a thousand precast beams in an in‐field bridge construction project. Results can demonstrate its outperformance not only on accuracy but also the efficiency and practicality when applied to large quantities of full‐scale precast beams.

Fragility Assessment of a Long-Unit Prestressed Concrete Composite Continuous Girder Bridge with Corrugated Steel Webs Subjected to Near-Fault Pulse-like Ground Motions Considering Spatial Variability Effects

Prestressed concrete composite girder bridges with corrugated steel webs (PCCGBCSWs) are extensively employed in bridge construction because of their low dead weight, fast construction, and high prestressing efficiency. Moreover, PCCGBCSWs will experience deformation and failure of the corrugated steel webs, including steel fatigue and fracture, during earthquakes. These changes will introduce safety hazards, which can be addressed via bridge disaster prevention and mitigation. Because near-fault pulse-like ground motions (NFPLGMs) have high peak accelerations, these motions can easily cause damage to a bridge. Therefore, in this study, a seismic fragility assessment is performed for long-unit PCCGBCSWs subjected to NFPLGMs considering spatial variability effects, and a sensitivity evaluation of the seismic fragility is conducted considering girder type, bearing type, ground motion type, and apparent wave velocity to offer a point of reference for seismic design. The results show that PCCGBCSWs are less vulnerable than concrete bridges. The shock absorption effect of the friction pendulum bearing is better than that of the viscous damper. The impact of NFPLGMs on bridges is greater than that of near-fault non-pulse-like ground motions (NFNPLMs) and far-fault ground motions (FFGMs). The seismic fragility under nonuniform excitation conditions is greater than that under uniform excitation conditions, showing an increasing trend with decreasing apparent wave velocity.

TIME PERFORMANCE ANALYSIS ON THE CONSTRUCTION PROJECT OF SUBALI BRIDGE IN SUTOJAYAN DISTRICT (D.G.008), BLITAR REGENCY, USING THE EARNED VALUE METHODOLOGY APPROACH

One of the project types is the Construction Project. The main activity components of this type of project consist of feasibility assessment, engineering design, procurement and construction. In construction projects very often delays occur where the realization in the field does not match the schedule of the implementation plan, due to several factors that occur, even though a careful plan has been prepared but in practice in the field there are still many problems in implementation. The purpose of this study was to determine the performance of time in the implementation that took place from week -1 to week 17 on the Subali Bridge Construction project, Sutojayan Kec. (D.G.008), Blitar Regency using Earned Value. From the results of the analysis it can be seen that the costs incurred are lower than the planned costs, this can be seen in the CPI value of 1.28 while the implementation time is slower than the planned schedule indicated by the SPI value of 0.71.

On the collapse of a post-tensioned reinforced concrete truss bridge during the construction phases

On March 2018 a post-tensioned reinforced concrete (RC) truss bridge, built inside a North American university campus using the Accelerated Bridge Construction (ABC) method, collapsed during the construction phase, while the bars of a diagonal member were being re-tensioned. This process was not part of the scheduled construction phases, but it was decided by the designers after having observed several cracks in the structural nodes.This paper aims to analyse the final design of the bridge useful to determine the hypothetical causes of the collapse. Several numerical analyses have been performed to reproduce the behaviour of the different structural elements during the construction phases. In particular, construction stage analyses have been carried out to obtain the internal actions acting on the structural elements and on the nodes during the different construction steps and in order to analyse in detail the critical phases where the occurrence of the collapse has been hypothesized. The collapse mechanism is identified in the shear failure of a node of the concrete truss during the re-tensioning of a diagonal element. In fact, the reapplication of the post-tension had increased the axial force of the diagonal and consequently the shear action on the node. Moreover, the results obtained have shown that the bridge has never been in safe conditions, mainly because the interface surface of the cold joints had not undergone any type of work and remained smooth.

Acoustic Non-Destructive Testing Technology in Concrete Bridge Inspection and Pile Foundation Detection

This article takes the actual construction project of a certain concrete bridge project as an example to analyze the application of acoustic non-destructive testing technology in its detection. It includes an overview of a certain bridge construction project studied and acoustic non-destructive testing technology and the application of acoustic non-destructive testing technology in actual testing. This analysis hopes to provide some guidelines for acoustic non-destructive testing of modern concrete bridge projects.