Search

Timber-framed wall buildings are seen all over Europe, especially in seismic regions, given its adequacy to resist earthquakes. The pombaline buildings, developed after the big 1755 earthquake that destroyed Lisbon, constitute one of the best examples of ancient seismic-resistant structures based on timber-framed masonry walls. But in addition to suffering natural degradation and frequent inadequate interventions, these buildings were not prepared to resist the severe seismic actions envisaged by today's structural codes. In this context, they increasingly have to undergo rehabilitation and reinforcing works. The success of these projects strongly depends on the accuracy of the structural modelling, which in turn depends on knowledge of the behaviour of the existing structure. Aiming at providing reliable data to be used in structural design, a series of tests was carried out on the base element that constitutes the timber-framed masonry walls: the Saint Andrew's cross. The experimental tests were numerically simulated in order to determine the parameters that lead to the most accurate results when using linear-elastic models. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to present experimental investigations on the structural behaviour of composite sandwich panels for civil engineering applications. The performance of two different core materials – rigid plastic polyurethane (PU) foam and polypropylene (PP) honeycomb – combined with glass fibre reinforced polymer (GFRP) skins, and the effect of using GFRP ribs along the longitudinal edges of the panels were investigated. Design/methodology/approach – The experimental campaign first included flatwise tensile tests on the GFRP skins; edgewise and flatwise compressive tests; flatwise tensile tests on small-scale sandwich specimens; and shear tests on the core materials. Subsequently, flexural static and dynamic tests were carried out in full-scale sandwich panels (2.50x0.50x0.10 m3) in order to evaluate their service and failure behaviour. Linear elastic analytical and numerical models of the tested sandwich panels were developed in order to confirm the effects of varying the core material and of introducing GFRP ribs. Findings – Tests confirmed the considerable influence of the core, namely of its stiffness and strength, on the performance of the unstrengthened panels; in addition, tests showed that the introduction of lateral reinforcements significantly increases the stiffness and strength of the panels, with the shear behaviour of strengthened panels being governed by the ribs. The unstrengthened panels collapsed due to core shear failure, while the strengthened panels failed due to face skin delamination followed by crushing of the skins. The models, validated with the experimental results, allowed simulating the serviceability behaviour of the sandwich panels with a good accuracy. Originality/value – The present study confirmed that composite sandwich panels made of GFRP skins and PU rigid foam or PP honeycomb cores have significant potential for a wide range of structural applications, presenting significant stiffness and strength, particularly when strengthened with lateral GFRP ribs. [ABSTRACT FROM AUTHOR]