Papers by Algirdas Juozapaitis
IABSE Congress Report, 2022
The article presents the methodology for designing an innovative pre-stressed cable-stayed steel ... more The article presents the methodology for designing an innovative pre-stressed cable-stayed steel bridge structural system using intersecting cables and string. The behavior of this new structural system under the effect of permanent and temporary loads is also taken into account. The article also discusses the design of the components of this new type of structure and presents the calculation methodology of this structural system taking into account geometrical nonlinearity. Installation sequence variants of such a bridge are also considered as well as the influence of string and cable pre-stressing on bridge displacement and component stresses. Equations for calculating bridge string stresses and displacements are presented. The article shows how to design this new steel bridge system which is more effective than the typical cable-stayed bridge structure according to the mass criterion.
The clay brick is one of the oldest building materials, and as the use of waste in the bricks can... more The clay brick is one of the oldest building materials, and as the use of waste in the bricks can reduce clay consummation and the environmental burden due to the accumulation of waste, the present study was chosen, the addition of mineral and organic waste to the clay brick. The added value of this work, which was carried out within the Institute of Building Materials at VGTU, is that the mixture studied is very special, because the raw materials used are: Yellow Clay (C) from Fez which is used only in the field of pottery; Pyrrhotite Ash (PA) which is a mineral waste produced during the manufacture of sulphuric acid from the roasting of pyrrhotite ore. This waste is stored in the open air since 1982 and until now it doesn't have any specific use; Cedar Sawdust (S) is an organic waste regenerate by the artisanal sector from Fez. The bricks' technological properties depended on the amount of ashes used. So, adding 5% S to the mixture (20% PA-80% C) gives rise to a new material that is light, porous with a natural brick red colour. Most importantly, this material exhibits mechanical strength according to the standards of a terracotta brick.
Transport, Jul 10, 2017
About 92% of Lithuanian bridges are made of reinforced concrete. Therefore, the problem of increa... more 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.
Journal of Civil Engineering and Management, Dec 31, 1996
Routledge eBooks, Jun 20, 2021
One of the main issues in the design of cable-stayed steel bridges is the way of stabilization of... more One of the main issues in the design of cable-stayed steel bridges is the way of stabilization of its initial form under symmetrical and asymmetrical loads. The main mass of the load-bearing structures is concentrated in the stiffening girder. The article presents a hybrid pre-stressed cable-stayed steel bridge structural system. The behavior of this new system of the intersecting stay cables and the flexible string under the effect of the permanent and the temporary loads are the issues under analysis. The efficiency of this proposed cablestayed steel bridge structure system was determined based of the performed numeric experiment.
Mathematical Problems in Engineering, 2017
The article is dedicated to the analysis of problems related to design of pedestrian bridges with... more The article is dedicated to the analysis of problems related to design of pedestrian bridges with flexible ribbon bands made of steel. The study is based on test results of a bridge model that has two spans (each with a length of five meters). A simplified analytical technique has been proposed for predicting vertical deformations of the bridge structure subjected to symmetrical or asymmetrical loading patterns. The technique also allows assessing the tension forces in the ribbons, which are very important for design of such structures. The analysis reveals the importance of the flexural rigidity of the ribbons that might cause significant redistribution of stresses within the steel bands.
Procedia Engineering, 2012
The article dwells on a new structural solution for pedestrian steel suspension bridges. This new... more The article dwells on a new structural solution for pedestrian steel suspension bridges. This new structural system of pedestrian stress-ribbon bridges includes suspension members with bending stiffness and a pre-stressed tie. The article looks into the behaviour of such suspension bridge under symmetrical and asymmetrical loads; it also presents analytical expressions for displacements, thrust forces and bending moments of such stiff suspension members. Then the article explains the effect of the cable's bending stiffness and the tie's axial stiffness on the bridge's stresses as well as the effect of the tie's pre-stressing on horizontal and vertical displacements of the bridge structure. The article then proceeds to comparative analysis, which considers the new structure and a traditional pedestrian suspension bridge. Numerical experiment determines the accuracy of the new engineering method developed for the analysis of stress-ribbon bridges. The efficiency of steel stress-ribbon bridge displacement stabilization through the bending stiffness is being discussed.
Civil-comp proceedings, Aug 6, 2015
Modelling of cable kinematic displacements is performed by FE, proposed by authors analytical and... more Modelling of cable kinematic displacements is performed by FE, proposed by authors analytical and engi-neering methods. The proposed analytical and FE methods results fit sufficiently well, when engineering methods yield significant errors.
