Investigation of potential deformations developed by elements of transport and pedestrian traffic restricting gates during motor vehicle–gate interaction

The mathematical model of transport and pedestrian traffic restricting gate is designed. One section of the gate restricted the traffic of motor vehicles while the other limited the traffic of pedestrians. The gate was modelled based on the first‐order one‐dimensional finite elements taking into account only the resilience of the gate elements and the impact of soil on the ground‐embedded parts of the gate support and auxiliary posts. The potential deformations of gate elements were determined based on the mathematical model designed. The specific traffic event was investigated using the mathematical model of gate designed – four situations of motor vehicle–gate interaction were simulated and investigated. First Published Online: 27 Oct 201

Structural safety of rolled and welded beams subjected to lateral‐torsional buckling

The expediency of using probability‐based approaches in the analysis of beams subjected to lateral‐torsional buckling is discussed. The values of buckling resistance moments and their uncertainties for rolled and equivalent welded I sections as particular members of the designed structures are analyzed. The safety margins of buckling steel sections exposed to permanent and variable vertical loads are modeled. The survival probability and reliability index of sections exposed to lateral‐torsional buckling are considered. The prediction of probability‐based safety of rolled and welded beams in buildings and civil engineering works are provided and illustrated by numerical examples. Santrauka Aptariamas tikslingumas naudoti tikimybinius metodus skaičiuojant šoniniu sukimu klupdomas sijas. Analizuojamos val‐cuotuju ir suvirintuju I profiliuočiu, kaip ypačiuju elementu, klupdomuju atspariu momentu vertes ir ju neapibrežtys. Mo‐deliuojama nuolatine ir laikinaja vertikalia apkrova klupdomu plieniniu profiliuočiu ribine sauga. Nagrinejama šoniniu sukimu klupdomu profiliuočiu išlikties tikimybe ir patikimumo indeksas. Pateiktas ir skaitiniu pavyzdžiu iliustruotas pas‐tatu ir inžineriniu statiniu valcuotuju ir suvirintuju siju tikimybines saugos prognozavimas. First Published Online: 24 Jun 2011 Reikšminiai žodžiai: plieniniai profiliuočiai, klupdymas šoniniu sukimu, ribine sauga, išlikties tikimybe, suvirintosios sijo

Erratum on the article ‘A feasibility study of using composite reinforcement in transport and power industry structures’ (doi:10.3846/16484142.2017.1342689)

"Erratum on the article ‘A feasibility study of using composite reinforcement in transport and power industry structures’ (doi:10.3846/16484142.2017.1342689)." Transport, 32(4), p. 43

A feasibility study of using composite reinforcement in transport and power industry structures

About 92% of Lithuanian bridges are made of reinforced concrete. Therefore, the problem of increasing the reliability and service life of their structures is most important for ensuring effective operation of transport buildings. The main factor causing transport building structures’ failure is associated with high water permeability and low resistance to attack by corrosive media of concrete used in construction. Ports, bridges, tunnels, viaducts make a group of transport structures strongly attacked by the aggressive media, e.g. cold air, water, ice, salts, etc. Though the members of these structures (e.g. columns, beams) are usually designed for 50 years of service, they often require a major overhaul or strengthening, when less than the half of this period has passed. Most of the damaged structures are the destroyed protective concrete layer and the corroded steel reinforcement. The corrosion of steel reinforcement is the main problem, causing the decrease of strength in the structures’ and their brittle failure. Now, composite reinforcement is the alternative material used for reinforcing in the considered structures. Its mechanical properties, including the tensile strength and resistance to the attack of aggressive media, are similar to or even better than those of commonly used steel reinforcement. The experimental data on using composite reinforcement in the compression members or in the compressed zones of flexural members of the structures are lacking. Therefore, most of design codes do not mention or even do not recommend using composite reinforcement in these cases. The paper presents the analysis of the possibilities of using composite reinforcement in transport and power industry structures

The application of a compound model for predicting reliability indices of engineering systems

