this paper presents an experimental study on seismic repair of damaged square reinforced concrete columns with poor lap splices, 90-degree hooks and widely spaced transverse bars in plastic hinge regions according to aci detailing (pre.1971) and (318-02) using gfrp wraps. three specimens were tested in “as built” condition and retested after they were repaired by glass fiberreinforced plastic s...

The effect of cumulative damage on the strength requirements of degrading structures is assessed through the evaluation of the target ductility and corresponding strength reduction factors of simple degrading structures. While the reduction on ductility is established through the use of Park and Ang index, the suggestions given by Bojórquez and Rivera are used to model the degradation of the st...

According to the different construction forms of PBL shear connectors in steel-concrete composite beam and steel-concrete joint section, eight finite element models in two groups of the two construction forms are conducted to study different mechanical properties of PBL shear connectors. Following conclusions can be drawn from the finite element method calculation results. The load-slip curve, ...

The exceptional properties of nanocrystalline materials lend themselves to a wide range of structural and functional applications. There is recent evidence to suggest that grain boundary impurities may have a dramatic effect on the stability, strength and ductility of nanocrystalline metals and alloys. In this study, transmission electron microscopy and atom probe tomography were used to charac...

Silica (SiO2) glass, an essential material in human civilization, possesses excellent formability near its glass-transition temperature (Tg > 1100 °C). However, bulk SiO2 glass is very brittle at room temperature. Here we show a surprising brittle-to-ductile transition of SiO2 glass nanofibers at room temperature as its diameter reduces below 18 nm, accompanied by ultrahigh fracture strength. L...

Timber platform-frame shear walls are characterized by high ductility and diffuse energy dissipation but limited in-plane shear resistance. A novel lightweight constructive system composed of steel columns braced with oriented strand board (OSB) panels was conceived and tested. Preliminary laboratory tests were performed to study the OSB-to-column connections with self-drilling screws. Then, th...

Current understanding of the brittleness of glass is limited by our poor understanding and control over the microscopic structure. In this study, we used a pressure quenching route to tune the structure of silica glass in a controllable manner, and observed a systematic increase in ductility in samples quenched under increasingly higher pressure. The brittle to ductile transition in densified s...

Hot–press forming steels are formed in a fully austenitic state followed by die– quenching in order to generate martensite and achieve a strong steel. The ductility however, tends to be limited. We explore in this work a novel steel design in which the forming operation is in the two–phase austenite and ferrite field, so that the quenching results in a dual–phase ferrite and martensite microstr...

iron-aluminum alloys are one of the most resistant alloys against sulfidation/oxidation environments with low oxygen partial pressures. the high sensitivity to hydrogen embrittlement is the main reason for decreasing of their room temperature ductility. there is a drop of strength above 600 c and their creep resistance is fairly weak. it is possible to increase ductility up to 15 percents and i...