Maximum Span Length Research Articles

Experiences from launching the bridge over Gottleuba‐valley (Gottleubatalbrücke)

AbstractThis article briefly describes the project background, timelines, structural data, actually achieved milestones and current stage of project of the bridge over Gottleubavalley in Pirna, Saxony, Germany. The bridge is being built using incremental launching method, the main challenges of the launching process are briefly described together with some learning points.The winning design from the architectural competition in 2006 proposed very slender (1 to 35 !) hybrid steel‐concrete semi‐integral frame crossing the 70m deep and 1000m wide valley with nine spans (92 – 116 – 120 – 120 – 124 – 108 – 92 – 76 m) with maximum span length of 124m. The paper describes the challenges the team faced during the preparation and launching of a very slender bridge deck with deflections up to 6m when touching down at the bridge pier. By the time of the venue, the incremental launching will be already finished, and the lowering works will be in progress.

Intelligent condition prediction model for bridge infrastructure based on evaluating machine learning algorithms

PurposePrediction models are essential tools for transportation agencies to forecast the condition of bridge decks based on available data, and artificial intelligence is paramount for this purpose. This study aims at proposing a bridge deck condition prediction model by assessing various classification and regression algorithms.Design/methodology/approachThe 2019 National Bridge Inventory database is considered for model development. Eight different feature selection techniques, along with their mean and frequency, are used to identify the critical features influencing deck condition ratings. Thereafter, four regression and four classification algorithms are applied to predict condition ratings based on the selected features, and their performances are evaluated and compared with respect to the mean absolute error (MAE).FindingsClassification algorithms outperform regression algorithms in predicting deck condition ratings. Due to its minimal MAE (0.369), the random forest classifier with eleven features is recommended as the preferred condition prediction model. The identified dominant features are superstructure condition, age, structural evaluation, substructure condition, inventory rating, maximum span length, deck area, average daily traffic, operating rating, deck width, and the number of spans.Practical implicationsThe proposed bridge deck condition prediction model offers a valuable tool for transportation agencies to plan maintenance and resource allocation efficiently, ultimately improving bridge safety and serviceability.Originality/valueThis study provides a detailed framework for applying machine learning in bridge condition prediction that applies to any bridge inventory database. Moreover, it uses a comprehensive dataset encompassing an entire region, broadening the model’s applicability and representation.

The Optimal Span Length of the Overhead Catenary System for the Gemas-Johor Bahru Electrified Double Track Project

The span term in the Overhead Catenary System (OCS) refers to the distance between two subsequent supports in the running track direction. Longer spans are preferable for economic reasons because they reduce the number of supporting structures. The maximum span along the track was suggested by OCS designers using a structure spacing table and chart with varying wind speeds and radius of curvature. The structure spacing chart is a logarithmic curve that is plotted based on the specifications of the project and design constraints. According to the current design, the maximum span length for the Gemas-Johor Bahru Electrified Double Track Project is 72 metres (GJBEDTP). The current OCS design can be upgraded to provide a greater maximum span. This study looked at the economic benefits of increasing the maximum span length of the GJBEDTP in terms of reducing the total number of supporting structures. The track is separated into many equal-length track sections, and their individual spans are selected using the wind study assessment report and the structure spacing chart. Divide the total track length by the average span to get the estimated total number of supporting structures. In this study, a graph showing the percentage of cost savings and the maximum allowable span is plotted. In this optimization issue, the Elbow approach is used to select a point where diminishing returns are no longer worth the extra expense of going for a longer span. According to the results, the maximum span of 72 m is the ideal span for the GJBEDTP.

Plant traits and environment: floating leaf blade production and turnover of Nymphoides peltata (S.G. Gmel.) O. Kuntze (Menyanthaceae).