Land Use Policy, 2015
ABSTRACT Early warning, neural networks, expert, decision support, fuzzy and other systems, barom... more ABSTRACT Early warning, neural networks, expert, decision support, fuzzy and other systems, barometers, housing and real estate bubble indexes have been developed in an effort to analyze and manage crises in housing market. Scholarly literature employs various concepts of housing market crises concepts, including overheated, heating-up, stable, stagnant market, freezing, healthy housing. There are numerous interest groups operating at the meso and macro levels of the housing market who would appreciate receiving recommendations during the various stages of a crisis in the housing market. Therefore, the Crisis Thermometer for housing market recommendations was developed applying the aforementioned intellectual systems and concepts along with the long-term backgrounds of these authors.
Procedia Economics and Finance, 2014
This article describes in detail the developed Biometric Advisory System to Analyze a User's Post... more This article describes in detail the developed Biometric Advisory System to Analyze a User's Post-Disaster Stress Management. The system is based on algorithms developed by the authors. The system was developed and fine-tuned in the course of the Android project. The authors based their Advisory System on the presumption that, by assigning a user post-disaster stress selfassessment and then looking for the interdependency with the user's biometric parameters (heart rate, blood pressure, pupil, skin conductance and humidity; body, forehead, nose, left and right cheek, chin, left palm and left middle finger temperatures, etc.) recorded at that time, it is possible to determine the link rather accurately. In other words, a user internally senses the actual rating of his/her personal post-disaster stress. Their existing experiences and intuition give users a rather accurate indication about their post-disaster stress. A sufficient number of studies have been performed worldwide and quite many systems have been developed that apply biometric technologies to establish different human states of stress. The global innovative aspects of the Biometric Advisory System, developed by the authors, are primarily that it determines the level and symptoms of the postdisaster stress, carrying out multivariant design of a disaster stress management life cycle (emergency response, recovery, prevention/mitigation and preparedness/readiness) and alternative recommendations applicable to a specific user (on ways to reduce post-disaster stress), performs a multiple criteria analysis of it and selects the ten most rational ones (disaster stress management life cycle and tips) for that user. The Impact of Event Scale-Revised (IES-R) is used as a self-assessment instrument to determine the symptoms of post-disaster stress stress and to draw up recommendations. Also, the users were assessed with the IES-R in order to define the significance of posttraumatic stress symptoms.
Increased deformability can be considered as the basic disadvantage of suspension bridges. One of... more Increased deformability can be considered as the basic disadvantage of suspension bridges. One of the ways to increase the rigidity of a suspension bridge is to transfer a part of stiffening girder rigidity to a suspension main cable. To give the suspension bridge more stable appearance, the authors propose to use the cables of varying bending stiffness. The main cables can be made of standard section shapes or have a composite section. The object of this work was to study a method for analyzing and determining the internal forces in the main cables and stiffening girder under static loading to provide recommendations for designing suspension bridges with stiffened cables. Simple formulas are presented for determining displacements, internal forces and stresses in the main cable and stiffening girder. Finite element modeling was performed. The final part of the paper discusses design procedures for such suspension systems. An example of a pedestrian suspension bridge is appended.Lie...
The article is dedicated to the analysis of problems related to design of pedestrian bridges with... more The article is dedicated to the analysis of problems related to design of pedestrian bridges with flexible ribbon bands made of steel. The study is based on test results of a bridge model that has two spans (each with a length of five meters). A simplified analytical technique has been proposed for predicting vertical deformations of the bridge structure subjected to symmetrical or asymmetrical loading patterns. The technique also allows assessing the tension forces in the ribbons, which are very important for design of such structures. The analysis reveals the importance of the flexural rigidity of the ribbons that might cause significant redistribution of stresses within the steel bands
Inverse Problems in Science and Engineering, 2016
Abstract One of the most difficult issues in the theory of reinforced concrete (RC) is an adequat... more Abstract One of the most difficult issues in the theory of reinforced concrete (RC) is an adequate modelling of deformation behaviour, cracking and, particularly, post-cracking behaviour, as one of the major sources of non-linearity. Applying the concept of average cracking and average strains, deformation behaviour of RC can be modelled by stress–strain tension–stiffening relationships. The authors proposed an innovative inverse technique for constitutive modelling of flexural RC elements. The technique is based on the smeared crack approach and layer model of RC section. The inverse technique aims at deriving tension–stiffening constitutive models from experimental moment–curvature diagrams. The present analysis takes into account the shrinkage effect that is often neglected in other studies. Based on the inverse technique, free-of-shrinkage tension–stiffening relationships are derived using test data of shrunk RC beams. Examples of the application for the analysis of the experimental data obtained by the authors are presented to illustrate the calculation efficiency of the proposed technique.
