This paper aims at pointing out some misconceptions concerning the evaluation of the walking-induced dynamic response of footbridges, and their impact on design procedures. First, a review of the existing Code provisions is briefly presented. In particular single-walker models and multiple-walker models are addressed; in doing so, models originally presented in different forms are made homogeneous for the purpose of comparison; their limits of applicability and advantages are pointed out. Then, the response of six steel box girder footbridges with different spans is evaluated following the provisions of existing Standards and Guidelines, and compared with allowable comfort levels. The comparison showed a wide scatter of the results, revealing some inconsistencies of the procedures, and underlining a clear need for their critical revision.
{"title":"Design Procedures for Footbridges Subjected to Walking Loads: Comparison and Remarks","authors":"A. M. Avossa, C. Demartino, F. Ricciardelli","doi":"10.3846/BJRBE.2017.12","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.12","url":null,"abstract":"This paper aims at pointing out some misconceptions concerning the evaluation of the walking-induced dynamic response of footbridges, and their impact on design procedures. First, a review of the existing Code provisions is briefly presented. In particular single-walker models and multiple-walker models are addressed; in doing so, models originally presented in different forms are made homogeneous for the purpose of comparison; their limits of applicability and advantages are pointed out. Then, the response of six steel box girder footbridges with different spans is evaluated following the provisions of existing Standards and Guidelines, and compared with allowable comfort levels. The comparison showed a wide scatter of the results, revealing some inconsistencies of the procedures, and underlining a clear need for their critical revision.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"94-105"},"PeriodicalIF":1.1,"publicationDate":"2017-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44115134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The tests and analyses presented in the paper are related to the 20/30, 35/50 and 50/70 penetration grade road bitumens as well as the asphalt binders obtained through modification of the 35/50 and 50/70 bitumens. The latter were modified by adding to it 3%, 5% and 7% of the Gilsonite natural asphalt and 15%, 25% and 35% of the Trinidad Epure Z 0/8 natural asphalt. The aim of the study was to assess the changes in the functional and rheological properties of the road bitumens that were modified by adding to them the Gilsonite and Trinidad Epure natural asphalts. The modified asphalt binders were subjected to the laboratory simulated short-term and long-term aging, where two methods, designed as part of the Strategic Highway Research Program, were used, i.e. the Rolling Thin Film Oven Test and the Pressure Aging Vessel, respectively. The study of the asphalt binders both those that were subjected to aging and those unaged includes thermal susceptibility (the Penetration Index) and resistance to cracking at low temperatures by tests carried out using the Bending Beam Rheometer. The analysis of the results revealed that the unfavourable impact of the aging process on the asphalt binder properties is limited if a suitable amount of the natural asphalt is used as a modifier.
本文对20/30、35/50和50/70渗透级路用沥青以及对35/50和50/50沥青进行改性得到的沥青结合料进行了试验和分析。后者通过添加3%、5%和7%的Gilsonite天然沥青和15%、25%和35%的Trinida-Epure Z 0/8天然沥青进行改性。本研究的目的是评估通过添加Gilsonite和Trinida-Epure天然沥青进行改性的道路沥青的功能和流变特性的变化。对改性沥青结合料进行了实验室模拟的短期和长期老化，其中使用了两种方法，即滚动薄膜烘箱试验和压力老化容器，这两种方法是作为战略公路研究计划的一部分设计的。通过使用弯曲梁流变仪进行的测试，对经过老化和未老化的沥青结合料的研究包括热敏感性（渗透指数）和低温下的抗裂性。结果分析表明，如果使用适量的天然沥青作为改性剂，老化过程对沥青结合料性能的不利影响是有限的。
{"title":"An Experimental Study of the Impact of Aging on Gilsonite and Trinidad Epuré Modified Asphalt Binders Properties","authors":"M. Słowik, Marcin Bilski","doi":"10.3846/BJRBE.2017.09","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.09","url":null,"abstract":"The tests and analyses presented in the paper are related to the 20/30, 35/50 and 50/70 penetration grade road bitumens as well as the asphalt binders obtained through modification of the 35/50 and 50/70 bitumens. The latter were modified by adding to it 3%, 5% and 7% of the Gilsonite natural asphalt and 15%, 25% and 35% of the Trinidad Epure Z 0/8 natural asphalt. The aim of the study was to assess the changes in the functional and rheological properties of the road bitumens that were modified by adding to them the Gilsonite and Trinidad Epure natural asphalts. The modified asphalt binders were subjected to the laboratory simulated short-term and long-term aging, where two methods, designed as part of the Strategic Highway Research Program, were used, i.e. the Rolling Thin Film Oven Test and the Pressure Aging Vessel, respectively. The study of the asphalt binders both those that were subjected to aging and those unaged includes thermal susceptibility (the Penetration Index) and resistance to cracking at low temperatures by tests carried out using the Bending Beam Rheometer. The analysis of the results revealed that the unfavourable impact of the aging process on the asphalt binder properties is limited if a suitable amount of the natural asphalt is used as a modifier.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"71-81"},"PeriodicalIF":1.1,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44363268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. A. Biancardo, F. Russo, D. Žilionienė, Weibin Zhang