BackgroundNymphaeid macrophytes, rooting in the sediment of water bodies and characterized by floating leaves, play an important role in wetland ecosystems. The present research deals with the effects of limited space, limited nutrient availability, water temperature and an unexpected inundation on the production, turnover and plasticity of floating leaves of the globally widespread species Nymphoides peltata (Fringed waterlily).MethodsThe effects of these environmental conditions were studied in two plots in outdoor concrete tanks (CT1, CT2, mesocosms simulating occurrence in small ponds) and in two plots in the floodplain oxbow lake Bemmelse Strang (BS1, BS2). Plot CT1 was situated in a stand coexisting with helophytes, plot CT2 in a monospecific stand, plot BS1 in the center and plot BS2 at the open water border of a monospecific stand. All floating leaf blades within the plots were marked at appearance at the water surface and subsequently length, width and damage of each leaf and maximum and minimum water temperatures were measured bi-weekly. Area and biomass of leaf blades were calculated based on leaf length and width and were used to calculate turnover rates and production.ResultsThe growth period started in May and ended mid-October with continuous production of floating leaves during nearly the whole vegetation period. In the tanks the water level was very stable, but the lake underwent an inundation by river water, causing a sudden loss of existing leaves. Considering environmental conditions and based on the assumed ranking from low to high nutrient availability, the ranking of the plots was CT1, CT2, BS1, BS2. This order was found for maximum leaf life span and maximum leaf length, and the reverse order was found for number of leaves, new leaves per day and duration of the vegetation period. Turnover rates appeared to be relatively similar for plots CT1, CT2 and BS1, but for the deeper border plot BS2 lower ratios were found. These results indicate that increased enclosure with expected nutrient limitation causes (1) the production of high numbers of small leaves with larger totals for leaf area and biomass, (2) a shift towards increased sexual reproduction by the production of more flowering stem leaves.

Dimensions of Network Polymers

AbstractThe mean‐square radius of gyration Rg2 and the graph diameter D of the network polymers formed through the random crosslinking of predetermined primary chains with a fixed number of intermolecular and intramolecular crosslinks are investigated by the numerical calculation based on the graph theory. In the case of ring‐free polymers, D is the longest end‐to‐end path length, sometimes referred to as the maximum span length. The expected Rg2‐value for a given D is found to follow a linear relationship, Rg2 = a D + b, similarly as in the cases of the ring‐free polymers. The proportional coefficient, a decreases approximately linearly with the number of intramolecular crosslinks kc, or the cycle rank in the graph theory, essentially independent of the total number k of crosslinks and the primary chain length distribution. The contraction factor g of the average Rg2 of the whole network polymer system is also governed by kc, and decreases with kc. One may be able to design and control the Rg2‐values of crosslinked polymers through the magnitude of D, which is usually easier to imagine than the complex 3D architecture.

Dimensions of Crosslinked Polymers without Rings

AbstractMean‐square radius of gyration Rg2 and the maximum span length LMS of each polymer molecule formed in the crosslinking of polymer chains that follow the Schulz–Zimm distribution are determined by using the Monte Carlo simulation method for the generation of various crosslinked polymer architecture. For the random crosslinking, it is found that the expected g‐ratio of Rg2 of the crosslinked polymer to that of a linear polymer for a given number of crosslinks k does not change with the crosslinking density up to the gel point. The g‐ratio for a given k is larger for broader primary chain length distribution, and a convenient formula for the relationship between g and k is proposed. The linear relationship, Rg2 = 0.178 LMS applies, at least approximately, regardless of the primary chain length distribution and the crosslinking density. The relationship is essentially the same as for the branched polymers. The effect of nonrandom crosslinking is investigated through the theoretical simulation for the free‐radical vinyl/divinyl copolymerization conducted in a steady‐state continuous stirred tank reactor (CSTR). It is found that the nonrandomness induced by this reaction system does not change either of the universal relationships, g–k and Rg2–LMS.