The article considers sophisticated formats of the multivariate integration of time-dependent technical reliability prediction for ductile series and parallel engineering systems as a structure embracing stochastically dependent components. The paper recommends the rational avoidance of complicated multidimensional integrals and the separation of dynamic (time-dependent) probabilistic models of auto-systems from the static models of general engineering systems. For assessing survival probabilities of auto-systems affected by random demands n and general systems comprised of correlated auto-systems m, the concept of the method for transformed conditional probabilities (TCP) and conventional correlation vectors (CCV) have been used. The article also discusses target reliability indices of engineering systems. The analysis of reliability indices to series and parallel engineering systems is demonstrated applying the numerical examples

Analysis of the Time-Dependent Reliability Index for Deteriorating Load-Carrying Members

AbstractThe probability-based prediction and analysis of time-dependent survival probabilities and reliability indexes of non-deteriorating and deteriorating structural members exposed to extreme gravity and climate action effects are presented. A degradation function of reinforced concrete members under corrosion actions and sulphate attacks is discussed. The time-dependent safety margin of particular members as a random finite sequence of auto structural members is analyzed. Their time-dependent survival probability and reliability index values are expressed in simplified analytical manner. The merit of the method of transformed conditional probabilities based on more accurate conventional correlation factors is demonstrated by numerical examples

Reinforced Spun Concrete Poles—Case Study of Using Chemical Admixtures

The current research paper is focused on the experimental investigation of features of chemical admixtures (superplasticizers C-3, ‘Dofen’ and formaldehyde resin ACF-3M) utilizing in reinforced spun concrete structures. For the sake of comparison, the results of studying the effects of chemical admixtures on physical and mechanical properties on vibrated and spun concrete are provided. As a separate part of spun concrete products, the supporting poles of overhead power lines are introduced. The results obtained indicate, that the positive effect of chemical admixtures for spun and vibrated concrete is most pronounced at an early age of concrete. The effective amount of chemical admixtures for spun concrete is 0.15% of cement mass when formaldehyde resin ACF-3M and 1% of cement mass when superplasticizers C-3 and ‘Dofen’ are used. Moreover, the brief review about the reinforced spun concrete members is provided

The Reinforced Spun Concrete Poles under Physical Salt Attack and Temperature: A Case Study of the Effectiveness of Chemical Admixtures

The present paper focused on the investigation of the effectiveness of using various chemical admixtures and their effect on the strength and deformability of the reinforced spun concrete members—the supporting poles of the overhead power transmission lines—under the unfavorable long-term combined action of the aggressive salt-saturated groundwater and the temperature changes. According to the long-term experimental program, 96 prismatic spun concrete specimens were subjected to multi-cycle (25-50-75 cycles) processing under the combined aggressive environmental conditions. It has been found that chemical admixtures which decrease the initial water-cement ratio produce a considerable positive effect on the mechanical properties of spun concrete used in hot and arid climates and exposed to physical salt attack (PSA). Superplasticizers decrease the initial water-cement ratio the most, and, due to a unique concrete compaction method used, they produce the most homogeneous and dense concrete structure. They can be recommended as most effective in increasing the durability of spun concrete used under the above-mentioned aggressive environmental conditions.Kliukas, R.; Jaras, A.; Lukoševičienė, O. The Reinforced Spun Concrete Poles under Physical Salt Attack and Temperature: A Case Study of the Effectiveness of Chemical Admixtures. Materials 2020, 13, 5111

The Impact of Long-Term Physical Salt Attack and Multicycle Temperature Gradient on the Mechanical Properties of Spun Concrete

The article is focused on spun concrete made with different chemical admixtures under long-term exposure to aggressive salt-saturated ground water and a cyclic temperature gradient. Over a long-term experimental investigation, 64 prismatic spun concrete specimens were subjected to multicycle (75–120) processing under combined aggressive ambient conditions. Prismatic specimens were soaked in water or saline and dried at a temperature of 45–50 °C. The long-term multi-cycle effect of the temperature gradient and physical salt attack on the compressive strength, Young’s modulus and durability of concrete was found to be negative. Chemical admixtures, though, improved the structure of spun concrete, thus having a significant positive effect on its physical-mechanical properties and durability