The study focused on grade-level rural two-lane two-way three-leg and two-lane two-way four-leg stop-controlled intersections located in the flat area with a vertical grade of less than 5%. The goal is to calibrate one Safety Performance Function at these intersections by implementing a Generalized Estimating Equation with a binomial distribution and compare to the results with yearly expected crash frequencies by using models mainly refered to the scientific literature. The crash data involved 77 two-lane two-way intersections, of which 25 two-lane two-way three-leg intersections are without a left-turn lane (47 with left-turn lane), 5 two-lane two-way four-leg intersections without a left-turn lane (6 with a left-turn lane). No a right-turn lane is present on the major roads. Explanatory variables used in the Safety Performance Function are the presence or absence of a left-turn lane, mean lane width including approach lane and a left-turn lane width on the major road per travel direction, the number of legs, and the Total Annual Average Daily Traffic entering the intersection. The reliability of the Safety Performance Function was assessed using residuals analysis. A graphic outcome of the Safety Performance Function application has been plotted to easily assess a yearly expected crash frequency by varying the Average Annual Daily Traffic, the number of legs, and the presence or absence of a left-turn lane. The presence of a left-turn lane significantly reduces the yearly expected crash frequency values at intersections.
{"title":"Rural Two-Lane Two-Way Three-Leg and Four-Leg Stop-Controlled Intersections: Predicting Road Safety Effects","authors":"S. A. Biancardo, F. Russo, D. Žilionienė, Weibin Zhang","doi":"10.3846/BJRBE.2017.14","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.14","url":null,"abstract":"The study focused on grade-level rural two-lane two-way three-leg and two-lane two-way four-leg stop-controlled intersections located in the flat area with a vertical grade of less than 5%. The goal is to calibrate one Safety Performance Function at these intersections by implementing a Generalized Estimating Equation with a binomial distribution and compare to the results with yearly expected crash frequencies by using models mainly refered to the scientific literature. The crash data involved 77 two-lane two-way intersections, of which 25 two-lane two-way three-leg intersections are without a left-turn lane (47 with left-turn lane), 5 two-lane two-way four-leg intersections without a left-turn lane (6 with a left-turn lane). No a right-turn lane is present on the major roads. Explanatory variables used in the Safety Performance Function are the presence or absence of a left-turn lane, mean lane width including approach lane and a left-turn lane width on the major road per travel direction, the number of legs, and the Total Annual Average Daily Traffic entering the intersection. The reliability of the Safety Performance Function was assessed using residuals analysis. A graphic outcome of the Safety Performance Function application has been plotted to easily assess a yearly expected crash frequency by varying the Average Annual Daily Traffic, the number of legs, and the presence or absence of a left-turn lane. The presence of a left-turn lane significantly reduces the yearly expected crash frequency values at intersections.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"117-126"},"PeriodicalIF":1.1,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44481210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the analysis of cracking due to tensile stress in a reinforced concrete pipe is presented. The tensile strength of concrete in case of the member of a high relative curvature is significantly different from the strength of uncurved elements. The current state of research indicates that only methods of nonlinear fracture mechanics lead to a satisfactory agreement between the results of calculations and experimental studies, and allow for compiling correctly the influence of basic parameters of stretched concrete and geometrical dimensions on the load capacity of crush pipes made from concrete. Obtaining consistent results of experimental and numerical research is still a very complicated issue. This paper presents the results of the experimental investigation performed on three pipes and the numerical model of the analysed element of the pipes made using the ATENA (Advanced Tool for Engineering Nonlinear Analysis) program. The numerical analyses of cracks were compared with the results of experimental studies.
