Abstract This paper examines the need for a Public Procurement Maturity Model (PPMM) in organizations with the role of road infrastructure buyers under public procurement legislation in a monopsony market structure. The environment used to contextualize the information is Romania and CNADNR (Compania Națională de Autostrăzi și Drumuri Naționale din România). The literature research, open data as well as my own practical experience are used as entry data for the four parts of the paper: (i) the context leading to the PPMM need identification, (ii) an overview of the existing public (procurement) maturity models; (iii) discussions and (iv) summary, limitations, and outlook. The paper provides arguments of an upstream intervention in the value chain of road transport infrastructure and highlights the benefits of such an intervention. Elements such as Romanian cultural dimensions, type of market structure or impact of the outcomes of public procurement process for road infrastructure are considered relevant entry data for an intervention which aims to contribute to the improvement of performance at a procurement process level. The results of this paper serve as a starting point for further reflection on the performance in road infrastructure public procurement area in Romania. In addition to the awareness of the need for an intervention at a contracting authority level, the paper arguments that market structure or national cultural dimensions must be considered as entry data in designing maturity models.
摘要本文研究了在垄断市场结构下，公共采购立法下的道路基础设施购买者组织对公共采购成熟度模型(PPMM)的需求。用于将信息上下文化的环境是罗马尼亚和CNADNR (Compania Națională de autostr zi și Drumuri Naționale din rom nia)。文献研究、开放数据以及我自己的实践经验被用作论文四个部分的入口数据:(i)导致PPMM需求识别的背景，(ii)现有公共(采购)成熟度模型的概述;(iii)讨论;(iv)总结、限制和展望。本文提供了在道路运输基础设施价值链上游干预的论据，并强调了这种干预的好处。罗马尼亚文化层面、市场结构类型或道路基础设施公共采购过程结果的影响等因素被视为旨在促进采购过程一级绩效改善的干预措施的相关进入数据。本文的研究结果可作为进一步反思罗马尼亚道路基础设施公共采购绩效的起点。除了意识到需要在合约当局层面进行干预外，本文还认为，在设计成熟度模型时，市场结构或国家文化维度必须被视为入门数据。
{"title":"Examining the need for a public procurement maturity model (PPMM) for infrastructure buyers in a monopsony market structure","authors":"V. Simionescu","doi":"10.1515/rjti-2016-0039","DOIUrl":"https://doi.org/10.1515/rjti-2016-0039","url":null,"abstract":"Abstract This paper examines the need for a Public Procurement Maturity Model (PPMM) in organizations with the role of road infrastructure buyers under public procurement legislation in a monopsony market structure. The environment used to contextualize the information is Romania and CNADNR (Compania Națională de Autostrăzi și Drumuri Naționale din România). The literature research, open data as well as my own practical experience are used as entry data for the four parts of the paper: (i) the context leading to the PPMM need identification, (ii) an overview of the existing public (procurement) maturity models; (iii) discussions and (iv) summary, limitations, and outlook. The paper provides arguments of an upstream intervention in the value chain of road transport infrastructure and highlights the benefits of such an intervention. Elements such as Romanian cultural dimensions, type of market structure or impact of the outcomes of public procurement process for road infrastructure are considered relevant entry data for an intervention which aims to contribute to the improvement of performance at a procurement process level. The results of this paper serve as a starting point for further reflection on the performance in road infrastructure public procurement area in Romania. In addition to the awareness of the need for an intervention at a contracting authority level, the paper arguments that market structure or national cultural dimensions must be considered as entry data in designing maturity models.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2016-0039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Very often, pavements constructed in an economical manner or matching surface elevations of adjacent lanes cannot be designed for the soil conditions of the existing subgrade. Therefore, there is a need to stabilize the soil with an appropriate chemical substance in order to increase its strength to a satisfactory level. For the enhancement of subgrade soil strength characteristics, lime and cement are the most commonly used stabilizers. An experimental program was directed to the evaluation of a clayey soil and its mixtures with different cement contents performing tests on the index properties, the moisture-density relation, the unconfined compressive strength, and linear shrinkage. There is a definite improvement in strength. The time interval used to cure the prepared specimens affected positively both strength and plasticity features of the mixtures. A comparison with mixtures of the same soil with lime has been made, because of the wide use of lime in clay soil stabilization projects.