Procedia Engineering, 2015
When facing a strategic leadership problem, a decision maker must choose an appropriate reasoning... more When facing a strategic leadership problem, a decision maker must choose an appropriate reasoning strategy for a given situation. Complex strategic choices sets focus upon providing deliberate and methodical support for decisionmakers engaged in strategic decision making. The increasing interest in the subject of leadership reflects the considerable importance of this phenomenon. This study in short presents methods of strategic leadership selection in construction. There could to be separated five levels of a decision maker: novice, advanced beginner, competent, proficient and expert. Each of them acts in different way. While working in complex environments, the human decision makers can always face situations where time constraints, high stakes, multiple players, ill-structured problems and situations are presenting strategic decision making the information is used to make high-risk decisions. There exists wide range of methods, which could to be applied to the leadership strategy selection. Based on literature overview, a LEVI 3.0 program based strategy selection model is presented.
European Journal of Environmental and Civil Engineering, 2015
The conceptions of the time-dependent reliability analysis of non-deteriorating and deteriorating... more The conceptions of the time-dependent reliability analysis of non-deteriorating and deteriorating spun concrete bridge piers, which are effected by permanent and transient loads, are discussed. There are analysed the first- and the second-order load effects of bracing bridge piers. The strength features of resisting bending moments used in ultimate limit state and probability-based designs are presented. A simplified analysis of non-deteriorating and deteriorating bracing spun concrete piers in persistent situations in limit state and probabilistic approaches is provided. The prediction of probability-based reliability on shafts of non-deteriorating and deteriorating bracing bridge piers is illustrated by numerical example.
Journal of Constructional Steel Research, 2006
The paper deals with a new structural system of pedestrian steel bridge consisting of carrying su... more The paper deals with a new structural system of pedestrian steel bridge consisting of carrying suspension members made of stiff (in bending) rolled or welded sections and a flexible cylindrical deck. Structural behaviour of such a suspension member subjected to unsymmetrical live loading has been discussed on a basis of kinematic conditions. Ways of stabilization of kinematic displacements have been under consideration. Effects of bending stiffness and geometrical non-linearity of the suspension structure are taken into account. Analytical expressions for the analysis of the flexible cylindrical deck have been proposed. In an alternative concrete deck, a layered model has been applied for the stress and strain analysis.
КРАТКИЕ ВЫВОДЫ 1. Применение балочно-вантовой системы для усиления деревянных балок чердачного пе... more КРАТКИЕ ВЫВОДЫ 1. Применение балочно-вантовой системы для усиления деревянных балок чердачного перекрытия позволило при Минимальных затратах повысить их несущую способность более чем в четыре раза, что обеспечивает достаточную их надежность при снижении рабочего поперечного сечения по вы соте и ширине на 35^-40%. \ 2. Особо следует отмстить простоту монтажа элементов пространственного блока покрытия и функ циональную увязку Hecvimrx .конструкций стропильной системы с вписанной в нее балочновантовой системой усиления деревянных балок чердачного перекрытия. 3. Стоимость усиленного чердачного перекрытия снижена более чем на 45% в сравнении со стоимо стью замены новым конструктивным решением. 4. Конструктивная схема пространственного блока покрытия с балочно-вантовой системой усиления внедрена в проект капитального ремонта кровли цеха. Это позволило получить натурную модель для проведения; экспериментальных исследований. Результаты этих исследований будут использо ваны при разработке рекомендации по эффективному применению-балочно-вантовых систем для усиления несущих конструкций чердачных перекрытий. Строительные конструкций СПИСОК ИСПОЛЬЗОВАННОЙ ЛИТЕРАТУРЫ 1. Уласевич В.П. Деформационный расчет и исследование напряженно-деформированных однопоясных раейорных систем. Автореф. диссерт.-М.: ЦНИИСК им. Кучеренко, 1984. 2. Уласевич В.П., Костюк О.В. Деформационный расчет гибких балочно-вантовых систем состоянии пологих-24 с. л методом конечных элементов в среде MathCAD //Вестник БГТУ. № 1(25): Строительство и архитектура.-2004. С. 111-117.
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Papers by Algirdas Juozapaitis