{"title":"Cracks Analysis in the Reinforced Concrete Pipes","authors":"L. Buda‐Ożóg, I. Skrzypczak, J. Kujda","doi":"10.3846/BJRBE.2017.11","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.11","url":null,"abstract":"In this paper, the analysis of cracking due to tensile stress in a reinforced concrete pipe is presented. The tensile strength of concrete in case of the member of a high relative curvature is significantly different from the strength of uncurved elements. The current state of research indicates that only methods of nonlinear fracture mechanics lead to a satisfactory agreement between the results of calculations and experimental studies, and allow for compiling correctly the influence of basic parameters of stretched concrete and geometrical dimensions on the load capacity of crush pipes made from concrete. Obtaining consistent results of experimental and numerical research is still a very complicated issue. This paper presents the results of the experimental investigation performed on three pipes and the numerical model of the analysed element of the pipes made using the ATENA (Advanced Tool for Engineering Nonlinear Analysis) program. The numerical analyses of cracks were compared with the results of experimental studies.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"88-93"},"PeriodicalIF":1.1,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46822198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Meškėnas, V. Gribniak, G. Kaklauskas, A. Sokolov, E. Gudonis, Arvydas Rimkus
Concrete is the most widely used material for bridge structures in Lithuania. A case study performed by the authors revealed that application of fibres might improve serviceability of such structures. However, adequacy of prediction of the post-cracking behaviour of steel fibre reinforced concrete might be insufficient. The latter issue is closely related to the assessment of the residual strength of steel fibre reinforced concrete. The residual strength, in most cases, is considered as a material property of the cracked concrete. However, in the prediction of the structural behaviour of the concrete members with bar reinforcement, a straightforward application of the residual strength values assessed by using standard techniques might lead to incorrect results. The present study deals with the post-cracking behaviour of structural elements made of concrete with aggregates and fibres provided by Lithuanian companies. Test results of three full-scale and sixteen standard steel fibre reinforced concrete beams with two different content of fibres (23.6 kg/m3 and 47.1 kg/m3) are presented. The full-scale beams were reinforced with high-grade steel bars. Effectiveness of the application of the mini- mum content of the fibres in combination with bar reinforcement was revealed experimentally.