{"title":"The role of curing period on the engineering characteristics of a cement-stabilized soil","authors":"A. Athanasopoulou","doi":"10.1515/rjti-2016-0041","DOIUrl":"https://doi.org/10.1515/rjti-2016-0041","url":null,"abstract":"Abstract Very often, pavements constructed in an economical manner or matching surface elevations of adjacent lanes cannot be designed for the soil conditions of the existing subgrade. Therefore, there is a need to stabilize the soil with an appropriate chemical substance in order to increase its strength to a satisfactory level. For the enhancement of subgrade soil strength characteristics, lime and cement are the most commonly used stabilizers. An experimental program was directed to the evaluation of a clayey soil and its mixtures with different cement contents performing tests on the index properties, the moisture-density relation, the unconfined compressive strength, and linear shrinkage. There is a definite improvement in strength. The time interval used to cure the prepared specimens affected positively both strength and plasticity features of the mixtures. A comparison with mixtures of the same soil with lime has been made, because of the wide use of lime in clay soil stabilization projects.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66974015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper aims to establish the interface conditions influence on the flexible pavement structures life. The methodology consists in using the interface constitutive model available in the Alizé calculation program to calculate the stresses and strains in the flexible pavement structures. The design criteria related to limiting fatigue cracking of asphalt layers and permanent deformations at the subgrade level from the road bed are used to estimate the flexible pavement structures lifetime. When calculating the critical stresses and strains, most mechanical design methods of the flexible pavement structures considers that the road layers at interfaces are perfect bonded or total unbonded. Proper modeling of the interface binding condition is an important aspect in understanding the real behaviour of in-service flexible pavement structures.
{"title":"Influence of the interface conditions on flexible pavement structures life","authors":"Ş. Lazăr, E. Diaconu","doi":"10.1515/rjti-2016-0040","DOIUrl":"https://doi.org/10.1515/rjti-2016-0040","url":null,"abstract":"Abstract This paper aims to establish the interface conditions influence on the flexible pavement structures life. The methodology consists in using the interface constitutive model available in the Alizé calculation program to calculate the stresses and strains in the flexible pavement structures. The design criteria related to limiting fatigue cracking of asphalt layers and permanent deformations at the subgrade level from the road bed are used to estimate the flexible pavement structures lifetime. When calculating the critical stresses and strains, most mechanical design methods of the flexible pavement structures considers that the road layers at interfaces are perfect bonded or total unbonded. Proper modeling of the interface binding condition is an important aspect in understanding the real behaviour of in-service flexible pavement structures.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2016-0040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract More than 1,24 million people die each year on the worlds roads and between 20 to 50 million suffer from nonfatal injuries. The UN Road Safety Collaboration Meetings under the leadership of WHO developed the Programme for the Decade of Actions for road safety taking nations into the responsibility of improving their accident figures by the five pillars of a national Road Safety Policy, safer Roads, safer Vehicles, safer Road Users and Post Crash Care. It is this Safe System Approach that takes into consideration the land use, infrastructure and transport planning, road user’s abilities and limitations and the close cooperation of all governmental and none governmental stakeholders involved. Following the European Transport Safety Council's (ETSC) 8th Road Safety Performance Index Report on Ranking EU Progress on Road Safety; June 2014 Romania has made progress during the last 10 year but had still the highest fatality rate of 93 fatalities per 1 million inhabitants in Europe. [1] The contribution will present the main activities of the fife pillars with a focus on PIARC's Road Infrastructure Management tools to improve safety and function of the road infrastructure based on the experiences with the land use problems in Asian, African and European countries. A GPS based accident data system will help researchers and practitioners to improve their countries road safety. The report will show the important steps for safer roads which had been developed in Romania and how actions of short and long term measures on all five pillars have reduced the number of traffic victims remarkable in Eastern Germany after reunification and in addition how the hierarchy of motorways, 2+1 express roads, the rural roads and traffic calming in built up areas, have improved the economic development of cities and villages in a safe way.
