Seismic Assessment of Roman Concrete Groin Vaults through UAV, NDT and 3D Analyses

Silvia Santini,Carlo Baggio,Claudio Sebastiani,Valerio Sabbatini

doi:10.3390/heritage5010017

Abstract

In Roman Baths, the Romans employed barrel and groin vaults of great dimensions, with maximum span more than 20 m; simple tools of structural analysis of ancient wide span vaulted halls are still lacking, due to geometrical and material complexity. In this paper, we study the collapse behavior, under horizontal static action, of a corner cross vault of the Baths of Diocletian in Rome (Hall I). Two methods of analysis are here used: non-linear incremental finite element and limit analysis. In both cases, 3D models have been developed by means of UAV inspection, NDT measures, and AVT monitoring. The construction of the overall 3D geometry has been here afforded with a specific pre-processing approach. Midas commercial software has been employed for FEM analysis, assuming a constitutive law specifically developed for Roman concrete. In limit analysis, masonry is discretized as a system of interacting rigid bodies in no-tension and frictional contact. The computational code consists in a linear approach, which makes use of a series of optimization packages via lower and upper bound techniques. Finally, a strategy based on FEM analysis including discontinuities was implemented, and the results were compared with the two previous approaches.

Highlights

The study of the structural behavior of historical masonry vaults has never been a simple task; for what concerns large Roman concrete vaults, the literature references are still insufficient
The technical literature usually deals with Roman masonry arches in bridges [1,2] and aqueducts [3], but few papers have been dedicated to the structural analysis of large Roman concrete vaults, except for the case of the Basilica of Maxentius in Rome [4]
The authors deal with the study of the large groin vaults that form the structural system of the Roman thermal complexes

Summary

Introduction

The study of the structural behavior of historical masonry vaults has never been a simple task; for what concerns large Roman concrete vaults, the literature references are still insufficient. Hall I was a corner room connected to the gymnasium and service areas (perhaps uncovered) as shown in Figure 3; it did not have any relevant massive elements in continuity with the adjacent structures [9] Hall I was a corner room connected to the gymnasium and service areas (perhaps uncovered) a(cs)shown in Figure 3; it did not hav(de)any relevant massive elements in continuity with the adjacent structures [9]. For this historical reason, and due toFigthuerem2.o(ad)eirnntersiuorrrvoieuwndoifnHgalnl oI,n(b-t)hsrteueslttirnugssrrooooff osftrHuacltluIVr,e(sc,) HmaodllerIncraeninfboerccedoncosindcererteedgraonin invaduelpt eonf HdeanlltIIst(rdu) chtiustroarlicsaylsptehmotofroofmthethcoesotrtuhcetriotnwoof rheainllfso.rced concrete vault of Hall II in 1936. Ianpethr,isthpeampeerc, hthaenimcaelcchhaanriaccatlecrhizaartaioctneroifzaRtoiomnaonf Roman masonrymhaassobnereynhassbuemenedasfrsoummethdefrfoewm athveaifleawbleavdaaitlaabplreodvaidtaedprboyviGdieadvabryinGi ieatvaalr.i[n1i0e]t al. [10] and BrunanedanBdruPneerauncdchPioer[u1c1c]h, iwo h[1o1c],awrrhieodcoarurtieedxpoeurtimexepnetrailmtensttsalotnesRtsoomnaRnovmauanltsva[1u2lt]s [12,13]. [13]

Visual Inspection by Means of UAV and Reference Point Cloud

A Hall II Hall I D CB

Modal Analysis

FEM Analysis with Discontinuities