{"title":"Experimental Investigation of Cracking Behaviour of Concrete Beams Reinforced with Steel Fibres Produced in Lithuania","authors":"A. Meškėnas, V. Gribniak, G. Kaklauskas, A. Sokolov, E. Gudonis, Arvydas Rimkus","doi":"10.3846/BJRBE.2017.10","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.10","url":null,"abstract":"Concrete is the most widely used material for bridge structures in Lithuania. A case study performed by the authors revealed that application of fibres might improve serviceability of such structures. However, adequacy of prediction of the post-cracking behaviour of steel fibre reinforced concrete might be insufficient. The latter issue is closely related to the assessment of the residual strength of steel fibre reinforced concrete. The residual strength, in most cases, is considered as a material property of the cracked concrete. However, in the prediction of the structural behaviour of the concrete members with bar reinforcement, a straightforward application of the residual strength values assessed by using standard techniques might lead to incorrect results. The present study deals with the post-cracking behaviour of structural elements made of concrete with aggregates and fibres provided by Lithuanian companies. Test results of three full-scale and sixteen standard steel fibre reinforced concrete beams with two different content of fibres (23.6 kg/m3 and 47.1 kg/m3) are presented. The full-scale beams were reinforced with high-grade steel bars. Effectiveness of the application of the mini- mum content of the fibres in combination with bar reinforcement was revealed experimentally.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"82-87"},"PeriodicalIF":1.1,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43830725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Choudhary, Dibya S. Chattopadhyay, Abhinay Kumar, Ashok Julaganti
For a fast developing economy like India, expansion, rehabilitation, and maintenance of transportation infrastructure is crucial and require huge quantities of high quality natural aggregates. Meanwhile, vast amounts of industrial wastes accumulating in the country pose problems related to safe and sustainable disposal. The present study investigated possible utilisation of marble dust, a waste from stone industry, and fly ash, a waste from thermal power stations, as filler materials in open-graded friction course mixes. Open-graded friction course mixes incorporating fly ash, marble dust, and two sources of stone dust as filler fractions were designed and evaluated for mix design properties including draindown, abrasion loss, air void content, and permeability. Morphology of each filler was characterised through scanning electron microscopy. Physicochemical properties of fillers were examined through Rigden voids, German filler test, methylene blue, and hydrometer analysis. Analysis of variance using Fisher multiple comparison procedure was performed to evaluate the effect of filler type on design properties of open-graded friction course mixes. Regression analysis using forward selection technique was performed to identify significant filler characteristics influencing open-graded friction course properties. Results showed that filler type affected open-graded friction course design parameters significantly. Open-graded friction course mixes with marble dust showed promising performance with lowest draindown, and highest durability, air voids, and permeability. Regression analysis identified Rigden void content of filler materials as a major filler characteristic affecting the mix design parameters of open-graded friction course mixes.
{"title":"Use of Industrial Wastes as Filler in Open-Graded Friction Courses","authors":"R. Choudhary, Dibya S. Chattopadhyay, Abhinay Kumar, Ashok Julaganti","doi":"10.3846/BJRBE.2017.13","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.13","url":null,"abstract":"For a fast developing economy like India, expansion, rehabilitation, and maintenance of transportation infrastructure is crucial and require huge quantities of high quality natural aggregates. Meanwhile, vast amounts of industrial wastes accumulating in the country pose problems related to safe and sustainable disposal. The present study investigated possible utilisation of marble dust, a waste from stone industry, and fly ash, a waste from thermal power stations, as filler materials in open-graded friction course mixes. Open-graded friction course mixes incorporating fly ash, marble dust, and two sources of stone dust as filler fractions were designed and evaluated for mix design properties including draindown, abrasion loss, air void content, and permeability. Morphology of each filler was characterised through scanning electron microscopy. Physicochemical properties of fillers were examined through Rigden voids, German filler test, methylene blue, and hydrometer analysis. Analysis of variance using Fisher multiple comparison procedure was performed to evaluate the effect of filler type on design properties of open-graded friction course mixes. Regression analysis using forward selection technique was performed to identify significant filler characteristics influencing open-graded friction course properties. Results showed that filler type affected open-graded friction course design parameters significantly. Open-graded friction course mixes with marble dust showed promising performance with lowest draindown, and highest durability, air voids, and permeability. Regression analysis identified Rigden void content of filler materials as a major filler characteristic affecting the mix design parameters of open-graded friction course mixes.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"106-116"},"PeriodicalIF":1.1,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48849706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Gražulytė, A. Vaitkus, Vitalijus Andrejevas, Gediminas Gribulis
