Optimal Design of Seismic Resistant RC Columns

Although the author is well aware that it is nothing special, presented here is the method that he uses to design the columns of a seismic resistant reinforced concrete structure, in hopes that this could be of use to someone. The method, which is directed at satisfying the capacity design requirements without excessively large sections, consists of proportioning the column so that the seismic action effects shall be resisted by the maximum of the bending moment\u2013axial force interaction curve. That design condition is defined by two equations whose solution provides the optimal aspect ratio (or, alternatively, the optimal section side length) and the maximum feasible reinforcement ratio. The method can be used directly to determine the optimal column for given beam spans and vertical loads, or indirectly to determine the optimal beam spans and vertical loads for given cross-sectional dimensions. The paper presents the method, including its proof, and some applications together with the analysis on the optimality of the obtained solutions. The method is intended especially for the practicing structural engineer, though it may also be useful for educators, students, and building officials

I primi Romani sul Nilo

Fin dal terzo secolo a.C. i Romani intrattengono rapporti diplomatici con l’Egitto, di cui imitano anche la monetazione. Nel secondo secolo a.C. Roma è già una potenza egemone in tutto il Mediterraneo e blocca le velleità espansionistiche di Antioco IV di Siria verso l’Egitto (e anche verso il nuovo stato maccabaico di Israele). Senatori romani saranno accolti con grande ospitalità sulle terre del Nilo. Tutto muterà con Cleopatra VII, amante di Cesare e M. Antonio, madre dei loro figli, ma che a tanti Romani sembrerà un fatale monstrum. Ma presso altri Romani continuerà la fascinazione del paesaggio e della civiltà del Nilo: Seneca vi trascorrerà parte della giovinezza, Caio Cestio si farà costruire a Roma una tomba a forma di piramide.From the 3rd century BC, Romans maintained diplomatic relationships with Egypt and imitated their monetization. In the 2nd century BC Rome had a hegemonic rule all over the Mediterranean Sea and blocked the expansionist ambitions of Antiochus IV of Syria towards Egypt (and towards the new Maccabean state of Israel). Roman senators were received with great hospitality in the Nile’s lands. Everything will change with Cleopatra VII, lover of Caesar and M. Antonius and mother of their sons. She will appear to be a fatale monstrum to a lot of Romans. However, the fascination of the landscape and the culture of the Nile will continue to be perceived by another part of the Roman society: Seneca will spend part of his youth in Egypt, while Caius Cestius will order a tomb to be built for him in Rome, pyramidal in shape

Shear strength of an anchor post-installed into a hardened concrete member

Literature has recently provided the analytical model that predicts the shear strength of the anchor embedded into masonry. It is apparent that this model does not apply to the anchor embedded into concrete, as the ultimate contact pressures are different. A gap in the literature was hence filled, but there existed a remaining gap. In order to fill that last gap, further research was done. This paper is herein an account of that work. The paper deals with the anchor post-installed by drilling into an already compact concrete structure, used to transmit applied loads from an attachment to the concrete, subjected to a force acting at the end that emerges from the concrete and orthogonal to the anchor (shear force with no axial force), with large clearance from the edges, either alone or with large clearance from other anchors. Being post-installed, the embedded part of the anchor is a straight shaft with no hook at the embedded end, and with no nuts, washers, or plates attached to the shaft. The paper presents an analytical model absent in literature prior to this study that predicts the maximum shear force the anchor can carry, thus called “shear strength” of the anchor. The assumptions of the analytical model were established from the results of a non-linear numerical model specifically constructed by the author. The predictive capacity of the analytical model and accuracy of its results were assessed and verified by experimental tests of real anchorages specifically designed and performed by the author. This paper also presents the numerical model and the comparisons of the analytical predictions to those experimental results, as well as com parisons to experimental results borrowed from literature and code provisions

Prevenzione sismica e rigenerazione architettonica mediante esoscheletri

Questo articolo tratta le nuove strutture realizzate all’esterno degli edifici esistenti, per la prevenzione sismica. Queste addizioni sono chiamate “esoscheletri”, con parziale corrispondenza alla zoologia; parziale perché, nelle costruzioni gli esoscheletri sono solo l’ossatura che dà sostegno, mentre nella zoologia sono anche una corazza protettiva. L’esoscheletro viene analizzato e considerato non solo per la mitigazione del rischio sismico ma anche per l’adeguamento statico, non solo quale mera soluzione strutturale ma anche come soluzione architettonica, e non solo come necessità ma anche come opportunità per una progettazione integrata volta alla rigenerazione degli edifici, anche là dove sono possibili soluzioni tradizionali. L’articolo parte dagli esoscheletri del nuovo, i quali rappresentano i riferimenti per il costruito (per gli edifici le cui fotografie più emblematiche sono coperte da copyright, si rimanda tacitamente al WEB)

L’innovazione nel settore delle strutture

A grandi linee l’innovazione nel settore delle strutture può sembrare analoga a quella di tutti gli altri settori; a ben vedere, invece, si differenzia drasticamente. L’articolo presenta il pensiero dell’autore sul tema, nella speranza che, un po’, possa contribuire a riportare l’ingegneria strutturale a quel ruolo centrale per la società che aveva in passato, prima di trasformarsi da ingegneria a ragioneria

All the way to the top! The energy implications of building tall cities

Density of urban form may be achieved under a variety of morphological designs that do not rely on tallness alone. Tall buildings have implications on the broader urban environment and infrastructure that lower buildings would not have, e.g. wind effects, sight-lines, or over-shading. They may also have an impact on energy use for reasons of buildings-physics, construction, and occupant practices. This study uses a statistical approach of neighbourhood level data to analyse the impact of building morphology (e.g. height, volume and density) on energy demand in 12 local authorities in London. The research shows that areas marked by tall buildings use more gas after adjusting for exposures surface area, volume, number of residents and other features. The implication for energy policy and planning is building taller without increasing density may have an energy penalty

Experimental investigation of a full-scale timbrel masonry cross vault subjected to vertical settlement

La versión de editor/PDF no puede utilizarse. Debe enlazar a la versión de editor con DOI. Author's post-print must be released with a Creative Commons Attribution Non-Commercial No Derivatives License[EN] Masonry cross vaults are among the most attractive structures ever created by the human race. Although cross vaults have been the subject of various numerical and experimental studies, they are still in need of further investigation. In the research described here, carried out at the ICITECH laboratories of the Universitat Politecnica de Valencia (Spain), a full-scale timbrel cross vault was constructed and tested under the vertical settlement of one of its supports. The geometry and construction technique of the vault resembled those in a church on the outskirts of Valencia, one of which had collapsed due to a soil settlement. The timbrel vault's behaviour was monitored by 23 sensors placed on its inner and outer surfaces and subsequently analysed from the results obtained in the tests. As expected, the vault experienced a fairly ductile response during the test, while peculiar crack patterns were observed in the form of bending cracks in the lateral arches, which were mostly found to follow the mortar joints in the upper surface of one of the diagonal elliptic arches.The authors wish to express their gratitude to the Spanish Ministry of Economy, Industry and Competitiveness for the funding provided through Project BIA 2014-59036-R, and also to LIC-Levantina Ingenieria y Constructiin and Grupo Puma for their invaluable assistance.Torres Górriz, B.; Bertolesi, E.; Moragues, JJ.; Calderón García, PA.; Adam, JM. (2019). Experimental investigation of a full-scale timbrel masonry cross vault subjected to vertical settlement. Construction and Building Materials. 221:421-432. https://doi.org/10.1016/j.conbuildmat.2019.06.015S42143222