Guide for the Structural Rehabilitation of Heritage ... - Test Input

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components (arches, walls, etc.), the increase of weight due to increase in the height of thebuilding, the reduction of the capacity of the soil due to the execution of excavations forneighbouring buildings, etc.Figure 23: Modelling of a masonry vault before and after strengthening (8)In the case of very heavy buildings it will be also convenient to take into account theassumed sequence of loading during construction.In the case of very complex buildings it will be convenient to use alternative orcomplementary models, starting from simple models and increasing the refinement of theanalysis taking into consideration the results that are being obtained. It is to be noted,however, that, with different models, substantially different results can be obtained in thesame structural element.In the case there is information about the dynamic characteristics (fundamental frequencies,damping, etc.), obtained from in-situ tests carried out on the building, they should becompared with those obtained through the modelling of the building, which will allow for theircalibration and for the refinement of the modelling.For the seismic evaluation, the following modelling methods can be used: static linearanalysis; dynamic modal (linear) analysis; nonlinear static (pushover) analysis; and, nonlinear dynamic analysis.In the case of common buildings composed of a system of external and interior bearingwalls, placed in various directions, and a system of intermediate diaphragms, efficientlyconnected to the walls in order to guaranty the so called “box-effect”, three-dimensionalmulti-degree of freedom shear systems, with masses concentrated at floor levels, will beadequate.In this case, calculations can still be simplified by taking into account only one horizontalcomponent of the seismic ground motion and analyzing the structure in each orthogonaldirection, separately. Linear static analysis will usually be performed, being the resultscorrected by the behaviour factor.In the case of buildings with large halls and without intermediate diaphragms, like churches,or when the diaphragms are not completely efficient, in which the collapse is mostly causedby the loss of equilibrium in limited portions of the building, it will be more adequate to usethe macro-modelling.29/48
In macro-modelling, the building is divided into structural components, the macro-elements,characterised by a substantial autonomous structural response (facades, halls, domes, etc.),to which linear or nonlinear static analysis will be conducted (Fig. 24). On each macroelementone or more collapse mechanisms (usually, out-of-plane damage and collapsemechanisms), will be identified and their vulnerability quantified.a) Overturning of facades b) Shear mechanisms in walls c) DomesFigure 24: Macro-models and collapse mechanisms in different heritage buildings (36)In the case of flexible buildings, like towers and bell towers, in which the influence of thehigher modes may be important, the dynamic modal analysis can be more adequate.However, the behaviour factors will be more difficult to establish, and they will depend,mainly, on the quality of the clamping between the walls and on the possible contact withother buildings.Nonlinear static (pushover) analysis is a non-linear static analysis under constant gravityloads and monotonically increasing horizontal loads. It will be appropriate for complexbuildings, using models that represent the global behaviour of the building and its resistancedeterioration (softening), in which the acting forces are considered proportional to themasses, or distributed linearly, or according to the first mode.Nonlinear dynamic analysis should be used in particular cases, only, when the complexity ofthe building and the contribution of different modes of vibration do not allow the assigning ofa seismic response to a single degree of freedom.4.4 Quantification of the strengths of the materials4.4.1 Mechanical properties of the materialsThe mechanical properties of the building materials to be adopted in the modelling of thebuilding will be, in principle, obtained from the results of appropriate tests, as it has beendescribed in section 3. In the absence of test results, strengths can be established fromcomparison with other buildings or even from data-bases, but, in those cases, conservativevalues should be used.When tests are carried out, the number will be, in general, very limited, so identification testsof the conditions of the building materials at strategic points of the building should be carriedout. Identification tests will also be necessary when the mechanical properties of the buildingmaterials are estimated from comparison with other buildings.30/48
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Page 10 and 11: - Reversibility of the intervention
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Page 14 and 15: a) Loss of material in columns (14)
Page 16 and 17: ) Arches, vaults and domesFigure 4:
Page 18 and 19: As tests are, in general, very expe
Page 20 and 21: a) Masonry core (21) b) Steel speci
Page 22 and 23: Figure 14: Shaking-table test of a
Page 24 and 25: a) Photogrammetric survey (16) b) L
Page 26 and 27: Figure 20: Flowchart of the actions
Page 28 and 29: Furthermore, in the case that safet
Page 32 and 33: It is to be noted that the mechanic
Page 34 and 35: As a reference, a reduction factor
Page 36 and 37: strengthening measures in the struc
Page 38 and 39: a) MasonryThe repair of masonry ele
Page 40 and 41: a) With anchor bolts (21) b) With c
Page 42 and 43: d) Framed elementsIn the case of ti
Page 44 and 45: the foundations (Fig. 35b). Another
Page 46 and 47: 6 QUALITY OF THE INTERVENTION WORK6
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Page 50 and 51: International Council for Research
Page 52 and 53: DISCLAIMERAll rights reserved. No p

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