In cold regions and areas where there is a huge difference between high and low temperatures asphalt pavements are subject to low temperature cracking. The appeared cracks form pavement discontinuities, through which water penetrates into pavement structure. It reduces the bearing capacity of the whole pavement structure, weakens adhesion between bitumen and aggregate, affects bonding between layers and increases the development of frost heaves. A sealing of cracks deals with these issues. However, additional inspections after each winter have to be carried out to identify both cracks that have newly appeared and cracks that need to be resealed. These activities significantly increase road maintenance cost. Selection of the appropriate asphalt mixture by its performance at low temperatures reduces or even prevents low temperature cracking of asphalt pavements. A number of methods such as the Indirect Tensile Test, the Bending Beam Rheometer Test, the Thermal Stress Restrained Specimen Test, Asphalt Thermal Cracking Analyser, the Single-Edge-Notched Beam Test, the Disc-Shaped Compact Tension Test, the Semi-Circular Bend Test, the Fenix Test, Asphalt Concrete Cracking Device and Spectral Analysis of Acoustic Emission are developed to evaluate asphalt mixture resistance to low temperature cracking. This paper presents an analysis of these tests, emphasizes their advantages and disadvantages and gives limiting criteria to evaluate asphalt mixture resistance to low temperature cracking. The test advantages and disadvantages are deciding factors in a test selection. Some tests such as the Thermal Stress Restrained Specimen Test and Spectral Analysis of acoustic emission can directly reveal the lowest temperature at which asphalt mixture can withstand induced thermal stresses.
{"title":"Methods and Criteria for Evaluation of Asphalt Mixture Resistance to Low Temperature Cracking","authors":"J. Gražulytė, A. Vaitkus, Vitalijus Andrejevas, Gediminas Gribulis","doi":"10.3846/BJRBE.2017.16","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.16","url":null,"abstract":"In cold regions and areas where there is a huge difference between high and low temperatures asphalt pavements are subject to low temperature cracking. The appeared cracks form pavement discontinuities, through which water penetrates into pavement structure. It reduces the bearing capacity of the whole pavement structure, weakens adhesion between bitumen and aggregate, affects bonding between layers and increases the development of frost heaves. A sealing of cracks deals with these issues. However, additional inspections after each winter have to be carried out to identify both cracks that have newly appeared and cracks that need to be resealed. These activities significantly increase road maintenance cost. Selection of the appropriate asphalt mixture by its performance at low temperatures reduces or even prevents low temperature cracking of asphalt pavements. A number of methods such as the Indirect Tensile Test, the Bending Beam Rheometer Test, the Thermal Stress Restrained Specimen Test, Asphalt Thermal Cracking Analyser, the Single-Edge-Notched Beam Test, the Disc-Shaped Compact Tension Test, the Semi-Circular Bend Test, the Fenix Test, Asphalt Concrete Cracking Device and Spectral Analysis of Acoustic Emission are developed to evaluate asphalt mixture resistance to low temperature cracking. This paper presents an analysis of these tests, emphasizes their advantages and disadvantages and gives limiting criteria to evaluate asphalt mixture resistance to low temperature cracking. The test advantages and disadvantages are deciding factors in a test selection. Some tests such as the Thermal Stress Restrained Specimen Test and Spectral Analysis of acoustic emission can directly reveal the lowest temperature at which asphalt mixture can withstand induced thermal stresses.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"135-144"},"PeriodicalIF":1.1,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47180688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The limited funding for the road industry leads to economizing in the planning of road network maintenance, to identifying the appropriate priorities of the activities with the greatest benefit for the society. The level of maintenance is the direct assessment of the road operation and maintenance service provided to the road users; it directly affects the road maintenance and for road users costs the better is road maintenance, the road users incur the fewer expenses and vice versa. Insufficient road maintenance in the winter time causes not only the danger of traffic accidents but also worsens the driving conditions, increases the fuel consumption, vehicle depreciation, transportation becomes more expensive. Many results of studies showed that the current choice of maintenance levels in the winter time taking into account only the road category and traffic volume does not ensure the indicators of the most advanced world countries and road functional purpose. The principle of the minimal expenses for the society should be the main criterion in identifying the optimal levels of winter road maintenance. The experience of Lithuania and foreign countries helped in creating the model of assessment of winter maintenance levels for Lithuanian roads of national significance, which can be applied in the other foreign countries as well. This model could be an effective tool for the selection of the optimal maintenance levels, which would economically substantiate the winter road maintenance strategy, that best corresponds to the needs of the society.