{"title":"The safe road transport system approach","authors":"H. Vollpracht","doi":"10.1515/rjti-2016-0042","DOIUrl":"https://doi.org/10.1515/rjti-2016-0042","url":null,"abstract":"Abstract More than 1,24 million people die each year on the worlds roads and between 20 to 50 million suffer from nonfatal injuries. The UN Road Safety Collaboration Meetings under the leadership of WHO developed the Programme for the Decade of Actions for road safety taking nations into the responsibility of improving their accident figures by the five pillars of a national Road Safety Policy, safer Roads, safer Vehicles, safer Road Users and Post Crash Care. It is this Safe System Approach that takes into consideration the land use, infrastructure and transport planning, road user’s abilities and limitations and the close cooperation of all governmental and none governmental stakeholders involved. Following the European Transport Safety Council's (ETSC) 8th Road Safety Performance Index Report on Ranking EU Progress on Road Safety; June 2014 Romania has made progress during the last 10 year but had still the highest fatality rate of 93 fatalities per 1 million inhabitants in Europe. [1] The contribution will present the main activities of the fife pillars with a focus on PIARC's Road Infrastructure Management tools to improve safety and function of the road infrastructure based on the experiences with the land use problems in Asian, African and European countries. A GPS based accident data system will help researchers and practitioners to improve their countries road safety. The report will show the important steps for safer roads which had been developed in Romania and how actions of short and long term measures on all five pillars have reduced the number of traffic victims remarkable in Eastern Germany after reunification and in addition how the hierarchy of motorways, 2+1 express roads, the rural roads and traffic calming in built up areas, have improved the economic development of cities and villages in a safe way.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2016-0042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66974066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The main goal of the research project was to develop and demonstrate the first Polish FRP composite road bridge, starting from concept design and material research, and going thru manufacturing technique selection, detailed FEM analysis and structural testing of elements. The R&D project comprises also the proof test of the completed bridge as well as structural monitoring in exploitation period. The objective of the paper is the description of the bridge and its structural solutions, i.e. FRP box girders and lightweight concrete deck slab acting compositely. Further the FEM analysis of the girder and the bridge span made on design stage has been presented. The VARTM manufacturing technique was used for girders production. Its main steps have been also presented. Finally the research on the new FRP box girder with LRC slab (hybrid girder) has been briefly showed. The full scale prototype girder with the total length of 22 m was tested to evaluate its carrying capacity, modes of failure, basic dynamic parameters as well as overall behaviour under ultimate static load. The FRP girder met the prescribed serviceability and safety criteria. The FEM model of the girder was validated against testing results and was further used for bridge design. Thanks to R&D project the first Polish FRP bridge is likely to be built late autumn 2015. The output of the research project gives a very promising future for the FRP composite bridge application. The research works showed in the paper have been partially financed by the Polish National Centre for Research and Development in the frame of the research project “ComBridge” (www.com-bridge.pl).