Growth Behaviour of Bt (Bacillus thuringiensis) Cotton as Influenced by Mepiquat Chloride under Varying Nitrogen Levels

Cotton is indeterminant and long duration crop. For synchronising in growth and to prevent heavy shedding of bolls different growth regulators used in cotton field. The present field experiment was conducted at National Seed Production Area of Choudhary Charan Singh Haryana Agricultural University, Hisar, India during kharif season 2018. The experiment comprised of three levels of nitrogen (100%, 125% and 150% Recommended Dose Fertilizer) and three spray of mepiquat chloride (control, single spray at 60 Days After Sowing and two spray at 60 and 75 DAS) was conducted in factorial randomized complete block design replicated thrice. Based on the research investigation, it was found that different phenological stages were delayed by 3 to 4 days with application of 150% RDF, while twice spray of mepiquat chloride resulted in 6 to 7 days earlier completion of these stages. Ginning out turn was statistically at par with different levels of nitrogen, while 100% RDF has shown maximum span length with lowest micronaire value. With single mepiquat chloride spray at 60 DAS ginning percentages decreases by 6.80% over control, it maybe seen beacause of shortened growth period. While span length reduces with two sprays of mepiquat chloride at 60 and 75 DAS by 0.62% over the control and single spray of mepiquat chloride at 60 DAS. However finest fibre (4.23 x 10-6g/inch micronaire value) obtained with single spray of mepiquat chloride. The result of present study reveals that, 100% RDF in Bt cotton along with single spray of mepiquat chloride at 60 DAS gives finest fibre with more span length by completing all phenological stages earlier than others.

A Simple Conceptual Model for Estimating the First Bending Natural Frequency of Bridge Superstructures

Several parameters affect the bridge’s natural frequencies while parameters related to the geometric characteristics of bridge components are more important. Maximum span length (SL) (length of the main or longest span), deck width, number of girders and spans, and girder’s height can be regarded as the main influencing parameters. In this paper, the first bending natural frequency (FBNF) of bridge superstructures of typical structural systems is assessed analytically using a simple conceptual model considering the main analytical parameters. The results show that the FBNF of bridges is strongly related to the SL of the longest span. It means that the other parameters are considered indirectly and may not be essentially considered as influencing parameters.

Influence of Seismic Loads Considering Soil Properties and Wave Passage Effect on the Seismic Response of a Multi-Span PSC Girder Bridge

This paper investigates the analytical results of the seismic response of multi-span prestressed concrete (PSC) I-girder bridges under seismic loads. To perform numerical analyses, a three-span PSC I-girder bridge with a width of 12 m, a total length of 100 m, and a maximum span length of 40 m was modeled, and a virtual location was selected to consider the soil properties of the area where the bridge was constructed. The seismic load acting on the PSC I-girder bridge was applied in consideration of the soil properties around the pier and the wave passage effect of the bedrock in the artificial seismic load generated, according to the U.S. Nuclear Regulatory Commission (NRC) standard. The analysis results confirmed that the seismic load, with consideration of the soil properties and wave passage effect, generated the maximum response acceleration and bending moment at the deck of the bridge—152% and 232% greater than without considering them, respectively. Therefore, in order to ensure the earthquake resistance of the bridge, the soil properties of the area where the bridge will be built and the wave passage effect of the bedrock must be considered.

Viaducto mixto en el acceso al Hospital Universitario Central de Asturias

El puente forma parte del nuevo enlace entre la AS-II y el Hospital Universitario Central deAsturias. Se trata de un puente pantalón de siete vanos y luz máxima 61.75 m en el troncoprincipal curvo al que se incorpora un ramal también curvo de dos vanos y luz máxima 48,00metros. La estructura presenta cuatro zonas:En los tres primeros vanos del tronco principal el tablero es de anchura 17.65 metros, compuestopor una viga cajón mixta con costillas a cada lado.En los dos primeros vanos del ramal el tablero está formado por una única viga cajón metálicacurva.Tras la confluencia de las losas de los dos cajones se desarrolla una zona de anchura variablehasta su convergencia a una sección constante de 21.30 metros. En esta zona la vinculacióntransversal de los cajones es potente, ya que se disponen cinco riostras transversales.Finalmente, la estructura continua con anchura constante de 21.30 metros hasta el estriboopuesto con sección con doble cajón.En la comunicación se comentarán los aspectos más singulares de la respuesta estructural delpuente, como el diseño de las costillas y riostras transversales, y el acoplamiento en la respuestade los dos cajones en la zona pantalón, así como los aspectos constructivos más significativos.

