Concrete Safety Barriers: a Safe and Sustainable Choice
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EUROPEAN CONCRETE PAVING ASSOCIATION PAVE Concrete safety barriers: a safe and sustainable choice EUROPEAN CONCRETE PAVING ASSOCIATION Photo: Gomaco CONTENTS 1. INTRODUCTION 1. Introduction 3 One of the top ten goals set by the White Paper on Transport (2011) is to reduce fatalities in road transport. The increase of the safety of the road infrastructure had been one of the seven 2. Benefits of concrete safety barriers 4 main aims of the policy orientations made by the European Commission (EC) regarding to road 3. History of concrete safety barriers in Europe 5 safety for 2011-2020. 4. The European standards: EN 1317 8 From 2010 to 2016, the number of road fatalities in the EU decreased from 31.500 – the equiva- lent of a medium town- to 25.500. This represents a 19% reduction over the last six years. 5. Performance and test methods for vehicle restraint systems 9 However, despite of the fact that the EU has the safest roads in the world, 70 people are still 6. Terminals, transitions and removable barrier sections 15 dying and 370 got serious injuries every day. These figures are insufficient if the EU wants to 7. CE marking of concrete safety barriers 16 meet its target of halving road fatalities between 2010 and 2020 (only 40 people by 2020). The European Commission also settled as a long-term goal to move close to zero road fatalities 8. Protection of motorcyclists 17 by 2050. 9. Road restraint systems and noise barriers 19 Car occupants account for the largest share of victims (46%). Motorcyclists, who are less 10. Sustainability of concrete safety barriers 20 protected during a crash, account for 14% of road fatalities. Put together, vulnerable road users, including pedestrians, cyclists and motorcyclists account for the same proportion and are 11. Design and construction 25 particularly exposed in urban areas. 12. Conclusions 29 One of the ways to achieve this goal, amongst others such as intelligent vehicles and better enforcement, is safer road infrastructure. The use of passive safety systems and, more 13. References 30 specifically, road restraint systems undoubtedly contributes to higher safety. There will also be more focus on vulnerable road users, motorcyclists in particular. [Ref. 8] Photo: M. Van Kerckhoven Photo: Deltabloc Concrete safety barriers: a safe and sustainable choice 3 2. BENEFITS OF CONCRETE SAFETY BARRIERS 3. HISTORY OF CONCRETE SAFETY BARRIERS IN EUROPE Another concern of the EC is the use of sus- below lists the benefits of concrete safety Since the 1970s, the central reserves of high- Figure 1 Versions of the old tainable solutions, fitting in the concept of barriers in the three domains of sustainable ways and motorways in Europe have been New Jersey barrier Green Public Procurement. Concrete safety construction: environment, economy and protected with (steel) guardrail structures. barriers give answers to both the issues of society. These statements will further be The necessary maintenance on the road road safety and sustainability. The figure discussed in this publication. due to damages from accidents led to con- gestion, especially at narrow road sections. This raised the question of how to develop other types of roadside safety structures. > ENVIRONMENT > SOCIETY NEW JERSEY PROFILE • 80% less embodied CO2 • Increasing safety for road user than steel systems and worker The need for durable construction with mini- One-sided version that was used in wider central • Minimum material usage • No break-through of mal maintenance and without unacceptable reserves and roadsides and waste collision vehicle reduction in safety soon arose. The concrete • Non polluting in service • Low maintenance increases safety barrier with what is known as a New • 100% recyclable road availability and reduces Jersey profile fitted these requirements. • Virtually maintenance-free over traffic congestion This type of barrier was originally designed their 50-year design life • Safe solution for motorcyclists in America by General Motors in 1955 and • Reduce traffic congestion and first used in New Jersey. The first applica- associated emissions tions in Europe were found in Belgium and France from the 1970s onwards. [Ref. 4] The New Jersey profile in Europe was more or less standardised in two versions: bearable Double-sided version, for (very narrow) central reserves ENVIRONMENT SOCIETY planet’ people’ CONCRETE STEP BARRIER (CSB) SUSTAINABLE Rijkswaterstaat, the Dutch Road Administra- viable euitable tion, explored other barrier profiles. In the 1990s they developed in the Netherlands the “embedded step” profile, based upon the English “single-slope” barrier. [Ref. 4] ECONOMY prosperity New Jersey barrier in the central reserve of a motorway Photo: W. Kramer > ECONOMIC FACTORS • Very long design life • Minimum space required • Almost maintenance-free • Remain functional even after severe collisions • High daily production of 400 to 800 m possible • Temporary systems available for road works 4 Concrete safety barriers: a safe and sustainable choice Concrete safety barriers: a safe and sustainable choice 5 One of the first applications IN SITU CAST AND PRECAST Surface mounted CSB of the concrete step barrier CONCRETE SAFETYBARRIER installation on motorway E429 in Belgium (1999) Photo: BAM Wegen A concrete barrier can either be cast in situ Photo: P. Van Audenhove or be precast in a production unit. The in situ installation is done by means of a slipform paver using ready mixed concrete. This kind of installation allows very high daily production rates and consequently com- petitive prices. The barrier can be tied to the substructure (a cement treated or asphalt base layer) or can be surface mounted with- out any anchoring. Prefabricated elements are manufactured in an indoor environment and assembled on the worksite, making their installation less dependent on climatic conditions. Since they can easily be displaced, they are very 0,05 often used for protection of the work site DEVELOPMENT OF NEW TYPES OF during road construction. 0,085 IN SITU CAST CONCRETE SAFETY Figure 2 Standard geometry of BARRIERS the concrete step barrier 9,0 gon For a long time, mainly between 2000 and 2010, the step barrier was the most used type of in situ cast concrete safety barrier in Europe. After 2010, following the revised 0,90 0,60 version of the European standards EN1317- Photo: L. Rens 1 and -2, new types have been developed, mostly improved versions of the new jersey Precast barriers in a permanent and a temporary installation 0,05 profile. Photo: Omnibeton – Deltabloc 9,0 gon 0,25 0,542 Photos: left:Givasa right: Deltabloc International 6 Concrete safety barriers: a safe and sustainable choice Concrete safety barriers: a safe and sustainable choice 7 5. PERFORMANCE AND TEST METHODS FOR VEHICLE 4. THE EUROPEAN STANDARDS: EN 1317 RESTRAINT SYSTEMS In the beginning of the 1990s, CEN, the standardised rules for different types of PERFORMANCE CLASSES – European Committee for Standardisation, road restraint systems. The initial and revised CONTAINMENT LEVELS set up a Technical Committee on road versions, including amendments, of the equipment (CEN/TC 226) and a working European standards of the EN 1317 series The first version of the European standard The low angle containment levels are in- group (WG 1), dedicated to the drafting of are the following (status February 2018): EN 1317-2 was published in 1998. A revised tended to be used only for temporary safety version was published in 2010. The original barriers. However, temporary safety barri- version defined 10 performance classes. ers can also be tested for higher levels of EN 1317-1:1998 Terminology and general criteria for test methods The higher the performance level, the containment. EN 1317-1:2010 (revision) stronger the construction needs to be in EN 1317-2:1998 + A1:2006 Performance classes, impact test acceptance criteria and test methods for order to withstand higher impact demands. A successfully tested barrier at a given EN 1317-2:2010 (revision) safety barriers including vehicle parapets Each performance class refers to a number containment level should be considered as of crash tests. A road restraint system, al- having met the containment requirements EN 1317-3:2000 Performance classes, impact test acceptance criteria and test methods for located to a specific class, must be able to of any lower level, except that N1 and N2 EN 1317-3:2010 (revision) crash cushions retain the specified vehicles at determined do not include T3. This is because level T3 Performance classes, impact test acceptance criteria and test methods for speeds and impact angles. Table 1 gives an includes a test with a rigid truck (TB41) while ENV 1317-4:2001 terminals and transitions of safety barriers overview of the different standardised crash for levels N1 and N2 only crash tests with tests. cars are provided. Product requirements and evaluation of conformity for vehicle restraint EN 1317-5:2007 + A2:2012 systems The very high containment levels H4a and CEN/TR 1317-6:2012 Pedestrian restraint systems – Pedestrian parapets H4b should not be regarded as equivalent and no hierarchy is given between them. Motorcycle road restraint systems which reduce the impact severity of The difference in tests TB71 with a rigid truck CEN/TS 1317-8:2012 motorcyclist collisions with safety barriers and TB81 with an articulated truck originates from the use of significantly different types Road restraint systems – Guidelines for computational mechanics of crash CEN/TR 16303-1 to 4:2012 testing against vehicle