{"title":"Design and research on the first polish FRP composite road bridge","authors":"T. Siwowski, Damian Kaleta, M. Rajchel","doi":"10.1515/rjti-2015-0037","DOIUrl":"https://doi.org/10.1515/rjti-2015-0037","url":null,"abstract":"Abstract The main goal of the research project was to develop and demonstrate the first Polish FRP composite road bridge, starting from concept design and material research, and going thru manufacturing technique selection, detailed FEM analysis and structural testing of elements. The R&D project comprises also the proof test of the completed bridge as well as structural monitoring in exploitation period. The objective of the paper is the description of the bridge and its structural solutions, i.e. FRP box girders and lightweight concrete deck slab acting compositely. Further the FEM analysis of the girder and the bridge span made on design stage has been presented. The VARTM manufacturing technique was used for girders production. Its main steps have been also presented. Finally the research on the new FRP box girder with LRC slab (hybrid girder) has been briefly showed. The full scale prototype girder with the total length of 22 m was tested to evaluate its carrying capacity, modes of failure, basic dynamic parameters as well as overall behaviour under ultimate static load. The FRP girder met the prescribed serviceability and safety criteria. The FEM model of the girder was validated against testing results and was further used for bridge design. Thanks to R&D project the first Polish FRP bridge is likely to be built late autumn 2015. The output of the research project gives a very promising future for the FRP composite bridge application. The research works showed in the paper have been partially financed by the Polish National Centre for Research and Development in the frame of the research project “ComBridge” (www.com-bridge.pl).","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2015-0037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The use of low temperature (LT) asphalt products can result in a significant decrease of temperature required for asphalt production. This reduces energy costs and consumption. Moreover, safety during asphalt production and laying improves because the amount of potentially harmful vapours and aerosols decreases. Temperature decrease, in addition to the above, reduces the short-term ageing of bitumen in the asphalt production process, and ultimately has a positive impact on the durability of pavements. COLAS Group in Hungary considers propagating the use of low temperature sorts of asphalt in road construction in Hungary as a high priority innovation task Between 2012 and 2014, COLAS Group equipped its asphalt mixers with units from different manufacturers, capable of producing foamed bitumen, at four COLAS Group mixing plants in Hungary. This was followed by several test production runs and course laying with asphalt mixes containing foamed bitumen. Some of the foam asphalt mixes were produced and laid at low temperatures. The other part of the mixes were produced at conventional temperature and were layed after 2 - 2.5 hours of transport. The test asphalt mixtures were made with 50/70 and 10/40-65 modified bitumen also containing 10-20% RA. We compared the compactability of foamed bitumen mixtures produced with four different foaming kits. We produced Marshall specimens at various compaction temperatures, tested the bulk densities of the specimens, then represented the bulk densities subject to the compaction temperature. We established the following: the Marshall bulk density (better compactability) of foamed bitumen asphalt mixes is higher for all asphalt types compared to the normal bitumen mixtures, higher Marshall bulk density of foamed bitumen asphalt mixes can be achieved both in normal (50/70) and modified bitumen mixtures (25/55-65,10/40-65), better compactability of foamed bitumen asphalt mixes is independent of the type of the foaming kit. It works for all types of foaming kits.
{"title":"New experiences with foamed bitumen asphalts in hungarian road building","authors":"Z. Puchard, A. Gorgenyi","doi":"10.1515/rjti-2015-0036","DOIUrl":"https://doi.org/10.1515/rjti-2015-0036","url":null,"abstract":"Abstract The use of low temperature (LT) asphalt products can result in a significant decrease of temperature required for asphalt production. This reduces energy costs and consumption. Moreover, safety during asphalt production and laying improves because the amount of potentially harmful vapours and aerosols decreases. Temperature decrease, in addition to the above, reduces the short-term ageing of bitumen in the asphalt production process, and ultimately has a positive impact on the durability of pavements. COLAS Group in Hungary considers propagating the use of low temperature sorts of asphalt in road construction in Hungary as a high priority innovation task Between 2012 and 2014, COLAS Group equipped its asphalt mixers with units from different manufacturers, capable of producing foamed bitumen, at four COLAS Group mixing plants in Hungary. This was followed by several test production runs and course laying with asphalt mixes containing foamed bitumen. Some of the foam asphalt mixes were produced and laid at low temperatures. The other part of the mixes were produced at conventional temperature and were layed after 2 - 2.5 hours of transport. The test asphalt mixtures were made with 50/70 and 10/40-65 modified bitumen also containing 10-20% RA. We compared the compactability of foamed bitumen mixtures produced with four different foaming kits. We produced Marshall specimens at various compaction temperatures, tested the bulk densities of the specimens, then represented the bulk densities subject to the compaction temperature. We established the following: the Marshall bulk density (better compactability) of foamed bitumen asphalt mixes is higher for all asphalt types compared to the normal bitumen mixtures, higher Marshall bulk density of foamed bitumen asphalt mixes can be achieved both in normal (50/70) and modified bitumen mixtures (25/55-65,10/40-65), better compactability of foamed bitumen asphalt mixes is independent of the type of the foaming kit. It works for all types of foaming kits.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2015-0036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The load transfer capacity of pavements is to a great extend influenced by aggregates. About 85% of the total volume of hot mix asphalt (HMA) mixtures consists of aggregates; thus, they are greatly influenced by aggregate properties like angularity (shape), roughness (texture), and gradation. Aggregate gradation controls the structure of voids. Current specifications for aggregate properties in HMA pavements require the aggregate blend to fall within a specified range of gradation values. Although the abovementioned requirement has ensured the construction of high quality HMA pavements, the properties are largely empirical and they are not based on performance-related tests. Marshall Stability is in principle the resistance to plastic flow of cylindrical specimens of a bituminous mixture loaded on the lateral surface. It is the load carrying capacity of the mix at 60oC. Aggregates with different gradations from the broader area of Xanthi, Northern Greece, have been used to prepare specimens for stability testing of hot asphalt mixtures in the laboratory. The research focused on the evaluation of the influence of aggregates in the overall stability characteristics of the mixtures. The maximum stability value has been obtained with an open-graded mixture having 5% asphalt and aggregate size 2.36 mm. However, the stability of the dense graded mixture is higher than this maximum value.