Loss Assessment for Sustainable Industrial Infrastructure: Focusing on Bridge Construction and Financial Losses

Bridges are important infrastructures for urban growth and the economic development of a country, because bridges allow a large volume of logistics and transportation by connecting rivers, canyons, islands and lands. As such, massive resources including financial, material and human resources are invested for bridge construction and management. However, although the latest bridge construction is undergoing rapid development of new technologies and designs, the management and prevention of risks still tend to rely on qualitative practices, which, as a result, calls for more quantified and systematic measurement and, thus, more sustainable management of potential risks. As part of efforts in managing risks to achieve quantitative risk management, this study aimed to predict losses of financial resources by identifying statistically significant risk factors based on the past record of insurance claim payouts (compensation for a loss that occurred as a result of a material damage in bridge construction projects) from a major insurance company in Korea, and conducted a multiple regression analysis to identify the loss indicators and to develop a loss estimation model. The statistical analysis confirmed that superstructure types, superstructure construction methods, and construction duration are the three significant risk factors that affects financial losses of bridge construction projects among the seven variables adopted as independent variables, which included the superstructure type, maximum span length, superstructure construction method, foundation type, floods, typhoons, and construction duration. Such findings, and the consequentially developed risk prediction model of this study, will contribute to sustainable construction management through cost reduction by predicting and preventing the future financial loss factors of bridge construction.

Sustainable Risk Assessment through the Analysis of Financial Losses from Third-Party Damage in Bridge Construction

Due to the recent introduction of innovative construction methods and technologies, construction projects increasingly require sustainability in their high degrees of specialization and complex work processes. This is due to a wide variety of new risk factors associated with construction projects that can lead to extensive and severe damage. When an accident occurs during a construction project, it can cause material, property, or bodily damage not only within the actual construction site but also outside, affecting third parties. This study analyzed the record of such third-party damage and the subsequent financial losses in bridge construction management, to identify the objective and quantified relationship of risk indicators related to the damage and losses. In order to assess the actual losses in construction projects, we adopted the loss claim payout data as recorded and provided by a major Korean insurance company, and conducted a multiple regression analysis to identify the loss indicators and to develop a loss estimation model. In this study, the analysis of the data indicated that the superstructure type, the foundation type, floods, and company ranking by the amount of the contract were the four statistically significant risk indicators that affected financial losses from third-party damage, among the nine variables used as independent variables, which included the superstructure type, foundation type, superstructure construction method, maximum span length, floods, typhoons, total construction cost, total construction period, and company ranking. As this study focused on identifying the risk factors and producing a loss assessment model quantified in numerical values, the results provide important references for assessing and minimizing the risks to third parties and the consequential financial losses in bridge construction, while promoting sustainability objectives.

Random Branching of Polymer Chains with Schulz–Zimm Distribution. 2. Radius of Gyration and Maximum Span Length

AbstractMean‐square radius of gyration Rg2 and the maximum span length LMS of each polymer molecule are investigated for the random branching of primary chains that follow the Schulz–Zimm distribution, by using the Monte Carlo simulation method. It is found that the expected g‐ratio of Rg2 of the branched molecule to that of a linear molecule for a given number of branch points k does not change with the branching density. The expected g‐ratio becomes larger for the primary chains with broader distribution. An approximate formula for the relationship between g‐ratio and k that accounts for the distribution breadth is proposed. The relationship between the weight fraction of the maximum span chain LMS/(degree of polymerization) and k shows the analogous behavior with that for g‐ratio and k. The magnitude of Rg2 is proportional to LMS, with Rg2 = 0.18 LMS, irrespective of the breadth of the primary polymer chain length distribution.