{"title":"Assessment Model of Levels for Winter Road Maintenance","authors":"Tomas Ratkevičius, Alfredas Laurinavičius","doi":"10.3846/BJRBE.2017.15","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.15","url":null,"abstract":"The limited funding for the road industry leads to economizing in the planning of road network maintenance, to identifying the appropriate priorities of the activities with the greatest benefit for the society. The level of maintenance is the direct assessment of the road operation and maintenance service provided to the road users; it directly affects the road maintenance and for road users costs the better is road maintenance, the road users incur the fewer expenses and vice versa. Insufficient road maintenance in the winter time causes not only the danger of traffic accidents but also worsens the driving conditions, increases the fuel consumption, vehicle depreciation, transportation becomes more expensive. Many results of studies showed that the current choice of maintenance levels in the winter time taking into account only the road category and traffic volume does not ensure the indicators of the most advanced world countries and road functional purpose. The principle of the minimal expenses for the society should be the main criterion in identifying the optimal levels of winter road maintenance. The experience of Lithuania and foreign countries helped in creating the model of assessment of winter maintenance levels for Lithuanian roads of national significance, which can be applied in the other foreign countries as well. This model could be an effective tool for the selection of the optimal maintenance levels, which would economically substantiate the winter road maintenance strategy, that best corresponds to the needs of the society.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"127-134"},"PeriodicalIF":1.1,"publicationDate":"2017-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41531519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The subject of the article is a three-dimensional numerical analysis of the impact of backfill quality on the deformation of corrugated steel plate culvert. In the numerical analysis, the author took into consideration three different backfill types. The paper presents the calculations performed with the use of Abaqus program based on finite element method. A steel shell was modelled with the use of the theory of orthotropic plates, and backfill with the use of elastic perfectly plastic Drucker-Prager model. The author made the numerical calculations under static live loads for the corrugated steel plate culvert with a span of 12.315 m and height of shell of 3.555 m. Soil cover over the shell crown was equal to 1.0 m. The steel shell consisted of the sheets of the corrugation of 0.14×0.38 m and plate thickness of 0.0071 m. The main aim of this paper is to present the impact of backfill quality (internal friction angle, unit weight, Young’s modulus) on the effort of the steel shell. The paper also shows the numerical calculations for the actual culvert, which previously had been studied experimentally. The author compared the obtained numerical results to the results of experiments. Parametric analysis showed that the angle of internal friction was a major factor in corrugated steel plate culverts. Considering the entire width of the corrugated steel plate culvert, the calculation model II was most favourable. The proposed method of modelling of the corrugated steel plate culvert allowed obtaining reasonable values of displacements and stresses in comparison to experimental results.