{"title":"Influence of aggregate gradation on hma mixes stability","authors":"E. Kalaitzaki, G. Kollaros, A. Athanasopoulou","doi":"10.1515/rjti-2015-0034","DOIUrl":"https://doi.org/10.1515/rjti-2015-0034","url":null,"abstract":"Abstract The load transfer capacity of pavements is to a great extend influenced by aggregates. About 85% of the total volume of hot mix asphalt (HMA) mixtures consists of aggregates; thus, they are greatly influenced by aggregate properties like angularity (shape), roughness (texture), and gradation. Aggregate gradation controls the structure of voids. Current specifications for aggregate properties in HMA pavements require the aggregate blend to fall within a specified range of gradation values. Although the abovementioned requirement has ensured the construction of high quality HMA pavements, the properties are largely empirical and they are not based on performance-related tests. Marshall Stability is in principle the resistance to plastic flow of cylindrical specimens of a bituminous mixture loaded on the lateral surface. It is the load carrying capacity of the mix at 60oC. Aggregates with different gradations from the broader area of Xanthi, Northern Greece, have been used to prepare specimens for stability testing of hot asphalt mixtures in the laboratory. The research focused on the evaluation of the influence of aggregates in the overall stability characteristics of the mixtures. The maximum stability value has been obtained with an open-graded mixture having 5% asphalt and aggregate size 2.36 mm. However, the stability of the dense graded mixture is higher than this maximum value.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2015-0034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The norms and standards for design of timber bridges, as well as other structures built from this material, were obsolete, design standards that were used dated from 1978 to 1980. The introduction of European Standards has created a new legislative framework in the field of designing and building timber bridges. Currently the design of such constructions use Norm NP 005-2003 and SR EN 1995-1-1: 2004 Eurocode 5: Design of timber structures. Part 1-1: General. Common rules and rules for buildings, SR EN 1995-2: 2005 Eurocode 5: Design of timber structures. Part 2: Bridges, along with their national annexes. The aim of this paper is to analyze the design of the beams for timber bridges in parallel, using on one hand Norm NP 005 - 2003, and on the other hand provisions of European standards. The design requirements for both norms as well as the results of a case study for a structural element of a timber bridge will be presented.