Analysis of Safe Span Length and Fatigue Life of Submarine Pipelines

Owing to the complex environmental conditions, suspension could induce complicated forces on submarine pipelines and even cause vortex-induced vibration, resulting in fatigue damage of pipelines. Through aiming at the 28-inch submarine pipeline in the East China Sea, the pipeline was segmented according to the similarity, considering the factors of pipe assembly, typhoon, current, wave and seabed topography. The effects of span length on natural frequency in each section of submarine pipeline were analyzed by finite element model. The maximum safe span length allowed by each pipeline section was verified by fatigue cumulative damage theory, and the fatigue life of each pipeline section were predicted. The results showed that each order natural frequency of the pipeline decreased with the increase of span length. The calculated results of empirical formulas were much smaller than those of the FEM analysis. The increase of the gap between the suspended pipeline and the seabed was beneficial to enhance the fatigue life of the suspended pipeline.

Distribution and growth of bivalve molluscs Serripes groenlandicus (Mohr) and Macoma calcarea (Gmelin) in the Pechora Sea

We studied distribution and growth of Serripes groenlandicus and Macoma calcarea in the southeastern part of the Pechora Sea. The hypothesis was tested that trends in the site-to-site variability of population characteristics of these two bivalve species were driven by their feeding types (suspension-feeder and deposit-feeder, respectively). However, such a trend was found only in the abundance distribution of these species and site-to-site variability in growth rates of S. groenlandicus. M. calcarea density on silty sediments was almost twice as high as on sandy sediments, while Serripes biomass was almost 1.5 times higher on sandy sediments than on silty sediments. The slowest-growing Serripes were found at the deepest stations and in habitats with the largest content of fine fractions (silt) in sediments. Differences in the growth of S. groenlandicus could reflect variability of feeding conditions of this suspension-feeder (e.g., hydrodynamic conditions). Thus, the growth rate of S. groenlandicus was sensitive to environmental conditions, which means it can be used as an indicator of their changes. In general, S. groenlandicus in the Pechora Sea is very slow-growing compared to other areas (maximum life span and shell length are 28 years and 70 mm, respectively). Their growth rate was closest to that in Arctic-influenced locations. On the contrary, the maximum life span and shell length of M. calcarea in the Pechora Sea (15 years and 30 mm, respectively) were similar to those in other parts of the distribution area. No significant differences were found in the group growth of M. calcarea from different studied localities.

Effects of combinations of lamina grade and thickness, and span-to-depth ratios on bending properties of cross-laminated timber (CLT) floor

The aim of this study was to investigate effects of wood species, thickness and lamina combinations, and span-to-depth ratio (Rsd) on bending strength and stiffness of cross-laminated timber (CLT) floor element. CLTs with three different thickness (90 mm, 120 mm, and 150 mm) were manufactured using two species, larch and pine. Rsd was 12:1 for shear specimens and 24:1 for bending specimens. Four-point bending test was carried out in accordance with prEN 16351. The higher density species (larch) CLT showed higher load resistance with larger span length. The load resistances of larch CLT was 1.2 times higher than pine CLT. The maximum span length of larch CLT was 1.1 times longer than pine CLT. As the thickness of CLT was increased, load resistance and span length were also increased. When the thickness of CLT was increased from 90 mm to 150 mm, load resistances was increased by approximately 308% for larch and 310% for pine, and span length was increased by approximately 90% for larch and 89% for pine.

