This paper contains a seismic assessment at urban scale of the cities of Sion and Martigny in Switzerland. These two cities have been identified for the present research based on their importance regarding size and the characteristics of the building stock for which information was available. Moreover, microzonation investigations are available for both cities. This results in a more accurate characterization of local expected ground shaking, which is expressed through specific response spectra. Sion and Martigny represent, respectively, the capital and second largest city of the canton of Valais. This region is characterized by the highest seismicity within Switzerland. The paper focuses on the assessment using Risk-UE methodology, namely the empirical method LM1 and the mechanical method LM2. The obtained results are compared in order to assess the related accuracy. Firstly, buildings of the two cities were surveyed in order to collect main structural characteristics in a database. Building stock is typical of that region and can be found similar to many other medium-sized Swiss cities. Around half of the buildings are unreinforced masonry buildings, while several others are reinforced concrete buildings with shear walls. Results show the most vulnerable part of the cities regarding earthquake. There are significant differences in global results between LM1 and LM2 methods. The mechanical LM2 method is more pessimistic since it predicts damage grades of about one degree higher than LM1 method. However, the main drawback of the empirical LM1 method is that an a priori determination of an adequate value of the macroseismic intensity is required. Nevertheless, LM2 method may lead to a global overestimation of damage prediction.
Digital technologies overcome typical constraints of traditional concrete construction processes caused by the high impact of labour costs and bring about many new possibilities to the conceptual design, dimensioning, detailing, and production of concrete structures. While the potential of geometric flexibility is being extensively explored, most digital technologies encounter difficulties in penetrating the market due to lacking compliance with structural integrity requirements. To maximise their impact, it is essential that digital concrete processes (i) integrate reinforcement resisting tensile forces and (ii) address conventional structures with geometric simplicity. This paper discusses the potential of digital concrete fabrication processes to reduce the quantity of reinforcement required in concrete structures. For example, "minimum reinforcement" can be tremendously reduced by (i) tailoring the concrete grade locally to the actual needs and (ii) ensuring small crack spacings and correspondingly reduced crack widths by means of crack initiators. An experimental study shows that the strength reduction in the interfaces between layers from extrusion processes can be quantified with reasonable accuracy, which allows using these weak interfaces as crack initiators. A mechanical model to quantify the corresponding potential for saving "minimum reinforcement" when using 3D printing is presented. It is found that weak interfaces in layer joints with 33% of the concrete tensile strength inside the layer allow reducing up to 80% the minimum reinforcement for a given maximum crack width requirement under imposed deformations.
EN 1992‐1‐2 generally limits the redistribution of bending moments from the intermediate supports to the span for continuous reinforced concrete slabs and beams in fire conditions to 15%. While higher redistributions are allowed if sufficient rotation capacity is provided, EN 1992‐1‐2 does not indicate how to assess the rotation capacity. However, plastic hinges caused by the rotation demand under fire conditions are highly relevant when predicting the global response and structural safety of a structure (partially) exposed to fire. Rotation capacity is specifically necessary at support regions subjected to negative bending and fire, where concrete in compression undergoes thermal degradation while the tension chord remains close to ambient temperature. This article presents a comprehensive model for the behavior of statically indeterminate members in fire conditions, enabling to estimate whether sufficient rotation capacity is provided. Material properties specified by EN 1992‐1‐2 are applied combined with complementary considerations concerning (i) the biaxial compressive strength of concrete, (ii) strain hardening and limitations of the ultimate strain of reinforcement, as well as (iii) tension stiffening. Tension stiffening detrimentally influences the ductility of the tension chord, limiting the rotation capacity. When comparing predictions obtained by the model to experimental results given in the literature, the correlation is good for the investigated one‐way continuous slabs and beams. However, considerable uncertainty exists regarding the type of concrete aggregate used. Moreover, uncertainties concerning the behavior of concrete under compression and fire conditions are highly relevant for modeling the region of supports with rotational restraint.
Background Technology development for sitting balance therapy and trunk rehabilitation is scarce. Hence, intensive one-to-one therapist-patient training is still required. We have developed a novel rehabilitation prototype, specifically aimed at providing sitting balance therapy. We investigated whether technology-supported sitting balance training was feasible and safe in chronic stroke patients and we determined whether clinical outcomes improved after a four-week programme, compared with usual care. Methods In this parallel-group, assessor-blinded, randomized controlled pilot trial, we divided first-event chronic stroke participants into two groups. The experimental group received usual care plus additional therapy supported by rehabilitation technology, consisting of 12 sessions of 50 min of therapy over four weeks. The control group received usual care only. We assessed all participants twice pre-intervention and once post-intervention. Feasibility and safety were descriptively analysed. Between-group analysis evaluated the pre-to-post differences in changes in motor and functional outcomes. Results In total, 30 participants were recruited and 29 completed the trial (experimental group: n = 14; control group: n = 15). There were no between-group differences at baseline. Therapy was evaluated as feasible by participants and therapist. There were no serious adverse events during sitting balance therapy. Changes in clinical outcomes from pre- to post-intervention demonstrated increases in the experimental than in the control group for: sitting balance and trunk function, evaluated by the Trunk Impairment Scale (mean points score (SD) 7.07 (1.69) versus 0.33 (2.35); p < 0.000); maximum gait speed, assessed with the 10 Metre Walk Test (mean gait speed 0.16 (0.16) m/s versus 0.06 (0.06) m/s; p = 0.003); and functional balance, measured using the Berg balance scale (median points score (IQR) 4.5 (5) versus 0 (4); p = 0.014). Conclusions Technology-supported sitting balance training in persons with chronic stroke is feasible and safe. A four-week, 12-session programme on top of usual care suggests beneficial effects for trunk function, maximum gait speed and functional balance. Trial Registration:ClinicalTrials.gov identifier: NCT04467554, https://clinicaltrials.gov/ct2/show/NCT04467554, date of Registration: 13 July 2020.
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