木桥的设计规范和标准，以及其他由这种材料建造的结构，是过时的，设计标准使用的时间从1978年到1980年。欧洲标准的引入在木桥设计和建造领域创造了一个新的立法框架。目前此类建筑的设计使用规范NP 005-2003和SR EN 1995-1-1: 2004欧洲规范5:木结构设计。第1-1部分:总则。建筑通用规则和规则，SR EN 1995-2: 2005欧洲规范5:木结构设计。第2部分:桥梁及其国家附件。本文的目的是分析平行木桥梁的设计，一方面采用规范NP 005 - 2003，另一方面采用欧洲标准的规定。本文将介绍两种规范的设计要求以及木桥结构元素的案例研究结果。
{"title":"Comparative design of the superstructure of timber bridges, using norm np 005 - 2003 and provisions of european standards","authors":"C. Chiotan, Dumitru Daniel Morlova","doi":"10.1515/rjti-2015-0033","DOIUrl":"https://doi.org/10.1515/rjti-2015-0033","url":null,"abstract":"Abstract The norms and standards for design of timber bridges, as well as other structures built from this material, were obsolete, design standards that were used dated from 1978 to 1980. The introduction of European Standards has created a new legislative framework in the field of designing and building timber bridges. Currently the design of such constructions use Norm NP 005-2003 and SR EN 1995-1-1: 2004 Eurocode 5: Design of timber structures. Part 1-1: General. Common rules and rules for buildings, SR EN 1995-2: 2005 Eurocode 5: Design of timber structures. Part 2: Bridges, along with their national annexes. The aim of this paper is to analyze the design of the beams for timber bridges in parallel, using on one hand Norm NP 005 - 2003, and on the other hand provisions of European standards. The design requirements for both norms as well as the results of a case study for a structural element of a timber bridge will be presented.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2015-0033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Brazilians mixtures containing asphalt rubber were evaluated by mechanical laboratory tests. A conventional mixture with asphalt CAP-50/70 was produced as a mixture control. With the aim of compare the Brazilians mixtures performance, a Portuguese asphalt rubber mixture was tested as well. The testing set involved the determination of the mechanical properties, fatigue and permanent deformation, of asphalt rubber produced by wet process through two different systems: continuous blend and terminal blend. The asphalt rubber morphology was evaluated in order to determine the compatibility of the systems. The asphalt rubber mixtures exhibit good resistance to permanent deformation and prolonged fatigue life in relation to mixture control. Therefore it is concluded that the application of asphalt rubber alters the characteristics of asphalt mixture in a very beneficial way.
{"title":"Constructing better roads with asphalt rubber","authors":"J. Pais, L. Thives, P. Pereira, G. Trichês","doi":"10.1515/rjti-2015-0035","DOIUrl":"https://doi.org/10.1515/rjti-2015-0035","url":null,"abstract":"Abstract Brazilians mixtures containing asphalt rubber were evaluated by mechanical laboratory tests. A conventional mixture with asphalt CAP-50/70 was produced as a mixture control. With the aim of compare the Brazilians mixtures performance, a Portuguese asphalt rubber mixture was tested as well. The testing set involved the determination of the mechanical properties, fatigue and permanent deformation, of asphalt rubber produced by wet process through two different systems: continuous blend and terminal blend. The asphalt rubber morphology was evaluated in order to determine the compatibility of the systems. The asphalt rubber mixtures exhibit good resistance to permanent deformation and prolonged fatigue life in relation to mixture control. Therefore it is concluded that the application of asphalt rubber alters the characteristics of asphalt mixture in a very beneficial way.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/rjti-2015-0035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rezumat Datorită degradării în timp a îmbrăcăminților rutiere, trebuiesc adoptate măsuri pentru reabilitarea acestora cu costuri cât mai mici. Una din soluțiile des utilizate îl reprezintă așternerea covoarelor asfaltice peste cele degradate. Problema principală care apare în cazul acestei soluții este transmiterea fisurilor din stratul existent în covorul de protecție (fisurare reflectivă). Adoptarea soluției optime în cazul straturilor asfaltice de protecție, din punct de vedere al comportării la fisurare, scade considerabil costurile de întreținere/reabilitare a structurii rutiere existente. De aceea sunt necesare studii experimentale efectuate în laborator, care presupune costuri mici, dar și o perioadă mai scurtă de timp față de sectoarele experimentale. În cadrul încercărilor de laborator efectuate, s-a urmărit și măsurat parametrii fisurării: deschiderea și lungimea fisurii în mixtură, deschiderea fisurii betonului, deformația probei și numărul de cicluri. Interpretarea acestor parametri, prin stabilirea unor legi de evoluție a acestora, ne poate oferi o imagine a modului în care fisura se transmite din betonul de ciment prefisurat în stratul de protecție și apoi se propagă pe întreaga grosime a acestuia. Se poate astfel stabili care este rețeta de mixtură asfaltică care se comportă cel mai bine la acest tip de fisurare, evitându-se astfel adoptarea unei soluții neadecvate care atrage după sine costuri ridicate de întreținere. Abstract Due to the pavement degradation in time, rehabilitation measures need to be adopted, maintaining the costs as lower as it can. One of the solutions often utilized is to apply a layer of asphalt concrete over the degraded pavement. The main issue of this method is that the fractures which exists in the old pavement are transmitted in the asphaltic overlay (reflective fracture). By adopting the optimal solution for the overlay, from the fracture’s behavior perspective, the maintenance/rehabilitation costs are considerably reduced. This is why experimental laboratory studies are needed to be conducted. They are cheaper and are less time-consuming than the experimental field studies. The fracture parameters were measured in the laboratory: the opening and length of the overlay fracture, opening of the existing pavement fracture, the specimen deformation, time (number of cycles). The interpretation of this parameters can give us an image of the way the fracture is transmitted from the old pavement to the asphaltic overlay and then it propagates trough the entire overlay thickness. This is the way the asphaltic mixture recipe that best behaves to this type of fracture can be established, avoiding an inadequate mixture design which involves higher maintenance costs.