Universal Relationships in Hyperbranched Polymer Architecture for Batch and Continuous Step Growth Polymerization of AB2-Type Monomers

Design and control of hyperbranched (HB) polymer architecture by way of reactor operation is key to a successful production of higher-valued HB polymers, and it is essential in order to clarify the fundamental structural characteristics formed in representative types of reactors. In this article, the irreversible step growth polymerization of AB2 type monomer is investigated by a Monte Carlo simulation method, and the calculation was conducted for a batch and a continuous stirred-tank reactor (CSTR). In a CSTR, a highly branched core region consisting of units with large residence times is formed to give much more compact architecture, compared to batch polymerization. The universal relationships, unchanged by the conversion levels and/or the reactivity ratio, are found for the mean-square radius of gyration Rg2, and the maximum span length LMS. For batch polymerization, the g-ratio of Rg2 of the HB molecule to that for a linear molecule conforms to that for the random branched polymers represented by the Zimm-Stockmayer equation. A single linear equation represents the relationship between Rg2 and LMS, both for batch and CSTR. Appropriate process control in combination with the chemical control of the reactivity of the second B-group promises to produce tailor-made HB polymer architecture.

Feasibility study of a hybrid FRP-steel cable-stayed pedestrian swing bridge

The paper illustrates the feasibility study of a cable-stayed, pedestrian, swing bridge crossing the Navicelli Canal in Pisa, Italy. The static scheme of the bridge is asymmetric with one tower and three pairs of stays. The maximum span length is 21.26 m and the useful width is 2.50 m. According to the proposed design, the bridge deck will be made of glass fibre-reinforced polymer pultruded profiles; the tower and stays will be of ordinary steel; stainless steel bolts and plates will be used for the connections. A finite element model of the bridge was developed to analyse its structural behaviour during construction, service life, and maintenance operations. Construction stages – with particular attention to the cable stringing procedure – were carefully studied to help reduce the overall deformability of the bridge. Structural verifications were carried out according to the EuroComp Design Code, Italian CNR instructions, and German DIBt specifications. The calculated total weight of the bridge deck is about 11 t, including non-structural elements. Thanks to the low self-weight of the deck, a 3 kW electric motor will be sufficient for movement, with savings in both installation and operational costs with respect to a full steel bridge.

Detailed Structural Analysis of the Hyperbranched Polymers Formed in Self‐Condensing Vinyl Polymerization

AbstractMonte Carlo simulation is applied to investigate the effect of reactor types on the formed hyperbranched architecture. When a continuous stirred‐tank reactor (CSTR) is used for the synthesis, the number of units incorporated into the largest cluster of dendritic units inside the hyperbranched polymer increases with molecular weight, while it does not increase in batch polymerization. The largest dendritic cluster formed in a CSTR consists of the monomeric units whose average residence time is large, while the average residence time of the singly connected peripheral units is small. The maximum span length as well as the mean‐square radius of gyration of the high molecular weight polymer is much smaller for the polymers synthesized in a CSTR, compared with batch polymerization. A universal relationship between the mean‐square radius of gyration and the maximum span length is found, which is valid for both batch and CSTR.

Survival Analysis of Bridge Superstructures in Wisconsin

Although survival analyses have long been used in biomedical research, their application to engineering in general, and bridge engineering in particular, is a more recent phenomenon. In this research, survival (reliability) of bridge superstructures in Wisconsin was investigated using the Hypertabastic accelerated failure time model. The 2012 National Bridge Inventory (NBI) data for the State of Wisconsin were used for the analyses. A recorded NBI superstructure condition rating of 5 was chosen as the end of service life. The type of bridge superstructure, bridge age, maximum span length (MSL) and average daily traffic (ADT) were considered as possible risk factors in the survival of bridge superstructures. Results show that ADT and MSL can substantially affect the survival of bridge superstructures at various ages. The reliability of Wisconsin superstructures at the ages of 50 and 75 years is on the order of 63% and 18%, respectively, when the ADT and MSL values are at Wisconsin’s mean values.