Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Abstract

The vibration performance of pedestrian structures attracts the attention of several studies, especially with respect to unfavorable operational conditions or possible damage scenarios. Given a pedestrian system, specific vibration comfort levels must be satisfied in addition to basic safety requirements, depending on the class of use, the structural typology and the materials. To this aim, guideline documents of the literature offer simplified single-degree-of-freedom (SDOF) approaches to estimate the maximum expected vibrations and to verify the required comfort limits. Most of these documents, however, are specifically calibrated for specific scenarios/structural typologies. Dedicated methods of design and analysis, in this regard, may be required for structural glass pedestrian systems, due to their intrinsic features (small thickness-to-size ratios, high flexibility, type and number of supports, live-to-dead load ratios, use of materials that are susceptible to mechanical degradation with time/temperature/humidity, etc.). Careful consideration could be then needed not only at the design stage, but also during the service life of a given glass walkway. In this paper, the dynamic performance of an in-service glass walkway is taken into account and explored via field vibration experiments. A set of walking configurations of technical interest is considered, involving 20 volunteers and several movement features. The vibration comfort of the structure is then assessed based on experimental estimates and existing guideline documents. The intrinsic uncertainties and limits of simplified approaches of literature are discussed, with respect to the performance of the examined glass walkway. In conclusion, the test predictions are also used to derive “perception index” data and scales that could support a reliable vibration comfort assessment of in-service pedestrian glass structures.

Issues on the Vibration Analysis of In-Service Laminated Glass Structures: Analytical, Experimental and Numerical Investigations on Delaminated Beams

“…The width of LG beams was fixed (b = 0.14 m), while the variations were represented by the total span L. For the majority of them, L was in the range of 2.4 m and 2.7 m. The minimum span-even with identical nominal section properties and restraints-was in the order of 1.45 m. Such a marked variability in the span was required-at the design stage-to accommodate some geometrical irregularities of the primary structure hosting the specimens. The examined LG beams are, in fact, currently part of an in-service glass walkway (in the form of handrails, see Figure 7), being constructed in the early 2000 in the context of a Roman age Basilica monument in Aquileia, Italy (see also [15,16] for further details on the pedestrian system).…”

“…are, in fact, currently part of an in-service glass walkway (in the form of handrails, see Figure 7), being constructed in the early 2000 in the context of a Roman age Basilica monument in Aquileia, Italy (see also [15,16] for further details on the pedestrian system). For all of the LG members, the end restraints were realized in the form of stainless steel point-fixings according to Figure 8a, with holes having 42 mm nominal diameter and positioned at a distance d = b/2 = 70 mm from the edges (see Figure 8b).…”

“…A key influencing parameter, for example, was represented by a certain degradation of the PVB interlayers (due to repeated non-controlled ambient conditions and time), with visible delaminated For all of the LG members, the end restraints were realized in the form of stainless steel point-fixings according to Figure 8a, with holes having 42 mm nominal diameter and positioned at a distance d = b/2 = 70 mm from the edges (see Figure 8b). are, in fact, currently part of an in-service glass walkway (in the form of handrails, see Figure 7), being constructed in the early 2000 in the context of a Roman age Basilica monument in Aquileia, Italy (see also [15,16] for further details on the pedestrian system). For all of the LG members, the end restraints were realized in the form of stainless steel point-fixings according to Figure 8a, with holes having 42 mm nominal diameter and positioned at a distance d = b/2 = 70 mm from the edges (see Figure 8b).…”

“…From a structural point of view, critical design conditions can include explosive events [3][4][5] and impacts [6][7][8], natural hazards and earthquakes [9,10], and dynamic loads in general (including moving loads, in the case of pedestrian systems [11][12][13][14][15][16]), whose effects need dedicated calculation methods.…”

Using Statistical Analysis of an Acceleration-Based Bridge Weigh-In-Motion System for Damage Detection

“…Bedon illustrated the effect of changing ambient conditions on bridge frequencies using a glass suspension footbridge [29]. Bedon et al used a glass walkway structure to demonstrate the correlation between the bridge frequencies and vibration comfort level [30].…”