{"title":"Experimental Modelling of Asphaltic Layers Behaviour at Reflective Fracture from Degraded Pavements – Parametric Studies","authors":"M. Lobază, M. Dicu","doi":"10.1515/rjti-2015-0031","DOIUrl":"https://doi.org/10.1515/rjti-2015-0031","url":null,"abstract":"Rezumat Datorită degradării în timp a îmbrăcăminților rutiere, trebuiesc adoptate măsuri pentru reabilitarea acestora cu costuri cât mai mici. Una din soluțiile des utilizate îl reprezintă așternerea covoarelor asfaltice peste cele degradate. Problema principală care apare în cazul acestei soluții este transmiterea fisurilor din stratul existent în covorul de protecție (fisurare reflectivă). Adoptarea soluției optime în cazul straturilor asfaltice de protecție, din punct de vedere al comportării la fisurare, scade considerabil costurile de întreținere/reabilitare a structurii rutiere existente. De aceea sunt necesare studii experimentale efectuate în laborator, care presupune costuri mici, dar și o perioadă mai scurtă de timp față de sectoarele experimentale. În cadrul încercărilor de laborator efectuate, s-a urmărit și măsurat parametrii fisurării: deschiderea și lungimea fisurii în mixtură, deschiderea fisurii betonului, deformația probei și numărul de cicluri. Interpretarea acestor parametri, prin stabilirea unor legi de evoluție a acestora, ne poate oferi o imagine a modului în care fisura se transmite din betonul de ciment prefisurat în stratul de protecție și apoi se propagă pe întreaga grosime a acestuia. Se poate astfel stabili care este rețeta de mixtură asfaltică care se comportă cel mai bine la acest tip de fisurare, evitându-se astfel adoptarea unei soluții neadecvate care atrage după sine costuri ridicate de întreținere. Abstract Due to the pavement degradation in time, rehabilitation measures need to be adopted, maintaining the costs as lower as it can. One of the solutions often utilized is to apply a layer of asphalt concrete over the degraded pavement. The main issue of this method is that the fractures which exists in the old pavement are transmitted in the asphaltic overlay (reflective fracture). By adopting the optimal solution for the overlay, from the fracture’s behavior perspective, the maintenance/rehabilitation costs are considerably reduced. This is why experimental laboratory studies are needed to be conducted. They are cheaper and are less time-consuming than the experimental field studies. The fracture parameters were measured in the laboratory: the opening and length of the overlay fracture, opening of the existing pavement fracture, the specimen deformation, time (number of cycles). The interpretation of this parameters can give us an image of the way the fracture is transmitted from the old pavement to the asphaltic overlay and then it propagates trough the entire overlay thickness. This is the way the asphaltic mixture recipe that best behaves to this type of fracture can be established, avoiding an inadequate mixture design which involves higher maintenance costs.","PeriodicalId":40630,"journal":{"name":"Romanian Journal of Transport Infrastructure","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2015-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66973344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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