The design and construction is described of a vehicle bridge made of glass-reinforced polyester pultruded box beams. The bridge has a simply supported span 11 . 6 m long and 4 m wide. It has been designed as a Class 30 (300 kN load capacity) according to DIN 1072 and represents a single traffic lane. The composite bridge consists of a 3-D truss structure made of thick-wall fibrereinforced plastic longitudinal box elements of hollow square cross-section. The bridge design proposed allows for fast construction as it consists of pre-fabricated, ready to assemble elements. The total of the composite bridge does not exceed 135 kN.

A combined theoretical and experimental study of a crack growth in a mixed-mode I-II loading is presented. A 160 x 40 x 20 mm marble beam, with an artificial crack 8 mm and 10 mm long each, was subjected to three point bending. The crack was located vertically to the beam's lower longitudinal fiber, through the whole width of the beam. The position of the crack was displaced from the center of the beam to one of the supporting points. The vertical force P, placed on the middle of the upper fiber of the beam, imposed the combination of the opening (mode I) and the sliding (mode II) modes on the crack mouth, creating the mixed-mode I-II loading case. The stress intensity factors K~ and KH, which describe the local stress and strain field around the crack tip, were determined by a suitable finite element program. The crack growth was defined by two classical fracture criteria of LEFM; the minimum strain energy density and the maximum circumferential stress criteria. The initial crack growth angle (0c) was calculated from both criteria and the critical load (Pc) from the minimum strain energy density (SED) criterion. These theoretical predictions were compared with some experimental results found from three marbles with different elastic constants; the Krystallina of Kavala, the Snow-white of Thassos and the White of Piges Drama. The theoretical results showed the same trend of 0c and Pc as the experimental ones and they are in good agreement.

A combined analytical and numerical study of an isotropic cracked plate that was repaired by using a bonded composite patch was conducted. The analytical work was based on Rose's equations, whereas for the numerical investigation a three‐dimensional finite element analysis was implemented. A number of cracked plates with different crack lengths and overall dimensions of the composite repair were considered. The composite patch was made of unidirectional laminates with different stacking sequences. Both, one‐ and two‐sided patches were analysed. Results are presented for the stress intensity factor in the patched crack and the maximum stress reinforcement stress and adhesive strain. It was found that for the case of a two‐sided reinforcement the results obtained by both methods were in good agreement. However, for the case of a single reinforcement the accuracy of the analytical method decreased due to the tendency to out‐of‐plane bending as a result of bonding a reinforcing patch to only one face of a plate, which is ignored in the analysis.

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