In recent years, previous work with numerical models of impact generated by a fall on edge protection systems (EPS), class C according to EN 13374, showed that current requirements for this system could be inadequate or dangerous for the integrity of injured people, leading to excessive impact factors. Special difficulties arise when the injured fall directly against the EPS supports. To confirm the results of numerical models, two series of experiments were developed using real size samples built with a steel frame and a safety net or other stop surfaces. The paper describes these experiments carried out according to EN 13374 and using a new design of supports with a curved slope to avoid direct impact against them. Data was recorded with a triaxial accelerometer and a high velocity camera. The first series, with a standard safety net, showed a very good behaviour, leading to acceptable impact factors and no direct impact against the frame. The second series was conducted on a reinforced frame and substituting the net by a thin steel bar grid, to reduce the deflection up to the minimum required in EN 13374. The results confirmed the numerical predictions and show that current requirements lead to excessive impact factors that can seriously injure the falling person, suggesting a revision of the European Norm.

RESUMENLa norma UNE-EN 13374 "Sistemas provisionales de protección de borde. Especificaciones del producto, métodos de ensayo" (1) clasifica los sistemas provisionales de protección de borde (SPPB) en tres clases (A, B y C), en función del ángulo de la superficie de trabajo y de la altura de caída de la persona a proteger. Los sistemas clase A son los indicados cuando la inclinación de la superficie de trabajo es menor de 10º. La norma establece los requisitos de flecha y de resistencia de los SPPB. Los requisitos se pueden comprobar tanto analítica como experimentalmente.El objetivo del trabajo ha sido la evaluación del comportamiento de los SPPB utilizados habitualmente en las obras y establecer los cambios necesarios para que cumplan con la norma UNE-EN 13374. Para ello se han evaluado analítica y experimentalmente tres SPPB clase A, fabricados con acero S235.Los resultados obtenidos muestran que, el sistema empleado de forma habitual en obras no supera los requisitos de la norma ni analítica ni experimentalmente. El tercer sistema supera los requisitos con las dos metodologías de análisis. El segundo sistema supera los requisitos cuando la evaluación se realiza analíticamente pero no cuando la vía utilizada es la experimental. 754-3 SUMMARY The standard UNE-EN 13374 "Temporary edge protection systems. Product specification, test methods" (1) classifies the temporary edge protection systems (TEPS) under three classes (A, B and C), based on the angle of the surface of work and the fall of the person to protect. The class

No abstract

We have tested under static and dynamic load temporary edge protection systems (TEPS) formed by a continuous fence, some are made of high density polyethylene (HDPE) and others have been manufactured using a composite material, adding glass fiber at a matrix of HDPE at a rate of 4%.Tests under static and impact have been performed according to standard UNE-EN 13374, class systems A and B. It has been found the influence of aging on TEPS and samples of the same materials as the TEPS.All tested TEPS exceed the strength requirements and accidental load and requirements compared to dynamic loads. The incorporation of glass fibers results in a composite material with a modulus of elasticity higher and significantly less creep. We haven't seen dependence on the results with the degree of aging or in SPPB or in the samples.Keywords: polymer; fiberre in forced; composite; flexural strength; creep. RESUMENSe han ensayado bajo cargas estáticas y dinámicas sistemas provisionales de protección de borde (SPPB) formados por una valla continua, unos fabricados con polietileno de alta densidad (HDPE) y otros con un material compuesto, añadiendo un 4% de fibra de vidrio a una matriz de HDPE.Los ensayos, bajo cargas estáticas y de impacto, se han realizado según la norma UNE-EN 13374, para sistemas clase A y B. Se ha comprobado la influencia del envejecimiento sobre SPPB y probetas de los mismos materiales que los SPPB.Todos los SPPB ensayados superan los requisitos de resistencia y de carga accidental y los requisitos frente a cargas dinámicas. La incorporación de fibras de vidrio da lugar a un material compuesto con un módulo de elasticidad significativamente más alto y con menor fluencia. No se aprecia dependencia de los resultados con el grado de envejecimiento ni en los SPPB ni en las probetas. INTRODUCTIONPolyethylene is a thermoplastic polymer combining a series of physical and mechanical properties such as a low density and a good strength-weight ratio, which together with the easiness to process it, becomes suitable for a great variety of applications, being plastic the mostly produced one (1, 2). Depending on the polymerization process employed, different types of polyurethane are obtained depending on the density. High density Polyurethane (HDPE) usually has densities in between 0.94 and 0.97 g/ cm 3 , the longitudinal elasticity is low, around 2000 N/mm 2 and presents high fluency values even for loads far from its elastic limit and for a short time, mainly for stress concentrators producing a fragile failure process (3-5).HDPE has excellent properties to be used as a component in collective protections (CP), where stresses are produced, mainly as impacts. The low value of the elasticity module, together with the great deformations reached before fracture, implies the possibility of absorbing a great quantity of energy. However, the low elasticity modules can be an inconvenience in certain occasions, as movements higher than the admitted by the standards regulating CP used are reached with HDPE systems. Moreover, agi...

No abstract

No abstract

No abstract

No abstract