{"title":"The Role of Backfill Quality on Corrugated Steel Plate Culvert Behaviour","authors":"D. Beben","doi":"10.3846/BJRBE.2017.01","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.01","url":null,"abstract":"The subject of the article is a three-dimensional numerical analysis of the impact of backfill quality on the deformation of corrugated steel plate culvert. In the numerical analysis, the author took into consideration three different backfill types. The paper presents the calculations performed with the use of Abaqus program based on finite element method. A steel shell was modelled with the use of the theory of orthotropic plates, and backfill with the use of elastic perfectly plastic Drucker-Prager model. The author made the numerical calculations under static live loads for the corrugated steel plate culvert with a span of 12.315 m and height of shell of 3.555 m. Soil cover over the shell crown was equal to 1.0 m. The steel shell consisted of the sheets of the corrugation of 0.14×0.38 m and plate thickness of 0.0071 m. The main aim of this paper is to present the impact of backfill quality (internal friction angle, unit weight, Young’s modulus) on the effort of the steel shell. The paper also shows the numerical calculations for the actual culvert, which previously had been studied experimentally. The author compared the obtained numerical results to the results of experiments. Parametric analysis showed that the angle of internal friction was a major factor in corrugated steel plate culverts. Considering the entire width of the corrugated steel plate culvert, the calculation model II was most favourable. The proposed method of modelling of the corrugated steel plate culvert allowed obtaining reasonable values of displacements and stresses in comparison to experimental results.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"1-11"},"PeriodicalIF":1.1,"publicationDate":"2017-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43157238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cement-stabilized macadam is the most widely used road base material in road engineering. The current study investigated the impact of fiber diameter on its performance. The authors prepared polyester fibers with diameters of 20, 35, 70, and 105 μm and added them to cement-stabilized macadam. Then, the indoor shrinkage tests and mechanical property tests at different ages were conducted. Then, the property changes of the polyester-reinforced cement-stabilized macadam were analysed. The water loss rate of the polyester-reinforced cement-stabilized macadam is subject to the combined influence of the “water loss surface effect” and “water loss porthole effect.”With increasing fiber diameter, the water loss surface effect becomes stronger, and the water loss porthole effect gradually decreases; thus, the overall effect transitions from the latter to the former. Moreover, the water loss rate shows an increasing trend of decreasing to its minimum. Therefore, with increasing fiber diameter, the average dry shrinkage coefficient of the polyester-reinforced cement-stabilized macadam first increases and then decreases, while the temperature shrinkage coefficients increase. The change in the fiber diameter does not significantly affect the compressive resilient modulus of the polyester-reinforced cement-stabilized macadam if the fiber content remains constant. These findings demonstrate the functional mechanism of the fiber diameter on the road performance of cement-stabilized macadam, thus improving our understanding of the road performance of the polyester-reinforced cement-stabilized macadam and laying a solid theoretical foundation for its many applications.
{"title":"Impact of Fiber Diameter On-Road Performance of Cement-Stabilized Macadam","authors":"L. Zhijun, Dongquan Wang, Wei Xiaobi, L. Wang","doi":"10.3846/BJRBE.2017.02","DOIUrl":"https://doi.org/10.3846/BJRBE.2017.02","url":null,"abstract":"Cement-stabilized macadam is the most widely used road base material in road engineering. The current study investigated the impact of fiber diameter on its performance. The authors prepared polyester fibers with diameters of 20, 35, 70, and 105 μm and added them to cement-stabilized macadam. Then, the indoor shrinkage tests and mechanical property tests at different ages were conducted. Then, the property changes of the polyester-reinforced cement-stabilized macadam were analysed. The water loss rate of the polyester-reinforced cement-stabilized macadam is subject to the combined influence of the “water loss surface effect” and “water loss porthole effect.”With increasing fiber diameter, the water loss surface effect becomes stronger, and the water loss porthole effect gradually decreases; thus, the overall effect transitions from the latter to the former. Moreover, the water loss rate shows an increasing trend of decreasing to its minimum. Therefore, with increasing fiber diameter, the average dry shrinkage coefficient of the polyester-reinforced cement-stabilized macadam first increases and then decreases, while the temperature shrinkage coefficients increase. The change in the fiber diameter does not significantly affect the compressive resilient modulus of the polyester-reinforced cement-stabilized macadam if the fiber content remains constant. These findings demonstrate the functional mechanism of the fiber diameter on the road performance of cement-stabilized macadam, thus improving our understanding of the road performance of the polyester-reinforced cement-stabilized macadam and laying a solid theoretical foundation for its many applications.","PeriodicalId":55402,"journal":{"name":"Baltic Journal of Road and Bridge Engineering","volume":"12 1","pages":"12-20"},"PeriodicalIF":1.1,"publicationDate":"2017-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43420155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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