Abstract
Concrete barriers offer significant advantages over other road restraint systems, such as easy installation, lower cost, the possibility of being built in situ avoiding high transport costs, use of recycled materials and delimitation of traffic lanes. However, statistics show that consequences of accidents against rigid concrete elements on the road are often severe. The BAHORIS project aims to solve the identified technical deficiencies in the current barriers, using a universal barrier, which offers high protection for all road users, low production and installation costs; while being environmental friendly, both in its manufacture and its composition.
The BAHORIS project was divided in two phases: the design and development of the barrier and the subsequent validation. In the first stage, two lines of research were carried out. On the one hand, simulations of vehicle impacts against concrete barriers were performed in order to know a priori the most appropriate structure of equipment used for the construction of the barrier "in situ". On the other hand, a study of materials of the barrier was implemented to define mechanical characteristics and a required sustainable building process of the barrier. The aim of the final stage was to validate the developed barrier by carrying out the tests defined in the protocol designed to assess this product.
This paper presents the adaptation of the software commonly used in crash calculations to impacts against concrete barriers in order to be able to design and develop an innovative barrier design much faster and with much lower cost than using traditional design methods. The testing methodology developed, which substantially reduces the cost of developing a concrete barrier, is also presented. The results showed a good correlation between the simulations and the experimental results.
The main technological challenge of simulating impacts against road barriers is the need to have an accurate characterization of barrier elements and materials such as the locking of the barrier with the ground, the deformation of the materials at high impact speeds, fracture modelling, correct definition of parameters such as friction between the elements that impact the barrier. On the other hand, crashes against road barriers can last several seconds of real time, unlike frontal crashes, which last only milliseconds. This requires new calculation settings in order to optimize the use of computing resources to model such long timescales.
After the adaptation process of the barrier and the vehicle, the impact dynamics is the same as in the real tests and accelerations are in the same range, so it can be concluded that a reliable simulation system was achieved. On the other hand, modifications in the barrier outline were not enough to achieve an ASI lower than the boundary value.
KEYWORDS – road restraint systems, concrete barrier, simulation, sustainable, low cost