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Mechanical and metallographic characterization of iron tie-rods in masonry buildings: An experimental study
Published in Koen Van Balen, Els Verstrynge, Structural Analysis of Historical Constructions: Anamnesis, Diagnosis, Therapy, Controls, 2016
C. Calderini, R. Vecchiattini, C. Battini, P. Piccardo
structure (vertical extensions, mergers, etc. ...), increment the load (usage variation), treat any instability that caused problems to the vulnerable parts of the structure, and lastly to counteract dynamic horizontal forces (seismic actions), thus preventing the effects of potential paroxysmal events. Because of their aforementioned functional variety, metal tie-rods can be found in a number of positions in historical buildings: inside perimeter and spine bearing walls; inside the floor system; at the base of timber trusses; at the abutments or at the haunches of an arch but also at its extrados level; etc. ... The present research concentrates on metal tie-rods, produced in the pre-industrial age, that were commonly used in Italy starting from the fifteenth century. Metal tie-rods in the pre-industrial age, made of forged steel bars in pseudo-circular or quadrangular sections, were anchored to the bearing structure and inserted with minimum traction. To anchor the tie-rods to the bearing walls, anchor plates (also known as "bolzone" in Italian) with a bar with a quadrangular section were used and inserted at the eye-end of the tie-rod. Some anchor bars were moulded in a wedge shape, while others had a constant section and were forced into the eye-end of the tie rod with the help of metal wedges (Fig. 4). The length and shape of the bars could vary. The length of the bars and the dimension of their section depended strictly upon the size of the interested building, the area in which they would be inserted and the type of stress they were required to counteract. In order to obtain the necessary tie-rod length, a number of bars had to be joined on the construction site, as bars were produced with standard dimensions due
Shake-Table Test of a Strengthened Stone Masonry Building Aggregate with Flexible Diaphragms
Published in International Journal of Architectural Heritage, 2019
Gabriele Guerrini, Ilaria Senaldi, Francesco Graziotti, Guido Magenes, Katrin Beyer, Andrea Penna
The first retrofit strategy was an improvement of the wall-to-diaphragm connections (Modena et al. 2005; Moreira et al. 2014, 2016; Valluzzi 2007), otherwise limited to the frictional resistance of joist supports. At the first two floors, the floor joists resting on masonry piers were connected to the North and South transverse walls with metallic elements (Figure 3a). 100-mm-wide steel angles (150 x 150 × 12 mm) were screwed to the joists and connected to an exterior steel anchor plate (140 x 150 × 10 mm) by a M16 threaded rod, inserted in sleeves inside the masonry. Anti-shrinkage mortar allowed a uniform stress distribution between the steel angles and the interior side of the walls; for the same purpose, 16-mm-thick neoprene layers were located between the exterior anchor plates and the stone masonry.
Earthquakes and Tie-Rods: Assessment, Design, and Ductility Issues
Published in International Journal of Architectural Heritage, 2019
Stefano Podestà, Lorenzo Scandolo
Knowledge of the ductility of tie-rod and anchor assembly depends on several aspects, both material and technological. Even if steel has high ductility (εu/εy) intrinsically, some defects due to historic material (Calderini et al. 2016), made with a non-industrialized process, and due to wrong design details, which can limit the displacement capacity of the device, might exist. The untimely collapse of steel sleeves before the maximum elongation of the tie-rod or the local crushing of masonry due to an underperformance of the anchor plate (i.e., undressed stones and very poor-quality mortar) are some shortcomings that can reduce the capacity curve of the mechanism and cause greater damage to the macroelement, until collapse. In these cases, the displacement approach is obviously not conservative.
An experimental and numerical comparative study on the uplift capacity of single granular pile anchor and rough pile in sand
Published in International Journal of Geotechnical Engineering, 2022
Jerin Joseph, Shailendra Kumar, Vishwas A Sawant, Jignesh B Patel
The GPA material consisted of a mixture of stone aggregate and sand. The proportion of the mixture was decided based on the method used by Kranthikumar et al. (2017) and Singh, Mital, and Arora (2019) i.e. carrying out trials in which mixtures with different proportions were compacted and proportion of the mixture with maximum density after compaction was selected. From the trial investigation, a mixture with a proportion of 35% sand (below 4.75 mm) and 30% stone aggregate (4.75 to 6.5 mm), and 35% stone aggregate (8 mm) attained a maximum density of 20.81 kN/m3 after compaction. A mild steel plate of diameter 50 mm and thickness 10 mm was used as the anchor plate, and a 5 mm diameter threaded mild steel rod served the purpose of the anchor rod (Figure 3b).